var term = new Array () ; term['AB powering']='Low DC voltage with a high internal resistance for powering condenser microphones connected to pocket transmitters.'; term['AB stereo']='Also known as time delay stereo, time difference stereo. 2-channel stereo recording technique which benefits mainly from the differences in time delay between the microphones (channels). Omni-directional microphones are used in most cases.
'; term['Absolute voltage level']='Used in sound studio technology to describe the ratio of a certain voltage Vx to a reference voltage of 0.775V. The absolute level is given in dBu and is calculated as follows: dBu = 20 x log (Vx/0.775). Thus, 0 dBu is equivalent to 0.775V, 6 dBu is equivalent to 1.55V and 15 dBu is equivalent to 4.4V. The current use of dBu relates to a voltage adaptation, while the former use of dBm relates to a power adaptation. The reference voltage of 0.775V is the same for both systems, and is derived from a power of 1mW in a resistance of 600 ohms.'; term['Absorption']='Sound is taken in and converted into heat. Opposite: reflection.'; term['Acoustic amplification']='A weak acoustic signal (e.g. the human voice) may be amplified by using mechanical means. A simple example would be the horn of a gramophone, or horn loudspeakers which are able to produce loud volume levels with little electric power. Further examples would be the bell of a trumpet, the case of a piano or the body of a violin.'; term['Acoustics']='The science of sound.'; term['Active antenna']='Antenna with an integrated or attached RF booster which is powered via the antenna cable.'; term['Active antenna splitter']='RF device for connecting several receivers to a single pair of antennas. Includes an antenna booster.'; term['Acute hearing loss']='Suddenly occurring hearing loss or hearing impairment – usually in one ear – caused by interference in the blood supply. It is accompanied by noise in the ear (tinnitus). The condition should be treated quickly in order to prevent the risk of long-term damage.'; term['Adjacent channel rejection']='The ability of a receiver to respond to the desired signal and to reject signals from adjacent channels.'; term['Adjacent channel rejection']=''; term['AF peak level']='The highest signal level which a unit can reproduce without distortion.'; term['AF sensitivity']='Specification used for judging the quality of acoustic transducers. A given sound pressure level will generate a certain voltage and vice versa.'; term['AF sensitivity (Clip-on microphone)']='Specification used for judging the quality of acoustic transducers. A given sound pressure level will generate a certain voltage and vice versa.'; term['AF sensitivity (Handheld transmitter)']='Specification used for judging the quality of acoustic transducers. A given sound pressure level will generate a certain voltage and vice versa.'; term['AF sensitivity (Headset microphone)']='Specification used for judging the quality of acoustic transducers. A given sound pressure level will generate a certain voltage and vice versa.'; term['AGC, automatic gain control']='Automatic control of the input sensitivity in order to prevent distortion and signal clipping.'; term['Alkaline cell']='A particularly efficient primary cell, non-rechargeable.'; term['Amplitude limitation']=''; term['Antenna']='An important part of a transmitter or receiver for transmitting or receiving the RF signal.'; term['Antenna connector']=''; term['Antenna gain']='The ratio of the signal of a directional antenna to that of a non-directional rod antenna, as a measure of the effectiveness of a directional antenna as compared to a standard non-directional antenna. The value is given in dB. Positive values are achieved in the direction of radiation, while negative values are achieved at the "back" of the antenna. Antenna gain is used to refer to both transmission and receiving antennas.'; term['Antenna type / antenna design']='Transmitting and receiving antennas can be classified as passive antennas (no gain) and active antennas (with a certain gain) depending on the design of their conductors. For example, a rod antenna or ground plane antenna is a passive antenna and does not have any gain. On the other hand, an antenna with directors and reflectors is an active antenna with a certain amount of gain and directivity.'; term['Application']=''; term['Atmosphere microphone']='(Omni-directional) microphones distributed around a room in order to add a controlled amount of reverberant sound.'; term['Attenuation']='A reduction in volume. Opposite of "amplification".'; term['Attenuation (active + passive)']='Reduction in ambient noise achieved by wearing (closed) headphones (passive attenuation) with NoiseGard active noise compensation (active attenuation).'; term['Attenuation (passive)']='Reduction in ambient noise achieved by mechanical means, such as wearing headphones or ear defenders.'; term['Audio-output-level']='Logarithmic value of the audio output voltage based on a standard reference level.'; term['Audio-Output-Power']='Refers to the output power of an audio amplifier, given in watts. This value shows which loudspeakers or headphones should be connected to your amplifier.'; term['Audio-XLR connector']='The most common connector for connecting microphones to amplifiers or mixing consoles or for linking audio units in the studio (usually 3-pin XLR connectors). XLR-3 connectors are also used for digital audio signals (AES/EBU).
In addition to audio applications, multi-pin XLR connectors are used for supplying power to e.g. ENG cameras.'; term['Audio input']='Specifies the type of plug mounted for an audio input.'; term['Audio memory']='Stores audio signals in a given data format; here: the length of the audio information stored.'; term['Audio output']='Specifies the type of plug mounted for an audio output'; term['Audio output level (balanced)']='Logarithmic value of the audio output voltage based on a standard reference value. A balanced circuit or connection uses separate signal lines for sending a signal, returning the signal and ground (3-pole connection).'; term['Audio output level (unbalanced)']='Logarithmic value of the audio output voltage based on a standard reference value. An unbalanced circuit or connection uses the ground connection (or screening) to return the signal (2-pole connection).'; term['Audio output voltage']='Voltage of the audio signal, given as a root-mean-square value.'; term['Audiogram']='The graphical representation of hearing ability. An audiogram determines the threshold of hearing related to the frequency. With the aid of an audiogram and the typical curves on the graph, it is possible to diagnose in which area of the ear the hearing difficulties occur.'; term['Audiology']='In general, the study of hearing or hearing perception. Includes all the technical aids that provide support in the case of hearing difficulties.'; term['Audiometer']='A device for measuring damage to hearing or for examining hearing acuity. Different tones and volumes are generated in order to determine the threshold of hearing of the test person. The measured values are represented in a graph called an audiogram.'; term['Automatic switch-off( absence of audio-signal)']='Infra-red modulators feature an automatic switch-off function which ensures that the device switches to stand-by in the absence of an audio signal. As soon as an audio signal is present, the device will automatically switch on again.'; term['Balanced circuit']='Special design for AF circuits and cables to reduce external interference. The audio signals are conducted in a circuit without connection to the screening or the housing. Therefore external interferences cannot generate any current flow and remain ineffective.
'; term['Band']='Here: Permissible frequency range for wireless systems. In the UHF range, this is a television channel.'; term['Bandwidth (- 3 dB)']='The frequency band in which the maximum signal amplitude (crest) falls by –3dB to lower and higher frequencies.'; term['Basic Blumlein']='A recording technique from the 1930’s, named after A.D. Blumlein. He used a stereo pair configuration of two figure-of-eight microphones crossed at an angle of 90°.'; term['Basswind System']='The transducer in a set of headphones radiates the audio signal not only in the direction of the auditory canal but also inversely in the opposite direction. If this reverse sound field remains unattenuated inside the headphones, this can often result in undesired resonances that will impair the sound reproduction quality. To prevent this from happening, Sennheiser uses the so-called Basswind system, which consists of a finely tuned system of damping materials and defined sound paths that avoids these resonances and maximises bass reproduction. The powerful bass reproduction is achieved above all by a bass tube that opens at low frequencies. This removes the pressure from the diaphragm, allowing it to vibrate freely and provide rich bass sounds. At the same time, this bass gain also compensates for bass losses that occur when the ear pieces are not tightly sealed around the ears and allow "air" to escape.'; term['Battery status indicator']='Indicates the battery status or remaining operating time of a Sennheiser accupack (rechargeable battery pack) using LEDs, an LCD display, etc.'; term['BNC connector']='Coaxial connector for RF connections.'; term['Booster']='RF amplifier which is powered via the antenna cable, which means that it can easily be connected into existing wiring.'; term['Boundary microphone']='Also known as Pressure Zone Microphone (PZM). In a boundary microphone, the capsule is fitted flush in a surface which is large and flat compared to the wavelength. This produces the ideal semi-omni-directional pick-up pattern.'; term['BTE hearing aid']='A hearing aid worn behind the ear. The sound is transmitted to the ear via a tube and an ear mould. The design of these devices is very universal and therefore they are currently the most widespread form of hearing aid.'; term['Cable attenuation']='Also known as cable loss. Attenuation which a signal experiences when it is transmitted via a cable. It is dependent above all on the length of the cable and the frequency of the transmitted signal. Given in dB/m.
'; term['Cable length']='The cable length is usually measured between the anti-kink sleeves of the cable (cable length without connectors).'; term['Capacity']='Short for ampere-hour capacity, i.e. the charge that can be delivered by a rechargeable battery. This value can be used to calculate the operating time of a unit which is powered by the rechargeable battery.'; term['Cardioid (pick-up pattern)']='A cardioid microphone has a cardioid or heart-shaped pick-up pattern. The angle at which the output is zero is 180°.'; term['Carrier']='Unmodulated RF signal. A pocket transmitter transmits such a signal when it is switched on but with no microphone connected.'; term['Carrier frequencies']='High-frequency waves which transmit a modulating voltage.'; term['Cascadable']='Ability of units to be daisy-chained. For example, charging units can be daisy-chained (connected in series) and powered by only one power supply unit.'; term['Cells']=''; term['Characteristic SPL']='The term characteristic SPL expresses the sound pressure level that headphones generate under certain measuring conditions. According to DIN 45 500 Part 10, the characteristic SPL of hi-fi headphones at an electric power of 1 mW and an audio frequency of 1 kHz should be at least 94 dB. Measurement is carried out using an artificial ear (a special microphone for measuring headphones). But how loud are headphones with a characteristic SPL of 94 dB? First a little theoretical background: The unit of sound pressure is the pascal (Pa). The smallest sound pressure that is perceptible by the human ear (threshold of hearing) is 0.00002 Pa. This value has been internationally fixed as the agreed reference sound pressure. If the sound pressure of a set of headphones measured using an artificial ear is set in a logarithmic relationship to the reference sound pressure, one gets the characteristic SPL in dB (at 1 mW). The value of 94 dB laid down in the DIN standard says that hi-fi headphones must generate a sound pressure that is above the threshold of hearing by a factor of 50,000! On the other hand, the characteristic SPL does not say anything about the maximum volume which headphones can reproduce without distortion, and says nothing at all about the sound quality! Therefore, headphones with a higher characteristic SPL are not necessarily better.'; term['Characteristic SPL (1 kHz, 1 mW)']='The term characteristic SPL expresses the sound pressure level that headphones generate under certain measuring conditions. According to DIN 45 500 Part 10, the characteristic SPL of hi-fi headphones at an electric power of 1 mW and an audio frequency of 1 kHz should be at least 94 dB. Measurement is carried out using an artificial ear (a special microphone for measuring headphones). But how loud are headphones with a characteristic SPL of 94 dB? First a little theoretical background: The unit of sound pressure is the pascal (Pa). The smallest sound pressure that is perceptible by the human ear (threshold of hearing) is 0.00002 Pa. This value has been internationally fixed as the agreed reference sound pressure. If the sound pressure of a set of headphones measured using an artificial ear is set in a logarithmic relationship to the reference sound pressure, one gets the characteristic SPL in dB (at 1 mW). The value of 94 dB laid down in the DIN standard says that hi-fi headphones must generate a sound pressure that is above the threshold of hearing by a factor of 50,000! On the other hand, the characteristic SPL does not say anything about the maximum volume which headphones can reproduce without distortion, and says nothing at all about the sound quality! Therefore, headphones with a higher characteristic SPL are not necessarily better.'; term['Characteristic (wave) impedance']='Also known as surge impedance. Impedance of an electric wire or cable. It is composed of the capacitances, inductances and resistances as well as the mechanical properties of the cable (e.g. diameter of the inner conductor). Unlike cable attenuation, characteristic impedance is not dependent on the frequency or on the length of the cable.'; term['Charging time']='The time required to recharge a Sennheiser accupack. After recharging, automatic chargers will automatically switch to trickle charging.'; term['Clip-on microphone']='Also known as Lavalier microphone. Especially small microphone for attaching to clothing or to the surface of the skin near the mouth.'; term['Clipper']='A simple type of limiter.'; term['Clipping']=''; term['Closed(-back) headphones']='see open/closed
'; term['Coaxial cable']='2-pole electric cable consisting of an inner conductor (core) and an outer conductor (copper wire braiding), preferably used for transmitting RF signals. The ratio of the inner conductor diameter to the outer conductor diameter determines the characteristic (wave) impedance.'; term['Coincident microphone']='Stereo microphone with capsules arranged on top of each other for intensity stereo.'; term['Colour']=''; term['Comb filter effect']='Also known as comb filter distortion. This is the result of phase additions and cancellations in the frequency response due to reflection of the sound.'; term['Compander']='Also known as noise reduction system. A system which improves the signal-to-noise ratio by compressing the dynamics on the transmitter side using a compressor, and subsequently restores the normal dynamics on the receiver side using an expander.'; term['Condenser microphone']='Also known as electrostatic microphone, capacitor microphone. In a condenser microphone, the transducer consists of a fixed electrode on which a metallised foil is attached to form a diaphragm. The stationary electrode and the movable electrode therefore form a capacitor. The sound waves striking the diaphragm change the distance between the electrodes, thus producing a voltage proportionate to the acoustic signal. The condenser microphone meets the highest demands with regard to sound quality, but it also requires a relatively high polarising voltage.'; term['Conector NoiseGard™-supply']='A standardised single or multi-pole plug for connecting units or accessories.'; term['Configuration']='Settings of (or the act of setting) a unit.'; term['Connection cable']='When one speaks about headphones, the emphasis is on such things as sound quality and frequency response. There is rarely any mention of the connection cable. Most Sennheiser headphones are fitted with an OFC (oxygen-free copper) cable. This ensures linear and low-loss transmission in the broad frequency spectrum of the headphones. Many Sennheiser headphones also have detachable cables, which make it very easy to replace them.'; term['Connector']='A standardised single or multi-pole plug for connecting units or accessories.'; term['Connector Headphones']='A standardised single or multi-pole plug for connecting units or accessories.'; term['Connector Microphones']='A standardised single or multi-pole plug for connecting units or accessories.'; term['Connectors for DI-Modules']='The receiver system is connected to the display interface via sub-D connectors.'; term['Connectors for Mainframe']='A Sennheiser-standardised, female multi-pin connector.'; term['Contact pressure']='The wearing comfort of a set of headphones is determined not only by its weight but also by the force with which the earpieces are pressed onto the ears. This force is given in newtons (N), whereby 1 N corresponds to the compressive force which a mass of about 100 g exerts on a solid surface. The DIN Standard 45500 Part 10 limits the maximum permissible contact force to 5 N. Values of between 1.3 and 4 N are common, although lower values apply for open headphones. Higher values can be found in the case of closed headphones. Here, a higher contact pressure is required in order to achieve sufficient sealing, which is important for the reproduction of low frequencies.'; term['Coverage area']='Indicates the largest possible area in which the signal of an infra-red radiator can be received.'; term['Crosstalk attenuation']='See stereo channel separation.'; term['Current consumption']=''; term['DAI adapter, direct audio input adapter']='Hearing aid adapter with a standard DAI connector for external signal sources (e.g. FM receiver, infra-red systems). The connector is sometimes also known as "Euro plug". The DAI adapter allows audio signals to be transmitted via a cable to the hearing aid in such a way that all individually adjusted frequency corrections are carried out in the hearing aid.'; term['Damage to hearing']='"Headphones should sound good – and be nice and loud!" It is obvious, of course, that headphones should sound good. But many people are not aware of the fact that constant listening at a high volume can lead to permanent damage to hearing. Volume is not a quality feature. Sennheiser headphones demonstrate their sound qualities even at low volumes'; term['Data transfer (Interface, Rate, Type)']='Gives standardised specifications for the data transfer between computers: connection, data format, data rate and data direction.'; term['dBm']='See absolute voltage level'; term['dBr']='See relative voltage level'; term['dBu']='See absolute voltage level'; term['dBV']='Used in some northern European countries and in Japan and the USA to describe the absolute voltage level. The reference voltage is not 775 mV as in Germany but 1 V. Therefore, 0 dBV corresponds to 1 V. In order to make the distinction, a capital V is written after dB. The difference between the two designations dBu and dBV is a fixed measure and is 2.2 dB.'; term['dB, decibel']='Relative unit for describing the ratio of two sound pressure levels. The threshold of hearing is frequently used as the reference value (absolute level). The decibel allows statements to be made about volume or noise pollution. For measuring the sound pressure of noise, special filters are used which simulate the subjective hearing impression. Values are then given in dB(A) – for values weighted according to DIN/IEC 651 – or dB(C), for values weighted according to CCIR 468-3.
The decibel is not an absolute measure like the metre or the gram, but is used to describe the relationship between numerical values. Taking into account the logarithmic sense of hearing of the human ear, the decibel is derived from 10 times the logarithm to base 10 of a voltage or power ratio. Thus, for example, 20 dB is the equivalent of a voltage ratio of 10:1 or a power ratio of 100:1.'; term['De-emphasis']='In order to reduce noise that is generated during frequency modulation in the higher-frequency part of the AF range, one makes use of pre-emphasis in the transmitter and de-emphasis in the receiver. In pre-emphasis, the higher-frequency useful signals are raised and in de-emphasis the AF signal is lowered by the same amount in order to reestablish a linear frequency response curve.'; term['Demodulation']='Separating the useful signal from the carrier signal.'; term['Deviation']='In frequency modulation, the deviation from the mid-frequency. Given in kHz. The deviation corresponds to the amplitude of the useful signal.'; term['Deviation display']='Display for monitoring the deviation.'; term['Diameter']='Refers to the outer diameter of a microphone etc.'; term['Diffuse field']='Also known as reverberant field. Sound propagation in a "normal" room. Due to reflections from the walls, etc., a sound field is created throughout the whole room. The sound "diffuses".'; term['Diffuse field equalisation (headphones)']='In an anechoic chamber, a number of loudspeakers emit noise signals independently of each other. In the central area of the chamber, the various sound data meet and are superimposed on each other to form a diffuse field, in which it is no longer possible to determine from which direction the sound is coming. This noise is then varied in distances of a third and reproduced alternately over the speakers and a pair of headphones. A large number of test persons then evaluate the difference in volume between the room noise and the noise in the headphones. The ideal state is when the volume impression between the diffuse fied and the headphones is the same. Diffuse-field equalised headphones provide a clearly more spatial impression and make it easier to determine whether sounds are coming from the front or rear. The sound events take place outside the head and are not confined to the space between the ears.'; term['Diffuse field equalised']='A diffuse field equalised pressure microphone is tuned in such a way that a smooth frequency response curve is achieved for diffused sound (i.e. sound from all sides). For on-axis sound, a rise in the frequency curve is achieved for high frequencies due to pressure build-up in front of the diaphragm.'; term['Digital protocol']=''; term['Dimensions']=''; term['Dimensions (Bodypack transmitter)']=''; term['Dimensions (Handheld transmitter)']=''; term['Dimensions (Plug-on transmitter)']=''; term['Dimensions (Receiver)']=''; term['Dimensions (Transmitter)']=''; term['Dipole antenna']='Symmetrical antenna with two opposing conductors in which one counterbalances the other. The mechanical length of the conductor is tuned to the wavelength of the transmission or receiving frequency.'; term['Directional antenna']='Due to their special (physical) design, these antennas are able to transmit or receive energy in/from a certain direction better than in/from other directions.'; term['Directional hearing']='Using the signals perceived by both ears, it is possible to recognise from which direction and from which distance a sound is coming. The hearing impression is evaluated according to the time difference, the volume difference and the spectral difference.'; term['Directivity index']='Index for the dependency of the pick-up pattern on the frequency. The lower this is, the better the quality of the microphone.'; term['Diversity reception']='Reception technique to reduce signal cancellation caused by reflection. The signal is received several times and the best signal is chosen for amplification.'; term['Drop-out']='Here: a "hole" in the reception caused by the cancellation of the high frequency at the antenna. The receiver hisses and speech reception is disturbed.'; term['Dual diaphragm']='Special capsule design in condenser microphones. This allows the pick-up pattern to be adjusted from "omni-directional" through "cardioid" to "figure-of-eight" by means of the diaphragm bias.'; term['Dummy head stereo']='Head-based 2-channel recording technique using a (plastic) separator body in the shape of a head between the two microphones.
'; term['Dynamic headphones (dynamic transducer)']='The diaphragm of a dynamic transducer is driven by a coil located in the air gap of a permanent magnet. When an alternating current (i.e. a music signal) is passed through the coil, the result is a magnetic effect – the voice coil is drawn into the air gap or pushed out a short distance. As a result of this vibration, sound waves are produced, thus reproducing the original signal. In dynamic headphones, the mass of the whole system must be kept as low as possible in order to ensure a fast transient response. For this reason, for their top-of-the-range headphones, Sennheiser uses coils made of aluminium/copper or even highest grade pure aluminium.'; term['Dynamic range']='The "bandwidth" of the differences in level between the quietest and loudest passages of a sound event, given in dB. Recording and transmission media must be able to process the dynamics without interference. The dynamic range of a microphone is limited at the lower level by its so-called self-noise and at the upper level by overload distortion or clipping. The dynamic range is determined from the difference between the maximum sound pressure level and the A-weighted equivalent noise level (evaluated in accordance with DIN/IEC 651). Studio microphones, for example, can process a dynamic range of up to 126 dB. The dynamic range of an RF system is the range between the inherent noise and the start of clipping, given in dB.'; term['Ear-protecion headcuffs']=''; term['Ear coupling']='A distinction is made between headphones which are worn on the external ear (supra-aural) and those which surround the ear (circumaural). Open headphones have foam ear pads that rest on the ears or ring pads that surround the ears. Closed headphones, on the other hand, nearly always have circumaural ear pads.'; term['Effektive radiated power']='Infra-red power emitted by an infra-red radiator.'; term['Electret microphone']='Full name: back-electret pre-polarised condenser microphone. Special type of condenser microphone which requires no high external polarising voltage and can be powered by low voltage internal batteries. The electric charge is permanently stored in a special plastic foil, the electret. Electret microphones can be made with very small dimensions and are therefore ideally suited for use as clip-on microphones.'; term['Electrostatic headphones (electrostatic transducer)']='In contrast to dynamic transducers, whose diaphragm is driven in a ring shape by a voice coil, the diaphragm in electrostatic headphones vibrates over its whole surface. This is achieved by an ultra-thin diaphragm sandwiched between two acoustically transparent electrodes which reacts to the slightest changes in the sound frequency voltage.
The two electrodes are made of special high-strength glass, and are perforated like a honeycomb, thus allowing sound to pass through. A polarisation voltage generates an electrostatic field. When the stepped-up signal voltage is applied, charges are displaced which causes the diaphragm to vibrate, resulting in sound waves which reproduce the original signal.
The elliptical shape of the diaphragm suppresses standing waves which usually occur at the edges of regular shapes. The low mass of the diaphragm also makes a major contribution to the precise resolution. Electrostatic headphones continually surprise the listener with their spatial width and depth.'; term['Emission']='Radiated power of the antenna of a wireless microphone/transmitter.'; term['ENG']='Abbreviation of electronic news gathering.'; term['Equivalent noise level']='The output signal of every microphone always includes a low noise signal in addition to the useful signal. In order to illustrate the extent of the noise voltage, it is given as a fictitious sound pressure level. In an ideally noise-free microphone, a sound pressure level of this magnitude would result in an output voltage of the magnitude of the noise. Self-noise is measured and weighted either in accordance with CCIR 468-3 or – in order to assimilate the measured result with the listening impression of the human ear – in accordance with DIN/IEC 651 (so-called A-weighted). Studio condenser microphones generally have an equivalent noise level of between 20 and 30 dB (CCIR) or between 10 and 20 dB(A).'; term['Equivalent noise level weighted as per CCIR 468-3']='The output signal of every microphone always includes a low noise signal in addition to the useful signal. In order to illustrate the extent of the noise voltage, it is given as a fictitious sound pressure level. In an ideally noise-free microphone, a sound pressure level of this magnitude would result in an output voltage of the magnitude of the noise. Self-noise is measured and weighted either in accordance with CCIR 468-3 or – in order to assimilate the measured result with the listening impression of the human ear – in accordance with DIN/IEC 651 (so-called A-weighted). Studio condenser microphones generally have an equivalent noise level of between 20 and 30 dB (CCIR) or between 10 and 20 dB(A).'; term['ERA, electric reaction audiometry']='A process for determining a hearing disability by evaluating the potential differences in the inner ear due to sound conduction. Measurement is carried out by an EEG (electroencephalogram), in which the AEP (acoustically evoked potentials) are recorded. The method is especially suitable for examining children and people with disabilities.'; term['ERP, effective radiated power']='The product of antenna input power and antenna power gain, expressed in kilowatts.'; term['Fan noise']='A-weighted volume measurement according to ISO.'; term['Feedback']='An electroacoustic "short circuit", produced when the signal from a loudspeaker is picked up by the microphone of the same equipment or of the same transmission line of a wireless system. The result is a loud whistling sound. Feedback can be avoided by suitable positioning of the microphone to the loudspeaker or by a suitable choice of microphone.'; term['Field strength indicator']='Approximate indication of the RF field strength at the antenna.'; term['Figure-of-eight (pick-up pattern)']='Also known as bidirectional. A microphone with a figure-of-eight pick-up pattern has a directivity shaped like a figure 8.'; term['Free-field equalised']='A free-field equalised pressure microphone is tuned in such a way that a smooth frequency curve is obtained for on-axis sounds (0°). The high frequencies of sounds from all other directions are reduced.'; term['Free field']=''; term['Frequency']='The number of (sound) waves per second, measured in Hertz (Hz). Low sounds have a low frequency and high sounds have a high frequency. The hearing ability of a young person with normal hearing ranges from about 20 Hz to about 20 kHz. With increasing age, the hearing sensitivity for high frequencies diminishes.'; term['Frequency response']='Frequency range for audio signals which an electronic device can process'; term['Frequency response']='The frequency response of a microphone is given within the limits defined by the manufacturer. In studio condenser microphones it is generally within the range of between 20 Hz and 20 kHz.'; term['Frequency response (headphones)']='The frequency response of a pair of headphones is given within limits defined by the manufacturer.'; term['Frequency response (microphone)']='The frequency response of a microphone is given within the limits defined by the manufacturer. In studio condenser microphones it is generally within the range of between 20 Hz and 20 kHz.'; term['Frequency setting']=''; term['Frequency synthesizer']='A circuit for the numerically precise and stable generation of high frequency.'; term['Front-to-back ratio']='Indicates the antenna gain for directional antennas, given in dB.'; term['Fuse']='Nominal currant a fuse can withstand. This fuse normally protects a device for short circuit or overload.'; term['Gain']='Ratio of input voltage to output voltage. A negative value means an attenuation.'; term['Goose neck length']='Overall length of an goose neck from microphone head to the other end for fastening'; term['Ground-plane antenna']='See omni-directional antenna'; term['Hand-held transmitter']='Also known as RF wireless microphone; radio microphone. A microphone, an RF transmitter and an antenna are installed in a common housing that is very similar to a wired microphone'; term['Harmonic distortion']='Unwanted signal components within a spectrum as multiples of the fundamental frequency. If this frequency is 1 kHz, the distortion produces signal components at, for example, 2 or 3 or 4 kHz (these components are given in % of the useful signal).'; term['Headphone connector']=''; term['Headphone output level']='The maximum, low-distortion volume level available at the headphone socket.'; term['Headphone volume']='Refers to the volume level range which can be adjusted by means of a potentiometer.'; term['Hearing-aid glasses']='Parts of the hearing aid are integrated into the frame of a pair of glasses. The sound is transmitted into the ear via a tube and an ear mould.'; term['Hearing aid connector']=''; term['Helical antenna']='Short antenna with a similar design to a small-diameter spring. Not very reliable in operation since proximity to other objects – in this case in particular the body of the wearer of a pocket transmitter – results in detuning and therefore to a reduction in radiated power.'; term['High-level audio signal']='This is a sound signal with a level of –10 to +6 dBu. This is the case, for example, for sound levels from studio equipment such as tape recorders or CD players, but also for signals which, for example, are transmitted via cables.'; term['High pass filter']='A high pass filter is a filter that allows only those frequencies above a so-called limit frequency (called the crossover point or cutoff) to pass. In electroacoustics, high pass filters are often called low cut filters, bass filters, bass cut filters, bass roll-off filters or rumble filters. High pass filters on microphones are usually used to reduce the effects of handling noise, pops, rumble (e.g. stage rumble) and low-frequency vibrations, or to reduce the proximity effect in close miking situations.'; term['Hirose connector']='Also known as HRS connector. Commonly used plug connector between a pocket transmitter and a clip-on microphone. Unfortunately without a fixed standard.'; term['Housing']='Gives the width (in inches) and/or the height (in units) of a housing.'; term['Hyperacusis']='Also known as hyperacusia. Abnormally increased acuity of hearing. A form of hearing impairment in which a patient perceives quiet sounds as too quiet and loud sounds as much too loud. In normal hearing, hyperacusis can be caused by damage to the outer hair cells.'; term['Identifier operating mode']='Indicates whether an identifier is transmitting continuously or has to be triggererd by an external signal.'; term['Image frequency']='Undesired carrier frequency, produced by the conversion of the receiving frequency into the intermediate frequency. The result is a second reception frequency as a "mirror image" around the intermediate frequency.'; term['Image rejection']='The ratio of actual receiving frequency to image frequency. Given in dB.'; term['Impedance']='Impedance expresses the AC resistance of a microphone or a set of headphones. It is dependent on frequency and is given at 1 kHz as the so-called nominal impedance. Impedance is measured in ohms. In recent years, an industrial standard has developed, setting the impedance of headphones at 50 or 600 ohms. Sennheiser headphones are manufactured according to this standard, thus practically ruling out connection problems. With microphones, the input impedance of the following microphone amplifier should have at least three times the value of the nominal impedance, in order to prevent it from unnecessarily attenuating the microphone signal.'; term['Impedance matching (headphones)']='Matched impedance between headphones and hi-fi amplifier. Ensures that the maximum power is delivered to the headphones.'; term['In compliance with']='Gives the guidelines and requirements which have to be met before a unit can be put onto the market. Such guidelines are published by e.g. standards committees, telecommunications authorities etc.'; term['Included angle']='Also known as mutual angle. The angle between the two capsules of a coincident microphone.'; term['Infrasound']='Sound of frequencies below the usual audible limit. High intensity infrasound causes nausea, as the body is caused to "resonate".'; term['Input impedance']='Input impedance expresses the AC resistance of an electronic input. It is dependent on frequency and is often given at 1 kHz as the so-called nominal impedance. Impedance is measured in ohms.'; term['Input voltage range']='Indicates the voltage range of the input signal within which a unit will work properly, i.e. as specified in its technical data.'; term['Input voltage range (Bodypack transmitter)']='Indicates the voltage range of the input signal within which a unit will work properly, i.e. as specified in its technical data.'; term['Input voltage range (Handheld transmitter)']='Indicates the voltage range of the input signal within which a unit will work properly, i.e. as specified in its technical data.'; term['Input voltage range (Plug-on transmitter)']='Indicates the voltage range of the input signal within which a unit will work properly, i.e. as specified in its technical data.'; term['Intensity stereo']='In intensity stereo, a stereo sound image is produced only by the difference in volume of the loudspeakers.'; term['Interface']='Electronic assembly which provides data in a certain format on the transmitter side of a (usually digital) unit. On the receiver side, the interface ensures that the incoming data is adapted for further processing.'; term['Interference']='Cancellation of a signal or parts of a signal with a counter-phase curve.'; term['Interference microphone']='Also known as interference receiver. In an interference microphone, a tube with equally spaced holes or a slit along its length is mounted in front of the capsule (shotgun microphone). When sound is received from the side, a partial cancellation of sound waves occurs due to mutual interference. The result is a highly directional lobar pick-up pattern. Below a limit frequency that is dependent on the length of the tube, no interference effect occurs. In this frequency range, the microphone operates as a pressure gradient microphone with a super-cardiod directivity. It picks up axial sounds efficiently, but discriminates against sounds arriving from all other directions.'; term['Intermodulation']='In RF transmission, the different carrier frequencies produce not only harmonics (integral multiples) but also a large number of (odd number) sums and differences of integral multiples of the input frequency components. These limit the number of usable frequencies within a certain band.'; term['Intermodulation attenuation']='In RF transmission, the different carrier frequencies produce not only hamonics (integral multiples) but also a large number of (odd number) sums and differences of integral multiples of the input frequency components. These limit the number of usable frequencies within a certain band. The intermodulation spacing gives the level difference between the carrier frequency and these unwanted frequencies.'; term['Intermodulation spacing']='In RF transmission, the different carrier frequencies produce not only hamonics (integral multiples) but also a large number of (odd number) sums and differences of integral multiples of the input frequency components. These limit the number of usable frequencies within a certain band. The intermodulation spacing gives the level difference between the carrier frequency and these unwanted frequencies.'; term['IR Diodes']='High-quality gallium arsenide diodes used in IR radiators to transmit modulated infra-red light.'; term['ITE hearing aid']='A particularly small hearing aid fitted directly into the auditory canal (ITE = in the ear). A distinction is made between pinna ITE devices and CIC (completely in the channel) devices. The former are fitted into the external ear while the latter are inserted into the auditory canal itself and are therefore invisible from the outside.'; term['Jack plug']='A common audio connector in consumer electronics and music industry. Available in various diameters; in the hi-fi segment, 1/8" and ¼" are widely used. Poles range from one to four. (Examples: headphone jack or jack of an electric guitar).'; term['Jack socket']='A common audio connector in consumer electronics and music industry. Available in various diameters; in the hi-fi segment, 1/8" and ¼" are widely used. Poles range from one to four. (Examples: headphone jack or jack of an electric guitar).'; term['Jecklin-Stereo']='also known as OSS-Stereo
'; term['Jecklin/OSS stereo']='Near-coincident technique using an absorptive circular baffle instead of a dummy head between the two microphones.'; term['Lavalier microphone']='See clip-on microphone.
'; term['Limiter']='An electronic circuit used to prevent the amplitude of an electric signal from exceeding a specified value.'; term['Load rating']='The load rating is the amount of electric power which - according to the manufacturer´s specifications - can be continuously supplied to a set of headphones over a period of time without causing damage. According to DIN 45500 Part 10, the load rating must be at least 100 mW. Testing is carried out using a special noise signal which is supplied to the headphones over a period of 100 hours.'; term['Lobar (pick-up pattern)']='A microphone with a lobar polar pattern has the highest possible directivity. A lobar pick-up pattern is achieved with a shotgun microphone.'; term['Low-level audio signal']='Sound signals with a level of approx. -60 to -10 dBu. These are usually signals that are directly generated by microphones.'; term['M-S stereo']='In the M-S stereo technique, one microphone with any pick-up pattern picks up the sound from the front (middle) while another microphone with a figure-of-eight pick-up pattern is positioned at right angles to it (side). The M-S stereo technique produces an optimum mono signal, and can be used to infinitely change the included angle.'; term['Mains frequency']='The frequency of the a.c. current supplied by a power line at the point of use.'; term['Mains voltage']='The voltage provided by a power line at the point of use.'; term['Maximum sound pressure level (passiv)']='The maximum sound pressure level is the maximum sound level which a microphone can process electrically, which means that the THD of the microphone amplifier is < 0.5%. The reference frequency is f = 1 kHz. If the microphone has an attenuator, this value can be increased by 6-10 dB.
'; term['Max. coverage area']=''; term['Max. Input voltage']='The maximum voltage that a unit can handle without signal distortion.'; term['Max. Sound pressure level (aktiv)']='The maximum sound pressure a unit can reproduce before a given THD is reached.'; term['Measuring microphone']='Chemical process, especially in NiCd cells. If the cells are not fully discharged and subsequently not completely recharged, a "window" is produced and the cells are then active only within this window. This means that even "fully charged" cells have only very short performance intervals.'; term['Media control']='Specifies the type of connector for the purpose of media control'; term['Memory effect']='Chemical process, especially in NiCd cells. If the cells are not fully discharged and subsequently not completely recharged, a "window" is produced and the cells are then active only within this window. This means that even "fully charged" cells have only very short performance intervals.'; term['Microphone connector']='Standardised socket for connecting a microphone (such as the microphone socket on an RF wireless transmitter) or connector of a cabled microphone (such as the XLR connector on most of Sennheiser’s cabled dynamic microphones).'; term['Microphone sensitivity']='The microphone sensitivity indicates the effective voltage which a microphone generates when it is exposed to a sound pressure of 1 Pa (equivalent to 94 dB). The value is given for a frequency of 1 kHz and a load impedance of 1 kOhm. In principle, somewhat higher values occur in no load conditions. Studio condenser microphones generally have a sensitivity (free field) of approx. 8...40 mV/Pa.'; term['Min. channel spacing']='The minimum distance between FM signals which has to be observed in order to avoid interference with adjacent channels.'; term['Min. terminating impedance']='Impedance at which the connected unit meets the specified technical data. If the unit is connected to a lower impedance, it will usually have a lower output voltage or a greater distortion.'; term['Modulation']='The process in which one wave is varied by some parameter of another wave, for example, an RF carrier frequency that is modulated by an audio signal. Types of modulation include amplitude modulation, frequency modulation, pulse code modulation and pulse width modulation.'; term['Modulator']='Electronic circuit which superimposes the AF signal to be transmitted onto an RF carrier signal. Opposite: demodulator.'; term['Monitor-Bus-Connectors for daisy-chaining']=''; term['Monitorbus-Connectors']='The channels of any daisy-chained mainframe can be monitored individually via the monitor bus.'; term['Moving-coil (dynamic) microphone']='The moving-coil microphone is the most frequently used dynamic microphone. It makes use of magnetic induction to represent sound: a coil connected to the diaphragm moves in a magnetic field and induces a voltage that corresponds to the curve of the sound. The microphone needs no external operating voltage – it always works!'; term['Multi-microphone technique']='The use of several microphones to record a large number of instruments and their position within the overall sound image.'; term['Multipath transmission']='Also known as multipath. In surroundings with high reflection, RF signals often reach the receiving antenna in phase opposition. This results in signal cancellations. Remedy: diversity reception.'; term['Mute, muting']='The audio output of a receiver is silenced depending on the field strength.'; term['Mutual angle']='See included angle.'; term['Neck induction loop']='A device for the wireless transmission of sound to the hearing aid. Induction loops worn around the neck can, for example, be connected to wireless FM receivers or infra-red systems. The induction loop is supplied with the audio frequency and excites a coil in the hearing aid by means of induction (electromagnetic field), thus allowing the wearer of the hearing aid to hear the sound.'; term['NiCd, nickel-cadmium']='Older rechargeable battery technology that still conceals the risk of the memory effect.'; term['Noise compensation (active)']='Reduction in ambient noise achieved by electronic means, such as the NoiseGard noise reduction system.'; term['NoiseGard-Supply']='Power supply required for powering the NoiseGard active noise reduction electronics.'; term['Nominal deviation']='Also known as reference deviation. The nominal deviation has been fixed at 40kHz to be able to give comparable technical data.'; term['Nominal impedance']='See impedance.'; term['Nominal impedance (active/passive)']=''; term['Number of cells']=''; term['Number of channels']='Frequencies which are available to transmit a signal.'; term['Omni-directional antenna']='Antenna without directivity which transmits or receives equally well in or from all directions.'; term['Omni-directional (pick-up pattern)']='A microphone with an omni-directional pick-up pattern picks up sound equally well from all directions (pressure microphone).'; term['Open/closed']='Also known as open-back ("Open-Aire") and closed-back. Generally speaking, a distinction is made between open and closed headphones. With closed headphones, the ear is completely sealed off from outside noise (pressure chamber principle). Typical featues of closed headphones are the acoustically sealed housing and the ring-shaped (circumaural) pads that completely surround the ear. The sealing around the ear has a decisive influence on the sound reproduction of closed headphones. If it is insufficient, the quality of the bass sounds will deteriorate. For this reason, the contact pressure of closed headphones is higher than that of open headphones. Closed headphones are often used by sound engineers to allow them to concentrate on the music without disturbance from outside noise. The problem of sealing does not exist with open headphones. In this design, the space behind and in front of the diaphragm lets through sound. Therefore, open headphones allow music to pass straight through the diaphragm without being "muffled", thus resulting in a more transparent and natural sound image. The distinguishing features of open headphones are their small size and low weight. These in turn make them extremely comfortable to wear, and no discomfort is felt even after prolonged periods of listening.'; term['Operating position']='Indicates how a unit should be mounted or set up for operation, for example, horizontally, vertically etc.'; term['Operating temperature']='Gives the range of temperatures at which a unit can be operated without damage.'; term['Operating time']='States how long a unit can be continuously used with one set of batteries / rechargeable accupack.'; term['Operating time (Accupack)']='Indicates the operating time with a new, fully charged accupack.'; term['Operating time (Battery)']='Indicates the operating time with a new, fully charged battery.'; term['Operating time (Bodypack transmitter)']='States how long a unit can be continuously used with one set of batteries / rechargeable accupack.'; term['Operating time (Handheld transmitter)']='States how long a unit can be continuously used with one set of batteries / rechargeable accupack.'; term['Operating time (Plug-on transmitter)']='States how long a unit can be continuously used with one set of batteries / rechargeable accupack.'; term['Operating time (receiver)']='Indicates the receiver’s operating time with a new, fully charged battery or accupack.'; term['Operating time (transmitter)']=''; term['Operating voltage (mains)']='Gives the (mains) voltage range for which a unit has been designed.'; term['Operating voltage (stand alone)']='Voltage type and level required for powering a unit.'; term['Organ of Corti']='The actual hearing organ in the cochlea, which transforms sound waves into bio-electrical signals, which are then conducted to the brain via the hearing nerve.'; term['ORTF stereo']='2-channel near-coincident technique accredited to French National Broadcasting (Office de Radiodiffusion Française, ORTF) which makes use of both the delay time and the intensity between the two channels (microphones). For that reason, this technique is also described as a "mixed" process. Recording is done by two cardioid microphones placed 17 cm apart with an included angle of 110°.'; term['Output impedance']='Gives the internal impedance of an a.c. source. If the input of a subsequent load has the same input impedance, we speak of a matched impedance. The maximum power is delivered to the load.'; term['Output level']='Older studio technology term for a matched impedance. Given as a logarithmic value which refers to an impedance of 600 ohms.'; term['Output voltage']='The (signal) voltage which a unit supplies at its output.'; term['Overhead miking']='overhead from above'; term['Pad']='Attenuator, usually with an attenuation of 10....20dB. Used in both audio and RF technology.'; term['PC-Interface']='Specifies the type of connector of a PC interface for data transmission'; term['PC, peak clipping']='Automatic volume limiting in hearing aids, in order to prevent unnecessarily loud sound from reaching the ear. Peak clipping requires very careful adjustment to avoid distortion of sound at normal volume.'; term['Peak deviation']='Maximum permissible deviation for FM.'; term['Phantom powering']='Almost all studio microphones are supplied with 48V ±4V phantom power (P48, IEC 268-15). This supply voltage is applied to both modulation lines, while the return current flows via the cable screen. Some microphones can also be powered by batteries or from plug-in mains adapters.'; term['Phase angle']=''; term['Pick-up pattern']='Also known as polar pattern, directivity. According to their acoustic design, microphones differ in their sensitivity towards sound from different directions. Pressure microphones have a sensitivity that is largely independent of direction (omni-directional pick-up pattern). Pressure gradient microphones have the pick-up patterns wide cardioid, cardioid, super-cardioid or figure-of-eight. Interference microphones can be used to achieve a further concentration of the pick-up pattern (lobar pick-up pattern). As a special case, dummy head microphones achieve the pick-up pattern of the human ear/head (dummy head stereo).'; term['Pick-up pattern (Clip-on microphone)']='Also known as polar pattern, directivity. According to their acoustic design, microphones differ in their sensitivity towards sound from different directions. Pressure microphones have a sensitivity that is largely independent of direction (omni-directional pick-up pattern). Pressure gradient microphones have the pick-up patterns wide cardioid, cardioid, super-cardioid or figure-of-eight. Interference microphones can be used to achieve a further concentration of the pick-up pattern (lobar pick-up pattern). As a special case, dummy head microphones achieve the pick-up pattern of the human ear/head (dummy head stereo).'; term['Pick-up pattern (Handheld transmitter)']='Also known as polar pattern, directivity. According to their acoustic design, microphones differ in their sensitivity towards sound from different directions. Pressure microphones have a sensitivity that is largely independent of direction (omni-directional pick-up pattern). Pressure gradient microphones have the pick-up patterns wide cardioid, cardioid, super-cardioid or figure-of-eight. Interference microphones can be used to achieve a further concentration of the pick-up pattern (lobar pick-up pattern). As a special case, dummy head microphones achieve the pick-up pattern of the human ear/head (dummy head stereo).'; term['Pick-up pattern (Headset microphone)']='Also known as polar pattern, directivity. According to their acoustic design, microphones differ in their sensitivity towards sound from different directions. Pressure microphones have a sensitivity that is largely independent of direction (omni-directional pick-up pattern). Pressure gradient microphones have the pick-up patterns wide cardioid, cardioid, super-cardioid or figure-of-eight. Interference microphones can be used to achieve a further concentration of the pick-up pattern (lobar pick-up pattern). As a special case, dummy head microphones achieve the pick-up pattern of the human ear/head (dummy head stereo).'; term['Pilot tone']='Signal of a certain frequency outside the range of hearing for the assessment of a squelch.'; term['PLL']='Abbreviation for phase-locked loop. Control loop for the frequency control of an oscillator; frequency generation by formation of multiples or fractions of a basic frequency.'; term['Polarisation voltage']='also known as bias. A condenser microphone needs a polarising voltage in order to generate the signal voltage which follows the audio signal.'; term['Pop noise']='Interference in the movement of the microphone diaphragm caused by air flow, in this case by plosive sounds.'; term['Power consumption']=''; term['Power supply']='Description of the power source used for powering a unit, for example mains, battery, rechargeable accupack, etc.'; term['Power supply (Bodypack transmitter)']='Description of the power source used for powering a unit, for example mains, battery, rechargeable accupack, etc.'; term['Power supply (Handheld transmitter)']='Description of the power source used for powering a unit, for example mains, battery, rechargeable accupack, etc.'; term['Power supply (Plug-on transmitter)']='Description of the power source used for powering a unit, for example mains, battery, rechargeable accupack, etc.'; term['Powering']='Common description, where the electric power comes from.'; term['Powering']='Common description, where the electric power comes from.'; term['Pre-emphasis']='In order to reduce noise that is generated during frequency modulation in the higher-frequency part of the AF range, one makes use of pre-emphasis in the transmitter and de-emphasis in the receiver. In pre-emphasis, the higher-frequency useful signals are raised and in de-emphasis the AF signal is lowered by the same amount in order to reestablish a linear frequency response curve.'; term['Presets']=''; term['Pressure gradient microphone']='Also known as pressure gradient receiver, directional microphone. In the pressure gradient microphone, both faces of the diaphragm are exposed to the sound field. In an ideal pressure gradient microphone, the voltage given off by the microphone depends only on the difference in pressure between front and back. This results in a figure-of-eight pick-up pattern. By adding time delay elements, one-sided pick-up patterns can be achieved, e.g. wide cardioid, cardioid and super-cardioid.'; term['Pressure microphone']='Also known as pressure receiver, omni-directional microphone. In a pressure microphone, only the front of the diaphragm is exposed to the sound field. The voltage given off by the microphone depends only on the sound pressure at the front and is therefore essentially non-directional (cf. omni-directional pick-up pattern). Depending on the diameter of its diaphragm, the pressure microphone becomes – to a certain degree – unidirectional with increasing frequency.'; term['Proximity effect']='Every directional microphone (pressure gradient microphone) has the property of providing a pronounced boost in low-frequency output when placed close to the sound source (less than 20 cm). This has physical reasons and is partly decisive for the sound of a vocal microphone.'; term['Pulse power']='In RF technology, this power is usually measured for a duration of one tenth of a period. There is no common definition in audio technology, it largely depends on the program material to be transmitted.'; term['PZM, pressure zone microphone']='See boundary microphone.'; term['Range']='See RF wireless headphones, transmission loss.'; term['Range of hearing']='Term used to describe the range between the threshold of hearing and the threshold of pain as well as between the lowest and the highest still perceivable frequency. Deviations from the "normal" hearing range can be adjusted at the hearing aid (change in frequency and volume). For this reason, range of hearing measurement is carried out before and after the application of a hearing aid.'; term['Ratio combining']='Evaluation circuit in "True-Diversity" receivers which uses the strongest incoming signal as the useful signal.'; term['RCA phono connector']='The most common connector in consumer electronics. Uses an unbalanced, single line for the signal, the screen (ground) is used to return the signal.'; term['Receiving frequency']='Gives the frequency/range of frequencies to which a receiver can be tuned.'; term['Recruitment']='See hyperacusis.'; term['Relative broadcast level']='Used in sound studio technology to describe the ratio of a certain voltage Vx to the maximum reference voltage of 1.55 V. The relative broadcast level is given in decibels (dB) and is calculated as follows: dB = 20 x log (Vx/1.55). Thus, 0 dB = 6 dBu = 1.55 V and 6 dB = 0 dBu = 0.775 V.'; term['Relative voltage level']='Used in sound engineering to describe the ratio of an output voltage Vout to an input voltage Vin. The relative voltage level is given in dBr and is calculated as follows: dBr = 20 x log (Vout/ Vin). Thus, 0 dBr means that there is no difference, 6 dBr is twice the voltage, -6 dBr half the voltage, 20 dBr ten times, 40 dBr 100 times and 60 dBr 1000 times the voltage. In practice often given only as dB.'; term['Remarks']=''; term['RF cascading socket']=''; term['RF frequency range']='The range of frequencies to which a unit (e.g. a receiver) can be tuned.'; term['RF input']='Socket for feeding the antenna signal to the receiver. Rack-mount receivers most commonly feature a BNC type socket; for bodypack receivers, various types of connector are used.'; term['RF output']='Socket for feeding the transmitter signal to the antenna (system). Rack-mount transmitters most commonly feature a BNC type connector; for bodypack transmitters, various types of connectors are used.'; term['RF output power']='Output power measured at the antenna socket.'; term['RF sensitivity']='The ratio of signal level at a unit´s input to signal level at its output.'; term['RF wireless headphones']='RF wireless headphone systems consist of a hi-fi stereo headset with an integrated RF receiver and an RF transmitter which is connected to an audio system or to another signal source. The audio information is first of all available as a low-frequency (AF) signal containing frequencies in the range between 20 and 20,000 Hz. The RF transmitter then converts this information into a signal suitable for radio transmission and transmits it via the transmitter’s antenna. The RF receiver in the headphones receives the RF signal and converts it back into the original signal, which is then reproduced directly in the headphones. The transmitter has a range of up to 100 m, and, since RF signals – unlike infra-red signals – can pass through walls and ceilings, wireless sound reception is possible throughout the whole house, or even outside the house, for example in the garden. Most Sennheiser RF systems have three selectable frequencies, making it possible to choose the optimum transmission channel in each case – although the transmitter and receiver must, of course, both be set to the same frequency. A special filter protects the RF receiver against interference from amateur radio transmissions'; term['Selectivity']='The ability of a receiver to carry out adjacent channel rejection.'; term['Sensitivity as per 121 TR 9-5']='Sensitivity as specified in the regulations issued by the Luftfahrtbundesamt (German aviation authorities).'; term['Sensitivity in free field, no load (1kHz)']='Voltage measured at the unloaded output of a microphone which is exposed to a sound pressure of 1 Pa and a frequency of 1 kHz in an anechoic chamber.'; term['Sensitivity to handling noise']='The extent to which noise caused by the cable rubbing on the clothes is transmitted to the headphones and perceived as interference during quiet music passages is generally determined by the material of the cable. Copper cables and insulation of the Sennheiser OFC connection cable serve to minimise the sensitivity to handling noise.
'; term['Shotgun microphone']='Interference microphone with a lobar pick-up pattern. Especially useful for reducing ambient noise in ENG applications.'; term['Sign language']='The use of certain movements of the hands, arms and body in order to communicate with deaf people about everyday situations.'; term['Signal-to-noise ratio']='The ratio of the largest possible output voltage to the smallest possible output voltage of an electroacoustic transmission device.'; term['Signal-to-noise ratio']='The signal-to-noise ratio is the difference between the reference sound level of 94 dB (equivalent to 1 Pa) and the equivalent noise level. Studio condenser microphones generally have a signal-to-noise ratio of 74 to 64 dB (CCIR) or 84 to 74 dB(A).'; term['Solist microphone']='See vocal microphone.'; term['Sound pressure level (SPL)']='Due to the impractical numerical values, the sound pressure is usually given as the logarithmic value of the sound pressure level according to the equation: dB SPL = 20 x log (po / 0.00002 Pa). The abbreviation SPL (sound pressure level) is added in order to make a clear distinction from other uses of dB. The reference sound pressure, which is at the same time the threshold of hearing, is then 0 dB SPL. The threshold of pain is 140 dB SPL. A difference in the sound pressure level of 1 dB is just about perceptible, while a doubling of the sound pressure corresponds to 6 dB and a doubling of the volume corresponds to a rise of 10 dB.
'; term['Sound pressure level (SPL) (Clip-on microphone)']='Due to the impractical numerical values, the sound pressure is usually given as the logarithmic value of the sound pressure level according to the equation: dB SPL = 20 x log (po / 0.00002 Pa). The abbreviation SPL (sound pressure level) is added in order to make a clear distinction from other uses of dB. The reference sound pressure, which is at the same time the threshold of hearing, is then 0 dB SPL. The threshold of pain is 140 dB SPL. A difference in the sound pressure level of 1 dB is just about perceptible, while a doubling of the sound pressure corresponds to 6 dB and a doubling of the volume corresponds to a rise of 10 dB.'; term['Sound pressure level (SPL) (Handheld transmitter)']='Due to the impractical numerical values, the sound pressure is usually given as the logarithmic value of the sound pressure level according to the equation: dB SPL = 20 x log (po / 0.00002 Pa). The abbreviation SPL (sound pressure level) is added in order to make a clear distinction from other uses of dB. The reference sound pressure, which is at the same time the threshold of hearing, is then 0 dB SPL. The threshold of pain is 140 dB SPL. A difference in the sound pressure level of 1 dB is just about perceptible, while a doubling of the sound pressure corresponds to 6 dB and a doubling of the volume corresponds to a rise of 10 dB.'; term['Sound pressure level (SPL) (Headset microphone)']='Due to the impractical numerical values, the sound pressure is usually given as the logarithmic value of the sound pressure level according to the equation: dB SPL = 20 x log (po / 0.00002 Pa). The abbreviation SPL (sound pressure level) is added in order to make a clear distinction from other uses of dB. The reference sound pressure, which is at the same time the threshold of hearing, is then 0 dB SPL. The threshold of pain is 140 dB SPL. A difference in the sound pressure level of 1 dB is just about perceptible, while a doubling of the sound pressure corresponds to 6 dB and a doubling of the volume corresponds to a rise of 10 dB.'; term['Source impedance']='See output impedance.'; term['Specials']=''; term['Speech audiometry']='Used to determine a hearing impairment. Certain words are spoken at a certain volume and the test person is asked to repeat them. See also tone audiometry. ie.'; term['SPL for peak deviation']='The sound pressure level to which a wireless microphone has to be exposed for peak deviation.'; term['Splitter']='Device which allows several receivers to be supplied with the RF signal from one antenna/a single pair of antennas. Since a splitter always has a basic attenuation, most are fitted with an integrated amplifier: active antenna splitter.'; term['Spot microphone']='A microphone located directly next to an instrument during multi-microphone miking.
'; term['Spurious emission']='Unwanted by-products in the transmission of RF.'; term['Squelch']='Adjustable value for muting a receiver if the RF power received falls below a certain threshold value.
'; term['Squelch threshold']=''; term['Standards']='Standards which apply for a product'; term['Stereo-Channel separation']='The level which can be heard (or measured) in a channel when an audio signal is present in the other channel. This level is lower by a certain dB value, and is also called channel separation or crosstalk attenuation.'; term['Stereo microphone']='Microphone with two transducers in one housing, usually a coincident microphone for M-S or X-Y stereo.'; term['Stereobase']='See included angle.
'; term['Storage temperature']='Gives the range of temperatures at which a unit can be stored without damage.'; term['Sub-D-Connector']='Standardised multi-pin connector, mainly used in the computer industry.'; term['Suitable charging unit']=''; term['Suitable power supply unit']=''; term['Super-cardioid (pick-up pattern)']='A microphone with a super-cardioid pick-up pattern has a more marked directivity than a microphone with a cardioid pick-up pattern. The recording angle is smaller. A super-cardioid microphone is least sensitive to sound at 126°.'; term['Suppression of harmonics']='Gives the level of attenuation of unwanted spurious emission.'; term['Switch']='An electrical or electronic component used to open or close an electric circuit.'; term['Switching bandwidth']='The frequency band in which frequencies can be switched directly.
'; term['THD + N, total harmonic distortion and noise']='The sum of all distortion products plus basic noise (the information most often given in technical data).
'; term['THD, total harmonic distortion']='Total harmonic distortion is a measure of non-linear harmonic distortion and is given in %. Non-linear harmonic distortions are signals which were not present in the original before the signal was converted by the headphones. These unwanted signals are caused by the diaphragm, whose movements do not precisely move in time with the electric signals that cause it to move. Unfortunately, this is a feature of all electroacoustic transducers. Although it cannot be completely eliminated, suitable steps can be taken to minimise it. However, the user is not interested in why this distortion takes place but in how great the level of distortion must be for it to become perceptible. According to the findings of several research projects, a total harmonic distortion of 1% in the frequency range of 100 to 2000 Hz is imperceptible. Below 100 Hz, the perceptibility threshold lies at 10%.'; term['Thread for mounting']='Gives the size of a thread on a unit. This thread is used to mount the device to a stand etc. (for example an IR radiator or an antenna).'; term['Threshold for automatic on/off function']='The minimum voltage needed for automatically switching a unit from stand-by to operation.'; term['Threshold of feeling']='Term in audiology to describe the human ability to perceive deep sounds in particular through the nerve cells in the skin. This sensitivity decreases rapidly at frequencies above 1000 Hz. Deaf people are able to perceive music in this way and, for example, dance to the bass rhythm in the floor.'; term['Time delay stereo, time difference stereo']='See AB stereo.
'; term['Tinnitus']='Sensation of ringing noises in the ear.
'; term['Tone audiometry']='Testing hearing using pure tones. These tones, defined according to frequency (in Hz) and volume (in dB), are played to the test person, usually via headphones. A more objective assessment is then possible. See also speech audiometry.'; term['Tone control']='Used for adapting the hearing aid to the residual hearing ability of the patient. Compensates for the insensitivity of the damaged hearing to certain frequency ranges by means of selective amplification. The tone control is adapted to the individual loss of hearing by the hearing aid acoustician.'; term['Total height']=''; term['Transducer principle']='Two transducer principles have become established for the conversion of electric energy into mechanical energy: electrodynamic and electrostatic transducers, whereby the latter is only to be found in audiophile systems, due to their relatively high manufacturing costs. Electrodynamic transducers basically consist of a ring-shaped permanent magnet and an oscillation coil, which is fixed to the receiver diaphragm. When an audio-frequency alternating current is passed through the oscillation coil, it is caused to vibrate in accordance with the audio-frequency alternating current, thus causing the diaphragm to vibrate in the same way.'; term['Transducer principle (Headphones)']=''; term['Transducer principle (Microphone)']='Operating principle of a microphone. The transducer may be dynamic, piezoelectric or condenser.'; term['Transducer; Headphone type']=''; term['Transducer; Microphone type']=''; term['Transducer; Microphone type (Clip-on microphone)']=''; term['Transducer; Microphone type (Handheld transmitter)']=''; term['Transducer; Microphone type (Headset microphone)']=''; term['Transfer ratio']='Specifies the voltage ratio at the input and output of a transformer. For example, a transformer with a ratio of 1:2 would deliver double the input voltage.'; term['Transmission loss']='The power that is lost in transmitting a signal from one point to another, for example when the signal passes through walls, ceilings, etc. The strength of the signal available at the receiver is reduced.'; term['Transmission/receiving frequencies']=''; term['Trickle charging']='Ensures that a rechargeable battery (Sennheiser accupack) is supplied with exactly the amount of charge which is lost by self-discharge.'; term['True diversity']='"Genuine" diversity reception using two separate receiver sections. The stronger useful signal is selected on the AF side.'; term['Tympanometry']='Part of an audiometric examination, used to measure the elasticity of the ear drum (tympanic membrane).'; term['Type approval number']='Before a unit can be put on the market, it has to be established whether it meets the applicable regulations and guidelines. Such guidelines are published by e.g. standards committees, telecommunications authorities etc.'; term['T.H.D. = Total Harmonic Distortion.']='Total harmonic distortion is a measure of non-linear harmonic distortion and is given in %. Non-linear harmonic distortions are signals which were not present in the original before the signal was converted by the headphones. These unwanted signals are caused by the diaphragm, whose movements do not precisely move in time with the electric signals that cause it to move. Unfortunately, this is a feature of all electroacoustic transducers. Although it cannot be completely eliminated, suitable steps can be taken to minimise it. However, the user is not interested in why this distortion takes place but in how great the level of distortion must be for it to become perceptible. According to the findings of several research projects, a total harmonic distortion of 1% in the frequency range of 100 to 2000 Hz is imperceptible. Below 100 Hz, the perceptibility threshold lies at 10%.'; term['Ultrasound']='Sound of a frequency above 20 kHz and therefore inaudible.'; term['Unbalanced circuit']='The cable screening is used to return the signal.
'; term['Use for']=''; term['Vocal microphone']='A type of microphone designed especially for close-miking, particularly insensitive to pop and handling noise as well as to humidity.'; term['Voltage']=''; term['Weight']=''; term['Weight incl. Accu']=''; term['Weight incl. cable']=''; term['Weight w/o cable']=''; term['Weight (Bodypack transmitter)']=''; term['Weight (Handheld transmitter)']=''; term['Weight (Plug-on transmitter)']=''; term['Weight (Receiver)']=''; term['Weight (Set)']=''; term['Weight (Transmitter)']=''; term['Windshield']='Open-cell foam cap placed over the grille or sound inlet (basket) of the microphone to prevent pop noise and wind noise due to air movement.'; term['XLR-Connector']='Most common form of connector in audio studio technology.'; term['XY-stereo']='2-channel stereo recording technique which creates a stereo image by means of the differences in the intensity of the sound at the two microphones (channels). Since the microphone capsules are close together, differences in delay time are negligible. Usually, cardiods are used, with an included angle between the microphones of 90°–135°.';