Glossary Of Technical Terms - Sennheiser DSP pro Gebrauchsanleitung

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Glossary of technical terms

Balance: Control for the balance between right and left channel, compensates level
differences, e.g. when the acoustic systems of a headphone have different volume levels.
With Sennheiser headphones, you will not need this control.
Band-pass filter: Electronic (here: digital) circuit, which only transmits frequencies in a
certain frequency band. The rear channel (surround channel) of a Dolby Surround system
only transmits frequencies between 100 Hz and 7 kHz.
Centre channel: Central audio channel located in the middle of a cinema screen or
underneath your TV set.
Dolby B / C noise reduction: Developed by Dolby Laboratories in the USA for cassette
recorders. During recording, certain audio frequencies are encoded, i.e. basically compressed,
and decoded again during play, i.e. expanded. Dolby B noise reduction improves the signal-
to-noise ratio by 10 dB, Dolby C by 20 dB.
DSP: Abbreviation of digital signal processing. A converter transforms the incoming
analogue audio signals into digital values, i.e. they become a quick succession of current
pulses (on/off). DSPpro's two processors – Dolby Surround and Toltec – then process the
digital signals; all filtering is calculated. After processing, the digital signals are converted
back to analogue, the headphone reproduces the audio signal.
Haas effect: Technical term from psychoacoustics. A phenomenon whereby a given sound
is assigned the direction from which it is first heard. The brain automatically neglects
reflections.
Pro-Logic: Active Dolby Surround decoder. Pro-Logic increases the differences in volume
between the individual audio channels and is able to perform a better analysis of the
directional information contained in the audio signal. It thus provides a better channel
separation than the passive Dolby Surround system. Pro-Logic also delays the surround
signal and thus increases the impression of depth within a room.
Surround channel: Creates the impression that the listener is surrounded by sound. In Dolby
Surround / Pro-Logic, the mono surround signal is fed to the two rear speakers. The
frequency response of the surround channel is limited to between 100 Hz and 7 kHz. This
reduction in frequencies is not noticed as the other channels (left, centre, right) radiate the
full audio frequency spectrum. The transmitted frequencies are limited for technical
reasons. In order to improve channel separation for Dolby Surround / Pro-Logic, the
surround signal is processed with Dolby B (see above). However, Dolby B would also
increase interfering signals of very low or very high frequencies. To avoid the otherwise
resulting "pumping" or hissing noise, the audio signal is fed to a band-pass filter (see above).
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