© 2005 Wohler Technologies Inc. ALL rights reserved
12
VM SDI Digital Series
User Manual P/N
821625
Rev-
A
Section 2:
Operation
Audio Amplifier and Speaker Configuration
General Description
All models in the
VM Series
contain high performance transducers (speakers) driven by three power amplifiers; two amplifier/
driver combinations handle midrange and high frequency information in the left and right (stereo) speaker channels, while the third
amplifier channel sums the left and right channel information
below
the 500 Hz crossover point in the woofer (bass) speaker(s). Note
that the woofer channel is NOT a dedicated
LFE
(subwoofer) or
Center
channel.
Speaker Configuration
The
VM Series
(1U) products are configured with two speaker channels (left and right) to reproduce midrange and high-range
audio frequencies (in stereo) and one woofer speaker channel to reproduce the summed (combined)
low-range
audio frequencies
from the left and right speaker input channels.
See below for a simplified diagram of the
VM Series
audio amplifier/speaker configuration.
Balance Control Characteristics
The balance control attenuates the signal from the source, so that the left and right bass frequencies (summed together and
reproduced in the woofer channel) will also respond to the balance control.
Example:
If an audio signal of a voice speaking English is fed to the "A" (left) input and a voice speaking Spanish is fed to the "B"
(right) input, then the left speaker channel will reproduce the midrange and high-range frequencies of the English
speaking voice, the right speaker channel will reproduce the midrange and high-range frequencies of the Spanish
speaking voice, and the woofer speaker channel will reproduce the summed (combined) low-range frequencies of
both
voices.
If the balance control is
panned to the left
, then the Spanish speaking voice in the right speaker channel will diminish in
volume, the Spanish speaking voice in the woofer speaker channel will also diminish, and the English speaking voice in
both the right speaker channel and woofer speaker channel will increase slightly (to maintain overall output level). The
converse is true if the balance control is panned to the right.
See the
VM Series (1U) Audio Amplifier and Speaker Block Diagram
above for placement of the balance control in
the audio amplifier circuit.
