User manual

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.