User manual

VM SDI Digital Series User Manual P/N 821625 Rev-A

Please refer to Figure-2a on the facing page to familiarize yourself with the front panel features of the VM SDI Digital Series

units. The following sections describe these features and are referenced, by number, to Figure-2a. Note that even though only the

VMMDA-1 front panel is shown, features and operation are identicle for the VMSDA-1.

Front Panel Features

Section 2: Operation

Speakers (Left, Right, and Woofer)

The VM SDI Digital Series audio monitors feature two mid-range speakers (left and right) and one woofer speaker. See

page 12 for a description and diagram of the audio amplifier and speaker configuration.

Volume Control

This adjusts the loudness of the audio reproduced by the internal speaker channels or connected headphone.

Audio Level Meter Bargraphs (Left and Right)

Audio levels for the selected source channels (left and right) are displayed via these two 10-segment LED bargraph audio

level meters. Meters have a dynamic range of 23 dB and levels are displayed using both VU and PPM dynamics.

SDI Lock Status LED

This LED indicates the lock status of the SDI source signal. It glows GREEN to indicate a locked SDI signal and is unlit to

indicate an unlocked SDI signal (or that no SDI source is connected). This LED indicates SDI lock status continuosly

regardless of any other selection settings.

SDI Group Channel Select Switch

This 8-position rotary switch selects one of the eight channel pairs (from SDI Groups 1-4) that will be monitored from the

connected SDI source. Note that in order to audibly monitor the selected SDI channel pair, the Source Select Switch

(Item 10) must be set to SDI.

Headphone Jack

This jack accepts the standard 1/4” phone type stereo plug. Select the headphone audio sources as you would for the

internal speakers. When you plug in headphones the speakers will mute.

Power Indication LED

This LED glows GREEN to indicate the unit is connected to mains power and an operation voltage is present.

Balance Control

This control adjusts the volume balance between the left and right speaker channels. See page 12 for a description of the

balance control characteristics within the amplifier and speaker configuration.

Phase Indication LEDs

These three LEDs indicate the instantaneous and average phase (polarity) conditions between the two signals in the channel

pair assigned to the left and right speaker channels. The two smaller LEDs labeled FAST show instantaneous phase

relationships in the signal. The larger LED labeled AVG will indicate the average phase condition. Indication is as follows:

• The left FAST LED glows (or blinks) GREEN for in-phase signals.

• The right FAST LED glows (or blinks) AMBER for out-of-phase signals.

• The large AVG LED indicates the average phase condition by glowing GREEN for in-phase signals, or RED for

out-of-phase signals.

In general, observing the AVG LED alone is sufficient for proper phase monitoring. While it is normal for stereo signals to

contain some intermittant instantaneous out-of-phase and in-phase conditions (FAST LEDs), a steady RED glow of the

AVG LED indicates an out-of-phase alarm condition.

Source Select Switch

This 3-position toggle switch selects the source to be monitored through the unit (SDI, AES, or analog).