Telos ZephyrExpress user manual Send Level Controls, Send Meters

Send Level Controls

The three large black knobs control the level of their respective signals to the send bus. They are calibrated in arbitrary gray dots that don’t mean much, since the best way to mix is by using your ears and the SEND meters.

SEND Meters

h t

The two 14-segment SEND level meters have a fast attack and slow decay time, to alert you to any problems in the transmitted level. They monitor the signal as it enters the audio encoder, which works best when it’s got reasonably high levels to work with. Adjust the mixer so that most of the green LEDs are lit during average program material, with the red ones flashing occasionally.

Heavily-compressed material, such as pre-recorded commercials and popular dance music, can be set to average in the red area as long as the OdB segment isn’t lit. Zero is the clip point, and there just isn’t any headroom above it.

SEND

CH A

-30 -20 -10 0dB

CH B

HOT TIP!

The meters donÕt operate on channels that are in standard telephone / G.711 mode. During Far Loopback test mode, both meters are off and the center segment is lit as a reminder that normal operation is disabled.

DIGITAL AUDIO TIP!

YouÕll notice that normal operating level is around -10dB and zero is at the top of the scale. This is different from analog VU and deciBel meters you may be used to, but itÕs standard practice on digital devices.

The reason is that analog equipment has a few dB headroom above the normal ÒzeroÓ level (and zero itself is arbitrarily matched to a particular voltage, magnetic strength, or modulation). Digital equipment, on the other hand, counts deciBels down from absolute full scale ÑÊthe condition where all bits are turned on Ñ and there just isnÕt anything that can be louder that that.

AUDIO OPERATIONS 4-7