Telos ZephyrExpress Manuel d'utilisateur télécharger pdf (Page 67)

AUDIO OPERATIONS 4-5

DEEP TECH NOTE!

The limiter activity depends on the peak-to-average ratio of the program

material and may appear to operate at less than 15 dB above nominal level,

depending on the audio being limited.

Why you might want to leave the limiter off:

· Dynamic range increases by about 7 dB, which may be desirable for non-

broadcast applications.

· Total harmonic distortion and noise figures are slightly better with the

limiteroff. You might want to turn off ZephyrExpress’ limiter if another limiter

is already being used in the circuit.

HOT TIP!

Some forms of non-linear processing, including clipping and multiband

compression, will make any perceptual coder less efficient.

Why you might want to leave the limiteron:

· It prevents digital clipping and overloading of the A/D converter.

· Total harmonic distortion and noise figures are quite acceptable with the limiter

engaged.

Mic Routing Switches

The front-panel MIC 1 and MIC 2 routing switches cycle through four settings, as indicated

by green LEDs above the buttons:

¥ A Mic is routed to the codec via the A send bus: this is the proper setting for almost

all mono transmission, and the left channel for stereo.

¥ B Mic is routed via the B send bus, for a second mono transmission under Layer 3-

Dual

or the right channel of a stereo signal.

¥ A B Mic is routed to both send busses. Use this setting for mono mics when mixed

with stereo line-level sources in a stereo transmission, or to send the same signal to

two sites under Layer 3-Dual.

¥ (OFF) LEDs don’t light and the microphone is turned off. Switching is instant and

pop-free, so you can use this setting as a mic mute. Phantom power is still applied

when the routing is off, so you can turn the signal back on without a “thump”.

The A and B LEDs are dual color: they’ll glow red when a mic preamp is overloaded.

Occasional overloads may be acceptable — the analog preamp can handle them

gracefully — but if the lights stay red, you should lower the preamp’s sensitivity in the

Mic 1 or Mic 2 menu.

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Telos ZephyrExpress Manuel d'utilisateur Page 67