OPTIMOD-AM DIGITAL
INTRODUCTION
1-19
ABSOLUTE PEAK
PPM
VU
Figure 1-1: Absolute Peak Level, VU and PPM Reading
Studio Line-up Levels and Headroom
The studio engineer is primarily concerned with calibrating the equipment to pro-
vide the required input level for proper operation of each device, and so that all de-
vices operate with the same input and output levels. This facilitates patching devices
in and out without recalibration.
For line-up, the studio engineer uses a calibration tone at a studio standard level,
commonly called line-up level, reference level, or operating level. Metering at the
studio is by a VU meter or PPM (Peak Program Meter). As discussed above, the VU or
PPM indication under-indicates the true peak level. Most modern studio audio de-
vices have a clipping level of no less than +21dBu, and often +24dBu or more. So the
studio standardizes on a maximum program indication on the meter that is lower
than the clipping level, so peaks that the meter does not indicate will not be
clipped. Line-up level is usually at this same maximum meter indication. In facilities
that use VU meters, this level is usually at 0VU, which corresponds to the studio
standard level, typ4 or +8dBu.
For facilities using +4dBu standard level, instantaneous peaks can reach +18dBu or
higher (particularly if the operator overdrives the console or desk). Older facilities
with +8dBu standard level and equipment that clips at +18 or +21dBu will experi-
ence noticeable clipping on some program material.
In facilities that use the BBC-standard PPM, maximum program level is usually PPM4
for music, PPM6 for speech. Line-up level is usually PPM4, which corresponds to
+4dBu. Instantaneous peaks will reach +17dBu or more on voice.
In facilities that use PPMs that indicate level directly in dBu, maximum program and
line-up level is often +6dBu. Instantaneous peaks will reach +11dBu or more.
Summary of Contents for OPTIMOD-AM 9300
Page 1: ...Operating Manual OPTIMOD AM 9300 Digital Audio Processor Version 2 0 Software...
Page 7: ...Operating Manual OPTIMOD AM 9300 Digital Audio Processor Version 2 0 Software...
Page 178: ...3 46 OPERATION ORBAN MODEL 9300...
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Page 222: ...6 22 TECHNICAL DATA ORBAN MODEL 9300 CONTROL BOARD PARTS LOCATOR...
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Page 229: ...OPTIMOD AM DIGITAL TECHNICAL DATA 6 29 I O DSP BOARD LEFT AND RIGHT ANALOG INPUTS...
Page 230: ...6 30 TECHNICAL DATA ORBAN MODEL 9300 I O DSP BOARD ANALOG OUTPUTS...
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Page 238: ...6 38 TECHNICAL DATA ORBAN MODEL 9300 FRONT VIEW REAR VIEW FRONT PANEL PARTS LOCATOR DIAGRAM...
