Orban OPTIMOD 8685, Operating Manual

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OPTIMOD SURROUND PROCESSOR INTRODUCTION
1-3
(the 8585), the 8685 offers new input/output capabilities that include support for
SDI and HD-SDI and for Dolby-E. Dual redundant power supplies help ensure maxi-
mum uptime. In addition to surround processing, the 8685 can simultaneously pro-
vide up to four channels of 2.0 processing, allowing it to provide all the audio proc-
essing necessary for a typical ATSC broadcast with multiple subchannels. Like the
8585, the 8685 is dialnorm-aware. Loudness control is excellent when measured by
the ITU BS.1770 standard (as specified in ATSC
A/85:2009)
or by the 8685’s built-in
CBS Loudness Meters. When properly installed and set up, the 8685 will automati-
cally make a station compliant with the CALM Act.
OPTIMOD 8685 is descended from the industry-standard OPTIMOD audio processors
for radio and television. Thousands of these broadcast-specific processors are at-
tracting and holding audiences all over the world. They have proven that the
“OPTIMOD sound” can attract and keep an audience even in the most competitive
commercial environment.
Take a little time now to familiarize yourself with OPTIMOD 8685. A small invest-
ment of your time now will yield large dividends in audio quality.
The rest of Chapter 1 explains how OPTIMOD 8685 fits into the DAB and DTV broad-
cast facilities and how to use it for netcasting. Chapter 2 explains how to install it.
Chapter 3 explains how to operate OPTIMOD 8685. Chapters 4 through 6 provide
reference information.
OPTIMOD 8685 was designed to deliver a high quality sound while simultaneously
increasing the average modulation of the channel substantially beyond that achiev-
able by “recording studio”-style compressors and limiters. Because such processing
can exaggerate flaws in the source material, it is very important that the
source
audio be as clean as possible.
For best results, feed OPTIMOD 8685 unprocessed audio. No other audio proc-
essing is necessary or desirable.
Absolute Control of Loudness and Peak Modulation
•
The 8685 includes third-generation CBS Loudness Controllers ™ for DTV appli-
cations. Separate loudness controllers are available in the multichannel and 2.0
processing chains and work with the both Two-Band and Five-Band structures.
The third-generation improvements reduce annoyance more than simple loud-
ness control alone, doing so without audible gain pumping. Attack time is fast
enough to prevent audible loudness overshoots, so the control is smooth and
unobtrusive. Loudness control is excellent when measured by the 8685’s built-in
ITU BS.1770 and second-generation (Jones & Torick) CBS Loudness Meters, allow-
ing stations to comply automatically with the requirements of the CALM act.
(See
Using the ITU BS.1770 and CBS Loudness Meters to Measure Loudness Con-
troller Performance starting on page 3-78.)
•
The 8685 precisely controls peak levels to prevent digital clipping. The
maximum level of the digital samples is controlled to better than 2%.