Optimod-AM 9400 V1.2 Operating Manual - Orban
Optimod-AM 9400 V1.2 Operating Manual - Orban
Optimod-AM 9400 V1.2 Operating Manual - Orban
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3-10<br />
OPERATION ORBAN MODEL <strong>9400</strong><br />
Starting with one of our suggested presets will help keep you out of trouble when<br />
you edit them to create user presets.<br />
We have supplied several presets tuned for the Microsoft WMA (V9) at 32 kbps. This<br />
codec has severe artifacts at this bitrate and no preprocessing can mask them completely.<br />
The 1100’s WMA presets strictly limit the amount of high frequency energy<br />
applied to the codec. To prevent the processing from adding L–R energy, these presets<br />
operate with full stereo coupling and without stereo enhancement.<br />
OPTIMOD-PC’s ability to maintain source-to-source spectral consistency is also an important<br />
advantage. Once you have set up the processing to minimize codec artifacts<br />
caused by a given piece of program material, OPTIMOD-PC’s will automatically<br />
minimize codec artifacts with any program material.<br />
Fundamental Requirements:<br />
High-Quality Source Material and Accurate Monitoring<br />
Very clean audio can be processed harder without producing objectionable distortion.<br />
If the source material is even slightly distorted, OPTIMOD-<strong>AM</strong> can greatly exaggerate<br />
this distortion, particularly if a large amount of gain reduction is used. Potential<br />
causes for distortion are poor-quality source material, including the effects of<br />
the station's playback machines, electronics, and studio-transmitter link, as well as<br />
excessive clipping settings in the OPTIMOD-<strong>AM</strong> processing. See Maintaining Audio<br />
Quality in the Broadcast Facility (an <strong>Orban</strong> publication downloadable from<br />
ftp.orban.com) for a discussion of how to improve source quality.<br />
A high-quality monitor system is essential. To modify your air sound effectively, you<br />
must be able to hear the results of your adjustments. Maintaining Audio Quality in<br />
the Broadcast Facility also contains a detailed discussion of how to efficiently create<br />
an accurate monitoring environment.<br />
Low-Delay Monitoring for Headphones<br />
In live operations, highly processed audio often causes a problem with the DJ or presenter’s<br />
headphones. Some talent moving from an analog processing chain will require<br />
a learning period to become accustomed to the voice coloration caused by<br />
“bone-conduction” comb filtering. This is caused by the delayed headphone sound’s<br />
mixing with the live voice sound and introducing notches in the spectrum that the<br />
talent hears as a “hollow” sound when he or she talks. All digital processors induce<br />
this coloration to a greater or lesser extent. Fortunately, it does not cause confusion<br />
or hesitation in the talent’s performance unless the delay is above the psychoacoustic<br />
“echo fusion” (Haas) threshold of approximately 20 ms and the talent starts to<br />
hear slap echo in addition to frequency response colorations.<br />
The normal delay through the <strong>9400</strong>’s analog channel processing is about 22 ms and<br />
the delay through the digital channel processing is about 15 ms. A 15 ms delay is<br />
comfortable for most talent because they do not hear echoes of their own voices in<br />
their headphones. However, a better solution to the monitoring conundrum is this:<br />
Any of the <strong>9400</strong>’s outputs can be switched to provide a low-delay monitoring feed,<br />
which is the same as the HD-processed output except that no peak limiting is applied.<br />
The monitor feed’s 5 ms delay is likely to be more comfortable to talent than