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OPTIMOD-PC
Using OPTIMOD-PC to Prepare Audio Files
Functionally, OPTIMOD-PC is two full-duplex sound devices and is seen as such by
the computer operating system. This means that it can support two streams of re-
cord and playback functions simultaneously. You can use any application or combi-
nation of applications that allows simultaneous playback and recording of audio
files to process the raw files before they are encoded with an encoding application.
Depending on the encoder application's design, you may have to first write a file
containing the OPTIMOD-PC-processed audio and then apply that file to the input of
the encoding application.
Any audio editing application that is Microsoft Windows WDM-compliant will work
with OPTIMOD-PC. For example, Adobe Audition supports batch processing, so you
could use it to process many audio files while unattended.
Most streaming encoders have a mode to record/encode in their native file formats
in real time. If you do not need the interim .WAVE file, encoding directly will elimi-
nate a step and will save disk space and time.
Loudness
You can expect a significant increase in loudness from OPTIMOD-PC processing by
comparison to most unprocessed audio.
An exception is recently mastered CDs, which may have already been ag-
gressively processed for loudness when they were mastered.
In radio broadcasting, it is generally believed that loudness relative to other stations
attracts an audience that perceives the station as being more powerful than its
competition. We expect that the same subliminal psychology will also hold true in
netcasting.
You can use OPTIMOD-PC's built-in CBS Loudness Meter to objectively compare the
loudness of various presets and to indicate the effect of any edits to them (see page
1-8). In addition, Orban offers a free Loudness Meter application than runs native
under Windows. This application, which contains CBS loudness, ITU-R BS.1770 loud-
ness, VU, and PPM meters running simultaneously, can monitor the loudness of ei-
ther 1101 Wave output. The application is available at www.orban.com/meter.
Choosing your Encoder
The state of the art in encoder technology is changing rapidly. At this writing, the
best audio encoder technology available is Dolby/Coding Technologies or Fraun-
haufer IIS AAC/HE-AACv2 (MPEG-4 Enhanced HE-AAC). Orban is the first provider of
this technology for streaming audio applications with OPTICODEC-PC. OPTICODEC-
PC can provide entertainment-quality stereo streams at 32 kbps. At 48 kbps, many
listeners prefer the sound to that of FM, since there is no pre/deemphasis to limit
high frequency headroom.
OPTICODEC-PC Streaming Encoder is designed to work exclusively with OPTIMOD-PC
to form an overall audio processing / coding chain with the highest audio quality
possible for a given bitrate. These two components are also available from Orban as
part of a turnkey system called OPTICODEC-PC Streaming Encoder, which includes a
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INTRODUCTION
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