Field Report: Orban Optimod-PC 1100

The Optimod 1100 merges the worlds of PCs and professional audio. It's a sophisticated DSP-powered audio processing system; an Optimod on a PCI card. In operation, the 1100 does all the work in its own DSPs, leaving the PC's CPU alone to handle other applications, such as a media encoder. The 1100 is functionally identical to the Orban 6200 DAB processor. It is not intended as a conventional FM or AM final processor because there is no NRSC, pre-emphasis or clipping used.

Some of the appeal of the 1100 is its lower cost, but more importantly, its performance and perfect suitability to the task establishes it as the standard of webcast processors.

The 1100 main processing system consists of a two-band AGC, three-band parametric EQ, five-band compressor/limiter, a look-ahead final peak limiter and selectable final low-pass filter. The card features two AES-3 or S/PDIF balanced digital inputs and one output, and one balanced analog stereo I/O. These all appear on one DB25 connector, but an optional pigtail cable with XLRs is available from Orban. The mixer application permits selecting and mixing any of these as the user might need. The user-adjustable parameter control panel offers 50 controls, and the mixer 56 controls. There's a tremendous range of adjustment available, which is particularly important for webcast applications.

Setup is simple. Power the PC down, plug in the card and reboot. Insert the driver CD when the new hardware found prompt is displayed. The process is typical Windows plug-and-play automatic install. The machine must be running Windows 2000 or XP. Drivers for Win98 are not included because the OS is not supported. Running the card on XP allows the user to feed the output of the 1100 to multiple applications simultaneously, even at different sample rates, which 2000 can't do without additional third-party drivers.

Performance at a glance
PCI bus audio processor
20 factory presets
PC needed only for setup
Includes I/O cable
Drivers for Windows and Linux
Look-ahead limiter

Because the 1100 is intended as a DAB/webcast/production/mastering processor, there is no peak clipping that would otherwise corrupt performance in subsequent data-reduced audio codecs.

Ready for action

The biggest challenge facing quality conscious webcasters is working around these audio codecs to deliver an acceptable entertainment quality product to the listener. For example, we use the Windows Media 9 codecs at Boomer Radio to reach the majority of already installed Windows users out there. Operating at a low enough bit rate to reliably support dial-up listeners (still the majority of the available audience), these codecs generate many unusual and non-musical artifacts in the encoding process. The massive task of reducing data by more than 35:1 (for 20kb/s mono) is the equivalent of throwing away more than 97 percent of the original information. That the end result sounds anything like the original is an amazing achievement, but the problem remains that certain things will sound strange, and sometimes obnoxious. Attention to every detail in preparing for this encoding process is vitally important, more than it is for traditional broadcast radio, where the medium is much closer to being transparent.

On top of this, different sources will excite different artifacts. For instance, one processor or setting that may work fine for one type of music may fall apart when driven by another type of music. The spectral and dynamic content of each song will make the codec do different things. A processor with a wide adjustment range is necessary to custom tailor the end result to reduce or mask the bad behavior of the codec. When processing for streaming codecs, one size does not fit all.

A functional block diagram of the Optimod 1100.

I have spent countless hours trying to fix this problem. The 1100 has turned out to be the most effective total package solution. We're currently using the 1100 on two of our streams, Classic Mix and The Acoustic Cafe. These two music formats require different treatment. Although the many presets that come with the 1100 can get you in the general ballpark quickly, we found we had to adjust each to keep the codecs from coming unglued.

The range of adjustments offerscomplete control over this and allowed us to make the necessary compromises that resulted in better overall end products for our listeners. In particular, being able to control the processor attack and release times, band mix levels and final output low pass filter cutoff in 500Hz increments, make a huge difference in taming the codecs.

Being able to handle a wide input level range is crucial for streaming because most sources are played back without any manual gain riding, and just normalizing files does not address differences between sources in intro and outro levels. This is important as most webcast listeners typically use smaller computer speakers and listen at lower office-appropriate levels.

If not dealt with properly this can sometimes result in a loud outro going into a low intro, or vice versa, placing a large instantaneous demand on the processing to make it up. The 1100 has a wide control range, 20dB each in the AGC and five-band limiter, so this is not a problem. It also does a nice job of handling this demand without punching holes or swelling, while still maintaining a good dynamic contrast.


The 1100 also has the ability for full remote control over a LAN. This is useful for a control point that is distant from the PC in question.

The only wish we have is for a future upgrade of the two-band AGC to the new 8400-style, window-control AGC. Having used the 8400, we have become spoiled with how well that AGC works. I understand there is enough DSP power on board to handle this and that it may be coming in a future release.

Blau is CTO of Integrity Media Group, owner of webcaster

Editor's note: Field Reports are an exclusive Radio magazine feature for radio broadcasters. Each report is prepared by well-qualified staff at a radio station, production facility or consulting company.

These reports are performed by the industry, for the industry. Manufacturer support is limited to providing loan equipment and to aiding the author if requested.

It is the responsibility of Radio magazine to publish the results of any device tested, positive or negative. No report should be considered an endorsement or disapproval by Radio magazine.

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