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PCX HR: Big Audio in a Small Package

With Digigram professional audio cards making up 60 percent of the world broadcast market, the arrival of the company's PCX HR (for "High Resolution") series opens a new era for broadcast production systems.

Sound Cards Offer DSP Monitoring, Breakout Box, Small Size, Enabling Easy Integration With PCs

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With Digigram professional audio cards making up 60 percent of the world broadcast market, the arrival of the company’s PCX HR (for “High Resolution”) series opens a new era for broadcast production systems. The PCX882HR is designed with capabilities that make it suitable for a range of broadcast needs.

The PCX882HR has an 8×8 analog I/O alongside an 8×8 digital I/O; its sister model, the PCX881HR, is 8×8 digital I/O only. The demo unit I tested came with the BOB8 breakout box. Because these Digigram products are sold to integrators and not to end users, I operated this in concert with the WinRadio v2.6 automation software, much as would be delivered to a station.

The card’s small form factor, less than 7 inches long, has been a signature of Digigram’s products for the past few years and seems to have been achieved with a sleight of hand, like starting with a card twice as long and folding it back on itself.

The components are neatly contained and protected inside. The advantage of the small size is that there is no integration issue with some PC configurations; this was a problem in the past with full-length cards physically conflicting with the layout of motherboards, cases and the like.

What’s packed into the small package is state-of-the-art. The card’s converters are full-bore 24-bit/192 kHz capable. The hardware converters provide sample rate conversion for each channel so a vast mix-and-match can take place, simultaneously recording different digital signals with different sample rates/frequencies, saving the need to standardize in-house. The card’s 66 MHz/64-bit Universal PCI interface has enormous bandwidth capacity.

The card’s primary connector is for a 62-pin Sub-D cable to the breakout box. Another pair of connectors for inside the computer case are for a companion board to double the I/O capacity and an inter-board synch to unify multi-card setups.
Product CapsuleTHUMBS UP:

Ample DSP processing power

Broad range of drivers

Easy to integrate into standard PCs


No printed documentation for utilities

PRICE: $390

Contact: Digigram in Virginia at (703) 875-9100 or visit
The optional BOB8 breakout box is a 2U rack unit with two rows of Neutrik XLR connectors. The eight mono analog inputs are on the left side over the eight mono outputs. The four stereo AES/EBU inputs are to the right over the matching stereo outputs. A word clock I/O, video sync input and SMPTE/LTC (Linear Time Code) input take up the far right side.

Getting connected

The manual for the PCX882HR was fairly skimpy at 26 pages. Digigram generally does excellent development work to create utilities, and the focus here is exclusively on the various controls in the OS.

Digigram’s communications manager at the time of my review Frank Seidel explains, “The concise paper-based documentation is [due to] the fact that the card has a very long life. During this lifetime, software updates occur frequently, which can be better reflected by a computer Help file that can be more easily updated.”

In any case, popping the card in and getting the drivers installed was a simple matter. I used two test beds – a now-antiquated PIII-800 MHz with 384 MG of RAM running Windows 2000 and a speedy PIV 3.2 GHz with a GB of RAM running Windows XP Professional.

The idea behind testing the card on PCs with different CPUs was to check to see if there was any need for a fast PC with its massive onboard DSP power. With the PIII, this minimum configuration identified the new hardware automatically.

Launching the HR Runtime driver package managed the installation with a variety of drivers (Digigram np Runtime, WDM DirectSound, Wave, ASIO) depending on the application. Checking the diagnostic utilities confirmed that everything installed seamlessly. From there, the WinRadio v2.6 application software also went in without any issue. In fact, things were up-and-running with ease.

Whatever tweaking is necessary comes from adjusting levels on the channels through the software providing analog and digital gain up to a scorching +24 dBu.

The bottom line on the setup is that it is likely to take more time in the typical installation to plug cables into the BOB8 breakout box than to set up the computer. A quick text of the audio quality in Sound Forge showed it to be more than adequate, near 100 dB S/N ratio.

Revving up the DSPs

Operation of the WinRadio package with minimal hardware was fine even when layering in loads of effects taxing the DSP power and not the computer’s CPU. A limit on both test computers was the standard PCI connector. The PCX882HR’s Universal PCI worked fine, and that leaves the card open to upgrades to a future system with a PCI-X interface. The standard PCI connection may run up against a bottleneck carrying a load of channels full-resolution, but I wasn’t able to choke it.

Also, I didn’t note much of a difference between the operation of the PIII 800 and the speedy PIV 3.2 GHz. That is not surprising given the enormous leap in DSP power over the previous generation PCX822v2. The older card used the Motorola DSP56303 chip operating at 80 MHz and the PCX882HR ups the ante to a Motorola DSP56321 operating at 240 MHz. That threefold gain in clock speed translates into a like increase in streaming capacity.

According to Digigram, the older card can mix three MP3 256 kbps 48 kHz stereo streams simultaneously, while the HR series upgrade handles 12. Similarly, the 16 MPEG2, 256 kbps 48 kHz stereo streams for the four physical outputs of the legacy card multiply to 68 stereo streams. The Digigram Control Center utility monitors the DSP’s usage to maintain a comfortable reserve of processing capacity (10 percent is recommended) to remain glitch-free.

Again, the lack of printed documentation for this utility left me wondering what the advantages might be for the various settings available. Help lies in a Help file – but it would help more to commit this to ink and paper.

Digigram’s HR series marks a new phase in the digital audio/computer production revolution. Not long ago, hardware capability was the limiting factor. Systems with the PCX882HR integrated into it will likely remain viable and vibrant for the foreseeable future. Putting in a second card can double these capabilities so you have a scalable solution able to take on the audio engineering needs of a considerable broadcast operation.