Digigram’s VXpocket PC Card sound card provides another way to bring digital technology to field recording. Although many equipment manufacturers (e.g. Roland) have added computer components to their high-quality audio gear, VXpocket adds high-quality audio to off-the-shelf portable computers.
Product PointsApplications: Computer recording/editing
Key Features: Type II PCMCIA card audio interface; balanced mic/line analog in S/PDIF digital I/O; balanced analog out; SMPTE in; Mac and PC drivers
VXpocket ($729) fits into the standard Type II PC card slot found on most recent Windows or Powerbook laptops. (Apple skimped on this key connector in the iMac, giving PC users a major price-edge) A VXpocket-equipped portable running your favorite software becomes a high-quality two-channel, multitrack hard disk recorder with balanced XLR analog I/Os and RCA S/PDIF digital connectors.
The VXpocket’s audio quality is very high, given the small form factor dictated by the PC card. This is the way to get quality audio in and out of a laptop, letting you set up a powerful, portable audio production studio without having to give up your favorite DAW software.
The major challenge in creating a sound card is noise filtration. The latest-generation PCI-based 24-bit sound cards attain 100 dB+ signal-to-noise ratios by dotting the cards with chips designed to screen out the haze of RF pollution typical in most consumer computers. Power supplies, CPUs, hard drives and motherboards all transmit RF to varying degrees.
Using balanced audio and proper filtration cuts out the bulk of the high-pitched squeals and howls that once plagued audio production in home computers. But, the VXpocket’s PC card format does not allow the luxury of such extensive filtration. There simply isn’t much real estate to place a lot of chips inside this tiny form. This has been a major obstacle with the various “prosumer” PC card setups I’ve tested. Most only manage around 70 dB SNR – not much of an improvement over the generic integrated audio hardware built into most laptops, and hardly up-to-snuff when it comes to making a quality digital master.
The clever folks at Digigram worked a design miracle on this little card. The VXpocket’s signal-to-noise performance was exceptional. Tests in Syntrillum’s Cool Edit 2000 at 16 bits/44.1 kHz averaged a terrific 96 dB. For comparison, that is just a shade worse than the 96.3 dB measured for Digital Audio Lab’s full-size PCI CardDeluxe. The major difference between the two was that the CardDeluxe achieved a near-perfect match between channels. The VXpocket showed a slight variation between left and right. The left channel was a tad quieter with a SNR of 96.2 dB. The right channel was 95.8 dB. It takes a slight tweak of the pan setting to make up the 0.4 dB difference.
At the VXpocket’s maximum audio quality of 24 bits/48 kHz, the specs improved about 2 dB. But the separation between channels improved a full decibel ö 98.9dB for left, 97.9 dB for right.
The VXpocket sounds terrific. I used it as a field recorder to capture the stereo board mix in a club. The sound card was installed in a standard Compaq Armada 7400 with a 333 MHz Pentium II CPU, a 6 GB UDMA hard drive and 192 MB of RAM. The software was IQS’ SAW32 multitracker running under Windows 98SE.
I also recorded the feed to a Sony MZR-55 MiniDisc to compare the quality. The stereo imaging was far better in the laptop recording. The MD’s compressed audio was okay, but lacked depth and detail. DAT aficionados can probably match this quality with a top-of-the-line recorder like the HHB PortaDAT. The venerable HHB unit, however, costs about as much as a VXpocket-equipped laptop. The advantage with the laptop is that the audio data is immediately available for editing and processing. Using a MD or DAT requires feeding the audio into a DAW in real time. With an external CD-R, I could have minted CDs of the show before the crowd cleared out.
On the downside, laptops are more vulnerable to damage than dedicated field recorders. Adding the VXpocket and the cable snake that attaches to it increase the chance of someone tripping over this rig. Basically, you need to keep an eye on the rig to keep it safe. PC drivers are available for Windows 9x and NT 4.0. Mac users have support for OS 8.X.
Since its introduction last year, the VXpocket has gone through one major revision. Version 2 includes an upgrade to the cable snake that adds an RCA SMPTE input with timecode support available through an ASIO2 extension. This restricts you to Cubase VST 3.7 (and later) or Nuendo under Windows, and Cubase VST 4.1 (or later) for the Mac. There is no SMPTE output, so the setup is restricted to being an LTC slave. The new cable snake is available to current owners for $75.
For the most part, my quibbles with the VXpocket are minor. Since it is limited to two tracks, it cannot compete against portable hard disk recorders with 8+ inputs. But, the huge advantage here is that you can work with the same software as on a studio-based DAW. There is no need to figure out a new interface. The VXpocket might not be enough for those looking to grab a full multitrack recording. Voiceover artists, radio reporters, and musicians working with a two-track mixdown, however, can use the VXpocket to set up a full-blown production studio most anywhere.Contact Digigram at 703-875-9100; www.digigram.com