Cedar BRX+ and AZX+
Debuzzer and Azimuth Correctors
Cedar has expanded its acclaimed X Series of audio restoration modules (DCX Declicker, CRX Decrackler and DHX Dehisser) with two new units, the BRX+ Debuzzer and AZX+ Azimuth Corrector. Priced at $6,555 (BRX+) and $5,695 (AZX+), these single-rackspace boxes can be used alone or daisy-chained in any combination, and feature 40-bit, 50MFlops floating-point CPUs for real-time processing.

There is no analog I/O, but all are equipped with S/PDIF (co-ax) and AES/EBU digital I/O, and provide 24-bit I/O resolution at any sample rate from 30 to 50k Hz. The front panels on both units belie the fact that there’s a lot going on within their central CPUs, but keep operations simple.

The AZX+ Azimuth Corrector fixes the timing differences created by azimuth errors and electronic faults in the signal chain. Not just for tape recorder head correction, the AZX+ also works with any signal where the phase alignment of the L/R sides are off, such as phono recordings where the cartridge is misaligned. In automatic mode, a tracking algorithm locks onto these errors, and AZX+ synchronizes the channels with an accuracy of 0.25 samples. A manual mode permits timing shifts as small as 0.01 samples. As azimuth correction has a major effect on stereo perspectives, the pre/post processed input can be monitored as a stereo, mono summed (L+R) or mono difference (L-R) signal.

On material exhibiting left/right timing errors, the AZX+ did an absolutely amazing job of restoring the stereo image and mono compatibility of the signal. And lest you think that azimuth correction is simply a mono concern, problems such as propagation delay (where only one side of the signal is affected) can crop up in digital recordings, and I have found numerous commercial CD releases exhibiting problems stemming from a misaligned playback deck. Once such recordings are archived to digital, the errors are there to stay, unless corrected, making the AZX+ an indispensable tool for the mastering/archiving facility.

Unlike a simple notch filter, the BRX+ debuzzer automatically identifies all the harmonics that form buzz and hum, such as AC power hum, dimmer noise and camera sounds, and removes them with virtually no effect on the input signal. In addition to film/video dialog restoration, applications include improving surveillance tapes and other forensic recordings. The BRX+ offers a combination of methods using either presets (at frequencies where hum tends to occur) or at any user-defined fundamental from 24 to 130 Hz. From there, the system will automatically track any minor frequency fluctuations in the noise, and the user simply adjusts the “buzz power” and attenuation pots until the desired effect is attained.

I used the BRX+ on a variety of material, both audio and video, including U-matic and vintage EIAJ reel-to-reel black and white tapes I was archiving to digital. The BRX+ made a enormous improvement in clarity on several recordings that otherwise were essentially unusable. On another session, the BRX+ rescued a telephone interview where the cassette recorder sat next to the back of a computer monitor and was awash in hum from the CRT’s choke. In every case, the BRX+ reduced or eliminated the offending noise (and its harmonics) while leaving the original unaffected.

Cedar, distributed by Independent Audio; 207/773-2424; www.independentaudio.com.
—George Petersen


CAD VSM
Cardioid Tube Microphone
Made entirely in the USA, the VSM (formerly dubbed the VSM 1) tube condenser mic features CAD’s patented Optema capsule, a 3-micron, 1.1-inch diaphragm, an input stage with a hand-selected, “burned-in” 12AX7 tube and a solid-state output stage. The pickup pattern is cardioid. A -3dB-at-80Hz highpass filter and a -8/-16dB pad are standard.

With an attractive silver gray body with matte-black trim, the VSM has an art-deco look and includes a custom flight case, a well-designed shock-mount, power supply and cable. The case holds the VSM mounted in the shock-mount as a single unit, saving the hassle of taking the shock-mount on and off during setup/breakdown. The rugged external power supply is switchable to 117 or 220 VAC. The 30-foot, 7-pin mic-to-power supply cable is high-quality Gotham cable with gold-plated Neutrik ends.

The VSM’s frequency response is rated at 10 to 20k Hz (impressive, especially to my dog, Bud). The mic has very low self-noise, especially considering it’s a tube mic. The numbers support what I heard, or more specifically, what I didn’t hear; S/N is rated at 79 dB at 94dB SPL.

The VSM is neutral sounding with a clear mid-high response. There are a few subtle bumps and dips in the midrange but nothing unacceptable. The low end is light and unobtrusive, surprising for a tube mic. Its generally flat response yields the sense of a mellow high-end rise starting at around 11 or 12 kHz that’s quite pleasant. There is, however, a smearing proximity effect starting around six inches and closer, making the VSM’s sweet spot just beyond that point, and about seven inches from the capsule was ideal.

The VSM is particularly complementary to edgy voices, as it tends to smooth out the sound. Sibilance is handled beautifully; tracks recorded with the VSM should need only minimal de-essing. Certain types of percussion instruments (shakers, cuicas, bean pods, etc.) also record very well. The mic imparts an airiness to their transients that sit nicely in the mix. It’s not my first choice on acoustic guitar—I prefer a smaller diaphragm like Neumann’s KM54 for better presence—but the VSM would do in a pinch. For overheads, I suspect this mic would work great, but, unfortunately, I only had one VSM for review.

With a list of $1,299, the VSM is a great value, offering VX2 technology in an affordable package. I’d even recommend it over some models that cost much more, but if a large-diaphragm condenser mic with heavy tube color is what you’re looking for, the VSM probably isn’t for you. Its strong point is its uncolored sound, its translucent quality: not things everybody will like, but qualities that help define it as a welcome addition to mic lockers in project and pro studios alike.

CAD Microphones; 440/943-0110; www.cadmics.com.
—Michael Denten

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Reprinted with permission from Mix Magazine, June, 2000
© 2000, Intertec Publishing, A Primedia Company All Rights Reserved