Snapshot Product Reviews

LUCID AD9624 AND DA9624 24-bit A/D and D/A Converters High-resolution 24-bit/96kHz converters seem to fall into two categories: pricey high-end devices

LUCID AD9624 AND DA962424-bit A/D and D/A ConvertersHigh-resolution 24-bit/96kHz converters seem to fall into two categories: pricey high-end devices and low-cost units intended for the MI market. Lucid has addressed this issue with its AD9624 ($899) and DA9624 ($749), two stereo converters that offer pro quality at an affordable price.

Although Lucid isn't exactly a household name in audio circles, over the past few years, the company-the high-tech, digital arm of Symetrix-has been producing no-compromise converter sets for Sonic Solutions workstations on an OEM basis. Now Lucid offers that same technology to end-users, in stereo (AES/EBU and S/PDIF) and multichannel versions (with Alesis ADAT Lightpipe or Sonic Solutions interfacing).

The AD9624 A/D and the DA9624 D/A offer 24-bit conversion at up to 96kHz sampling rates. Housed in half-rack enclosures, both units feature 20-segment LED metering with peak-hold, AES/EBU and S/PDIF (optical and coaxial) digital ports and balanced XLR analog interfacing, as well as an extra set of TRS outputs on the D/A converter. A backlit display shows sample rate and status. The A/D converter has a BNC word clock input; the D/A converter automatically locks to any digital input. Both converters use external power supplies, but at least these use "lump in the line" transformers, rather than wall warts.

The front panels are to the point: Plug in, set what you need and go. One possible source of confusion is a drawing of an ADAT next to the hookup section in the manual, leaving some users to believe that the units' TosLink S/PDIF optical ports support Lightpipe, which they don't. (To connect to ADATs or other Lightpipe peripherals, Lucid makes the multichannel ADA8824-ADAT model.) Both devices support sampling rates of 96/88.2/48/44.1/32 kHz, and for connecting to 16-bit devices, the AD9624 has an onboard noise-shaping function. The A/D can send output to AES/EBU and S/PDIF ports simultaneously.

Features aside, the best part about this converter pair is how they sound. The conversion is first-rate, with attention to detail not only in the digital domain, but also in the analog circuitry. This is a set of well-made tools that will improve the quality of your DAT or CD mastering now, and they're more than ready when you make the jump to 24-bit/96kHz production. Yeah!

Lucid Technology: 425/742-1518;

DANISH PRO AUDIO 4006Low Noise Omni MicrophoneI don't know about you, but too often when a company changes its name or comes out with a new model that's "just the same as the old one," I tend to be suspicious. So last year when Bruel & Kjaer studio microphones became Danish Pro Audio (DPA), I had a few reservations. After all, this wasn't just some drumstick company, but B&K-a revered name that's almost synonymous with precision transducers. I decided to check the DPA 4006 and see if it lived up to the original.

Retailing at $2,060, the 4006 is the standard 48-volt phantom-powered version of the company's low-noise-15 dB(A)-omni. The mic's fitted storage case comes with a mic clip, windscreen and two interchangeable grids. The standard silver grid is designed to provide linear on-axis response in near-field applications; for diffuse- or far-field recordings, the black protection grid adds an on-axis 6dB boost centered around 15 kHz.

Aside from the DPA logo on the mic body (the capsules themselves still say B&K) and a black rather than mahogany-finish mic box, the main difference in the package is the manual. The DPA 4006 booklet only covers that mic; previously, B&K issued a combo manual covering all the 4000 Series. Options include a highly effective shock mount, an alternate nose cone that ensures true omni performance-even at the highest frequencies-and a variety of push-on acoustic pressure equalizers that can change the mic's character in seconds.

Miking a variety of sources ranging from piano to piccolo trumpet, and triangle to 12-string, I compared the sound of the DPA and an older B&K 4006, routed through a Millennia Media HV-3 preamp and monitored on Meyer HD-1s. No difference between the two mics was discernible. And, despite a five-year age difference between the models tested, the two were virtually indistinguishable, even in blind listening tests, with both delivering the wide, flat, transparent low-noise performance that always has been a hallmark of the B&K sound. It certainly is not true with all products and companies, but in this case, there may be a diffferent name, but the sound's the same.

DPA Microphones/TGI North America: 519/745-1158;

WHIRLWIND QBOXMultifunction Audio Line TesterWhether you work in live sound, installations, broadcasting, remote recording or studio work, you probably spend WAY too much time troubleshooting. Frequently, the reason that something doesn't work can be traced to problems such as broken cables, bad connections, incorrect patches and other operator errors that, despite their simplicity, prove vexing in a hurried production environment. One useful tool for handling such emergencies is the Whirlwind Qbox(r), a combination mic/line tester offering a 440 Hz generator, phantom- or intercom-present LEDs, and an internal speaker/headphone jack that lets you actually hear the source under test.

Qbox is housed in a fuzzbox-sized, composite-molded package with 9VDC battery powering and a belt-clip for easy access. Top panel controls include a three-position (-20/+4/-50dB) output level attenuator, tone/internal mic switch, volume control for the internal 211/44-inch speaker or 11/44-inch headphone output, a power on/off LED, and yellow and green LEDs to indicate the presence of phantom or intercom power. The unit's front face has male/female XLR jacks wired in parallel, so any connector can act as either a mic line input or output; a 11/44-inch TRS doubles as either a line input or output to a high-Z, IFB-type mono earpiece. And in-between testing connections, Qbox can also double as an intercom monitor, or two Qboxes hooked to either end of a line can create an inpromptu intercom system.

While Qbox won't help with component-level repair on a multilayer surface-mount PCB, it can quickly tell you which line on a snake is dead, or whether the SM57 that the forklift just rolled over is still alive. Priced at $189, Whirlwind's Qbox rates as one of those "How did I ever get along without this?" gems that just about any audio pro could use.

Whirlwind: 716/663-8820;

HHB CLASSIC SERIESTube Signal ProcessingWell-established as a manufacturer of recording media, DAT decks, CD recorders and studio monitors, HHB now offers two lines of tube processors. Its Radius Series is designed for project studios and budget-conscious applications; I was more interested in HHB's Classic Series (built to HHB specs by Britain's Tony Larking Audio), designed for those seeking higher-end performance, for mastering and other critical applications.

Classic Series products are stereo (or dual-mono) units; behind their distinctive "HHB purple" front panels, these devices function beyond what their names imply. All of the units include balanced and unbalanced line-level inputs (and outputs), along with front panel, 11/44-inch, direct box-style inputs and onboard mic preamps (with phantom power), making them ideal for direct-to-tape tracking from any source. Solid-state power supplies deliver a full 250 volts to the tubes while reducing heat; large perforated metal grilles enable passive cooling.

The series includes the Classic 60 Tube Compressor ($2,395), the Classic 80 Pentode Tube Mic Preamp ($1,850) and the Classic 70 Tube Parametric Equalizer ($2,950). The Classic 60 features switchable 90Hz highpass filters, sidechain inserts, dual-mono/stereo linking, VU monitoring of output level or gain reduction, and continously variable parameters on all controls, including variable input gain, threshold, attack/release times, compression ratio and gain makeup. The Classic 80 preamp has high/lowpass filters on mic and line inputs, with three cutoff frequencies and illuminated VU meters.

To get a feel for the Classic Series, I checked out the Classic 70, a true parametric, which has full, continuous control of center frequency and "Q," and six tube stages per channel-one in each of the four EQ bands followed by a pair in the output stage. The mic preamps are solid-state followed by tube stages. This hybrid design delivers low-noise performance with a response that's flat from 20 to 40k Hz. Insert points on the rear panel allow the IC preamp stages to be bypassed, for access to a pure tube EQ stage or just the mic preamps without the tube circuitry. A cathode follower stage before the master output allows users to tweak the amount of tube distortion, just as the channel/master volume blend on a guitar amp might be set.

The equalization is flexible, with plenty of overlap in the bands. The full counter-clockwise Q setting is quite wide, and the opposite provides a medium-wide Q, so this EQ is designed for musical, program-style equalization, rather than tight, notch filter-style operation. Tracking bass and synths in the control room, I appreciated the Classic 70's direct inputs. The preamps are mostly uncolored and neutral, although color can easily be added, if desired. A bit of tube warmth seems the perfect complement to digital tracking, and the stereo function (in which the knobs of Channel A control both sides simultaneously) saves time in mastering and other program EQ applications. Offering a combination of whistle-clean audio specs, with preamps, DI functions and smooth, musical EQ, the HHB Classic 70 is definitely on the way to becoming a classic in its own right.

HHB Communications USA: 310/319-1111;

THE HOLLYWOOD EDGETMH Digital Audio Test DiscsTMH Corporation and Tom Holman (the mastermind behind THX technology), working with The Hollywood Edge, offer a comprehensive set of audio test discs designed to help pro and high-end consumer users align sound systems and check the quality of room acoustics.

Disc 1 has setup tests for stereo and surround monitoring for pro studios, project rooms and home theaters. Among these are the usual channel ID, panning, pink noise and background noise tests, but also headroom transients at various frequencies and LCRS/subwoofer reference level setups.

Disc 2 offers a collection of instrument calibration and general audio tests in both analog and digital domains, such as crosstalk checks, frequency response tones, sine/square waves, dither and fade-to-dither tracks and meter calibration routines. Disc 3 focuses on acoustics, with tracks for determining room acoustics, background noise, reverb time, transient bursts and vocal intelligibility. Disc 4 offers electroacoustical tracks for loudspeaker evaluation, such as pink noise and swept sine waves, and transient reproduction tests.

Each CD includes a number of demonstration sound effects. And many of the tones, such as channel IDs, sine and pink noise, are repeated on the various discs, so that if you are only testing one aspect of a system, there's no need for constantly switching discs. The set also comes with a 90-page guide that walks the user through the tests and provides background information. At $299, the TMH Digital Audio Test Discs set is highly recommended for anyone seriously interested in sound system optimization.

The Hollywood Edge: 213/466-6723;