Eddie’s Rodeo Review
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This rodeo-style review features an analog router, a digital audio converter (DAC) and a digital router — products that are manufactured by Studio Technologies, Aardvark and Z-Systems, respectively. Product choice was based upon my own personal need to integrate a workstation and mixer. Maybe you’re in the same boat?
THE ECLECTIC SOUND CRIB
At my project studio, Chez Dog, there is no recording console. At twenty-six inches wide, a "vintage" Roland M-240 mixer fits on a sliding shelf under a computer keyboard. Its 24 line inputs are ready to monitor any combination of digital eight track decks or MIDI gear that might drop by. Intended as a keyboard mixer, there are no mic-preamps, equalizers or "convenience" features such as Talkback, Solo or Mute. All serious mixing gets done on a Soundscape SSHDR1 hard disk recorder/editor. To fully integrate these and other components into a user-friendly system, I was on the lookout for third-party products that make life easier.
The first product I chose was the Studio Technologies STUDIO COMM, a very clever stereo source selector. It has become one of my Essential Accessories along with the Z-Systems Detangler, an electronic patch bay for digital audio signals. Together, these two units helped me test the 16 bit Aardvark Aardverter. In one compact package, the Aardverter does the A-to-D and the D-to-A dance at three sample rates (32, 44.1 and 48 kHz). It also features input level knobs, input and output level trims, XLRs for all I/Os and the ability to sync to an external source. The combined list price of this trio is slightly over $4500. Some digital audio converter sets can do similar damage your wallet and not be as functional.
Just as I was wrapping up this "Rodeo Review," the Spectral Translator Plus showed up. It speaks all tongues: Tascam’s TDIF-1, Alesis Optical, Yamaha’s Y2, standard AES plus Sony’s PCM-800 eight-channel (on a DB-25 connector) AES. The Translator Plus will allow digital transfers between the ADAT and DTRS (DA-38/88, PCM-800) formats, from AES to either format and back. This means I can finally transfer digital multitrack tapes into Soundscape without detouring to the analog domain.
THE RODEO LAB TEST
I wanted to compare the D-to-A converters of a Panasonic SV-3800 and the Soundscape SSHDR1 with that of the Aardvark. Before doing so, all of their outputs had to be made equal. By pressing Aardvark’s "Mode" button, the A-to-D outputs a test tone at digital zero (or no tone = digital silence). This signal was routed via Z-system’s Detangler to the SV-3800 and the SSHDR1. (The Aardvark D-to-A automatically takes its cue from the A-to-D when in "Test" mode.) Monitoring in the analog domain was via Studio Comm. Its DUB output was connected to a Fluke 8060A RMS voltmeter for level confirmation.
Note: Aardvark’s digital meter unfortunately indicates only the A-to-D level. It does not — at this time —also have the ability to indicate the incoming signal to the D-to-A.
Aside from -10/+4 level selection, Studio Comm does not provide individual level trims. Soundscape’s output was adjusted via its internal mixer. The front-panel software of the SV-3800 permits its output to be trimmed in 1 dB steps while the Aardvark has mechanical analog level trims. All three devices were made to agree within one-tenth of a dB. An external analog oscillator, set to 30 Hz, was then fed to the Aardvark A-to-D and faded until it just about disappeared into the noise floor. Each D-to-A was remarkably well behaved; none exhibited any "birdies," grain, harmonic oddities or difference in noise spectrum.
THE RODEO FREE STYLE TEST
I then recorded acoustic guitar in a wonderfully ambient, 12’ x 40’ space with a reverb time that complimented the tempo of the music. A pair of AKG SE300B mics were used (with cardioide capsules) into an Aphex Tubessence Mic preamp. The Detangler simultaneously routed the Aardvark A-to-D to the Panasonic DAT, the Aardvark D-to-A and the Soundscape SSHDR1. All three were monitored in the analog domain through the Studio Comm. Yet another surprise. Even with complex source material (transients from the guitar and decay from the room) all three D-to-A converters delivered the same image and spectral balance.
THE OTHER SIDE OF D/A FENCE
Knowing that the D-to-A converters all exhibited similar behavior, it was now time for the more difficult task; feeding the same analog signal to all three A-to-D inputs. I made a "triple Y" cable and routed my oscillator to its three destinations and again listened to several tones fading each into the noise floor. Again, all three boxes were surprisingly well behaved.
Note: I had hoped that, with the aid of the Studio Comm, DAC idiosyncrasies would be more obvious. That I was not able to detect obvious sonic differences among the three units under test could have been the result of one or more of the following:
BACK TO THE STUDIO
Whether simply selecting various sources or investigating potential sonic discrepancies, the Studio Comm does so with an ease that is not taken for granted. There is a slight switching ramp that smoothes transitions so there are no clicks or crackles, just a momentary level dip. Since most digital sources are internally clocked, using the Detangler as source selector in conjunction with a D-to-A converter is not as seamless. There will always be a click when switching between sources. The solution would be to clock all devices from a common reference. This is not possible with some gear but it is a feature on the Aardverter.
Another group test enlisted the acoustics of my lobby as live chamber. Soundscape has four outputs, two of which were used as a reverb send for vocals, acoustic guitar plus gated kick and snare. Via Studio Comm’s Studio Output, this signal was sent to an amplifier and speaker. Without disturbing the send to the chamber, I was able to independently monitor its return (via the same mic, preamp and A-to-D combo) as well as the mix of the dry and wet.
Up until this review, I have avoided making sound quality comparisons amongst devices because there was no way to make repeatable A/B tests. Combining the Z-Systems Detangler with Studio Technologies Studio Comm permits a multitude of monitoring options — enough to catch an audio criminal in the act — or at least make one’s life easier. That I didn’t have to crawl behind any racks was also much appreciated.
Till next time, Adios Amoebas!
MANUFACTURER: Studio Technologies, Inc. 5520 West Touhy Avenue, Skokie Illinois 60077. Voice: 847-676-9177 Fax: 847-982-0747
APPLICATION: Facilities normally associated with recording consoles are now available for workstations and budget mixers.
SUMMARY: A one-of-a-kind box that is a lifesaver.
STRENGTHS: The packaging is quite robust. The manual is most generous and thorough. All features are easily front-panel programmable. A spare stereo input and Dub output are provided on the front of the rack panel.
WEAKNESSES: It would be nice to be able to trim the level of each input.
Part of their STUDIO COMM series, the Studio Technologies’ Model 50 packs seven balanced stereo inputs and five stereo outputs into a single rack space. Each input has programmable input sensitivity (-10dBV/+4dBu) so that the various output levels (produced by a D-TO-A converter, CD player, mixer, DAT, open reel or cassette deck) can be in the same ballpark. (Wow! That’s six already!) The Studio Comm has outputs for main control room A/B monitors, studio monitors, a stereo headphone system and dub (for tape copies). The Model 50 comes alive with the Model 51, a compact remote controller that communicates via MIDI. About the size of a low profile cigar box, the remote features a big knob for Control Room Level that is augmented by switches for Mono, Talkback/Slate, Dim and the A/B amplifier selection. In parallel with the seven source-select switches are three columns of LEDs to indicate that signals have been independently routed to Control/Studio, Studio/Headphone and Dub outputs. The smaller knob is for Studio Level and has its own Mute switch. Programming is accessed via the Configure switch at the top left corner of the Model 51. To reconfigure, it is necessary to hold this switch for two seconds, a length of time that minimizes MBA (modifications by accident). There is also a separate headphone box — with its own level control — that mounts on a mic or music stand. The dub output has sufficient power to drive several devices, but for guaranteed isolation, Studio Technologies also makes a distribution amplifier (the Model 85). Together, these two products are well suited as the front-end to a small, real-time cassette duping station.
MANUFACTURER: Aardvark, 202 East Washington, Suite 306, Ann Arbor, Michigan 48104. Voice: 313-665-8899 Fax: 313-665-0694
APPLICATION: Analog-to-Digital-to-Analog converter set.
SUMMARY: An affordable dedicated converter that can be locked to an external reference.
STRENGTHS: Well designed package with Input and Output level trims. (Input trim can be either via knobs or recessed pots.)
WEAKNESSES: LED Meter displays the converted digital output only.
Q: Why are dedicated Digital Audio Converters (DACs) so expensive?
A: Because the A-to-D, power supply and D-to-A are in separate enclosures to ensure that nothing interferes with or contaminates the signal in either the analog or digital domain.
For those who are either not satisfied with — or not sure of — the sonic performance of the converters in your DAT or digital signal processor, the answer is a dedicated converter set. Problem is, DAC prices typically live in the neighborhood of $5,000. Aardvark, of Ann Arbor Michigan, have managed to bring the price down to earth. Their 16 bit Aardverter is an all-in-one DAC package for $1695. What you are not paying for is the separate packaging and power supply hardware.
Aardvark managed to squeeze all of that performance into one package by meticulous design of their four-layer circuit board. (They tell me it took a few tries before getting it right.) As you may know, printed circuit boards (PCBs) replaced interconnecting wiring that was once common with vintage vacuum tube equipment. But at the PCB level, what replaces shielded wiring for sensitive signals? The answer is to carefully route sensitive signals away from potential "noise" sources such as digital clock signals. In addition, PCB traces can serve as shields and be sandwiched between layers to minimize "cross-town traffic." Aardvark also ties all XLR pin-one grounds to an all-metal chassis. This and RF filtering keep unwanted noises from undermining good circuit design.
Aardvark provides these jumpers for user configuration of:
MANUFACTURER: Z-Systems Audio Engineering, 4641 NW 6th Street, Gainsville Florida 32609. Voice: 352-371-0990 Fax: 352-371-0093
APPLICATION: Electronic patch bay for Digital Audio Signals.
SUMMARY: Eight inputs and eight outputs (8 x 8). Four AES, two SPDIF and two optical.
STRENGTHS: 79 user presets for every possible configuration.
WEAKNESSES: Front panel silk screening could be more user friendly.
PRICE: The "4-2-2" in this review $1,080 * AES only $980 * Remote version w/MAC/PC software $1100
The z-8.8 digital patch bay eliminates the inevitable tangles that result from direct connections between various pieces of digital gear. Your wiring may have started out clean, but after a few sessions, things have a way of getting out of control. z-8.8 to the rescue. Not only can it interconnect all of your gear, it has user presets for 79 user permutations.
The front panel has a pair of rotary controls TO select a destination FROM a source, respectively. Above them is an alpha-numeric LED display for the sources with silk-screening below for destinations. Four switches (Cancel, Load, Save and Route) do the business. I never used the operators manual — the unit is that friendly — though I do think the front panel silk-screening could be more intuitive. For example, the "TO" knob selects which I/O channel to be modified, while the "FROM" knob increments or decrements the LED display. When Loading or Saving presets, however, the "TO" knob now increments and decrements. This threw me at first...
Before the Detangler, all artistic experiments required some pain. Apres Detangler, je suis tres jolie!
The Detangler comes in several flavors. The z-8.8 featured in this review is also referred to as the "4-2-2" because of its four AES ports, two SPDIF ports and two Optical ports. There is also an AES-only version, a Have-It-Your-Way version and the z-8.8r, which features remote control via MAC or PC.
Like the Studio Technologies "Studio Comm," the Detangler is in a robust metal package. It not only facilitated the review and interconnection of several products, it also allowed me to have more fun. I only get down on all fours for one person!