Mike Masztal

October 1997

True Dimensional Sound
TDS-II Analog Audio Processor

During my 22 years in hi-end audio, I’ve seen a lot of accessories come to market all with the promise to enhance the audio experience. By 1977, Dolby noise reduction was established and commonly found on all but budget level cassette decks. Around that time, the audio community saw the release of DBX tape noise reduction and dynamic range expansion to combat signal compression inherent in the recording technology of the time. Phase Linear introduced the Autocorrelator, a noise reduction/dynamic range expansion device that could be used on all sources of playback. At $349. the Autocorrelator wasn’t cost prohibitive, so I bought one and it did what it claimed. The improvement was more than subtle, but not mind-blowing. At that time audiophile interconnects were also in development, but early design simply had thicker insulation and gold plated RCAs. Clearly, audio engineers were onto something.

These days we have $2000 interconnects, $800 wood discs, $5000 vibration isolation devices, sandboxes, air bladders, contact enhancers, green paint for CDs, etc. All of these devices work to varying degrees (usually subtle), but I’ve noticed their positive (or negative) effects are often system dependent necessitating auditioning before buying.

While attending the 5 day CEDIA conference in Atlanta, fellow SoundStage! writer, Jim Saxon, and I saw the latest in home theater components, home automation devices, and some offerings by hi-end companies. A lot of companies are working very hard to advance the state of the art in audio, but in my opinion, one of the most stand-out audio products at the show was the True Dimensional Sound, TDS-II analog audio processor. After listening to a demonstration in the less than ideal environment of the cavernous World Congress Center, both Jim and I agreed the TDS-II needed a closer look. After a lengthy talk with Chris Knecht, Marketing VP and Art Garcia, co-inventor, we coaxed them into loaning a unit to demo at my home that night. After 3 hours of listening in my system, our initial impressions were confirmed and we thought a formal test was in order.

The Product

The genesis of the TDS began years ago when the co-inventor Arturo Garcia was developing a sound enhancement device for submarine SONAR to enable exact recognition of other vessels. Arturo’s son, Art, saw an application for audio and spent 5 years developing an audio version of his father’s technology. A professional version was first developed and is presently being used in several music and film recording studios. The TDS-II, a consumer version, is a $295 device (physically about the size of a VHS cassette) that is designed to be placed into the system before the pre-amp or in the tape loop. The unit is powered by a 12 volt wall adapter, has a front mounted on/off switch and gold plated RCAs on the back. The TDS-II offers no phase shifting or time delay. Their technology is patented with additional patents pending. The TDS-II is designed to restore the harmonic loss inherent in the recording/ playback process. Theoretically, this should allow each instrument to harmonically sound like itself and not decay into a tone of unidentifiable origin. [The late pianist and recording engineer, Glenn Gould, also noted this phenomenon and saw great potential in digital recording technology to correct this anomaly.] Chris Knecht, noted that TDS was used to enhance the sound track of the film, "Jerry Maguire," and earlier testing in Sony’s recording studio, the engineers were unable to reproduce the TDS’s enhancement. I would like to note that TDS also makes a unit capable of being used in car audio.

The Sound

My testing was done in three modes:

1. Original system
2. TDS in system, but in bypass mode
3. TDS in system, working

After inserting the TDS-II between my DAC and pre-amp, I wanted to determine if there would be any significant deterioration in sound with the unit in the bypass mode. There was a slight decrease in the body of the sound and depth of the soundstage, but width was retained. Some change would be inevitable, but these changes were slight and would likely be unnoticed by all except the hard core audiophile. I initially thought the device may be analogous to the once common "Loudness" control found on any number of electronics, but testing with a sound pressure meter showed a fairly uniform response across the frequency spectrum.

Activating the TDS-II brought a transformation to the music. It went from sounding like excellent sound reproduction to having the energy of a live performance. The body and depth of the music were improved compared to the "TDS-II off" status and the changes were not subtle! An analogy would be looking through a dirty window. You can see the colors and shapes, but after cleaning the window, colors become more vivid and shapes become better defined. The TDS-II also seemed to increase the sound level a bit, but Art stated this was a normal occurrence with the unit as more of the harmonic structure of the music was being realized. After making sound level adjustments, the TDS-II’s effects were still evident.

The TDS-II makes the sound of a studio recording sound like a live, in your room, recording. Tonally, the most obvious improvement I heard was in the "back end" of notes as well as substantial improvement in decay and ambience. Macro and micro dynamics were also improved and attack was also more natural. Even with the sharpest of transients, there is a usually a millisecond or so of build up before the full amplitude of the transient is experienced. The TDS-II brought out this aspect in the recordings I used. Vocals were more palpable and stringed instruments were particularly improved. Many piano recordings can sound thin with a lack of sustain likely due to harmonic loss as well as other recording problems. The TDS corrects this problem giving all stringed instruments the correct fullness to their sound.

On some of the CDs I listened to, the TDS-II tended to thicken the sound. Not terribly, but enough to be disconcerting to an audiophile. This phenomenon seemed to occur only with heavily processed recordings, such as Enya, Watermark (Reprise 9 26774-2), and Emmy Lou Harris, Wrecking Ball (Asylum 61854-2). The rest of the recordings all benefited to varying degrees.

Conclusion

Many system tuning devices are available to the audiophile these days. Power cords, interconnects, speaker cables, power line conditioners and isolation devices are generally cost effective and offer good value, but the TDS-II is in another league. . The TDS-II is one of those rare products whose performance belies it’s price and I can think of no other device that will make such a substantial improvement to an audio system. In my opinion, anyone owning an inexpensive to mid-fi priced system would have to spend at least five times the cost of the TDS-II to approach the improvement this unit will make. The big-buck audiophile might want to wait for the passive (and pricier) unit due out next year. Granted, the level of improvement will vary depending on the price and resolution of your present system, but the company offers a 30 day money-back guarantee on the TDS-II, so what have you got to lose!

I would like to add that in order to fully realize the benefits of the TDS-II, one should replace the supplied interconnects with a good quality one like the Kimber PBJ. Also, a $5 EMI/RFI plug-in filter to go in between the adapter and the wall receptacle would minimize any hash the adapter might put back into the power line.

In summary, the TDS-II receives my highest recommendation. Hats off to Arturo and Art Garcia for their contribution to sound reproduction enjoyment. I look forward to listening to the audiophile grade passive unit and I fully expect it to find a home in my system.

...Mike Masztal
mikem@soundstage.com