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Equipment Review

May 2000

Taddeo Digital Antidote Two

by Jon Gale


Review Summary
Sound "A just-detectable softening overall, not to the degree of reducing top-end air or life in a recording"; "slightly better articulation when the strings got busy," and "most well-centered female vocals seem to widen, or bloom, just a bit more between the speakers," but overall Jon found the effects to be "subtle."
Features Interesting technology that aims at improving digital sound; single-ended inputs and outputs only.
Use Works exclusively in the analog domain, which means it requires an extra pair of interconnects.
Value A definite in-home-audition product, as Jon found its effects to be subtle but there nonetheless.

A new addition to the long line of digital "fixes" is the Taddeo Digital Antidote II, manufactured by Taddeo Loudspeaker Company. Said by the designer to incorporate more of his proprietary phase technology with less of its inherent high-frequency roll-off, the Digital Antidote Two may be another black box on your rack, but it is a rather sleek-looking one. At 19"W x 9"D x 2 1/2"H, it nicely complemented my Theta DAC. It has a very sturdy case with a thick routed front panel and no knobs or other controls. And yes, I like the blue LED on the front that is popular of late. Two pairs of high-quality RCA jacks round out the rear along with a detachable power cord. The jacks are for line-level input from your DAC or CD player and output to your preamp; the Digital Antidote Two works exclusively in the analog domain.

When it comes to digital, I'm probably like you: Until the standards for any of the new digital formats are agreed upon, I’ll be sticking with my very good but slightly dated digital front-end. Also, while the current 44.1kHz digital format is about to be replaced, there are a great many audiophiles who have assembled large collections of music in this format. As these collections will quite probably never be fully replaced, we are all seeking a technology that will allow greater perceived resolution. This certainly applies to me, so I agreed to review the Digital Antidote II; I’m the target consumer for this kind of product.

The trouble with digital

It has long been known that the present 44.1kHz-sampling rate basically runs out of room (sampling points) in the high frequencies. This problem manifests itself in two ways: a very slight shifting of frequency around 15kHz and above, and a phase-error group delay of up to 90 degrees at 20kHz. The brickwall filters used in all 44.1kHz-sampling-rate CD players and DACs causes this phase error. It is in this phase error, dictated by the low sampling rate, most of the blame for the harsh, two-dimensional, "digital" nature of the reproduced sound can be attributed.

When viewed with hindsight, the 44.1kHz recording standard is a flawed medium. But this system, when launched, taxed the affordable technological horsepower of hardware available to consumers at the time. Basically, a barely adequate sampling rate was chosen to accomplish the needed 20kHz bandwidth. With the sampling rate being so close to the needed upper-frequency bandwidth, a very steep, hence brickwall, filter is needed to block any ultrasonic noise from being reproduced. Unfortunately, the steepness of the filter brings inherent distortions, namely ringing on transients and the aforementioned phase distortion.

The Taddeo solution

Taddeo Loudspeaker Company designer Tony Taddeo believes he has a cure. The Digital Antidote Two starts by splitting the analog output of any CD player or DAC into two full-signal feeds. It delays one of the feeds by approximately 16 microseconds, and then sums this delayed feed with the unaltered feed. What this is said to accomplish is the addition of a sampling point between the two existing sampling points in the direct feed. This averaged-in sampling point is claimed to reduce the phase error and also increase amplitude resolution. (Taddeo claims an increase to 16 3/4 bits of usable resolution.) The original Antidote used a delay of 22 microseconds, the width of the sampling pulse, which gave this unit a slightly better phase response. Unfortunately, this gives us a roll-off in response at just over 11kHz. In the Antidote II, the delayed feed is reduced to 16 microseconds, sacrificing a bit of resolution but gaining a response roll-off beginning around 15kHz.

The arrival of the Digital Antidote Two is accompanied by some very heady claims from the manufacturer: that the output of a CD played through the Antidote Two will sound slightly better than a 24/96 DVD or 50kHz-bandwidth SACD. Also claimed is that the output of 24/96 software or 50kHz-bandwidth SACD, when played through a Digital Antidote II, will sound slightly better than 24/192 or 100kHz bandwidth. Now, the issue of proper phase integration, along with absolute polarity, is still hotly contested in audio circles. Our instruments tell us there certainly is phase distortion going on in present-day digital. What we still don’t know is how susceptible the human ear is to these distortions. Indeed, we don’t even know how the ear correlates phase information at these frequencies.


My main audio system is housed in a dedicated room whose dimensions are 25'L x 14.5'W x 7. 5'H. An Enlightened Audio Designs T-1000 transport feeds Camelot Technology's Dragon Pro-2 Mk. I (for jitter reduction and resolution enhancement). Next is the Theta DS Pro Gen. III D/A converter, which in turn feeds a Balanced Audio Technology VK-3i preamp. The Bryston 4B-ST holds down amplification duty. The Bryston admirably powers a pair of Vandersteen 3A Signature loudspeakers. A pair of Vandersteen 2W-Q subwoofers augments the speakers. Cables are generally handled by a system-wide use of MIT: MIT MI 330 Proline Terminator Balanced, MIT Digital Reference, MIT-330, MIT-MH-750 BI-Wire, MIT-MH 750 Plus, MIT-Z Cord II. Also in use are Kimber KCAG, Altis Ultimate AT&T glass-fiber, and van den Hul The First cables. Acoustic treatment consists of an assortment of ASC Tube Traps and Flat Traps. I also use an assortment of Sorbothane pucks and machined cones.

My budget home-theater system consists of five Anthony Gallo Acoustics Micros with two M-1 passive woofers, also called Bassballs. The front-end consists of a Denon DVD-1500 DVD player feeding a JVC 778-VBK receiver. Viewing source is via a Proscan PS35122 35" direct-view monitor. As this is our living room, that’s it for the equipment list. My wife "just wanted some music up here," so I snuck in five speakers and a DVD player. Perfect!


For the first real listening session with the Antidote II, I assembled many of the, shall we say, less than Perfect Sound Forever discs in my collection. While I certainly did not enter this review expecting to be swept away with Beautiful Sound for the Time Being, I was taken aback by the degree of subtle change in sound. In the treble region, there was at times a just-detectable softening overall, not to the degree of reducing top-end air or life in a recording, though. And this was certainly not to the extent some scribes have mentioned of any predictable roll-off of the high frequencies. Taddeo's adjustment in the amount of delay, from 22 microseconds to 16, seems to have eliminated any perceptible roll off.

Take two on the Digital Antidote Two

I auditioned the Taddeo Digital Antidote Two in two separate systems over the course of a month. The unit was first installed in my main system (sans my Wilson X-1 Grand SLAMMs, which are in for an upgrade) using a pair of NHT 3.3 speakers, with Rowland and Coda electronics. The Antidote Two was placed between the preamp and my DVD player via RCA connections. A second set of outputs on the DVD player bypassed the Digital Antidote Two, being fed directly to the preamp, which enabled direct A/B comparisons (the Coda preamp allows for input switching by remote control). A second system was also brought into service through the kindness of my audio buddy, Joey Clark. His system, which I’m very familiar with, includes Audio Research electronics and Wilson Watt/Puppy speakers.

My initial methodology was simply to insert the Taddeo device into my rig and listen for a week or so. I must say that I was having a hard time identifying a difference in the sound of my system with the inclusion of the Digital Antidote Two. There was definitely not a night-and-day difference happening. This caused some distress on my part because everything causes some change to the sound! It took repeated A/B comparisons to detect what was going on. Once identified, though, it was easy to duplicate in both systems. A total dissection of the audible spectrum was required to pin it down.

Simply put, a slight improvement was wrought in the bass to midbass region. A general tightening to notes made bass lines easier to differentiate. It was as if this specific region was cleaned up, which offered more apparent resolution to the music. The strange thing (at least to me) was that nothing else was affected. The rest of the frequency range, soundstaging, noise, and dynamics just to name a few areas, remained the same. Without listening to music with a bass guitar or similar instrument, it was impossible for me to detect a change. Béla Fleck & The Flecktones' Flight Of The Cosmic Hippo [Warner Bros. 9 2656-2] provides ample example of the phenomena. The title track showcases Victor Lemonte Wooten’s abilities and clearly illustrates the Digital Antidote doing its thing. Notes that were a little blurred seemed clearly delineated and strong. The bass sounded at once more vibrant and energetic. The attack and decay of drum whacks also benefited notably with more jump in the music. I must reiterate that my observations were totally dependent on the musical selections I used. The Béla Fleck disc showed a clear improvement, various others showed none.

More so than most components I’ve auditioned, the Taddeo Digital Antidote Two has one identifiable characteristic, though it took me some time to detect it. Home audition in your system is advised to determine if the change in bass character is noticeable and/or important. For me it was very subtle and took focused listening in an A/B format to identify. As with most things audio, system synergy is the rule. In another system, the problems the Antidote Two claims to cure may produce a far greater impact.

...Jeff Fritz

Next I decided to get serious and bring on the good stuff: software both demanding in system resolution and balance in the upper octaves. One of my favorite discs musically, and a wonderful disc with which to test upper-frequency balance, is the Handel Water Musick with Nicholas McGegan and the Philharmonia Baroque Orchestra [Harmonia Mundi HMU 907010]. This disc, recorded with period instruments, can go a bit over the top in an unbalanced system. But played back on a system that holds the upper frequencies together, it is glorious in the amount of delicate recorded acoustic captured. Another disc played during this session was Passage, featuring the Empire Brass Quintet [Telarc-CD-80355]. This disc will swamp your room in a huge recorded ambient envelope, while also having some of the best brass sound ever put to digits. With the Water Musick disc, the Digital Antidote Two seemed to help my system exhibit ever so slightly better articulation when the strings got busy, while also receding the soundstage slightly behind the plane of the speakers. With the Passage disc, there did seem to be an increase in the upper-octave resolution of the horns, but this was accompanied by a slight reduction in the wonderful ambient envelope this disc projects.

I single these two discs out because they seemed to show the most differing presentation when used with the Digital Antidote II. While I say "most differing presentation," I must also add a caveat. I spent a whole night listening to these discs and never really felt confident in my ability to discern these differences. I found myself straining, to the extent of distraction, to discern any repeatable effect the Digital Antidote Two had on the presentation.

I then decided to try a different approach by using some moderately well-recorded commercial discs featuring female vocals. I put on The Judds' River of Time [CURB 9595-2-R], and listened to "Young Love" and "Sleepness Nights." (I confess to being a sucker for heart-tugging ballads; I’m also quite smitten with Mama Judd.) In "Sleepless Nights," there is a point in the refrain ("…please let it be…") where the mother/daughter team's harmony seams to beat against each other. This effect seemed just a bit easier to follow, and still resolve both voices individually, with the Digital Antidote Two in the playback chain. Once again, though, I found myself straining to hear this effect. We have all had this experience at one time where the harder you concentrate, the less you hear. I found I could keep this level of concentration up for only an hour or so each night before dropping the critical façade and just playing some music.

Perplexed at this situation, I then decided to try the Taddeo unit in a different system. Inserting the Digital Antidote Two in my low-budget home-theater system, once again I was hoping for a reduction in upper-midrange roughness inherent in this collection of components. The Digital Antidote Two did seem to have a more pronounced effect on the more modest system. Once again, though, the change was very subtle. Throughout the review period, the only repeatable phenomenon observed was in imaging. Specifically, most well-centered female vocals seem to widen, or bloom, just a bit more between the speakers, this without being pushed forward in the mix.


Subtle seems to be the opportune term to describe the effect of the Taddeo Digital Antidote Two in my systems. Therefore, I'll keep my conclusion to this review short and sweet. I suggest that anyone contemplating the purchase of any digital band-aid on the market to demand a home audition. As I most certainly do not have your systems, both audio and value, your mileage just may vary from mine with the Taddeo Digital Antidote Two.

...Jon Gale

Taddeo Digital Antidote Two
$995 USD.
Warranty: Two years parts and labor.

Taddeo Loudspeaker Company
2604 Elmwood Ave., Suite 105
Rochester NY 14618
Phone: (716) 473-9076
Fax: (716) 244-4106

Website: www.taddeo-loudspeaker.com

Taddeo responds:

In activities such as sports or playing a musical instrument, there is a degree of skill and associated learning curve involved. So too it is with listening to music. In fact, this is half the battle when first learning to play a musical instrument.

I mention this because I see a trend developing. Before our recent advertising campaign, most of our customers were musicians, analog listeners or people who listened to a lot of live music. They typically thought that the improvement wrought by the Digital Antidote Two was dramatic. Since implementing our advertising program, we are increasingly seeing more mainstream audiophiles whose main source of listening is CD. This group tends to find the effect of the Digital Antidote Two somewhat subtle. This is to be expected, as any normal human being is going to have his musical ear get a bit rusty from listening to CD. Younger audiophiles having never heard analog will never have developed a good ear. Perhaps this is why there are so few of them.

If you are listening to CD, you are not listening to music; you are listening to a semblance of music. Don't worry, the learning curve to regaining and developing a musical ear is relatively short one. If you have gravitated to this hobby, you almost certainly have a potentially good musical ear. You just have to develop it. The new digital formats will accomplish this. Analog would do the same thing, but asking an audiophile to play records is like asking him to replace the electric starter in his car with a hand crank. You would also do this with a Digital Antidote Two, but as we have a money-back guarantee, we don't want and can't afford to be a lending library for impatient audiophiles. Instead, I would recommend that those audiophiles with DVD players purchase some 24/96 discs from Chesky or Classic Records. Even from the analog outputs of a cheap DVD player, a 24/96 signal will be superior to the best $20,000 CD player. Classical music is the best for developing your ear; just play it as background music for a few weeks on a daily basis. Your subconscious mind will soon develop your ear and your CD player will begin to sound bad. Then come see us about a Digital Antidote Two.

OK. Now about the review. First, both Jon Gale and Jeff Fritz are nice people and wrote an honest review about what they heard. I think they are also very representative of the typical mainstream audiophile. They heard most of the right things, but they were subtle. Actually, they are not subtle. The phase-shift curve included by the Digital Antidote Two is easily measured and not a subtle amount. You might or might not like it, but you should be able to readily hear it. I think the improvement in square-wave performance by the Digital Antidote Two is absolute proof that its effects are positive.

Jon stated that the effects of phase distortion are not known. This is not true. Phase distortion affects sound in two ways relative to music. First is sound localization. In fact, most of the "pseudo 3D sound systems" that tried to get 3D sound from stereo made extensive use of phase manipulations. To audiophiles, this translates into imaging and soundstaging. Because we use this aspect of phase for navigation for everyday life, it is probably readily audible by any audiophile. The second aspect of phase distortion is tonal fidelity. Going back to the 1930s, Bell Labs tested for phase distortion. For the most part, they tested with very large amounts of phase distortion, as this is typical of telephone lines, which was their main concern. Their findings were that phase distortion had minimal effect on intelligibility, but did affect tone. With telephones, intelligibility is number one. With music, tonality is number one. Many musical special-effects devices purposefully use phase distortion to alter the sound.

Two instruments -- say, a violin and a piano -- can play the same musical note -- for example, 1000Hz at the same volume. The two sounds when viewed on an oscilloscope are both basically sinewaves, but each has its own pattern of overtones or little sinewaves riding on it. If you go to our website, you will see a 1000Hz square wave from a CD player. A CD player will distort the signals from the violin or piano just as it does the square-wave signal. This is why a 1000Hz square wave has been a standard test signal for the last half century. If this were 1970 and some audio magazine were to publish a square wave like the one produced by a CD player in a review of a phonograph cartridge, technicians all over the country would be rolling around on the floor laughing.

Now we are going to talk about filters for a second. Sorry to take so much of your time with this, but it is important, and there is so much misinformation. Your digital front-end probably represents you last large audio expenditure. My suggestion about listening to 24/96 DVD to develop your ear will also pay dividends when you buy your new-format player.

This is how the filter chain works. First, at the recording studio, the signal must be brick-wall filtered before it can be stored in the digital medium. The medium cannot store information above 44kHz, so all information above must be eliminated. Unfortunately, this causes the upper octaves of the information to be phase distorted. The information is now stored on CD. When you play your CD, it must go through another filter called the anti-aliasing filter. In early CD players, this filter added a tad more distortion. Modern CD players use oversampling, which pretty much eliminates this source of distortion. Upsampling is just another form of oversampling and has the same effect. Some new CD players don't use any filter at all. But the filter in your CD player, be it oversampling, upsampling or none at all, is not going to have much impact, as the real problem was way back at the head of the chain -- when the information was brick-wall filtered. Modern recording equipment uses oversampling filters (AD converters) back at the recording end. This does help a tad. It sort of breaks the first filter into two component filters -- the information filter and the electronic filter. The electronic-filter component is oversampling and now distortionless. The filter formed by the information itself has to remain at 44kHz as the system cannot hold information above this frequency. The inherent brick-wall filter and inherent phase distortion remain.

With the Digital Antidote Two technology, we have quantified this distortion and implemented a corrective curve in the analog domain. Total correction would unfortunately cut too deeply into frequency response. The amount of correction is about enough to bring a CD to about the same performance of a 96kHz sampling rate. In a 96kHz system, the audio signal is the first 20kHz where the system is reasonably phase linear, but not perfect. If you play a 24/96 disc through a Digital Antidote Two, the applied phase correction will get it about perfect.

Jon also talked about the changes we have made in the latest version. These exploits the inherent advantage in the active version over the early passive version. With the active version, the delay line can be peaked or made frequency-variable to achieve a more ideal phase-correction curve.

One last point. The Digital Antidote Two is not a band-aid. Like most small audio manufacturers, I do have a lot of my heart and soul in this product. The phase distortion is the only readily scientifically measurable distortion in CD. Multinational companies had to resort to a whole new medium to solve the problem. A small, little-known high-end company managed to achieve the same solution with the existing CD format. From this perspective, the Digital Antidote Two may well be the most innovative piece of audio technology to ever grace an audio system. By the way, the technology is not simply proprietary; it is patented.

SoundStage! editor Marc Mickelson has assured me that there will be a follow-up review by someone with an "in shape" musical ear. I welcome this and feel most readers will find the contrast most interesting and informative. I would love to see the shortcomings of the CD be the topic of a major exposé. The bulk of two decades of our musical heritage is forever trapped in this substandard format. While it may well have been the state-of-the-art technology for a consumer product, the recording industry should have had the foresight to archive in analog or a high-sampling-rate medium. There is no excuse for not doing this, and someone should be held accountable.

Tony Taddeo
Taddeo Loudspeaker Company

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