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.
Systems
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!
Sound
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 TwoI 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
jeff@soundstage.com |
|
|
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.
Conclusion
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
jon@soundstage.com
Taddeo Digital Antidote Two
Price: $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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