Thiel Model 04 loudspeaker
The Thiel Model 04 is unusual in appearance, as are most systems where time alignment has been attempted. The fact that time alignment itself has never been conclusively proven to matter one way or the other is probably irrelevant; better to be safe, and time align, than not to and risk the possibility that the sound might be degraded [but see "Sidebar"—Ed]).
I was interested to note that these speakers use bass-reflex loading for the woofer. That particular woofer loading system has endured more than 20 years of audiophile scorn, scorn occasioned by the one-note boom common to most early examples of the technique. Bass-reflex loading is now getting a second look from a number of designers seeking ways to wring the best bass from an enclosure of limited size. And theory has always held that a properly designed, properly damped reflex system need not produce boomy low end.
I had not been convinced of this. We've had several reflexed systems in-house recently, and every last one of them had more low-end hangover than the non-reflexed, sealed-box systems we've heard in past years. The Thiel is an exception.
First of all, I must report that the Thiel 04 has a serious problem—one whose magnitude is such that I am amazed the manufacturer has not picked it up and remedied it, because it is very easily remedied. On certain bass notes, the intensity of the breeze emanating from the reflex port is such that it flaps the grille cloth, causing a most irksome rattle. I was able to fix this by placing two small buttons of Plasticene (permanently soft modeling clay) on opposite sides of the reflex port hole, between it and the grille cloth. However, the result—two small bumps on the front surface—was not engaging in appearance. Thiel could use some kind of adhesive, and I cannot advise them too strongly to do that, because without it the speaker is unworthy of serious consideration. Bear in mind, then, that the balance of this report refers to the 04's sound after the grille flap was suppressed.
So saying, I can now proceed to declare that this is one of the most musically natural-sounding systems I have heard, combining warmth and richness with a high degree of detail and definition through most of the audio range. Its errors are almost entirely those of omission, which are much easier to live with than things which are there but shouldn't be.
The system is a shade on the "polite" side, both in terms of bite and apparent power, and there is a slight veil over everything, at least in comparison with the most detailed systems I have heard. Despite its modest size (and assumed input-power limitation), however, the Thiel 04 can make a grand and glorious noise, reproducing orchestral tutti at surprising levels without strain. It will not reproduce symphonic music at row-A type levels (except in a small, bright room), but will easily generate the loudest sounds one is likely to hear from a mid-hall seat at a live concert. When overloaded, the system tells you so in no uncertain terms. The woofer lets loose with a startling BLATT, which one would have to be stoned or aurally impaired t‡ ignore. If you require your music loud enough to make interpersonal communication almost impossible, this isn't the speaker of choice.
Imaging is very good but not fantastic. Despite the obvious care that went into minimizing enclosure edge diffraction, there is a moderate amount of vertical-venetian-blind effect, which impairs the uniformity of the image as one moves across the listening area, rather than the stability of the image.
Bass/treble balance is just about perfect, and in terms of perspective the 04s are as close to being absolutely neutral as any system I have heard, neither backing things off nor bringing them forward. On top of that (pun intended), the speaker's high end is gorgeously smooth and sweet, albeit a little softish. Nonetheless, the sound is remarkably real and alive, with none of the aggressive middle-range colorations or hardness that one tends to find in systems having this degree of reach-out-and-touch-someone immediacy.
Instrumental timbres are very well-rendered, allowing (for example) one to hear the wooden body of the viola as well as its strings, or to distinguish easily between a wooden flute and a metal one. One acid test is the violin in Sheffield's Strauss and Dvorák album; with these speakers it sounds not steely-hard (as is common), but like what it actually was: a brilliantly toned fiddle.
The above attributes aren't bad for starters, but it is the 04's low end that really makes one sit up and take notice. No one would pretend that $640 is cheap for a pair of loudspeakers, or that a system of this price should not be able to deliver respectable low end. But when we consider the size of the 04's woofer (the same size as the midrange driver in many systems) and of its enclosure, the bottom end performance of this system seems out of place! Bass drum, double bass, and all but the lowest pipes of an organ come blasting through with the kind of floor shaking authority I have come to take for granted from 12" woofers but certainly not from 6-inchers. This is another one of those cases where subjectivity conflicts with objectivity, because while the 04's measured low end is broadly humped at 50Hz and falls off rapidly below that (fig.1), it sounds virtually flat to below 40Hz. And there is not a trace of that one-note drumminess that has so long been considered an earmark of reflex loading.
Fig.1 Thiel 04, frequency response, note similarity to Quad ESL below 300Hz.
It is only in bass detail where the Thiel 04 must yield to a lot of other systems. The melodic bass line is easily discernible, but some of the gutsiness of the bass—the thrummm of a bowed bass string, the leather throated roar of diapason organ pipes—is glossed over, leaving pitch and impact but little texture at the bottom.
Now that I have complained, I should state that I really like the sound of these speakers. They are a pleasure to listen to, largely because they obtrude less than most speakers, and reproduce the essence of musical sound as only a handful of other systems I have heard, including some embarrassingly expensive ones. Unfortunately, the potential naturalnes s of the 04's sound is, like a butterfly's wing, a delicate thing, readily lost through mismatching with colored ancillaries or the use of fotzed-up program material. The RCA and CBS recordings that earned those companies an audiophile's derision sound painfully gimmicked, and the system's unusual musicality can go right down the drain through a bad choice of associated electronics.
Thiel recommends Conrad-Johnson's massive Premier One [monoblock] as the driving amplifier of choice, but even if anyone was so wacko as to consider mating a $4350 amplifier with a $640 pair of speakers, I find the speaker better married to good solid-state electronics than to tubes. The things that most tubed amplifiers do—softening of high end and warming up the overall sound—can only detract from the performance of a speaker whose musicality is already right on the hump, so to speak. The same goes for preamplifiers and phono units. The 04s do not need compensatory anything, so feed them the most neutral signal you can find. And that kind of associated equipment is hard to find in a modest price range.
A final note: the 04's slightly restricted output-level capability (estimatd at around 95dB, since our IVIE analyzer/SPL meter is on the fritz) could prove to be a liability for a listener who plans to "go digital," or who already uses the wide-range material available on analog disc (in Vol.5 No.10 we checked sources and found the Telarc analog/digital LP of The Flying Dutchman Overture to have a wider dynamic range than our most dynamic CD). While none of the compact discs from CBS, DG or Decca have challenged the dynamic range of most speakers, CDs from the audiophile record companies may be a different story with, perhaps, an unhappy ending for many music listeners.
Many of us do not live where we can take advantage of unrestricted dynamic-range sound reproduction—there are such things as noise ordinances—but for those of us who can, the maximum volume capability of a loudspeaker we are thinking of buying is a more serious consideration these days than it ever was. If your listening-level requirements are not all that high, the Thiel 04 is worth more than just serious consideration. Just make sure the grille cloths are anchored next to the reflex ports.