The major departure from conventional design here is the system's unique directional characteristics, with most of the sound coming from eight rear-facing speakers and the rest from a single front-facing speaker. According to Dr. Bose's literature, this was done to simulate the conditions in a concert hall, where measurements have shown that only about 11% of the sound reaching a listener is direct sound, coming straight from the instruments, while the rest is reverberant energy,…
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Now, let's consider for a moment some of the basic premises on which Dr. Bose based the design of the 901.
This is what the Bose 901 does, on a small scale. Fig.2 shows the paths of sound waves coming from a left-channel 901. A listener hears not only the front-facing speaker A, but also the right-rear reflection B and the left-rear reflection C which, bouncing from the side wall, effectively spreads the source of reflections beyond the limit of the rear wall and partway around the side wall. The reduced output from the front speaker (11% of the total) prevents it from dominating the entire sound "stage" and thus contracting the apparent radiating area to a small point. And since the distance…
There are two other things about the design of the 901 that we question, too. One of these is the use of electrical equalization to compensate for deficiencies in the speakers at the high and low ends of the audio range. Equalization of this kind is fine, of course, if only a small amount is needed to add the last nth degree of perfection (?) to a system, and if the loudspeakers can take it without swapping extended range for increased distortion. What bothers us about the 901, though, is the amountof compensatory boost that has been used, rather than the fact that it is used at all.
The…
Sidebar 1: Specifications
Description: Moving-coil loudspeaker housing 9 full-range 4"-cone drivers arranged for 11% direct-radiated and 89% reflected sound. Supplied with variable active equalizer consolette. Nominal impedance: 8 ohms.
Price: $476/pair.
Manufacturer: Bose Corporation, 1 Strathmore Rd., Natick, MA 01760 (1971). Bose Corporation, Mountain Road, Framingham, MA. Tel: (800) WWW-BOSE (999-2673). Fax: (508) 820-3465. Web: www.bose.com (2001).
Sidebar 2: Manufacturer's Comments
Our technical analysis of the theory behind the 901 differs from Stereophile's in a number of respects. Since the final test of a speaker is in its sound with actual program material, we urge Stereophile readers to audition the Bose 901 and then judge for themselves whether Stereophile or the 15 other US and foreign reviews, which draw completely different conclusions, is correct.—Bose
GUY CLARK: Keepers
Sugar Hill SHCD-1055 (CD). 1997. Guy Clark, prod.; Miles Wilkinson, prod., eng.; Johnny Rosen, eng. AAD? TT: 64:45
Performance ****½
Sonics *****
Sugar Hill SHCD-1055 (CD). 1997. Guy Clark, prod.; Miles Wilkinson, prod., eng.; Johnny Rosen, eng. AAD? TT: 64:45
Performance ****½
Sonics *****
In the past 25 years two men have come to quietly dominate the Texas Troubador tradition begun by Lefty Frizzell, Ernest Tubb, and Willie Nelson: Guy Clark and Townes Van Zandt. Unlike Frizzell, Tubb, or even Nelson, both Clark and Van Zandt began in the late '60s and were influenced not by Bob Wills or Hank Williams but by Bob Dylan, Joni Mitchell, and the Beatles. In their hands, what was essentially a rural,…
I couldn't believe it. Something was off.
I had just spent more than 200 hours playing my system 24 hours a day in order to break in some new Bybee devices in my speakers. During the same period I'd switched power regenerators, installed better-grade electrical outlets, and finally replaced my dedicated line's fuse box with a circuit breaker. I'd even installed audiophile-grade fuses in my tube amp and DAC.
The break-in period sorely tested the patience of my spouse, who detests the sight of all the silvery cables that hold the system together. Sound carries everywhere in our…
"More power!!!"
If you're thinking you've just heard the war cry of Tim "The Tool Man" Taylor, from TV's long-running sitcom Home Improvement, you'd be...wrong. No, that was Luke "The Tube Man" Manley, from high-end audio's long-running manufacturer VTL, and he's trying to convince me that, when it comes to amplifier power, more is definitely more.
"One ST-85 is fine when you're driving these Joseph Audio RM-7si's, and probably with the Thiel CS.5s, but I think those NHT 2.5i's would work better with two."
"Maybe so, Luke, but how's about I go with just one amplifier for…
Inside, it's a classic "keep it simple" VTL design, using a pair of EL34 output tubes per side in a tetrode configuration (footnote 1). (Unlike some of the higher-priced and -powered VTL models, the ST-85 can't be switched into triode mode.) Four 12AT7s wrap up the tube complement.
The output transformers aren't the Signature models found in VTL's higher-priced amplifiers, but they're similar (though simpler) in winding layout and construction—and, of course, smaller. Removing the metal cage that protects you from the tubes (and vice versa), one finds bias-measurement points and trim…
Double or nothing
Mr. Tube Man paid another visit, and brought a second ST-85—just as he'd promised. We hooked them up so that one handled the midrange and tweeter for both NHT 2.5i speakers, the other the bass. Doing it that way, instead of giving each speaker its own amplifier, made it easy to compare the performance of one to two—a couple of quick changes at each speaker was all it took. Luke listened for a bit, nodded his approval, and headed back home.
Mr. Tube Man paid another visit, and brought a second ST-85—just as he'd promised. We hooked them up so that one handled the midrange and tweeter for both NHT 2.5i speakers, the other the bass. Doing it that way, instead of giving each speaker its own amplifier, made it easy to compare the performance of one to two—a couple of quick changes at each speaker was all it took. Luke listened for a bit, nodded his approval, and headed back home.
It wasn't long before, to my surprise, I was nodding in the affirmative as well. I didn't expect much of a change—perhaps more…