Description: Three-way, floorstanding, reflex-loaded loudspeaker with double-walled enclosure, milled and enameled aluminum front panel. Drive-units: 5" by 1" ribbon tweeter, two 5.5" (140mm) magnesium-cone midrange units, two 9.5" (245mm) paper-cone woofers. Crossover frequencies: 180Hz, 1.8kHz. Crossover filters: second-order Linkwitz-Riley. Frequency response: 32Hz-28kHz, ±3dB. Power rating: 400W. Impedance: 4 ohms nominal, 3 ohms minimum. Sensitivity: 90dB/W(2.83V)/m.
Dimensions: 58.3" (1495mm) H by 12.1" (310mm) W by 24.2" (620mm) D. Weight: 220 lbs (…
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Sidebar 1: Specifications
Sidebar 2: Dieter Burmester chats with Larry Greenhill
Larry Greenhill: When did you start building audio products?
Dieter Burmester: I have been an audiophile and musician since age 14. I played guitar in clubs every weekend and later studied electronics at the university. After my education, I went into business making electronic sensors for medical diagnostic systems that ran automated blood tests. I owned Quad electrostatics driven by a Quad 22 amplifier. The amplifiers broke often because the tubes didn't last.
I decided to build my own amplifier in 1977, using the…
Sidebar 3: Associated Equipment
Analog source: Linn Sondek LP12 turntable with Lingo power supply and Ittok tonearm, Spectral moving-coil cartridge.
Digital sources: Krell KRC-28 CD transport, Sony SCD-C555ES multichannel SACD player.
FM tuners: Day-Sequerra FM Reference Classic, Rotel RH-10, Magnum Dynalab MD-102 with 205 Sleuth RF amplifier, Fanfare FT-1A.
Preamplifiers: Krell KCT, Sony TA-P9000ES, Mark Levinson ML 7A with L-2 phono section, Conrad-Johnson Premier 18LS, Margulis and Duntech MX 10 MC phono preamplifiers.
Power amplifiers: Mark Levinson No.334, Krell FPB 600C…
Sidebar 4: Measurements
Stereophile's reviewers seem to be currently enamored of large, heavy loudspeakers. As with the 270-lb B&W Signature 800 that Kalman Rubinson reviews elsewhere in this issue, it was not possible for me to lift the 220-lb Burmester B99 off the ground for the acoustic measurements. As a result, there was an unavoidable "floor bounce" of the speaker's output that contributed some visible roughness to some of the frequency-response graphs.
I must also comment on the "thinking out of the box" that led Burmester to place the terminals in a recess on the…
The B99's dispersion in the vertical plane (fig.5) features a sharp notch at the upper crossover frequency for standing listeners, but the response doesn't change significantly as long as the speaker is auditioned on an axis between the centers of the two midrange units. (Ignore the smooth rise above 15kHz in the second trace from the bottom, which I believe is due to an averaging error when I took the measurement: I measure outdoors, and minuscule differences in path length due to slight breezes can lead to such errors.) At extreme off-axis vertical angles, the ribbon's output is well-…
Everyone knows the story: Isaac Newton got hit on the head by an apple and suddenly discovered the physics of gravitation. Like the one about Archimedes discovering the basics of hydrostatics while taking a bath, this story turns up everywhere. Even Michael Stipe, in R.E.M.'s "Man in the Moon," sings "Newton got beaned by the apple good."
Trouble is, these stories are all wrong. Now, there are few things uglier than an academic who complains that the general population knows little about this or that esoteric subject, so I'll complain only once: I would love it if the world cared as much…
One of the challenges I faced in optimizing the performance of the Thiel CS7.2 loudspeakers that I reviewed in February 2000 was controlling and tuning their interaction with my listening room. Intuition, experience, trial and error—all came into play, as did several of the procedures and calculations covered by Jonathan Scull in his "Fine Tunes" column.
I even had expert guidance—in the form of visits from Bruce Brisson and Joe Abrams of MIT, and Art Noxon of Acoustic Sciences Corporation (ASC), who led me through a two-step process. First, we concentrated on getting smooth overall…
The sonic effects were more subtle than the measurements would suggest, but still noticeable. The Thiels had had excellent focus and precision before; with the room treatment, they became truly extraordinary. The same was true of their pure, uncolored sound: outstanding before, truly exceptional in the treated room.
The second part of the process—expanding the soundstage's width and depth, and adding ambience by incorporating reflected information—was accomplished by a systematic process of rotating the Tube Traps to expose their reflective sides. This was done in stages—first the…
Joan Manes wrote about Tube Traps in January 1997 (Vol.20 No.1):
You have to draw the line somewhere. I drew mine at the front door.
I have spent many years as an audio spouse. I know that it's the sound that matters. I accept that our living room will be filled with all sorts of absolutely essential pieces of equipment, large and small, and that new pieces will appear out of nowhere. (Surely that black box squatting in the corner wasn't there when I looked 10 minutes ago?) Like hangers and paper clips, audio equipment reproduces spontaneously. The difference is that audio…
You can bet Infinity plans on selling a respectable number of $8000/pair Prelude MTS speakers (reviewed in the May 2000 Stereophile) over this ambitious, full-range design's anticipated lifespan. But will the company make enough money to recoup the megabucks spent on researching, designing, and developing the all-new CMMD (Ceramic Metal Matrix Diaphragm) drivers, BASH (Bridge Amplifier Switching Hybrid) powered subwoofer, and RABOS (Room Adaptive Bass Optimization System) bass-equalization system? NOWAY (Never Over-Estimate What Acronyms Yield).
Part of Infinity's grand…