Also noteworthy is the…
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Needless to say, no record mat of any kind should be used with the Ovation. The insertion of any type of mat only serves to break the coupling between platter and record. To improve that coupling, a record clamp is provided. It fits over the spindle and allows the application of considerable pressure to the record—at least over the label area. Though quite effective with flat or slightly convex records, it is unable to keep the entire surface area of a dished record in contact with the platter. This is where a vacuum holddown system has a significant edge.
The second problem was of VTA adjustment. Because of the thickness of the Ovation's platter, I had to operate the Graham arm at its maximum VTA elevation, which meant that I didn't have enough range to experiment in with some records. What I needed was a 0.25" shim that would fit right under the arm's SME base plate so as to elevate the base of the arm relative to the surface of the platter. Basis Audio was kind enough to make such a shim for me; I'm told that it's now available to any customer contemplating a Basis/Graham marriage (footnote 4).
Sonic impressions
The vibrational…
Sidebar: Specifications
Description: Belt-driven LP turntable. Speeds: 331/3, 45rpm. Wow & flutter at 331/3: 0.02% DIN standard. Rumble: –90dB DIN Standard. Speed accuracy: ±0.02%.
Dimensions: 23" W by 16.5" D by 5.25" H. Weight: 70 lbs.
Serial number of sample tested: 0891067.
Price: $4395 (1993); no longer available (2006). Approximate number of dealers: not disclosed.
Manufacturer: Basis Audio, Inc., Nashua, NH (1993); 26 Clinton Drive #116, Hollis, NH 03049. Tel: (603) 889-4776. Fax: (603) 889-5402. Web: www.basisaudio.com.
"The large peak at 16kHz reported by Stereophile...was nowhere in evidence...The most probable explanation of this discrepancy is that the [Waveform supertweeter's] very light ribbon depends on the air load for damping, and that load is much smaller in the thin air up there at 7000' in Santa Fe than at altitudes where less lightheaded and scientifically more accountable reviewers dwell." Thus spake Peter Aczel (footnote 1), erstwhile loudspeaker designer and Editor/Publisher of the reincarnated The Audio Critic, a publication that advertises itself as having "unusual credibility among the top…
Postscript: Further Experiments (previously unpublished)
A 1991 trip to Atlanta and Washington DC gave me the opportunity to measure loudspeaker systems both in Santa Fe and at sea level. I took along with me the magazine's MLSSA system, mounted in a Compaq 286 transportable computer, EAR microphone preamplifier, DPA 4006 microphone, and a pair of small loudspeakers, these Wharfedale Diamond IVs on loan for review. (The review appeared in the July 1991 issue of Stereophile.) I would have liked to take a pair of panel speakers with me also, but it wasn't logistically possible to take more…
A science-fiction parable I read too many years ago to remember who wrote it used the image of a glass jar stuffed with colored plastic spheres. The story's protagonist was asked whether the glass was full. "Of course," was his reply, whereupon a hidden faucet was turned, the jar filled up with water, and fish swam in the spaces between the balls.
The high-end loudspeaker industry reminds me of that story. Given the literally hundreds of manufacturers in existence, each offering audiophiles a more or less complete line of speakers at every possible price point, how could there be…
It took me quite a while to find the best positions for the Model 88s in my room, which, at around 3000ft3, is somewhat smaller than Focus recommends. The entire bass range, while clean-sounding, was generally elevated above the midband level; if the bass was not to sound too boomy, the speakers needed to be farther away from room boundaries than the B&W Silver Signatures that usually fill my room with sound. And even then, it was essential to use the spikes to preserve the low-frequency definition. (While the Focus 88 has two sets of speaker terminals for bi-wiring or bi-amping, it is…
Sidebar 1: Specifications
Description: Three-way, floorstanding, reflex-loaded loudspeaker. Drive-units: 11" (280mm) Nomex/Kevlar-cone woofer, 7" (178mm) Nomex/Kevlar-cone midrange unit, 1" soft-dome tweeter. Measured crossover frequencies: 180Hz, 2kHz. Frequency response: 22Hz-25kHz, ±3dB. Sensitivity: 89dB/W/m. Nominal impedance: 6 ohms. Amplifier requirements: 200W recommended.
Finish: black piano lacquer.
Dimensions: 38" (965mm) H by 9" (229mm) W by 24" (610mm) D. Weight: 120 lbs (54.5kg) each.
Serial numbers of units tested: 48L/R (first samples), 88L/R (second samples).…
Sidebar 2: System Context
The Focus 88s were positioned some 2' from the rear wall of my room (which is faced with books and LPs) and approximately 5' from the side walls (which also have bookshelves covering some of their surfaces). This placed the midrange units well out in the room. The woofers were on the outside edges, the tweeters on the inside. The amplifiers used were either a Pass Labs Aleph 3 or a Mark Levinson No.332. The preamplifier was the remote-controlled Mark Levinson No.38S, with a Mod Squad Phono Drive EPS used to amplify LP signals from a Linn Sondek/Cirkus/Trampolin/…
Sidebar 3: Measurements
With an estimated B-weighted sensitivity of 88dB/2.83V/m, the Signature 88 will play quite loud with only a few amplifier watts. Certainly the 30W Aleph 3 had no problem raising decent sound pressure levels in my room. The impedance (fig.1), however, drops to a low 3 ohms at 65Hz, with a punishing combination of 4 ohms and -50 degrees electrical phase angle just a little lower in frequency. Although the impedance remains above an amplifier-friendly 7 ohms above 120Hz, the Model 88 still needs to be driven by a beefy amplifier. Note that the shape of the impedance…