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The Magnepan CC3 is a similar, small, two-way planar magnetic, but measures 36" W by 10.5" H by 5.5" D. Careful examination through the grillecloth with a high-power flashlight revealed that the CC3 is very much like an MGMC1 laid on its side and curved in the horizontal plane: The quasi-ribbon tweeter extends along the entire length of the speaker's upper edge. The curve is flattened in the very central portion of the diaphragm, but the curvature somewhat lessens the horizontal beaming one would expect from a flat MGMC1 in that orientation. The CC3 was placed, of necessity, atop the "soon to…
While the ICBM runs off a chintzy-looking wall wart, its construction and performance were serious and solid. While remaining powered up at all times, the ICBM added no perceptible hum or noise. In fact, once I'd set it up to my satisfaction, it required no further attention until I changed another component in the system.
There's little more that need be said about the ICBM. It did the job it was intended to do, and I could hear no sonic compromise while using it. It was difficult to A/B it, as I'm not sure there's any way to completely bypass all its circuits, pots, and switches.…
It didn't seem like such a big deal. After all, when designer Kevin Voecks added a passive radiator to the bottom of Revel Loudspeakers' powerful Ultima Sub 15 subwoofer, no one expected that the resulting 6dB increase in bass output below 35Hz would be so audible. However, Revel's sophisticated double-blind listening tests (described in my review of their flagship Ultima Salon full-range loudspeaker in the March 1999 Stereophile, revealed that a big change had occurred. With now twice the radiating surface, the modified Sub 15 produced significantly deeper, more powerful bass.
This…
Initial adjustments included channel identification and phase checks using the Stereophile Test CD (STPH002-2). The phase test revealed that my system's phase response was reversed with the Sub 30 connected and its Phase control set to 0 degrees. Yet this control affects only the subwoofer output, not that of the main speakers.
Next I used the Revel Low-Frequency Optimizer Test Signal CD, which Revel includes with the sub, and a RadioShack 33-2050 analog sound-level meter to measure the Sub 30's in-room response. To analyze the results in order to properly set the controls of the Sub 30…
The Sub 30 delivered bass-drum notes with authority and no trace of overhang. The deepest bass notes were produced with pitch-perfect precision, giving the low frequencies a tight, rhythmic quality. Take the furious bass-drum beats that punctuate Liberty Fanfare, from Winds of War and Peace (CD, Wilson Audiophile WCD-8823). The drum erupts into huge, gut-punching whacks. While loud and deep, these whacks were not trailed by the sustained dying notes of rich tonalities that I had heard with the Velodyne FSR-18 (see the August 1998 Stereophile, Vol.21 No.8).
Similarly, the Sub 30 handled…
Sidebar 1: Specifications
Description: Powered subwoofer with auxiliary bass radiator, built-in parametric equalizer, and optional installation software. Drive-unit: 18" ultra-rigid cone of Kevlar, pulp, and alloy composite with inverted metal dome, 15" piston diameter, 3" diameter, four-layer voice-coil, and 4.7kg magnet system. Auxiliary bass radiator: 15" metal cone. Inputs: L/R balanced (XLR), unbalanced (RCA). Line-level outputs: L/R balanced (XLR), unbalanced (RCA). High-pass filter: 30-80Hz, variable in 10Hz increments at 12 or 24dB/octave (nondefeatable). Low-pass filter: 30-80Hz…
Sidebar 2: Associated Equipment
Analog source: Linn Sondek-Lingo turntable, Linn Ittok tonearm, Spectral moving-coil cartridge.
Digital sources: Krell KRC-28 CD player, Sony SCD-C555ES multichannel SACD/CD player.
FM tuners: Day-Sequerra Classic, McIntosh MR-78, Sony ST-5000.
Preamplification: Mark Levinson ML-7 preamplifier with L3A moving-coil phono cards, Duntech MX-10 head amplifier, Margulis phono section, Krell KCT preamplifier.
Power amplifiers: Mark Levinson ML-2 monoblocks and No.334, Krell FPB 600c.
Loudspeakers: Quad ESL-989, Bohlender-Graebener Radia 520i…
It is always a matter of great interest when a difficult question, in this case the audibility of differences between amplifiers, is put to an empirical test. When the question is tested by such intelligent, knowledgeable, and unbiased investigators as John Atkinson and Will Hammond (see the July issue of Stereophile, Vol.12 No.7, p.5, the interest is even greater. Unfortunately, when the test turns out to have been flawed by errors in design and in use of statistics, as was the case here, the disappointment is also even greater.
In this article (footnote 1), we first explain the…
Our point about the proper use of chi-square is, by the way, quite well established statistically and not a matter of debate. The error made in this analysis is a very common one and is frequently singled out for discussion in statistical textbooks. For example, in his authoritative 1981 statistics text, Hays warns that "caution may be required in the application of chi-square tests to data where dependency among observations may be present, as is sometimes the case in repeated observations of the same individuals." Earlier, in his classic statistics text, McNemar (1962) pointed out that the…
Given that the results came out as they did, can we conclude that the differences between the amplifiers are not audible? That is, of course, one possible conclusion, but a null result such as this raises many questions and alternative hypotheses and is essentially uninterpretable. While a positive result points to one or to a small set of conclusions, a null result tells us very little. Anything that can mess up a study can cause a null result. It is much easier to run a flawed study than a valid one and hence very easy to get a null result. (For this reason is it virtually impossible to…