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Canton Vento Reference 1 DC loudspeaker Measurements

Sidebar 3: Measurements

My estimate of the Canton Vento Reference 1 DC's voltage sensitivity was 89.7dB(B)/2.83V/m, a little higher than the specified 88.5dB and a good 3dB higher than average. Its impedance, however, was generally on the low side, ranging mainly between 4 and 8 ohms, with a minimum value of 3.8 ohms at 29Hz (fig.1). The electrical phase angle is moderate except at infrasonic frequencies, suggesting that the speaker will be relatively easy to drive despite its lowish magnitude (and daunting appearance).

Fig.1 Canton Vento Reference 1 DC, electrical…

Linn Troika MC phono cartridge

Some six or so years ago, the Linn Asak cartridge set new standards for imaging and soundstage reproduction. I can remember the first time I heard an Asak in a system using Quad ESL-63s—I had never experienced such depth of soundstage and solidity of imaging from any system, and that with Quad amplification! The Asak was relatively quickly overshadowed in this area, however, and in any case, soundstaging precision by itself didn't seem to be a high priority for the Linn design team, who were apparently more concerned with dynamics and a musical integration of the sound across the frequency…

Linn Troika MC phono cartridge Specifications

Sidebar 1: Specifications

Specifications: Low-output moving-coil cartridge with unique three-point fixing arrangement. Recommended tracking force: 1.5–1.7gm. Stylus type: Nude Vital superelliptical.
Price: $1250 (1987); no longer available (2006). Approximate number of dealers: 100.
Manufacturer: Linn Products Ltd., Floors Road, Waterfoot, Eaglesham, Glasgow G76 0EP, Scotland. Tel: (44) (0)141-307-7777. Fax: (44) (0)141-644-4262. Web: www.linn.co.uk. US Distributor: Audiophile Systems, Indianapolis, IN (1987); Linn Products Inc., 8787 Perimeter Park Boulevard, Jacksonville, FL…

Linn Troika MC phono cartridge Measurements

Sidebar 2: Measurements

Output is about normal for a low-output 'coil (around 0.2mV at 5cm/s), and the tubed SP-10 had no noise problems. With the downforce set at 1.7gm, the Troika just failed the 70µm lateral modulation cut on the Ortofon Test Record at 78°F (it was a hot day); with the downforce increased to 1.8gm, it managed to clear the 70µm cut, but 2.1gm was needed for the maximum 80µm cut. It cleared the 50µm vertical cut at 1.7gm downforce. While not quite as surefooted as the Shure V15 V MR (others report that the Troika is less secure at lower temperatures), this is pretty…

Music in the Round #21

I've been tweaking my weekend multichannel system for years, but with my city system I've kinda faked it. I now realize that I listen more actively to the weekend system, and not only because that's when I have the time for it—the sound of that system is simply more engaging and psychologically immersive. So, with the growth of my library of SACD and DVD-Audio recordings to almost half the size of my CD collection, I told my wife that it was time to transform of "our" city stereo rig into a full-blown multichannel system.

I added a third B&W 802D loudspeaker for the center channel…

Music in the Round #21 Page 2

Since then, from the home-built Altec A-7s of grad-school days, through homemade transmission lines, and on to the B&W 802Ds I now enjoy, almost all of my speakers have been full-size floorstanders. Somewhere in there I had a lingering affair with a pair of Stax ELS-F81s; they were beguiling, but drove me in desperation toward the bottom end, and to one ill-mated subwoofer after another. Nothing worked right—not until the rise of home theater and multichannel sound did the science of subwoofing flower.

Here's why. Multichannel sound means multiple speakers, and few domestic living…

Music in the Round #21 Recordings In The Round

Sidebar: Recordings In The Round

PENDERECKI: Credo
Harasimowicz-Haas, Pasiecznik, sopranos; Rehlis, alto; Zdunikowski, tenor; Tesarowicz, bass; Polish Radio & National Philharmonic Choirs, Cracow Philharmonic Boys Choir, National Polish Radio Symphony; Krzysztof Penderecki, conductor
Polskie Radio PR SACD 1 (SACD). Available from www.lipinskirecords.com.

This is a major recent work composed and conducted by a living master. Krzysztof Penderecki's music is dramatic, engaging, and accomplished with a mix of tonalities and melody that is both modern yet immediately…

Hot Stuff: Loudspeaker Voice-Coil Temperatures

As Hans Christian Oersted, the Danish physicist and founder of electrodynamics, discovered in 1819, an electric current passed through a wire generates a magnetic field. Place that wire close to a permanent magnet and the interaction of the two fields will generate a force. That, in two sentences, summarizes the operating principle of the motor that energizes every moving-coil drive-unit in millions of loudspeakers worldwide. It sounds simple, but—like everything in audio—it isn't.

To generate sufficient force, the wire in a moving-coil driver must be many meters long and so is…

Hot Stuff: Loudspeaker Voice-Coil Temperatures Page 2

A current source, by contrast, has an output impedance that is large compared to the load impedance, so that now its output current is largely unaffected by fluctuations in load impedance. This is significant in the context of thermal compression because it is the current through the voice-coil that generates the driver's motive force. If this is unaffected by changes in voice-coil resistance, then thermal compression cannot occur.

The trouble is, you can't simply substitute a current-source amplifier for a voltage-source amplifier when the loudspeaker expects to see a voltage source.…

Hot Stuff: Loudspeaker Voice-Coil Temperatures Making The Measurements

Sidebar: Making The Measurements

The simplest way to determine a device's electrical resistance is to pass a known DC current through it, measure the voltage developed across it, and use Ohm's Law (voltage equals current times resistance; ie, resistance equals voltage divided by current) to calculate the required result. This is essentially the method used here and previously employed by others (footnotes 1, 2), although it is complicated somewhat by the need to perform the measurement in the presence of a large AC signal driving the loudspeaker. Key issues are: 1) isolating the DC-…