Monthly Archives: August 2012

Member Profile: Ken Bird, Speaker Designer

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Ken Bird (BSEE, Washington University) is an audioXpress article contributor who has been reading the magazine since 1989. In the September 2011 issue, he presented his tower omnidirectional speaker design project (“Castle Tower Omni Speakers”).

Ken Bird with a 12″ woofer

Bird’s member profile follows.

Affiliations: He is a member of the ARRLHam Call. His amateur radio (ham) call sign is W0KLB.

Audio Interests: Ken enjoys speaker and tube amplifier building, the Ham radio, and restoration of old radios.

Most Recent Purchase: Ken bought two Lepai TA 2020 Class C amplifiers from Parts Express. He said the audio performance of the amps is great for the money.

Current Audio Projects: Ken restored a 1983 JVC RS33 receiver and two Altec Series 9 speakers for a friend. He is currently working on a three-way speaker system with dual 8″ woofers in an unusual cabinet design called the Cathedrals. He said he might write an article for audioXpress about this project.

Dream System: Ken’s dream system consists of two of the original 1953 Electro Voice Patrician enclosures, and they would be driven by a McIntosh MC275 amplifier. He added that he also needs to dream for a room that will be big enough to accommodate them.

Bird’s tower castle speakers

Wiring for the castle tower speakers

Audio Crossword Answers (September 2012)

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The answers to the crossword puzzle published in audioXpress September 2012 are below. The issue is now available. 

Across

2.     BOOMY—A type of vibration that occurs if the speaker is not well damped by either the amps output circuit or the particular installation

5.     CONECRY—Notes or tones that are higher or lower in frequency than the intended note [two words]

6.     PI—The name Robert Nance Dee gave the pre-amplifier interface design in his audioXpress article (August 2012)

10.   AGGRESSIVE—Usually indicative of a lightweight, low-mass cone structure and a large magnet

11.   SCANSPEAK—In recent months, columnist Vance Dickason has put a number of high-end audio drivers from this Danish company to the test [two words]

14.   CASPER—This audioXpress contributor shared an easy-to-build amplifier for computer speakers in the November 2011 issue

16.   PRESENCENOTCH—The major fundamental resonance of a loudspeaker, which is mainly determined by the spider and the mass of the cone [two words]

17.   BREAKUP—Comb filtering and other anomalies that create the texture of the overall sound

18.   NEODYMIUM—A material used for the rare-earth magnets

19.   RAREFACTION—That phase of a sound wave during which the air pressure is below the normal atmospheric pressure

20.   PASS—In the January 2012 issue of audioXpress, this contributor described his modification to the JBL L300 loudspeakers

Down

1.     HONKING—A peaked 800 to 1200 Hz midrange that is up several decibels from the low end

3.     OUTPUTTRANSISTORS—In his October 2011 audioXpress article, “Upgrading the Phase Linear 200 Amplifier,” Patrick Brunner recommended changing these for higher gain [two words]

4.     ELECTROSTATIC—The “unique beam-splitter bass cabinet” was the twist in Charlie Mimbs’ construction of this type of hybrid-style loudspeakers (audioXpress, April 2012).

7.     VOICECOILRUB—Usually occurs after too much power is applied to a speaker for too long [three words]

8.     BELLMODES—The many minor resonances and new frequencies that result in response to the input signal when the speaker cone vibrates [two words]

9.     LIS—Our annual directory, which provides information on industry trends, speaker parts, and resources as well as components, software, and test equipment

12.   SURROUND—The area out at the periphery of the cone that usually has one to three corrugations

13.   THEPANHEADS—In the March 2012 issue of audioXpress, David Pellegrene shared this innovative speaker design that resembles a Harley-Davidson engine [two words]

15.   GAPENERGY—Measured by the Gaussmeter [two words]