Getting the top cover off is an easy matter, involving undoing four Philips-head screws on the sides; getting it on again proved more difficult, for some reason known only to Murphy. Construction is to a high standard. (Sumo actually…
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The fact that both low-pass signals of either polarity are available makes it a cinch to use bridged amplifiers to drive the subwoofers—one output is taken to one half of a stereo amplifier, its inverse to the other half, and the subwoofer connected across the two "hot" speaker terminals. (The amplifier in question must not have "floating" outputs.)
I noticed another soundstage enhancement due to the stereo subwoofers: due to Cathedral regulations, I was forced to place the Calrec Soundfield mike some 15 feet above the conductor's head, meaning that some instruments—bass drum and timps—and the soloists were to the side. Conventionally, these are reproduced as coming from the extreme sides of the soundfield, ie, at the speaker positions. With the Sumos in circuit, these images came from beyond the SL600 positions and were stable. And the thwack from the bass drum at Letter 10 in the introduction now knocked off not only my socks but my…
Sidebar 1: Review System
I chose to use Monitor Audio R952s and Celestion SL600s to audition the Samson & Delilah combination, as both speakers feature the bass quality I like: a very fast, tight low end, with very well-defined leading edges to the sound. Both speakers are free from upper-bass overhang; although the ultimate weight of bass-guitar tone may not be there, the considerable degree of clarity very easily allows the listener to identify the type of instrument and how it is played, both factors germane to the music.
Auditioning involved the following permutations and…
Sidebar 2: Measurements
The Sumo Samson's nominal impedance is quoted as 8 ohms. In fact, I measured a minimum value of 8 ohms at 170Hz, the value below that frequency averaging about 12 ohms. This is an easy load for any amplifier, and supports Sumo's recommendation that bridged amplifiers work best with Samson. (Bridging a 4-ohm rated amplifier may double the voltage swing into the load, but it effectively turns the amp into one best suited to 8-ohm loads.) The plot of impedance with frequency (fig.1) revealed the basic box resonance to lie at 52Hz with the reflex ports tuned to 27Hz…
Sidebar 3: Specifications
Samson: Reflex-loaded subwoofer. Drive-unit: 15" (380mm) pulp-cone woofer with 4" (100mm) edge-wound voice-coil. Frequency response: 25-125Hz !q1dB. Recommended crossover frequencies: 50-125Hz. Sensitivity: 91dB (2.83V, 1m). Nominal impedance: 8 ohms. Minimum recommended amplifier power: 200W RMS. Maximum recommended amplifier power: 1000W.
Dimensions: 22" (560mm) H by 29" (740mm) W by 19" (480mm) D. Weight: 150 lbs (68kg).
Price: $650.
Delilah: Two-way electronic crossover with high-pass outputs, in-phase and anti-phase low-pass outputs, and…
Ten seconds to ignition. Relax, buckle in, and welcome to Stereophile's Good Times time machine. Flux capacitors fully energized. Ignition. Not to worry, that slight tingling sensation is perfectly normal. Roll back your calendar to...June 28, 1933. We're at the Eighth Annual convention of the Institute of Radio Engineers in Chicago. Harry Olsen is on the podium, describing a new wide-range cone loudspeaker for high-fidelity sound reproduction.
Quiet, please, Mr. Olsen is about to describe the disadvantages of multiple–drive-unit systems. "The radiating surfaces must be separated by a…
That did it. The possibility of a dynamic speaker on a par with a high-grade ESL did me in—I had to have a pair! The PA-1 arrived first, the almost visually identical Reference a month later. Because of obvious family similarities, it seemed reasonable to combine the reviews under one umbrella. But to be fair to each of these products, I'll relate my sonic impressions in chronological order.
Technical details
Pawel Acoustics was established in a small Swiss village in 1981 to produce high-end audio equipment for both the consumer and professional markets. A physical examination of…
Most of my listening sessions incorporated the Air Tight ATM-2 power amp. At 80Wpc, the ATM-2 provided an ideal power rating. But, even more important, it allowed the full spatial-resolution capabilities of the PA-1s to bloom. Lately, I've gotten in the habit of feeding the output of my Theta Pro Basic digital processor directly into the ATM-2's front inputs. These inputs are provided with volume pots so that a line-level signal maybe fed into the amp—bypassing the preamp's line stage. With the Ensembles, it was readily obvious just how much signal degradation an additional gain stage,…
Another favorite of mine is The Weavers: Reunion at Carnegie Hall—1963 (Vanguard VSD-2150). A wealth of low-level detail was clearly revealed by the PA-1, including the audience's participation on "Goodnight Irene." But what was really exciting was the degree to which the PA-1 cleared up any confusion about instrument placement. Mike pickup patterns were so clearly exposed that it became absolutely clear just how many mikes were used and where everybody was.
Because the PA-1 is so revealing of spatial information, it ruthlessly revealed the artificiality of multi-miked recordings. An…
Sidebar 1: Fruit Flies & Impulse Responses
While on the subject of foam diaphragms, I recently ran across an interesting article, by Dr. H. C. Bennet-Clark, in the March 1969 issue of Wireless World. Bennet-Clark is a zoologist and an avid audiophile. At the time he was involved in a research project examining the courtship of fruit flies, in the course of which pulses of sound were played to the flies to simulate their courtship sounds. This "love song" is apparently produced when the fly flaps its wings and consists of a single cycle of pressure change lasting 3ms. It was this sort…