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The first time I encountered Dunlavy's Signature Collection loudspeakers was at the 1993 Chicago Summer CES. I was familiar with, and had a lot of respect for, the speakers John Dunlavy had designed for the Australian Duntech brand, but I thought this new line clearly transcended his previous efforts—and at significantly lower prices. The model that I ended up reviewing—and, after the review (Vol.17 No.4), buying—was the SC-IV, subsequently honored as Stereophile's 1994 Loudspeaker of the Year and Product of the Year. In 1995, the SC-IV underwent changes, including a new woofer and a…
Obtaining improved bass performance from a loudspeaker is seldom just a matter of substituting a "better" woofer. The ScanSpeak woofer apparently has great low-end extension, but it also has some nasty peaks at the top of its passband. John Dunlavy says that he almost abandoned using the woofer for this reason, but kept coming back to it as the best driver for providing the bass extension and power handling he wanted. His solution to the problem consisted of several resonant circuits in the crossover, providing electrical compensation for the peaks.
In fact, another major difference…
The effects of such a low level of speaker coloration were several. First of all, there was a timbral accuracy to a wide variety of instrumental sounds and voices that was at times quite startling. Ida Levin's violin on Duet (Stereophile STPH012-2) had the combination of sweetness and astringency I remember from her concert at HI-FI '98. Singers whose voices I'm familiar with from live performances sounded more like themselves and less like reproductions. There was also a significant improvement in resolution.
The SC-IV is certainly no slouch in this department, but with the SC-IV/A I…
Sidebar 1: Specifications
Description: Three-way dynamic loudspeaker. Drive-units: 1" composite textile-dome tweeter, two 5.5" paper-cone midranges, two 10" long-throw paper-cone woofers. Crossover: first-order design (frequencies not specified). Biwire and biamp capability. Frequency response: 25Hz-20kHz, ±1.5dB; -3dB at 20Hz (anechoic). Sensitivity: 92dB/W/m. Impedance: 5 ohms nominal; 3.0 ohms minimum, 7.5 ohms maximum. Recommended amplifier power: 50W minimum into 8 ohms. Recommended listening distance: 8-25'.
Dimensions: 72" H by 12" W by 18" D. Weight: 190 lbs.
Serial numbers…
Sidebar 2: Associated Equipment
Analog source: Linn LP12/Lingo turntable, Linn Ittok tonearm, AudioQuest AQ-7000nsx phono cartridge.
Digital source: PS Audio Lambda II CD transport, Audio Alchemy DTIPro32, and Sonic Frontiers Processor 3.
Preamplifier: Convergent Audio Technology SL-1 Signature Mk.III.
Power amplifiers: Sonic Frontiers Power 2, Cary Audio Design CAD-572SE (two pairs), Bryston 7B-ST.
Cables: Illuminati D-60/Orchid digital links, TARA Labs The Two interconnects and Decade power and speaker cables.
Room treatment: Argent RoomLens.
Accessories: Chang CLS-…
Sidebar 3: Measurements
As specified, the Dunlavy SV-IV/A is a sensitive speaker, my B-weighted measurement of 91dB/2.83V/m being within measurement error of the specified 92dB figure. (Note that with its low impedance, the speaker actually draws closer to 2W from the amplifier than 1W to achieve this sound-pressure level.) The variation of the impedance magnitude and electrical phase angle are plotted in fig.1. The value hovers around the 4 ohm line for much of the audio band and reaching a minimum value of 2.9 ohms at 63Hz. The phase angle is low, however, minimizing the strain on the…
John Dunlavy has always emphasized that the vertical spaced array nature of the drive-units in his designs means that the speaker's reference on-axis will not be achieved at distances closer than 8'. Unfortunately, the physical restrictions placed on my speaker measurements by Stereophile's listening/measuring room makes it impossible for me to make meaningful measurements much farther away than 50", which is why I have standardized this distance for the response measurements published in the magazine.
At this distance, the SC-IV/A looks reasonably flat, but with slight depressions in…
In the time domain, the Dunlavy's impulse response on the tweeter axis (fig.7) is excellent and typical of a first-order design that physically recesses the shallower drive-units. There are a couple of early reflections noticeable, however, which I assume are from the relatively firm felt used in the tweeter's acoustic environment. These give rise to the small ripples seen in the on-axis frequency response, which are subjectively benign. The step response (fig.8) indicates excellent time coherence, the acoustic outputs from all five drive-units arriving at the microphone at the same time.…
Manufacturer's Comment
Editor: Once again, what can we say—the Stereophile review by Robert Deutsch and John Atkinson of our new SC-IV/A loudspeaker seems to have said it all!
RD's perceptions and descriptions of the relatively small but important audible differences between our standard SC-IV and the new SC-IV/A loudspeakers certainly characterize him as a reviewer possessing an uncommon ability to accurately assess and describe such differences.
Indeed, we at DAL feel honored by RD's final observation: "Remember the frog whose jumps always take him halfway toward his…
A FollowUp appeared in July 2000, Vol 23 No.7:
Dunlavy SC-IV/A loudspeaker
When Robert Deutsch reviewed Dunlavy's floorstanding, three-way SC-IV/A loudspeaker in November 1998, he found nothing to criticize: "The SC-IV/A has reached the point where—with the best source materials and associated equipment—it sounds less like a speaker and more like the music that's being reproduced," he summed up. And when I consulted him for his thoughts on where in Stereophile's "Recommended Components" the Dunlavy belonged, Bob was unequivocal: "Class A."
Yet, as regular readers will know,…