Dunlavy Audio Labs SC-I loudspeaker Manufacturers Comment
Editor: We are indebted to Stereophile for another excellent and well-written review of one of our products. As a designer and manufacturer of high-end audiophile products intended to represent the true cutting edge of new technology, it is satisfying to know that a magazine exists with a well-intentioned and competent editorial staff concerned with the needs of both manufacturers and their customers. In this regard, we believe that Stereophile serves a serious need that many magazines might wish to note and better emulate.
Since John Atkinson's review is quite complete and accurate in an overall sense, I have only a few observations to share with readers.
First, John's perception that the bass end of the SC-Is sounded a bit on the "lean" side in his listening room may be true in the context of the acoustical properties of his room and/or the locations of the speakers and the listening position within the room. His observations might also be attributed to comparing the low end of the SC-I with the often exaggerated bass response typical of ported enclosures or designs employing underdamped bass alignments.
Our own experience, gained from an average of some 10 visitors per week to our plant who evaluate the sound quality of our loudspeaker models in a well-damped listening room (24' W by 14' D by 8' H), is quite different from John's. We always begin with the SC-I and, using the same recorded material, progress to successively larger models, ending with our SC-VI. I would estimate that at least three out of every four listeners guess that they are listening to either our larger SC-III or SC-IV models rather than the "pint-sized" SC-I.
However, as a designer well educated in the limitations imposed by the laws of physics, I have not been able to extract the full sound of a giant concert drum from an efficient loudspeaker as diminutive in size as the SC-I without using a port, passive radiator, or underdamped bass alignment, all of which inaccurately reproduce bass transients.
With regard to the 95dB loudness "speed limit" John attributes to the SC-I, I can only add that the speaker was designed to represent the best possible combination of overall accuracy, efficiency, and low-end bass extension vs size. Originally, the SC-I was conceived and designed to fill the need for a highly accurate, dependable, and efficient "nearfield reference monitor" for use in high-end recording and mastering studios (a job it has been doing nicely for more than a year). There was never any intention for the SC-I to compete with less-accurate loudspeakers with respect to super-loud playing and bass-end whomp. We sincerely believe, from the incredible level of SC-I sales (and a very large number of highly favorable comments from satisfied customers), that the loudspeaker meets its design goals. We also agree with John's comments that "A speaker like this is an essential reviewing tool," and "If more recording engineers used monitor speakers as accurate and revealing as the Dunlavy SC-Is, they wouldn't be so pedantic about bits being bits."
John's measurement of resonant modes in the walls of the loudspeaker enclosure by means of an accelerometer does permit a comparison with the amplitude of the sound directly radiated by the drivers. As such, it is virtually impossible to determine the audibility of such resonant vibrations based upon merely knowing their existence without knowing their farfield amplitude. At DAL, we assess the radiated amplitude of cabinet modes by a method called "time-domain spectrometry," which permits us to move a distance/time-of-arrival "window" across the relevant external front and side surfaces of the enclosures. Since this window can be made as narrow as an inch, we can accurately determine the ratio of the sound radiated by the drivers to the sound radiated by the vibration of enclosure boundaries. With respect to the SC-I, such vibrations have been reduced by internal bracing and damping to a level well below audibility throughout the audio spectrum.
John's comments about the impedance of the SC-I are well taken: the modulus of impedance vs frequency is extremely flat and well-behaved, as well as being almost entirely resistive over the entire audio spectrum. This very flat curve of impedance, in conjunction with a much-higher-than-average sensitivity (90–91dB/2.83V), allows the SC-I to be fed by most credibly designed tube and solid-state power amps.
With respect to the off-axis response of the SC-I, it has been our experience that the SC-I is one of the very few loudspeakers that permit a listener to move up and down from the seated position or around the listening room without perceiving more than small changes in spectral balance, much of which can be simply attributed to the acoustical energy reflected from the room boundaries. We encourage prospective buyers to do this test and compare the results with those of any competitive loudspeakers, regardless of price.
In closing, we sincerely thank John and the staff of Stereophile for their excellent effort in assessing the merits of the SC-I, and agreeing with its status as a "reference tool" for those discriminating users requiring the most accurate reproduction available from a loudspeaker of small size (and at an affordable price).—John Dunlavy, CEO, Dunlavy Audio Labs