Dunlavy Audio Laboratories SC-IV loudspeaker Follow-Up, March 1995
The $4995/pair Dunlavy Audio Labs SC-IV—which I gave a rave review in April 1994 (Vol.17 No.4), and which was subsequently named "Product of the Year" in December '94 (Vol.17 No.12)—has recently undergone some significant modifications.
Manufacturers modify products for a variety of reasons. If a product has been around for some time and sales are dropping, the manufacturer is virtually compelled to come out with a New/Improved/Series II/Signature version just to stay competitive. However, the Dunlavy SC-IV hasn't been on the market long enough for this to be the case; in fact, the demand for the speaker has outstripped the supply. Another possible reason to change a product is to correct problems that have been identified in a review or by dealers and customers. Again, there's no indication that this applies to the SC-IV. The review pair, which I bought, has been sounding better than ever.
Which leaves us with one other possibility: the manufacturer's ongoing research and development may reveal that improvements can still be made to what's already a well-performing product. According to Dunlavy Audio Labs, this is the reason for the changes to the SC-IV. The original SC-IV used a 10" Morel woofer, which was quite satisfactory; but Dunlavy has been working with Vifa, the supplier of the midrange and the tweeter, to develop an even better woofer. The new 10" Vifa unit is said to be better-damped, and to have 2–3Hz more bottom-end extension than the Morel. The Vifa driver has now been incorporated into the SC-IV, with some consequent modification of the woofer-to-midrange transition in the crossover.
There's also a change at the top. The original SC-IV tweeter had excellent impulse response—the sine qua non for John Dunlavy—and an on-axis frequency response that was pretty flat to about 16kHz, with a gentle rolloff above that. The new SC-IV (there's no change in model designation) tweeter is a silk-dome unit rather than a composite fabric, and is said to offer even better performance, with top-end extension essentially flat to 20kHz, and impulse response that's at least as good as the original (footnote 1). To match it precisely to the midrange (which remains the same 5.5" Vifa cone), some changes in crossover values were required. Dunlavy also took this opportunity to improve the layout of the crossover, and to strengthen the cabinet's bracing.
In my review, I had criticized the binding posts, which I found too thick for the spade lugs on most cables, and difficult to tighten properly. John Dunlavy himself was apparently not completely satisfied with those binding posts; the new speaker's binding posts are of higher quality, have better spade-lug compatibility, and can be tightened with a nut driver or that nifty Postman tool.
So, let's see...a new woofer, new tweeter, modified crossover, new binding posts, a change in cabinet bracing—yup, a Follow-Up is definitely in order.
System & Setup
Associated equipment for this Follow-Up was much the same as that in my original SC-IV review. Analog: fully dressed Linn LP12 (Lingo, Cirkus) with QR/DNM Design Ringmat, Ittok, AudioQuest AQ 7000NSX. Digital: PS Audio Lambda transport driving a Sonic Frontiers SFD-2 processor and Sonic Frontiers UltraJitterbug, digital connections via TARA Labs AES/EBU cable. Preamps: Convergent Audio Technology SL-1 Signature and Sonic Frontiers SFL-2. Amplifiers: Threshold T-200, Carver Lightstar Reference, YBA-1 Alpha, and a pair of Bryston 7Bs. Interconnects, AC line cords, and speaker cables were all latest-generation TARA Labs RSC Master.
Following Jack English's and Jonathan Scull's lead, I placed The Original Cable Jackets on all the AC-line cords and speaker cables—a very fussy-looking but worthwhile tweak.
Both the "old" and the "new" SC-IVs were set up in the same position (but not, of course, at the same time!), along the long wall of my 16' by 14' listening room, subtending an angle of about 75°. Most of my listening was done with the speakers placed on Michael Green's Audiopoints, and with the grilles removed. To break-in the speakers, I put on the Purist Audio System Enhancer CD whenever I left the house. Like the original SC-IV (and like the SC-I reviewed by JA), the speakers continued to improve with additional break-in.
The review pair of SC-IVs was attractively finished in a rosewood–look-alike veneer Dunlavy Audio Labs calls Dalwood Rose, which raises the price to $6000/pair. The new binding posts are certainly much improved: the TARA Labs speaker cables' spade lugs now fit properly, and I was able to use a nut driver to tighten the connection.
As this is a Follow-Up rather than a full-scale review, it's not accompanied by official Stereophile-conducted measurements; but John Dunlavy sent along his own measurements on the speakers, and I was able to compare these with the measurements made on the original speakers.
Both the new and old speakers have amplitude and phase-response measurements that are textbook-perfect (footnote 2), the variation in amplitude response from the midbass to mid-treble hardly straying outside a ±1dB window. The new speaker does show greater top-end extension, the on-axis frequency response remaining level with the midrange up to 20kHz, and the MLSSA cumulative spectral-decay, or waterfall, plot shows slightly faster decay of resonances in the midrange and treble.
Although I have the greatest regard for John Dunlavy's ability as a speaker designer, my first listen to the new pair of SC-IVs involved a degree of trepidation. Would the changes represent genuine improvement, or would they merely be an exercise in gilding the lily? It's certainly possible for an audio product to show technical improvement that's not musically significant; it might even represent a backward step. (I think the original Advent loudspeaker was sonically superior to any of its later iterations, and I'm still not convinced that the Quad ESL-63 is, overall, superior to its predecessor.) The original SC-IV was so good that, if I'd been its designer/manufacturer, my inclination would have been to leave it alone.
It's a good thing that I'm not the SC-IV's designer/manufacturer! The virtues of the original SC-IV have been retained, and the changes indeed represent improvements. The most obvious difference is at the top end. Compared to its competition, the original SC-IV was certainly not deficient in this area; but the new one sounds cleaner and more extended.
Just prior to receiving the new SC-IVs, I'd been listening to the latest set of Mercury CDs—especially Hi-Fi à la Española/Popovers (Mercury 434 349-2). Playing this disc at the same level on the new SC-IVs, I was immediately aware that percussion and other instruments with significant treble energy had acquired a greater sense of aliveness, and that the music generally seemed quicker. (During pauses and very quiet passages, the tape hiss of the original recording was also more evident, but it was masked by music the rest of the time.) Cymbals and bells were revealed to have a shimmering quality that sounded closer to the real thing. Resolution in the upper octaves has been significantly increased, without adding any excessive brightness or becoming unduly forward.
With really good recordings, such as one of my Records To Die For picks, Chris Norman's The Beauty of the North (Dorian DOR-90190), the realism of instrumental timbres and the illusion of musicians being in the room was simply breathtaking. On some CDs—a recently received CD of Jule Styne overtures (RCA Victor 61939-2) being a striking (or do I mean "strident"?) example—the top end was brighter than optimal; but comparison with a wide range of recordings—LP and CD—showed that the frequency-response imbalance in these cases was intrinsic to the records themselves. Still, I'd be careful not to combine the SC-IV with components that have a tipped-up treble.
The original SC-IV's bottom end was one of its strengths—deep, tight, and tuneful. Well, I'm now here to tell you that the bass response of the new version is deeper, tighter, and, if anything, more tuneful. In my review of the SC-IV, I reported that, testing with an oscillator, I found the speaker's bass response to extend to a clean 23Hz. With the new speakers in the same position in the room, I'm now getting useful response to 20Hz. I played Mickey Hart's "Temple Caves," from Planet Drum (Rykodisc RC-10206), for the distributor of a well-known line of subwoofers, and his response was an involuntary "Wow!"
In comparing new and old versions of a product, one is inclined to emphasize the differences rather than the similarities. In fact, both original and revised versions of the SC-IV are full-range loudspeakers with state-of-the-art levels of tonal neutrality, resolution, imaging, and dynamics. However, comparison in the context of a familiar sound-system shows that the revised SC-IV has a more extended top and bottom—which translates to higher resolution at these frequency extremes. Further, the change in binding posts has made the speaker more compatible with audiophile speaker cables. In short, the speaker that I described as "fabulous" is now even better.—Robert Deutsch
Footnote 1: The tweeter is the same as the one used in the Dunlavy Audio Labs SC-I, reviewed by JA in December 1994 (Vol.17 No.12).—Robert Deutsch
Footnote 2: The illustrations of excellent impulse and step responses in Robert Harley's The Complete Guide to High-End Audio were taken from the review of the SC-IV.—Robert Deutsch