April 2004

ProAc Response D38 Loudspeakers

by Marc Mickelson

Do loudspeakers, like people, have personalities that are formed at least to some extent by their country of origin? I note similarities among Canadian speakers from Paradigm, Energy, PSB, and Axiom, which in general measure very well and aim at sounding as full-range as possible given price constraints. There are American companies like Thiel, Aerial Acoustics and Wilson Audio, which do things in grander, and pricier, fashion, trying to push performance to new levels every time out. Then there are the British speakers, whose refined, buttoned-down sound seemingly trades appeasing engineers for pleasing listeners.

I can't say that I've been a fan of UK brands like Spendor, Harbeth and Quad, whose speakers have always struck me as being polite to the point of producing apathy. I will concede to them a certain midrange refinement and ease, which for some listeners is enough to buoy their interest. Not me -- I need more than any one sonic region done really well, even to my idea of perfection. I want a sense of the whole musical picture, a North American kind of perspective, I suppose.

In the past, ProAc, a British brand to be sure, impressed me enough with a good many of its models that I took the plunge and bought the company's top-of-the-line offering, the Response Four. It was a speaker that could take over a room like few speakers can, and while it could be driven with lower-power tube amps and sound good, it sounded its very best with some beef behind it. There certainly was refinement to the Response Four's sound, but that speaker was also full-range and could play loud, all the while never turning ugly.

I had discovered from Richard Gerberg, ProAc's US distributor, that there were some significant changes to current Response-series speakers. Given this and my previous ProAc experience, I was very interested in hearing the new Response D38, which replaced the Response 3.8, a speaker I had heard a few times and enjoyed greatly.

A new Response

The Response series is ProAc's best, although owners of Studio and Tablette models are certainly zealous about their speakers. The new Response lineup includes the D100 ($24,000 USD per pair), D80 ($14,000), D38 ($8000), D25 ($5000), and D15 ($3000). There is also the Response 1SC ($2000), a holdover from the previous Response series that I bet will be replaced sometime soon.

All previous Response-series speakers used silk-dome tweeters sourced from Scan-Speak and modified by ProAc. No more. The tweeter used currently, still a silk-dome unit, is sourced from D.S.T. of Denmark. Except for the earliest floorstanding Response speakers like the 3.0 and 3.5 or the smaller models, woofers were either 9" ATC or 7" Scan-Speak carbon-fiber jobs. But with the D100 and D80, ProAc began an affiliation with Volt, a pro company based in England. ProAc used a modified version of a Volt woofer in the D100 and D80, but a little over two years ago Volt began producing a new driver built to ProAc's specifications. This new 6 1/2" woofer is used in D38 and D25. The D80 uses Visaton dome midrange drivers, while the even larger D100, like the Response Four, uses the famed ATC dome midrange, one of the most expensive speaker drivers extant.

Changes are not limited to the D38's drivers, however. The Response 3.5 and 3.8 were front- and rear-ported speakers respectively, but for the D38, ProAc designer Stewart Tyler came up with a novel and elegant new scheme. Near the bottom of each speaker, just above the plinth, is a wide channel that runs from one side of the speaker to the other. If you look into this channel and upward, you'll see the actual port for the cabinet. It fires downward and its output makes it to the outside world via the channel. Therefore, the D38 is actually ported on the bottom of its cabinet, which is pretty much impossible without a solution like the one ProAc employs. Very neat.

The D38's cabinet is constructed of 25mm, 22mm, and 18mm medium-density fiberboard that's heavily damped with bitumen. Indeed, ye olde knuckle-rap test indicated a cabinet that was well damped. Binding posts are the same Michell rhodium-plated numbers that were on my Response Fours, two pairs of them for biwiring/biamping. These binding posts are nice, but the supplied jumpers, which are thicker-than-normal rhodium-plated pins, make it hard to single wire the speakers with spade-terminated speaker cables. The pins are too thick to allow the spades to make good contact with the binding posts. It's probably hard to imagine what I'm talking about here, but if you try using the jumpers, you'll understand.

ProAc says the D38 is 91.5dB sensitive, a jump of 4.5dBs over the sensitivity of the Response 3.8. Frequency response is quoted as 20Hz to 30kHz with no +/- variation given, while nominal impedance is 4 ohms. The crossover frequency is 2.8kHz, with both woofers covering the same frequency range. But Stewart Tyler pointed out that because the crossover is shunted, there is a larger-than-normal overlap in the tweeter's and woofers' output.

The D38 measures 49"H x 9 1/4"W x 13 1/2"D and weighs 88 pounds. ProAc speakers may be rectangular boxes, but they are attractive ones, due not only to their proportions but also the beautiful veneers. They look almost as though they are hewn from the trunk a tree. Buyers can choose from four standard and four premium finishes for their speakers (premium yew or ebony would be my choice) as well as others on special order.

One final new feature is the D38's plinth, which is now permanent and not something you have to put on for use and take off for shipping. The speakers also come with some of the best spikes I've used. They're broad enough to give the speakers ample stability but pointy enough to pierce carpet with ease. They screw into threaded inserts on the underside of the plinth.

Review system and setup

The Response D38s were the first review product to take up residence in my new listening room. I'm fortunate -- my new room is larger than any other I've had, a whopping 20' x 29' with a 10' ceiling, and that size affords me many additional options for placing speakers. I'm always surprised that reviewers don't talk much about their listening rooms. Just the dimensions can give readers so much context for a reviewer's comments, especially regarding speaker reviews. And it really is the truth that the room can greatly affect the final sound. Witness all of the complaining at audio shows.

I had a spate of amps on hand to use with the Response D38s in all manner of circuit configurations. They included Lamm ML1.1 push-pull tube, Song Audio SA-300B MB single-ended-triode, Atma-Sphere MA-2 Mk II.3 output-transformerless, and Simaudio W-6 solid-state monoblocks. I also used Odyssey Audio's Khartago solid-state stereo amp. Preamps were Lamm L2 Reference and Atma-Sphere MP-1 Mk II two-box tube units. Sources were Esoteric DV-50 and UX-1 universal players, and Mark Levinson No.37 or 47 Labs PiTracer transports connected to a Zanden Model 5000 Mk III DAC. Cables were primarily from Nordost -- Valhalla and Valkyrja -- but I also used for a short time DH Labs Revelation interconnects and Q-10 speaker cables. Power cords were Shunyata Research Anaconda Alpha, Anaconda Vx, Taipan and Python, while a Shunyata Hydra Model-8 conditioned power coming from the wall. For the most part, the preamps and amps rested on Silent Running isoBase 3.0 bases, with preamps/bases and all other gear on a pair of Michael Green Designs racks, with CD transports supported on a Bright Star Audio sand-filled Big Rock on top of which sits a Townsend Seismic Sink.

Even though ProAc says the D38s are more sensitive than the Response 3.8s they replaced, I found that they sounded their very best paired with the most powerful amps I had around, which meant the Atma-Sphere MA-2 Mk II.3 OTLs and especially the powerhouse Simaudio W-6 monoblocks (I recall that Simaudio's W-5 stereo amp drove my Response Fours extremely well). The Song Audio single-ended amps just couldn't drive the D38s -- no surprise, I guess, given their 8W output. Tonally, the D38s matched best with the Atma-Sphere and Simaudio amps as well. As a rule of thumb, any reasonably powerful amplifier with a neutral balance should perform well with the D38s. ProAc USA used Sudgen electronics at the CES this year, and in the past they've relied on amps from Audio Research.

Setting up the D38s took some experimentation as well. Slight adjustments of an inch or so produced noticeable gains in image specificity and soundstage depth. I found I could place the D38s farther apart than I anticipated and still have the speakers fill in the soundstage between them. Ultimately, the speakers ended up 48" from the front wall, 50" from the side walls, roughly 11' apart, and toed in so their output was summing right at my listening position. Any closer to the walls and the bass was too thick; any less toe-in and the treble sounded overly mellow. I listened with the grilles on. They seemed to effect very little sonic penalty and dressed the speakers up some.

The speed of sound

Have you heard about NASA's new X-43A experimental jet that reached Mach 7 -- a cool 5000 miles per hour? Before you start booking your seats, the X-43A flew unmanned and "landed" by crashing into the Pacific Ocean, so there's a heavy emphasis on this jet being "experimental." At this point, a person traveling at Mach 7 is little more than a concept, and may never be more than that.

The X-43A dovetails nicely with something Stewart Tyler said to me when I interviewed him at CES 1998: "If you built the perfect loudspeaker, nobody would probably buy it." Thus, while concepts like Mach 7 travel and perfect loudspeakers can certainly be newsworthy, they have little consequence in people's lives. Tyler believes that music, more than anything else, is about emotion. "A lot of designers try to blind with science," he told me. "I’m an emotional person, and if there’s no emotion, the speakers don’t do anything."

To be sure, the Response D38 is an emotionally involving speaker, easily one of the two or three best that I've heard in this regard. Driven by the right amp, the D38 is the sort of speaker whose sound you settle into like a favorite sweater or chair. Long listening sessions come easily, and even when you're in evaluation mode, you'll find it's no effort to let the music the D38s produce wash over you as you revel in its unique blend of beauty and truth. Yes, designing speakers involves science, but it's an artistic endeavor as well. Few speakers I've heard illustrate this as well as the Response D38.

I found myself listening to more classical music than usual while I evaluated the D38s, most of it on various JVC XRCD remasters. These are superior CDs in every sense, mating performances of historical importance with terrific sound. The sound of Offenbach's Gaîté Parisienne [JVC JVCXR-0224-2] floated free of the speaker cabinets, instantly defining this feat as a characteristic of properly positioned D38s. They are box speakers that definitely do not sound boxy.

There was a nimble, open and detailed quality to the sound that I know my Response Fours couldn't match. On "Another World" from the Deluxe Edition of Joe Jackson's great Night and Day [A&M B0000701-02], the xylophone sounded effortlessly detailed, the rest of the dense, percussion-laden instrumentation (which features no guitar) filling in all around. This is not an easy piece of music to unravel, but the D38s made easy work of it.

Past ProAc Response-series speakers I've heard had a golden tonal hue, one that didn't sound quite neutral but did sound very pleasing. The D38s retain a small bit o' this honey, but compared to my departed Response Fours, for example, they offer greater clarity and airiness, and not as much overt friendliness. Perhaps this is due to the change in tweeter or a general revoicing of the speaker, but the Response D38 (and I'll bet the other new Response-series speakers) sound more neutral while retaining a small measure of their characteristic sweetness. "Fruits of My Labor" from Lucinda Williams' World Without Tears [Lost Highway 088 170 355-2] sounded clear, detailed and enjoyable to the extreme. ProAc treble has always been something to behold, and with the D38, it's a touch more delicate and finely drawn. It's gorgeous.

As a sign of their low-end resolution, the D38s clearly differentiated the bass line on "Righteously," also from World Without Tears, sounding agile and quick, yet well extended in the process. This reminded me of the bass of the Thiel CS2.4 -- deep but without exaggerated weight. In fact, even though the D38s are two-way speakers with dual 6 1/2" woofers, they could display notable power and slam when called on to do so. I've used Suzanne Vega's Nine Objects of Desire [A&M 31454 0583 2] to test the low end of many speakers, and the ProAcs passed the test -- provided that they had ample power driving them. The 110Wpc Odyssey Khartago sounded dynamically compressed in the bass driving the D38s, "Headshots" displaying obviously less power. But with the Simaudio amps in particular, the D38s could charge even my large listening room with surprisingly deep and powerful bass.

The midrange of the Response D38s is a deft combination of high resolution and pleasing smoothness -- voices are rife with nuance and texture. The D38s don't have the fullness of darker-sounding speakers (including the Response Fours), but their particular balance is enjoyable to the extreme and encourages listening to all kinds of vocal music. I had purchased Bonnie Raitt's Silver Lining [Capitol 31816] months before hearing it for the first time on the ProAc D38s. Nick of Time [Capitol 7 912668 2] and Luck of the Draw [Capitol C2-96111] may be more popular, but Silver Lining sounds just as good and has the same blend of bluesy music. Raitt's voice can sound rough and ragged, but it was like butter over the Response D38s. "Back Around" from Silver Lining showed off the D38s' full arsenal -- effortless, free-from-the-speaker-cabinets sound, a detailed and sweet midrange, plenty of air around performers, and robust low frequencies. However, this CD illustrated that image density, the sense of a singer's complete presence, is not a strength of the D38s, which sound more ethereal than full-bodied, but the speakers' capacity here fits in perfectly with their overall presentation. Great sound is about the proportions of the elements that make it up, with no single quality grossly surpassing any other. The sound of ProAc D38 is certainly in proportion.

Comparisons

Comparing the Response D38s to Wilson Audio WATT/Puppy 7s, at a shade over $22,000 per pair, is not an unfair act. The two share some traits, though these traits are not part of each speaker's sound in equal abundance. The D38s are not as dynamically agile or quite as detailed as the WATT/Puppy 7s, and not their equal in terms of bass depth or power. I praised the Wilson Sophia, $11,700 per pair, a while back, calling it a "human" loudspeaker, and this also applies to the WATT/Puppy 7. But the Response D38 improves on this quality by sounding a little sweeter and more light-filled than either of the Wilson speakers, which counter with greater image solidity and a slightly more detailed presentation. The D38s were the most difficult of the three to drive. The two Wilson Audio speakers sounded very good driven by 18W Lamm SET monoblocks, for instance, whereas the ProAcs sounded their best in my room with at least 200 watts behind them.

I could spend much more space talking about the differences of these three very fine speakers, but in the end it is something that they share that defines them most. I own the WATT/Puppy 7s, and have heard the Sophias and now the D38s at length in my system. All three offer truth and beauty in abundance -- not in identical ways, but both are present and accounted for. Thus, while you can analyze with any of these three speakers in your system, you can relax, enjoy and connect as well. I can't give higher praise than this.

In the end…

The new ProAc D38 has an ample amount of the graceful sound for which British speakers are known and a great deal of sonic resemblance to earlier Response-series speakers. However, it is also its own speaker, sounding open and effortless, sweet in the treble, gutsy down low, and very involving with all types of music. To my ears, it retains Stewart Tyler's sought-after emotion and mixes it with a lighter, more detailed and boxless presentation. The D38 sounds more transparent than earlier Response-series speakers as well, but it never casts off its family resemblance.

Summing up the ProAc D38s is difficult because above any of their particular sonic characteristics is their great overall appeal. Stewart Tyler has succeeded in making a speaker that enhances the emotional connection with the music and has bettered his previous best, the $20,000-per-pair Response Four, in some meaningful ways. In fact, if the D38s had been available when I bought my Response Fours, I would have purchased them instead. Such improvement at a far lower price is something about which ProAc can be very proud.

...Marc Mickelson
marc@soundstage.com

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