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Equipment Review
September 1998

ProAc Response Four Loudspeakers

by Marc Mickelson

"When are you going to review the ProAcs?"

Over the last two years I’ve gotten more than an e-mail a month asking if and when I’d write a review of ProAc’s flagship speakers, the Response Fours. I haven’t done so up to this point for one reason: I’ve been too busy reviewing products that have been submitted to SoundStage! to review one that I bought myself.

What’s changed? First, the sheer number of messages I received -- we really do listen to you, you know -- and then meeting and talking with ProAc’s Stewart Tyler at the CES last January. All of the audio designers I’ve met are unique, but Tyler stands apart because he just doesn’t think like all of the others. Sure, he’s committed to his product and design goals (he spent a year designing and fine-tuning the Response Fours, and personally tests every pair), but more than this he’s a person -- even when he’s at the CES -- who simply enjoys music and makes speakers that impress him. "If you built the perfect loudspeaker, nobody would probably buy it," he told me with a smile. "So design something that you like." Thus, to perhaps a greater degree than with any other designer, discussing the engineering of the Response Fours means discussing Tyler’s beliefs on life and music. "A lot of designers try to blind with science, Tyler said. "I’m an emotional person, and if there’s no emotion, the speakers don’t do anything." Amen.


The Response Fours are big boxes, 63"H x 14"W x 17"D and weighing 300 pounds each. To their credit, however, they are also immensely beautiful boxes, with mirror-matched veneer on all sides except the back, which is black in color. It’s happened more than once that someone first entering my listening room gasped when he or she saw them. My pair is in the standard yew finish ($19,000), a sort of honey-mustard colored veneer, with numerous knots and a distinctive crab-like pattern on the sides. It’s waaaay gorgeous and, in my opinion, should dissuade anyone from paying $2000 extra for a premium finish.

The Response Fours use one of the Scan-Speak silk-dome tweeters that are ubiquitous for ProAc Response-series speakers. The tweeters in the Fours are not identical to the tweeters used in, say, the Response 2.5s, but they are similar. The Response Fours also use pairs of the most famed and costly midrange drivers available, the 3" ATC soft-domes, along with two 9" ATC bass drivers. The drivers are aligned vertically, although they are not directly above each other. The picture of a Response Four speaker can illustrate this better than I can explain it.

On the back of the speakers are two sets of Michell rhodium-plated binding posts. The Response Fours come with sets of spikes for coupling the speakers to your floors -- be sure you can stand putting holes in your floor before you install the spikes! -- and sets of rhodium-plated strapping pins so that you can use the speakers with single runs of speaker cables. The Response Fours come packed in substantial boxes with lots molded foam and styrofoam. Richard Gerberg at Modern Audio, the US distributor of ProAc speakers, told me that the replacement cost for the boxes and packing is $1000 -- a $teep punishment for those who toss the boxes, which naturally are bigger than the speakers themselves, and then need them later.


Because the Response Fours have been the centerpiece of my system for over two years, they have played along with a ton of other equipment -- literally, I bet. However, for the past eight months or so, I’ve used them along with the same lineup: Lamm ML1 mono amplifiers (which are an ideal match for the Fours) and L1 linestage, Timbre TT-1 DAC and Wadia 20 transport, JPS Superconductor2 interconnects and NC Series speaker cables, Audio Magic Tubed Interconnect, Marigo Apparition Reference Series 3A digital cable and AC Distribution Center, and various Target and Bright Star stands. It’s important for me to mention that the Fours have worked superbly with all of the equipment I’ve had in for review, never creating mismatches with amps because of their benign impedance characteristics (8 ohms nominal) and reasonable sensitivity (a claimed 89dB/W/m).

The Response Fours, unlike some other high-priced, high-quality speakers, sound very good -- even phenomenal -- with electronics that are not in their same price range. At one point I used a Mesa Tigris integrated amp ($2500) to drive the Fours, with a CAL Audio DX-2 CD player as source, and the sound was splendid and stereotypically ProAcian. Of course, with supreme electronics like those from Lamm, the Response Fours climb a very high sonic peak. But the Response Fours are easy to care for -- just feed them and they thrive.


All discussion of the ProAc Response-series speakers must begin with their treble, which is the most engaging I’ve heard from any line of speakers. I’ve had the pleasure of hearing other models in ProAc’s Response lineup -- the 3.5, 2.5, Two S, One SC and new Five -- and they all share the rare ability to resolve lots of detail without turning hard or grainy or amusical. The treble of the Response Fours is noticeably smoother than that of any speaker I’ve heard at length -- except for the other Response-series ProAcs, that is. Cracker’s Kerosene Hat [Virgin 39012 2] is a busy, less-than-perfect recording of intelligent, post-punk music. The Response Fours help create a reasonably intelligible wall of sound that bypasses the ills of the recording -- and perhaps the general idea of the music itself -- to make the disc involving. Do the Response Fours, then, hinder enjoyment of audiophile CDs? No way. The JVC XRCD2 release of The Modern Jazz Quartet’s Concorde [XRCD 203] provides as much great sound as a 43-year-old recording can. Although John Lewis’ piano is somewhat muffled in the mix, Milt Jackson’s vibe work resonates through the room, the notes dying only after long, long lives. In terms of audio thrills, the treble of the Response Fours (and the other Response-series speakers) is as equally noteworthy and deserving of long-standing praise as, say, the bass of a Krell amp or the midrange of a CAT preamp. It’s as close to perfect as we may now know.

Once you get by the beauty of the Response Fours’ treble -- no easy task -- you find that the fine points that audiophiles pay great attention to (and money for) are all there too. Image outlines are strong, the images themselves having fullness and three-dimensional presence. Greg Brown and Bill Morrisey’s CD Friend of Mine [Philo CD PH1151] includes a cover "The Road," a tune popularized by Jackson Brown. In my room, Morrisey sits directly on top of the right Lamm ML1 monoblock (the transformers in the back -- how else to use it as a stool?), Brown on the left. The guitars are slightly outside of the voices, which makes sense. This unique and precise placement of the performers and their instruments is not a feat that every audio system can pull off, but the with help of the Lamm ML1 monoblocks, the ProAc Response Fours do it with ease.

In my room (13'x22'), I placed the Response Fours 8.5' center to center, which puts them roughly 18" from the side walls, and 5' out from the rear wall. It’s important to get them out into the room to give them room to breathe and conjure up their standard immense soundstage. This doesn’t mean, however, that the Response Fours will artificially replace the sense of space and place on a recording with one they create. You’ll get whatever the music dictates -- including cues beyond the boundaries of your room. "Get your Lies Straight," from Terry Evans’ wonderful Blues For Thought [Pointblank/Charisma 39064 2], illustrates this perfectly, producing sound with a great lateral spread -- wall to wall -- and depth beyond the back wall. Picking out individual instruments is no problem. Outlines, once again, are crisp but not exaggerated, and placement is exact. The Response Fours do not sonically disappear like some other speakers (probably because their front baffles are too broad). Instead, when optimally set up, they conquer the room, melting away its boundaries. Physically, the Response Fours need space, mostly in back of them, and a stout floor of course.

You would expect big speakers like the Response Fours to have a prodigious low end, and they do -- flat to 20Hz in my room with no obvious smearing, which I guess qualifies them as having great bass. The bass line on Ted Hawkins’ rendition of "Biloxi," from The Last Hundred Years [DGC DGCD-24627], is very deep -- if you can’t hear it with your speakers, oh well. It’s also pitch-defined, with no bloat or lack of articulation. And rock pulsates over the Response Fours; discs such as The Presidents of the United States of America [Columbia CK67291] just beg to be turned up to 11. This is certainly due to the way the Response Fours handle the bass, but it’s also a matter of their ability to find at least a kernel of musical truth in ho-hum and downright ugly-sounding recordings. Wayne Kramer’s loud The Hard Stuff [Epitaph 86447-2] is a quintessential bad recording, but the Response Fours resurrect it, not by glossing over the hard treble and thin midrange, but rather by making these less of a going concern. I can just see the furrowed brows of those in the accuracy-at-the-expense-of-enjoyment crowd. Get over it! With the Response Fours you’ll still know that your bad recordings are bad, but you won’t care as much -- or at all.

One night I pulled out the Frente!’s Marvin the Album [Mammoth 92390-2], a CD, as I would learn, that spotlights the Response Fours’ many virtues. "Girl," the first cut, is intimate and sweet, as it should be. Angie Hart’s voice is perfectly centered and three-dimensional -- no room for improvement here. The combination of vocal and guitar on "Labour of Love" swings, and when the recorder enters for a few bars, it’s a deft move on the part of the band to break the pattern of the tune and heighten the listener’s interest. "Ordinary Angels" lets you know that Marvin the Album is not a solely acoustic effort. Hart’s vocals are pellucid, even amongst the more complicated instrumentation. Perhaps the biggest treat, however, is "Lonely." The tempo changes, the guitars enter and exit, as does the programmed percussion, but Angie Hart’s waif-like voice carries the song and draws all attention. Other speakers try, but Marvin the Album (and any number of other discs) only sounds this involving when the ProAc Response Fours are in use -- no qualification needed.

The big money

So often we believe that paying the big money for a piece of fine audio equipment gets us more -- more treble extension, more bass, more resolution, more transparency. But what the very best equipment delivers is something more elusive and complex. It wipes away preconceived notions -- that equipment is either musical or accurate, transparent or mellow, enjoyable to listen to or a clinical exercise. Great equipment transcends boundaries and creates that illusive illusion of music that commands complete attention.

And this is what the ProAc Response Fours do -- command your attention, although only vicariously because they serve the music first. In fact, they go beyond this reviewer’s bromide to make you ignore response curves, sampling rates, tubes and all of the other audio detritus. I’m sure there must be a speaker on the planet that measures better -- flatter from very high to very low -- and I’m equally sure that the Response Fours won’t be everyone’s cup of sonic tea, tastes being what they are. But if music matters to you, really matters, then the ProAcs are a logical choice because of the way they open up your collection, finding what’s most inviting in the recordings you have without pelting you with the kind of sound that great measurements can breed. The Response Fours are very expensive -- and very big, which means they deserve a big room -- but if you can swing the ultimate cost, you should hear them set up properly and playing any disc that I can think of.

As designs go, the Response Fours are long in the tooth, having been publicly debuted at the 1993 Chicago CES. There aren’t CESes in Chicago anymore, and I’m sure Stewart Tyler is working on a replacement for the Response Fours, which may be available next month or next year -- or maybe neither. I’ll believe that the new speakers are an upgrade and not a replacement when I hear them. Until then, I have some listening to do.

...Marc Mickelson

ProAc Response Four Loudspeakers
Price: $19,000 USD per pair in standard finishes

Highpoint Road
Buckingham Road Industrial Estate,
Brackley, Northamptonshire
NN13 7BE, England
Phone: 44 1280 700147
Fax: 44 1280 700148

US Distributor:
Modern Audio/ProAc USA
P.O. Box 812
Brooklandville, MD 21022
Phone: 410-486-5975
Fax: 410-560-6901

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