ProAc Response Three loudspeaker Response 3 Signature, April 1994
Although the Response 3 Signature has not replaced ProAc's well-respected Response 3 (still available for $6500/pair, and reviewed in Vol.14 No.9, p.126), it is an evolved refinement of the basic design, and is intended to stand on its own. But is the 3 Signature worth $3500/pair more than the 3?
The Response 3 has a rich, full mid/upper bass; a lush, musical midrange with wonderful harmonic structures; a clean, quick presentation; a smooth, extended treble that lacks any textural coloration; and outstanding soundstaging which develops around and behind the speaker cabinets. It has wonderful resolution of width and depth, with pinpoint, three-dimensional images within the stage. Such superlative performance can be achieved when the speakers are set up well away from both the rear and side walls, with adequate distance between the speakers as well as from the speakers to the listening position. The proper amount of mass-loading, use of the supplied spiked feet, proper toe-in (ie, drivers aimed right at the listening position), and appropriate amplification are required to achieve this musically satisfying level of performance. Still, the 3 does suffer from slight but problematic resonances and a lack of true deep-bass extension.
The Signature's cabinet incorporates two significant improvements: additional internal damping to address criticisms of the speaker's resonance problems, and new veneers (burr oak, Madagascar ebony, birdseye maple, and silk oak/lacewood) specifically selected because their tight grain structures enhance cabinet rigidity. The new veneers look better, cost more, and aren't derived from endangered trees. The review pair was finished in silk oak and had a gorgeous, rich, golden hue with almost iridescent grain. More important, the new cabinet sounded deader than the old when I rapped on it in various places.
The driver complement of the Signature appears to be identical to that of the 3: dual 6½" polypropylene midranges from Scan-Speak surrounding a ferrofluid-cooled, soft-dome, 1" tweeter. The tweeters, however, differ in their doping and tolerance selection/matching—the Signature's tweeter purportedly exhibits greater extension. Other major differences include the increased use of rhodium plating in the Signature's spikes, bolts, terminals, and crossover traces. There are also changes in the internal wiring and in the topology and parts (eg, silver film capacitors) of the crossover.
Knowing the best location for the 3s in my room, I installed the Signatures' spiked feet, loaded the sand, and placed them in the same locations as their forebears—I didn't expect to have to do a lot of experimenting with room placement. Like the 3s, the Signatures worked best when placed well away from the rear and side walls, and toed-in directly at the listening position. I was surprised by the amount of sand recommended for each speaker—27 lbs. I'd found it necessary to use 32 lbs in my 3s to tame the cabinet resonances—any less, and the midbass bloom was excessive. The Signatures, with only 27 lbs of sand, were significantly less resonant than the 3s. This confirmed the results of my rap test and verified the efficacy of the improved internal damping and the different veneers.
Recordings with lots of midbass information, such as Bela Fleck's Flight of the Cosmic Hippo (Warner Bros. 26562), Suzanne Vega's 99.9°F (A&M CDB 0005), or Sara K.'s Closer Than They Appear (Chesky JD67), amply demonstrated the Signature's improved bass performance. While there was no obvious change in the extension or quantity of the bass, its real-sounding, natural character was considerably enhanced—not only was it cleaner and quicker, it also sounded more open. These changes added to the 3's already dynamic, richly harmonic character. The reduction in resonance was also most apparent in the midbass region. These changes eliminated distractions to the music by reducing the overall noise floor; the sound was more transparent and more revealing of inner detail.
Subtle bits of musical information were more noticeable with the Signatures than they'd been with the 3s; eg, the decaying bells on Lucia Hwong's Secret Luminescence (Private Music 2021), or the purity of the rubbed water glasses on Rickie Lee Jones's cover of Jefferson Airplane's "Comin' Back to Me" (Pop Pop, Geffen 24426). Another example was the wonderful direct-to-CD Dick Hyman Plays Duke Ellington (Reference RR-50DCD)—many of the non-musical sounds convinced me that Hyman really was there playing the computer-activated Bösendorfer. With many of the LPs and CDs I played, I heard either more information or improved clarity of subtle sounds.
My other major criticism of the 3s concerned their lack of extension into the deepest bass. Neither the 3 nor the Signature was able to re-create the realistic wallop of the timpani on Symphonie Fantastique (Chesky CR1), the Telarcian whomps from Alborada del gracioso or "Fandango asturiano" on Capriccio espagnol (CD-80208), or the power of the mass of acoustic basses on Ray Brown and friends' Super Bass (Capri CPR 74018). The Signatures reproduced everything more cleanly and with greater rhythmic precision, but there was nary an ounce of deeper bass.
Although not as substantial an improvement, the Signature's midbass did sound slightly more lively and dynamic. I didn't hear this effect on every LP or CD, but it was audible on recordings containing sweeping dynamic transitions, such as PJ Harvey's Rid of Me (Island 314 514 696).
The ProAc Response 3 Signature is indeed an improvement over the 3 in its lower cabinet resonance, better midbass articulation, improved resolution of inner detail, and slightly enhanced dynamic capability. Though the Signature costs $3500/pair more than the 3, the latter's deep-bass limitations remain unaddressed. The Signature is a sonic winner, but fares poorly in a price/performance comparison with the 3.—Jack English