RBH 641-SE loudspeaker Page 2

The 641-SE was not nearly as sensitive as the Thiel CS1.6—I wouldn't suggest using less than 100W with this speaker. However, the RBH had sweeter-balanced top octaves—perhaps a little too sweet, considering that the Thiel is a little laid-back in this region. There wasn't quite the "air" I was expecting from the Analogue Productions SACD of Bill Evans' classic Waltz for Debbie (APO CAPJ 9399 SA) that I've heard from other speakers. Nevertheless, the Utah speaker's treble was extremely detailed, and proved well capable of differentiating between the antique cymbals drummer Billy Drummond used on Rendezvous (Stereophile STPH013-2).

In fact, I kept noting during my auditioning how clean the 641-SE's high frequencies were. To judge from the ABKCO sampler SACD I have, the DSD remastering of the early Rolling Stones albums must have been done with great care. Charlie Watts' drums sounded better than on my well-chewed '60s vinyl, and the characters of inner voices—like the marimba on "Under My Thumb" and the difference between Bill Wyman's slightly overdriven bass and his overdubbed fuzz bass guitar on the same cut—were readily audible, but with no sense that that detail was being thrust forward at the listener.

The upper midrange was similarly clean, but a trace of "character" was audible lower in the frequency range. Female voices sounded a bit too warm, for example, the clarinet on my Mosaic recording (Stereophile STPH015-2) occasionally acquiring some of the character of a soprano saxophone, and the solo violin some of the woody character of a viola. In absolute terms, however, this coloration was low in level.

I mentioned above that the 641-SE's low frequencies extended down to the 40Hz region. Overall, however, the bass region was a little shelved-down. The multiple-octave D chord at the start of Morten Lauridsen's Lux Aeterna (RCM 19705) didn't have the expected majesty, and familiar piano recordings, such as Robert Silverman's Beethoven sonata cycle (Orpheum Masters KSP-830), were reproduced with the instrument sounding a little smaller than expected. Because of the layout of my room, I can't place speakers closer than 3' or so from the wall behind them. But if you can place the RBHes within a foot or so of the wall, they should benefit from some useful boundary reinforcement of their low frequencies.

But even with the speakers well away from the walls in my room, there was enough low-frequency energy to make sense of the music. The low double-bass and harp notes underpinning the harmonies at the resolution of the slow movement in Benjamin Zander's performance of Mahler's Symphony 5, with the Philharmonia Orchestra (Telarc 2SACD-60569), were well-resolved. (For obvious reasons, I was listening to the two-channel DSD-encoded data on this "fully loaded" hybrid CD, which includes multichannel DSD, two-channel DSD, and two-channel "Red Book" LPCM tracks.)

And the image of Bob Silverman's Bösendorfer in the acoustic of the small Santa Monica hall where I had recording the Beethoven set was vividly clear, as was the semicircle of musicians on Mosaic. The soundstage thrown by the pair of RBH 641-SEs was consistently wide and deep, with no feeling that sounds were localized at the loudspeaker positions. Peculiarly, I got the consistent impression that centrally located images were higher than ones to the sides. This is usually a sign that a speaker has some treble-response anomalies that mimic the modifying effect of the pinnae of the listener's ears. But I couldn't identify any such coloration, and none was evident in the measured response (see sidebar).

The 641-SEs' soundstage was so consistently wide that I initially suspected a phasing problem with one of the tweeters. However, listening to pink noise in dual-mono resulted in a narrow, stable central image, suggesting that everything was okay in the drive-unit phase department. I confirmed this by looking at the individual step responses of both samples' drive-units. I can only assume that the 641-SE's very narrow baffle and its small drive-unit radiating area from 150Hz up has optimized the speaker's lateral dispersion, hence its imaging capabilities.

Conclusion
It is important not to make too much of the poor integration I noted between the RBH 641-SE's woofers and midrange when the speaker was correctly wired. This frequency region is strongly affected both by the behavior of the speaker in the room and the size of the room; what might be the theoretically correct wiring might not be the optimal connection in every room. But if it isn't, the 641-SE's dual binding posts for biwiring make the fix simple: remove the jumpers and flip the electrical connection of the woofers of both speakers.

Once that matter had been addressed, I was impressed with the 641-SE. For what is really not a lot of money, sweet-balanced, grain-free high frequencies are allied to a detailed midrange. While the low frequencies are somewhat lightweight in absolute terms, there is sufficient bass to create a musically satisfying balance, particularly with rock music. Where the RBH speaker really scores, however, is in the generous sweep of its soundstaging and stereo imaging. Recommended, therefore, with a caveat regarding the woofer connection.

COMPANY INFO
RBH
976 N. Marshall, Bldg. 2, Unit 4
Layton, UT 84041-7261
(800) 543-2205
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