Mar 06, 2004

I was fortunate to be extended an invitation by a Berklee professor to attend yesterday’s Music Technology divisional meeting, where Dave Moulton gave a presentation on B&O’s Beolab 5 speaker. The presentation was followed by a question-and-answer session, and an hour-long listening session. I missed the first part of the presentation, but I was able to hear about some of the technologies behind the speaker.

Quick notes from the presentation:

• The computer used for the calibration is firmware upgradeable via an RS232 port. In response to a question, Dave mentioned that there is no real-time output from the computer, so audiophiles can’t tweak settings on the fly.
• The microphone used for calibration is located at the bottom of the speaker, and moves to 3 different positions to determine the driver performance and the room performance. Based on the demo, the speaker appears to use warble tones to perform the calibration (presumably to minimize standing waves). Dave indicated that 10 Hz to 300 Hz test tones are generated for the calibration.
• The computer compensates for thermal compression characteristics of the driver, so the speaker performance should not degrade as the drivers heat up during long/loud listening sessions.
• Each speaker contains 4 Class-D amplifiers to power the bass, mid-bass, mid-range, and treble speakers. Total rated power is 2500 watts per speaker.
• The speakers are rated at 108 dB per pair at 10 ft.
• I had a chance to ask Dave about the possibility of Sausalito Audio Works or B&O making the acoustic lens available for the DIY market. Dave said that it was considered, but unlikely to happen soon (if ever). The acoustic lens apparently requires a fair amount of engineering and cross-over work to properly integrate with the tweeter and the rest of the system, so in its present form it may not be suitable for DIY’ers. Too bad.

For the demo, we listened to a variety of music including pop (Paula Cole), Jazz (Count Basie), gospel, hip-hop (Outkast), classic rock (Led Zeppelin), and classical (Mahler’s 3rd Symphony). My impressions from the listening session:

• The Beolab 5 has, by far, the best bass response I have ever heard in loudspeaker. I will admit that I was somewhat skeptical of the room correction function. Frankly the Beolab 5’s room calibration system works, and works well.
• The treble response was airy and detailed, without being overly harsh or bright. In short, very good, but I think I still prefer the sound of ribbons.
• A pair of Beolab 5’s had absolutely no problem in filling the (approx) 50ft by 50ft by 20ft David Friend Recital Hall with sound. The bass and soundstage were fairly uniform throughout the hall, despite the difficult conditions in the hall.
• Those suckers get loud! The audience (mostly composed of recording engineers I presume) kept asking Dave to crank up the volume, and at one point I would guess the sound level as well over 90 dBA on average, with peaks approaching or exceeding 100 dBA. The speakers showed no signs of stress at all, and my ears gave up before those speakers did. (BTW, given how comfortable the rest of the audience appeared to be during the loudest levels, I think everyone in that room needs to get their hearing checked!).
• Hip-hop fans might be disappointed in the bass response. If the track has real low-end, the Beolab 5 will shake the room, but most hip-hop tracks seem to be mastered for playback on bandpass boxes that accentuate the 50 to 60 Hz range. The Beolab will precisely reproduce bass, but it’s not going to emphasize the mid-bass like some ported home and car audio speakers.
• My only critique: while the speakers did project a wide soundstage, I was disappointed in the imaging. While listening to very good speakers, you can usually close your eyes, and point out the piano, vocalist, etc. I couldn’t with the Beolabs. For example, during the a capella portion of Paula Cole’s “This Fire,” Paula seemed to be about 10 feet wide. Granted, I was never able to listen to the speakers at the “sweet spot,” and the recital hall was challenging to say the least. I may need to listen to these speakers in a more suitable environment.

In short, while these speakers are not quite the best I’ve ever heard (that honor goes to the Wilson Watt/Puppy), they’re definitely among the best. I highly recommend that every audiophile give them a listen. The bar has certainly been raised, if not for overall speaker design, then certainly for bass performance.

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