Beolab 5 - Four Questionable Technologies

""The term applied to the use of comb filters to obtain special sound effects."

Is that what you mean by flanging?

Henry

What I mean by flanging is exactly that. In the case of two tape recorders playing the same signal slightly out of time then you will get a "comb filter" frequency response - some frequencies double where the signals reinforce and other frequencies completely cancel. There is a harmonic relationship between the signals that cancel and the signals that reinforce. The sound can be either "full" or "thin" depending on the instrument. True "flanging" as done on the guitar will give a "swirling effect", perhaps this is what Marty expected to hear and did not, --- with true flanging the time delay is varied (not fixed) with a foot pedal and this creates dramatic movements of the sound.

In the case of the Beolab 5, the sound is bouncing off the frizbee on top, it is also posssibly bouncing off the bottom frizbee on the bottom and thirdly it is hitting your ears directly from the dome drivers themselves ( no bounce ). So in essence it is like having three tape recorders all playing exactly the same music with a FIXED time delay between each recorder and the volume levels different (the loudest sound probably comes from the reflected sound bouncing off the underside of the frisbee above the dome driver, the next loudest may be either the direct energy from the driver itself or the sound reflected again off the bottom frizbee after it has already hit the top frizbee) These three signals are identical except they are offset (time delay) with respect to eachother and of course the principal one is much louder than the others. Critically these all radiate into the room with their fixed delay. So your ears will hear all three signals mixed or muddled together (they are much too close in time to separate into "echos"). The time delays are very similar to natural reflections and what I am describing are all well known facts about how audio delay can affect the perception of audio. Notice how Figure 5 - Comb Filter With Signal Level Adjustment bears a slight resemblance to this frequency plot.

In the case of the Beolab 5 the delays (if they exsit) would be of the order of 1/2 to 1.5 millisecs (governed by the distance between the frizbees of around 8 inches and the speed of sound in air). This may affect cymbals, horns, vocals and lead instruments. IMHO, it will likely make the treble sound less harsh or piercing.

With me was an experienced audiophile friend. He has a pair of Wilson Sophia speakers at home. He was not impressed. He described the sound as "analytical" "dry" and "lacking certain timbral nuances."

I would agree with your friend. I found the sound to be slightly congested/cluttered in upper midrange. Treble sounds were not crystal clear and precise. It made for a softer more agreeable and less revealing sound then I would normally associate with Wilsons or another forward "precise" type speaker. I agree about the timbral nuances and this is perhaps my perceived issue with the lower mid range sounding too "thin" (and this could indeed be room related). However, as Marty pointed out the speaker was, on the whole, very neutral sounding.

Bear in mind that my criticisms are aimed at a $23,000 speaker...on the whole the sound was what most anyone would call wonderful, amazing or awesome (as it darn well should be at this price!!). The bass response, as I have previously stated was particularly impressive.

However, given my taste for transparent sound; take my comments with a good pinch of salt! I want to hear the sound as close as possible to what is on the source...additional colorations, no matter how pleasing, are something I try to avoid. Since you are looking for something that you can live with for twenty years then your judgement is what counts!

Marty and Shardone,
Thanks for the ongoing discussion! It helps educate me before I spend a large amount of money.

The biggest concern with these innovative speakers that you both share is the missing soundstage. I gather you are referring to the lack of the illusion of the musicians laid out properly in space in front of you. I wonder if that flaw is the price one pays for the benefits of the Acoustic Lens technology? This technology allows for a much wider “Sweet Spot” but perhaps the sweet spot we get isn’t as sweet as it would be in a more conventional speaker.

Being new to High End Audio, I can’t say that I’ve developed my skills at detecting the soundstage yet; but it must greatly enhance the sense of “being there.” To help accomplish this, do Audiophiles always try to sit at precisely the right spot when they are doing active listening?

You both also complained about “congestion/compression” and “congested/cluttered in upper midrange”. Please help me understand. I’m guessing that you mean that in parts of the music the differences between instruments might blur, which makes it hard to differentiate or even identify the instruments?

Funny that you should end the last post by writing “I want to hear the sound as close as possible to what is on the source...additional colorations, no matter how pleasing, are something I try to avoid.” I spent a couple hours in the afternoon listening to the B&W 800Ds in a very fine listening room. The words that kept coming to my mind were “natural” and “real”. Perhaps those are the speakers I will buy…

But I remain deeply interested in the Beolab 5s. One variable that has undoubtedly had a big impact on all of our listening experiences was poor listening rooms. It would seem to me that the ideal next step would be to get the Beolab 5s and the B&W800Ds into my listening room at home, preferably at the same time for some extended A:B comparisons.

Is that a reasonable next step?

Design has much merit and is well thought out. My problem with a all digital amped, DSP loudspeaker is time. We all know how well computers age will this loudspeaker be fairly worthless in the future like a old computer or DAC? Will advancements in dig amps and DSP make it primitive in the near future? While folks who bought conventional loudspeaker designs can still upgrade amps etc. Will the digital section hold up as well as the transducers or if it gets a voltage spike is it toast?

Hdomke,

To get a sense of soundstage go to a nearby high end dealer and ask him to demo any speaker that he feels will impress with its soundstage. Most will be able to find a recording and system that will make it very clear what the term means. Ironically, some people (justifiably) point out that you rarely hear this type of spacial illusion at a real performance. Usually, that is quite true. Yet, the quality in a stereo is critical to me. YMMV.

BTW, I can't state with confidence that the Beolab 5 doesn't image (soundstage) well. Few speakers will do so when jammed into corners. Also, the congestion I heard at demo may be due to distortion generated by the speaker as loudish, complex musical passages tax the drivers and force them to misbehave. Or, as I noted, it could have been the set-up or some defect. I was not listening at crushing levels and I found the problem instantly identifiable. I find it hard to believe that neither of the reviews linked to this thread mentioned the problem, so I'm inclined to believe that it was unique to the Beverly Hills set-up.

OTOH, Shadome may have heard a similar problem. It's quite possible that the wide dispersion pattern makes distance from the side walls critical to best results. A speaker which pours so much energy off axis may sound congested due to early side-wall interactions. Shadome, how was the set-up at your demo?

To sum up, I left the demo feeling like I knew very little about the speaker, other than buying this speaker would require an in-home demo and a large listening room. I don't know if B&O would accomodate such a request.

Good Luck,

Marty

I gather you are referring to the lack of the illusion of the musicians laid out properly in space in front of you.

Yes Exactly.

I wonder if that flaw is the price one pays for the benefits of the Acoustic Lens technology? This technology allows for a much wider “Sweet Spot” but perhaps the sweet spot we get isn’t as sweet as it would be in a more conventional speaker.

No. Other conventional box speakers can have wide dispersion and hence a large sweetspot AND image like there is no tomorrow. Like Marty - I fully expect a vocalist to appear as a solid single image in a mix - clearly positioned - not dispersed vaguely in front of me. When a duet is singing I can clearly hear that they are positioned two feet apart in the soundstage when they are mixed that way. I felt that the Beolabs hinted or gave glimpses of precise imaging in certain sounds or vocals but did not do so solidly all the time - much of the time there was a certain diffuseness to everything)

To help accomplish this{Soundstage}, do Audiophiles always try to sit at precisely the right spot when they are doing active listening?

No it is not necessary to sit at precisely the right spot on widely dispersive high quality speakers such as you can find at this price. Location of sound is NOT all about volume level in fact this is a misconception propagated by the industry to try and sell more center channels. You can have one speaker 10 DB louder than the other and yet the sound can come from directly between them....it is timing that tells us the location much more than volume level (most people are unaware of this). Of course the image will move slightly as you sit in front of one speaker or the other but the soundstage should not collapse. Also if timing is messed up or poor then volume level will weigh more heavily in how you determine the position of instruments in the soundstage.

You both also complained about “congestion/compression” and “congested/cluttered in upper midrange”. Please help me understand. I’m guessing that you mean that in parts of the music the differences between instruments might blur, which makes it hard to differentiate or even identify the instruments?

Yes is was "blurred" or not razor sharp clear in the upper mid range. It sounded "softer" or less piercing and less harsh then I would expect from natural sound. It made for a less exciting or involving sound as there was no "edge" to leading instruments or vocals. If this is indeed the 3' Vifa Dome Midrange driver that is being used then it only has a linear Xmax of +/- 0.5 millimeters - which is not much better than most tweeters (i.e. terrible) - this dome midrange will compress all to easily if driven too low in frequency which means that either you lose lower midrange energy from compression at high levels or you need to crossover very high into the midrange with the 6 inch woofer - either way this concerns me but it is conjecture as I have no proof that is definitely is the 3" Dome Midrange from Vifa that Beolab 5's are using. (The midrange dome on my speakers has an Xmax of 3.0 mm or six times more linear excursion than the Vifa mid - so I get more than enough crystal clear midrange energy before non-linearities/compression sets in)

I spent a couple hours in the afternoon listening to the B&W 800Ds in a very fine listening room. The words that kept coming to my mind were “natural” and “real”. Perhaps those are the speakers I will buy…

Yes do buy these over the Beolab - far better, IMHO. This is a fine speaker. A bit hard to drive but with the right SS amplification they will sing. The large midrange tends to "beam" slightly in the top of the midrange (less wide dispersion or even sound field from 2 to 4 Khz) and they come on a bit strong around 4 Khz (when the widely dispersive tweeter kicks in) - however this is nitpicking - this is an absolutely outstanding speaker. World class.

It would seem to me that the ideal next step would be to get the Beolab 5s and the B&W800Ds into my listening room at home, preferably at the same time for some extended A:B comparisons.

I am not sure I agree but it is your taste that counts not mine. (As you know by now I think the 800D is a far better speaker, however, I also think you owe it to yourself, at this price, to audition a few other speakers. It would be worth the price of a weekend trip to CES just check out other designs, at your price point.)