Listened to a beolab 3 for some time now, and compared to classic speakerdesign I think I miss some "midrange". I don't know but perhaps I like the more straightforward sound of a non-acoustic lens speaker. Has anyone here had the same thoughts? I ask this because the acoustic lens design seems to get little or no critisism, reviews are without exeption very positive. Listening to the 3's I think the sound is perhaps too much dispersed, it's hard to hear a "focus" of the sound, also the sound is very light-weight (although the bass is good), perhaps some will call that "transparant", but I think I miss a bit of directness (if that's  proper English), and body. 

Would like to hear some opinions about these issues.

Are you using them right?

B&O consistently fails to mention that acoustic lenses are supposed to have their sound reflected from side walls, relative to the listener. You are supposed to get a direct wave of sound from the speakers, combined with the reflection of the sound from the side walls. The slight delay as well as reduction in SPL of the sidewall reflections will augment the tone that reaches your ears.

Even without such sidewall reflections (symmetrical placement of speakers relative to walls and listening position is ideal), the acoustic lens will reduce the amount of floor/ceiling reflections, which is good as our hearing is designed to work along a horisontal band "through our heads." Dave Moulton has written much about the philosphy behind the lenses over at his website, as has his co-inventor, Manny LaCarrubba.

http://moultonlabs.com/ 

http://www.sausalitoaudio.com/company_overview.html

B&O marketing speak reduced the invention to "place them wherever you want" which is not very wise, unfortunately.

Even without sidewall reflections, the speakers measure flat as a dead calm in the region you are considering.

I have had a pair of Beolab 3's for a few years now, and I love them. Soundproof is absolutely right about the placement of speakers with acoustic lenses. Sometimes there's a lack of bass. but I can't complain about the midrange, however both improve when you add a Beolab 11.

Agreed.

B&O has long had a reputation for all show and no go when it came to speakers. The ALT technology was to put a big dent, but it seems that either B&O themselves didn't quite understand what they had, or didn't trust the clients to and so put the technology out there as a convenience feature.

I'll also mention that they should be listened to sitting down. It's a shortcoming of the B&O showroom design that you're often listening to loudspeakers standing up when the speakers are at ear level. It's not so much an issue of comfort (though you should be comfortable when auditioning speakers), but that the tight vertical dispersion of the ALT gives the music a hollow character if you're standing up too close to the speakers. It's like some of the sound is missing you.

Based on the way my house is set up, I'm listening to 3s and 9s the most and have to say that, to the extent that I still register an awareness of the technology, the 3s are often the standouts to me as they seem to outperform their size to a greater extent than do the 9s and 5s. 

To each their own, however. I still have older clients whose ears were nursed on speakers and amplifiers of a different age who still prefer the BeoLab 6000s as the best speaker. 

Can we expect a new alt loudspeaker this year Trip?

Trip: B&O has long had a reputation for all show and no go when it came to speakers

What about the seventies speakers? They gained a very good reputation, something I can understand as I own also a pair of Beovox S45-2, connected to a Beomaster 7000. 

Regarding the placement of my 3's; they are standing on top of their stands in a large (90m2) room without sidewalls very near to them. (switch set to "free").  

About the Beolab 6000 (which gets a lot o critisism here), I listened to those recently in the house of a friend, Chopin pianoconcerto was being played, and I was surprised how good they sounded, very clear and easy to listen to. 

Happy New Year, everyone!  May you prosper mightily this year!!!

jc makes an interesting point, and he's not wrong.  The BeoLab 3 is a 2-way speaker, and there is NO way that a 2-way speaker can cover the entire audio spectrum.  

Keep in mind that I use BL3s for professional production work, find them viable and like them a lot.  Nonetheless, there is less midrange energy (ca. 1.25-2.5 kHz.) than I'd like, simply due to the way the woofer is crossed over to the lens tweeter.  Lots of engineering thought (i.e. trade-offs) goes into a critical decision like that, and I for one don't want to second-guess the B&O acoustic designers that did that work, even though it might not have been my choice.  

I can live with it however, and enjoy the speakers a lot.  That characteristic has nothing to do with the lens function – it is simply a crossover decision.  But jc is physically correct, and his description is also, to my ears, accurate.    

Best regards,

JC, I'm referring to our reputation in the audiophile press and among audiophiles themselves. While I believe our speakers always sounded terrific, we were not taken seriously at our price-points. This may have been a different story in the 70s, but when I picked up the thread in the 90s, this was certainly the case. The BeoLab 5s seemed to be a turning point. 

@Mr Moulton: Thank you for your reaction, as it's very interesting to hear these technical background details from the person who knows the engeneering proces that produced the ALT speakers inside-out.

Can I therefore conclude that the crossover issue will be solved with the addision of a Beolab 11?

@ Trip: With the Beolab 5, perhaps the "audiophile" press in the end accepted that B&o in fact puts a lot of effort in R&D, a practice that up to then wasn't (and by some still isn't) recognised. But that's off topic.

jc:

Can I therefore conclude that the crossover issue will be solved with the addision of a Beolab 11?

The BeoLab 11 crosses over at much lower frequencies (80 Hz I believe, I could be wrong) which won't affect the midbands to that extent.

There is a good argument as to why using a subwoofer would help clean up the midband (reduction in harmonic distortion from the BeoLabs and less upward masking etc...) but it won't change the tonality of the midband...

I believe one's expectations of speaker performance needs to be related to their size. I'm quite amazed by what the BL3s are capable of, but have also experienced that they shouldn't be pushed too loud, and one would be waiting for the impossible if one expected pounding bass from them.

But they read very true for the kind of music I enjoy, and I feel very guilty about having mine as rear surrounds after having moved the BL4000s elsewhere.

The op feels that acoustic lenses are not doing justice to the the midrange, and that the sound is "too much dispersed."

Moulton is certain to have the specifics as to that. I have spent some time evaøuatong the same, and feel very certain that a similar size driver directed towards the listener in traditionalmfashion doesn't send as much energy towards you as do the lenses. It's easy to forget that the "ledge" and "cap" actually direct sound energy towards you that would otherwise have gone up and down with a regularly placed element.

B&O speakers in the 70s were not universally liked. I actually think that many of the speakers were actually designed for the relevant systems and their frequency responses designed with regard to this. The Beovox 1200 for instance are pretty ropey speakers when used with most systems, but really come into their own with a Beomaster 1200.

B&O did have various 'accidents' though, and the S45-2 and S120 speakers are ones which stand out as quite superb in their own right.

About the BL5 and other ALT speaker placement, bare with me, as I probably don't use the correct words to describe this...

 

So the speakers should be placed on a 90 degree axis to the walls behind them? And not be "toed in" towards the listener, which is very common to be used with traditional speakers?

A long time ago, Dave Moulton answered that specifically (I don't remember if to the board or to a pm), recommending straight placement. If acoustic lens technology is real, then that answer makes sense. But then, I am currently listening to a BS1 pointed the wrong direction, so what do I know?

symmes:

A long time ago, Dave Moulton answered that specifically (I don't remember if to the board or to a pm), recommending straight placement. If acoustic lens technology is real, then that answer makes sense. But then, I am currently listening to a BS1 pointed the wrong direction, so what do I know?

I'm quite sure I've read the same. Can't find the thread anymore, though.

Let's face it,most B&O buyers did't have the right placements.

i hope that AST would be standard in all beovisions.

koning:

Let's face it,most B&O buyers did't have the right placements.

i hope that AST would be standard in all beovisions.

AST won't make any difference with this particular issue (tonal balance) unfortunately....

I remember that thread also, about toe-in. I think it sprang up when razlaw had his Beolab 9s pointed in just slightly.

And then there was the comment about how the initial listening tests of ALTs mistakenly had them toed-in.

In response to jc's question:

I've never auditioned the BL11, and have no opinion of it.  However, it will not solve the problem I discussed.  2 drivers (as a general rule) do not have enough bandwidth to cover the 10 octaves of the audio spectrum (say, 20 Hz. to 20,000 Hz.).  A good, well-implemented driver might cover 2.5 octaves in a reasonable way.  So, 2-way speakers (including the BL3, which actually is a bit more than a 2-way) have serious limitations.  

One of these almost always has to do with a dip in output at the crossover point between the woofer and the tweeter.   The other has to do with the bottom two octaves of the spectrum, which are always deficient with a 2-way design (a driver big enough to move the volume of air needed to create an 18-meter long  wavelength – 20 Hz.) is too big (and has too much mass, generally) to produce the 10 cm. wavelength - 3 kHz. - at the crossover with the tweeter).  

Subwoofers are an attempt to fill in those bottom octaves, and may work more or less well, depending on a lot of things.  However, the midrange problem is entirely different, and can only be resolved by changing the woofer into a midrange (which means re-engineering the cossover design, among other things).  None of this is easy.  

The acoustic lens can actually help the tweeter extend a bit farthr down into the spectrum, but it is a really a dispersion altering dvice, not a spctrum altering device.  It can be scaled to fit any spectrum band you want (as in the BeoLab 5, which uss 2 lenses).  In the BeoLab 3, the crossover is at a typical frequency (ca. 3 kHz., as I recall), and there is a consequent dip below that which I hear and have to account for when I'm working.  

The brilliance of the BeoLab 3 lies in exending the low frequency response of the woofer through using passive side radiators with a different resonance than the driven front-firing woofer, thereby teasing almost an extra octave out of a tiny design.  I wish I'd thought of that!  

As for the other question on the thread about how to aim Acousic Lens speakers, the answer is, it doesn't matter much.  For years, I simply pointed them directly into the room, not at the listener.  I've also tried pointing them at each other, away from each other and other sillinesses.  

Right now, as part of retirement, I've re-invented stereo (for me) and have arranged my BL5s in a pentagonal array, aiming all five speakers at the listening position.  You can read about this at:

http://www.moultonlabs.com/more/happy_accident_a_better_way_to_play_back_stereo/

It works great!  I'm quite sure it would also work great with BL9s or 3s.  How good is it? One of my colleages auditioned his latest stereo release on it and said, "Ahhh.  This is why we do this work!"  

Thanks for listening.  

Alex:

koning:

Let's face it,most B&O buyers did't have the right placements.

i hope that AST would be standard in all beovisions.

AST won't make any difference with this particular issue (tonal balance) unfortunately....

 

I know...But you don't have a sweet spot in the 5.1 set-up

Dave Moulton:

I've never auditioned the BL11, and have no opinion of it.  However, it will not solve the problem I discussed.  2 drivers (as a general rule) do not have enough bandwidth to cover the 10 octaves of the audio spectrum (say, 20 Hz. to 20,000 Hz.).  A good, well-implemented driver might cover 2.5 octaves in a reasonable way.  So, 2-way speakers (including the BL3, which actually is a bit more than a 2-way) have serious limitations.  

The brilliance of the BeoLab 3 lies in exending the low frequency response of the woofer through using passive side radiators with a different resonance than the driven front-firing woofer, thereby teasing almost an extra octave out of a tiny design.  I wish I'd thought of that!  

This brings up two related questions:

- It seems like the shape of the Beolab 11 make it almost like a vertical acoustic lens- does it not such a dispersment issue as an ALT since the frequencies are so low?

- There are remarks made about the Beolab 2 being "slow" for bass because of the passive side radiators- if this really an issue, wouldn't it also be a problem with the BL3's? Here is a very positive comment about passive side radiators, but most comments related to the BL2 seem negative.

 

Guh, how irritating, I just posted a great big long response then accidentally closed the tab!

I know I can respond to the first question with some degree of knowledge if I may?

The lower the frequencies you're expecting your speaker to handle, the larger your horn or 'directivity device' needs to be. In the case of a subwoofer, this would have to be massive. An 'Acoustic Lens loaded' subwoofer would have to be wider than your average estate car is long. A horn-loaded BeoLab 5 subwoofer would have to be at least 8.5 metres across in order to make the deepest notes directional. This is because longer wavelengths wrap around smaller objects more easily. With an Acoustic Lens, you're trying to STOP the sound from wrapping around the horn, you want it to get directed in the 180ºx30º arc heard in the BeoLab 5, 9 and 3.

A BeoLab 11 is producing notes which have wavelengths as long as 6 metres, even longer in some cases. Even the highest notes it reproduces will have a wavelength of 1.5 - 2.0 metres. All of these are sufficiently long that they can wrap around the tulip design of the BeoLab 11 without being affected by it's shape at all. As the drivers are so close together, their sounds add together almost perfectly and more-or-less double the volume output. The BeoLab 11 is IMO a fantastic design!

As far as the BeoLab 3/2 thing goes, I have some theories in my head, but Dave will have much more knowledge about these two designs than anybody else on the forum! IMO, the tuning of the BeoLab 2 passive radiators is too low. A subwoofer of that size really shouldn't be able to reproduce such low frequencies at the sort of volumes the BeoLab 2 does. The result of this is higher levels of distortion. That's all in my opinion though!

Good questions:

The shape of the BL11 has little effect on its dispersion, because all of the wavelengths it produces are "large" relative to the device (ca. 3 - 18 meters).  It is definitely NOT an acoustic lens!  

Regarding the BL2, I've never believed it was "slow" in an auditory sense, as described by many.  I've found it to be really nice with BeoLab 3s for both video/film and music.  I don't use it in the studio bcause (a) for my production work BL3s alone are better and (b) with 5 BL5s on hand, I can "check the bass" extraordinarily easily!  The physics of passive side radiators are well known, and particularly with the mass added on the BL2 there must be some lag, manifested as phase shift,  relative to the driven woofer.  The difference between that and what I suspect happens with a BeoLab 3 has to do with the difference in size.  The BeoLab 3 will have negligible lag (relative to the BL2) because the size of the drivers is so much smaller.  

So I'm one of the ones that doesn't have a problem with this, especially on the BL3s.  I think they are both great examples of audio engineering!  

Thanks for listening!  

Dave Moulton:

The brilliance of the BeoLab 3 lies in exending the low frequency response of the woofer through using passive side radiators with a different resonance than the driven front-firing woofer, thereby teasing almost an extra octave out of a tiny design.  I wish I'd thought of that!  

Dave, thanks for you comment to my earlier question. One more thought though about your BL3 comment and BL2s and the extra octave, just an observation- do the BL2's get further down in the frequency range for the same reasons? I heard a BL2 in a store years ago that were with BL1s, and as a test track I had an organ piece which featured a soft 64' stop, which is around 8Hz. So this is well below the "spec" but it made a rumble! Later I tried the same track on BL5 and frankly didn't hear so much. Of course the 64' stop was a "resultant" stop, meaning it is really two pipes, neither 64' long for practical reasons, a 32' stop (16Hz low C) and a 2nd rank tuned a fifth above (24) so the beat frequency is 8, this is sometimes done for very low notes on organs. Of course any two tones close in frequency has a beat (major 3rd in equal temperament at some ranges).

The crossover characteristics of the Beolab 3's as discussed above did remind me of a earlier thread about the presumed lack of midrange of the Beolab 9's. Does anyone know if the 9's are designed with comparable crossover frequencies?