Kal's Beolab review is out!

[watchnerd]

It must be difficult the US has been in the vanguard of audio electronic design for decades but now finds itself rather lagging, have you read the nonsense spouted by the Dave Wilson in the Stereophile piece, he doesn't appear to know anything about loudspeaker design whatsoever.
Keith

Link?

 

[amirm]

I am not pointing fingers but, sometimes, it is hard to determine the differences between snide, satiric and sophomoric around here.

Indeed. We have mastered that art quite well here.

 

[Sal1950]

Link?

http://www.stereophile.com/content/...r-wamm-master-chronosonic#rPslrCZv6hg8esiW.97

 

[amirm]

FWIW, the review is accessible now at this link address: http://www.stereophile.com/content/bang-olufsen-beolab-90-loudspeaker#EtGzgLBrbKF7MXey.97

Thanks Kal. A little disappointing that after all the talk about off-axis response, JA did not make this measurement due to practicality I assume.

 

[RayDunzl]

The way I see it, the thing about DSP is that (given some reasonable drivers and amps), you can set it up to give you any impulse response you like - at one position in space.

I did that last night.

Before "corrective" DSP, Step, JBL LSR 308:

After

And the "after" at a different point in space, 100 cm to the left. It is still "corrected", but the waves from each speaker arrive at different times. Here, the wavefront of the left speaker arrives 3 ms before the wavefront of the right speaker. This is what happens when you sit to the left of the sweet spot in front of a stereo pair.

So, the correction gives correction in more than one point in space, though only one point (or line between two speakers) is fully corrected.

 

[RayDunzl]

From Kalman's Stereophile Review:

• "In Wide mode, the BeoLab 90s sounded like very good conventional loudspeakers, with a two-channel sound that was on a par with the best I've heard in this room: well balanced, with powerful, extended bass and wide, deep soundstages. However, when I switched to Narrow mode, it became apparent that the standard stereo presentation of Wide mode—and, indeed, of most other pairs of speakers I've used—was flawed. Narrow mode simply erased a hash of spurious ambience that flanked the central soundstage. That hash exaggerated the width, and contributed to the impression of "audiophile air."

That's a nice reviewer description of what I'm hearing with my "conventional" JBL LSR 308 vs my dipoles.

• "Also, in Narrow mode, the stereo image snapped into a new level of precise stability."

That's what I get from my dipoles, comparatively.

• "In Narrow mode, the BeoLabs delivered what I heard as increased resolution, detail, and tonal honesty, unsullied by the interference of short-latency reflections. Users of dipole speakers, in which the interference of the outputs of the front and rear drivers causes cancellation of lateral dispersion, will have experienced something similar—but not to this degree."

That's as good a description of the difference between sound of cones and domes and my electrostats in my room as I've read.

Now I just have to work on a less-than-$85,000 improvement to the degree...

See this post for what I think might be that "hash".

 

[RayDunzl]

The next step would be to send a pair, no, wait, one speaker is all they need for this, to Harman and repeat the test that gave my dipole design such a poor score. (Speaker M in the graphic below)

Maybe the Beolab will acheive a new scientifically and statistically verified low in preference.

 

[amirm]

B&O is one of the few outfits outside of Harman that performs double blind tests of speakers. Have they published such for these?

 

[Cosmik]

So, the correction gives correction in more than one point in space, though only one point (or line between two speakers) is fully corrected.

A great demonstration. I presume that if you were to move up or down, though, the drivers' contributions would begin to 'separate' a little. Also, if there was more of a mismatch between the dispersion characteristics of the drivers, things would begin to get a little strange off axis.

So is there an audible difference between the corrected and uncorrected versions?

 

[watchnerd]

B&O is one of the few outfits outside of Harman that performs double blind tests of speakers. Have they published such for these?

I would like to see that. I'm going to assume B&O isn't insane and wouldn't bring such an expensive undertaking to market unless they have strong reason to believe people liked the sound of it.

Because from the measurements, the Beolab 90 just seems like a hot mess unworthy of the asking price; it makes me wonder if all the gushing praise is because it's "better" or just because it's "different?"

 

[Cosmik]

I would like to see that. I'm going to assume B&O isn't insane and wouldn't bring such an expensive undertaking to market unless they have strong reason to believe people liked the sound of it.

Because from the measurements, the Beolab 90 just seems like a hot mess unworthy of the asking price; it makes me wonder if all the gushing praise is because it's "better" or just because it's "different?"

I think that the DSP-active difference (in a well set up demonstration) is so obvious compared to what went before, that ordinary people are bound to be impressed even if the DSP isn't truly optimal. Couple that with some big woofers, smoothly contoured enclosures, and understressed drivers, and I imagine it sounds pretty sweet.

(I have heard some dodgy demos of DSP-active speakers too, though...)

On the general point of only selling something anointed by trained audiophile listening panels (e.g. Harman?), I think this is a very conservative idea: audiophiles with decades of exposure to to vinyl, valves and passive crossovers are 'set in their ways'. They may effectively be deaf to the advantages of the finer points of the new technology.

Traditionally, when I listened to the quality of the sound reproduced by my audio playback equipment, I focus on tonal balance (frequency response), dynamics of the sound (SNR), residual noise floor ( inaudible ), distortion ( inaudible ).

Interestingly, all of the above characteristics can be assessed and visualized in frequency domain. It was simply the easiest way to listen to the sound and evaluate what I was hearing, but I now realize, that I was only considering the steady-state analysis in the frequency domain...

I was doing the same type of analysis over, and over again for years, and grew accustomed to this ritual. It was easy to compare with measured results, so it felt comfortable, that I can correlate my measurements with what I can easily hear (or can not hear). Recently, things have changed for me. ...

... I came to the conclusion, that my listening tests were only a starting point of what I should have listened to when examining linear-phase loudspeakers. To put it simply – I needed to significantly extended the evaluation of timedomain characteristics of the loudspeaker in my listening habits. ...

...I have pointed out one perceptible difference – I felt closer to the stage/musicians. This was more of an accidental and unexpected impression, to which I did not pay much attention. But this indeed relates to time-domain characteristics of a loudspeaker, rather than frequency domain. ...

...The remaining part of this paper is my crude attempt to summarise audible attributes of linear-phase loudspeakers. This is what you need to listen for when evaluating linear-phase loudspeakers. I do not pretend, that the list is complete, but it’s a start. It clearly points to the time-domain characteristics of the loudspeaker, and this is something, which may of us (till recently, including myself) are not accustomed to. I simply did not know what to listen for.

 

[Thomas savage]

I would like to see that. I'm going to assume B&O isn't insane and wouldn't bring such an expensive undertaking to market unless they have strong reason to believe people liked the sound of it.

Because from the measurements, the Beolab 90 just seems like a hot mess unworthy of the asking price; it makes me wonder if all the gushing praise is because it's "better" or just because it's "different?"

JA stereophile says it measures brilliantly, a tour de force no less....?


To say I was impressed with how the BeoLab 90 measured in its Narrow mode would be an understatement. This loudspeaker demonstrates just how much can be achieved with intelligent use of DSP to optimize its acoustic performance. As Kal Rubinson summed up, it is a tour de force. Wow!—John Atkinson




Read more at http://www.stereophile.com/content/...-loudspeaker-measurements#OBQgfjZVyVjsL9Tb.99

 

[Purité Audio]

Page 14 onwards,
http://www.bang-olufsen.com/~/media...redesign/bang-olufsen-beolab90-whitepaper.pdf

Keith

 

[watchnerd]

I think that the DSP-active difference (in a well set up demonstration) is so obvious compared to what went before, that people are bound to be impressed even if the DSP isn't truly optimal. Couple that with some big woofers, smoothly contoured enclosures, and understressed drivers, and I imagine it sounds pretty sweet.

It might sound sweet in a "more real" way, but it might also perform as a gimmick like all those "stadium", 'hall", "jazz club", etc settings on AVRs that sound cool at first, but eventually get boring and turned off.

 

[fas42]

I would like to see that. I'm going to assume B&O isn't insane and wouldn't bring such an expensive undertaking to market unless they have strong reason to believe people liked the sound of it.

Because from the measurements, the Beolab 90 just seems like a hot mess unworthy of the asking price; it makes me wonder if all the gushing praise is because it's "better" or just because it's "different?"

People were gushing about its predecessor, Beolab 5 - the Dalek. Went to B&O's very slick showroom, were hugely entertained by the saleman's efforts to make the ridiculous CD player with vertical sliding tray work, as in play at least one CD - we now had good feedback on the robustness of B&O's engineering ...

When eventually something decided to work, and sound came out, it was nothing to get excited about - reasonable, conventional audio - nothing particularly wrong with it, but there wasn't anything noteworthy either.

 

[watchnerd]

To say I was impressed with how the BeoLab 90 measured in its Narrow mode would be an understatement. This loudspeaker demonstrates just how much can be achieved with intelligent use of DSP to optimize its acoustic performance. As Kal Rubinson summed up, it is a tour de force. Wow!—John Atkinson

JA's ability to turn a blind eye to his own measurements has precedent.

Regarding B&W, he's said "I am always puzzled by the fact that B&W speakers don't measure as well as they could," i.e. they measure kind of ******.

Or the Zu Audio Soul Supreme, which a) has a measured sensitivity ~6 dB below spec (come on Zu..that's not manufacturing tolerances, that's just fibbing) and more importantly b) clearly goes into cone break-up mode.

About this he said, "Finally, the Zu Soul Supreme's cumulative spectral-decay or waterfall plot (fig.7) looks awful, with a significant resonant mode at 2.8kHz—that accounts for Herb's presence-region rise—and hashy-looking delayed energy in the top audio octave. Yet, other than noticing a somewhat clanky quality with recordings of acoustic piano, I didn't find the Zu to sound as bad as this graph implies." Wow, so intentionally messy acoustic engineering isn't called out because it doesn't sound as bad as the graph might make you think...

That might be an acceptable assessment if evaluating a $199/pair 8" monitor from Monoprice, but for a $4500/pair speaker? Come on...

 

[amirm]

Page 14 onwards,
http://www.bang-olufsen.com/~/media...redesign/bang-olufsen-beolab90-whitepaper.pdf

Keith

Thanks. Wish they had documented their graphs better. This one for example is presented with no reference in text:

I don't understand the coarse resolution of outer graphs. By lowering the resolution of the graph you can more or less have as smooth of a response as you want.

Any prettiness disappears when you change the settings from narrow:

To this disaster that is wide:

And polar plot of the same:

No wonder Kal did not like omni mode.

 

[amirm]

Found this video from Soundstage on design philosophy. It is informative but sadly makes no reference to blind listening tests:

 

[Cosmik]

The Beolab 90's impulse response is nothing to write home about, either
B&O's explanation is latency related to DSP. But, still....that's no bueno.

In contrast, if you compare the impulse response of the Dynaudio Focus 200 XD (MSRP $7000 pair), which also uses a DSP crossover (and Class D amps) and some mild contour shaping filters (admittedly much less intense that what the Beolab 90 is trying to do), you get this:

Having read the review, I think I agree with you: the reviewer says it shows "optimal crossover topology", but I would have thought that at the listener's position, "optimal" would be a real step, as you show in your second image. I seem to remember seeing something similar in a review of a Meridian speaker - that you might have expected to be time-aligned.

 

[RayDunzl]

So is there an audible difference between the corrected and uncorrected versions?

Yes, but except for bass, or a FR adjustment if requested, time correction is more subtle, and maybe more content specific. DRC doesn't clear up the imaging problems which I have yet to prove to be due to reflected energies.

They may effectively be deaf to the advantages of the finer points of the new technology.

That's a nice read, seems to correspond to some of my impressions. Particularly page 5.

Here is the uncloaked link - http://www.linkwitzlab.com/Attributes_Of_Linear_Phase_Loudspeakers.pdf