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B&W 804S quasi-anechoic measurements

I don't think "they knew what they were doing" is incompatible with this design being a trainwreck. If we make the assumption - I think a very safe assumption given their target clientele - that the customer isn't going to use EQ and doesn't want to use EQ, then it makes sense that they would be willing to sacrifice both on-axis linearity and accurate directivity for the sake of the spaciousness effect you describe. Because who cares if you can't EQ the speaker if your buyer is purchasing it precisely because it (allegedly) doesn't need to be EQ'd and the buyer doesn't believe in EQ?
Right... my point is that this is not "a trainwreck" if they did this on purpose and it also ends up sounding okay in-room. I'm not convinced it wouldn't sound okay, but I'm also not 100% sure they did this on purpose.

So if they knew what they were doing and this is on purpose, I wouldn't call it a trainwreck so much as a creative design with technical flaws.

If they didn't know what they were doing and this was an accident, I'd be pretty disappointed.
 
I did one more measurement holding an old iPad cover under the tweeter, just to see what happens when the sound from the tweeter doesn't interfere with the midrange driver.

The result: +/- 2.3 dB from 200Hz to 20 kHz.
I saw this and the first thing I said, after you did that, was "Jesus, that is a stupid design."
Putting the tweeter in its own little sub-cabinet like that and having a reflection-caused interference dip that severe off the cabinet around it is just such bad design I don't even know where to start.
 
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Right... my point is that this is not "a trainwreck" if they did this on purpose and it also ends up sounding okay in-room. I'm not convinced it wouldn't sound okay, but I'm also not 100% sure they did this on purpose.

So if they knew what they were doing and this is on purpose, I wouldn't call it a trainwreck so much as a creative design with technical flaws.

If they didn't know what they were doing and this was an accident, I'd be pretty disappointed.
I get what you are saying. With that said, my initial reaction and my view are well summarized by dfuller:

I saw this and the first thing I said, after you did that, was "Jesus, that is a stupid design."
Having the tweeter in its own little sub-cabinet like that and having reflection caused interference dip that severe off the cabinet around it is just such bad design I don't even know where to start.
 
Right... my point is that this is not "a trainwreck" if they did this on purpose and it also ends up sounding okay in-room. I'm not convinced it wouldn't sound okay, but I'm also not 100% sure they did this on purpose.

So if they knew what they were doing and this is on purpose, I wouldn't call it a trainwreck so much as a creative design with technical flaws.

If they didn't know what they were doing and this was an accident, I'd be pretty disappointed.
My hope is that maybe they have private blind listening data that suggests this sort of response is more preferred.

What's probably more likely is that they've done it to stand out in quick comparisons and/or try to capture a smaller part of the preference pie. In an era where most speakers are becoming more and more neutral, it might be most lucrative to differentiate your sound from the rest, especially when your speakers are as visually beautiful as their high end Dalek inspired designs are. Given that their speakers are growing more and more "unique" with each version, despite it becoming easier and easier to design a neutral loudspeaker, I think this is the most likely explanation(Occam's razor)

In a high end hifi shop, if one is comparing these side by side with KEF Blade 2 Meta, Revel Salon2, Magico A5, Vivid Kaya 90, the 802D4 is going to be the only one that really stands out from the rest. While it may be true that most people prefer those more neutral speakers, they're all going to be splitting the vote, so to speak. Perhaps it's more profitable to be the only manufacturer targeting a particular response that only 10% of people prefer than it is to be 1 of 20 other manufacturers competing for the response that those 80% prefer.

I definitely don't think it's an accident. Having seen their factory and processes, there is far too much tech, and far too many great engineers at work for that to be the case.
 
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I did some more testing today. Since it's very easy to remove the tweeter, I measured it with reversed polarity:

View attachment 370640

The 5 kHz dip is gone, but (of course) there's now a larger dip at the crossover frequency (3.5 kHz).

I did one more measurement holding an old iPad cover under the tweeter, just to see what happens when the sound from the tweeter doesn't interfere with the midrange driver.

The result: +/- 2.3 dB from 200Hz to 20 kHz.

Maybe that's what B&W did when they came up with the specifications (attached). ;)

Frequency response: 38Hz – 20kHz ±2dB on reference axis


View attachment 370643

View attachment 370647

This is what the tweeter looks like btw.

It can be removed without using any tools. Just unscrew the long shiny bolt at the back and use it to push the tweeter assembly forward.

View attachment 370642
this is even more facepalm for myself as if a bloody ipad can fix that dip (Hurray, apple !!), the cabinet design of that "statement" look is a absolute fail.... maybe at distance the interference wouldn't be that great(?) and it will sound fine? or just the old sighted burn in of the brain can deal with it.
 
B&W has produced speakers that clearly don't observe a flat frequency response for many years. In a showroom their brightness can attract a novice buyer. However, once you spend a bit of time with elevated treble the ears experience fatigue and you are soon looking for a different speaker or EQ to address the issue.

In this case, we are seeing a rather large dip in the 4.5K to 7K range. What does a 5K signal sound like?


Yeah, it's your Tinnitus kicking in. Not the ideal speaker Frequency Response for anyone suffering from Tinnitus.
 
I saw this and the first thing I said, after you did that, was "Jesus, that is a stupid design."
Putting the tweeter in its own little sub-cabinet like that and having a reflection-caused interference dip that severe off the cabinet around it is just such bad design I don't even know where to start.

I'm not sure that's the problem.


With the smaller 805S, there are cancellation issues in the crossover area, but no 5 kHz dip even though it's using the same tweeter and cabinet design as the 804S.

It seems like the dip only occurs with speakers that have the FST midrange.

702 S2 (FST midrange and tweeter on top):
518BW702fig3.jpg

518BW702fig5.jpg

518BW702fig8.jpg



705 S3 (Tweeter on top, but no FST midrange):
723-BW705fig3-600.jpg

723-BW705fig5-600.jpg

723-BW705fig8-600.jpg



I did a few more measurements today, at 30cm, in front of the phase plug (on the FST midrange).

IMG_2625.png


The result was as expected. A huge dip.

804S 30cm FST midrange.png


I then blocked the tweeter using a piece of cloth and a rubber band (with the tweeter grille on ;) ).

804S 30cm FST tweeter blocked.png


Finally, I tried blocking the midrange instead (with a piece of acoustic ceiling tile).

IMG_2629.png


The tweeter response is uneven (measured at an angle), but the 5 kHz dip is gone.

804S 30cm FST blocked tweeter free.png


All three measurements. At this distance and angle, the tweeter and mid cancel each other out at 4.2 kHz:

804s tweeter or midrange blocked.png



Another measurement, at 50cm:

Blue = Tweeter axis, nothing blocked
Red = Acoustic ceiling tile in front of the midrange

804s midrange blocked.png



Just for fun, I compared the 804S to Revel F208.

I know measuring at midrange axis, and at 30cm is unusual, but I wanted to see how the F208 performs in comparison.

F208: +/- 2.5 dB (+/- 2dB up to 10 kHz)
804S: +/- 11.8 dB ( :) )

804s vs F208 midrange axis.png


IMG_2638.png
 
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1715974083465898.gif

I once admired B&W.
 
They were my first high end speakers. I bought CM4s. Which if anyone remembers we’re 2-1/2 way floorstanders that did not have the B&W tweeters on top of the cabinets. They did not look nearly as cool as 804s but were a nice finish and if memory serves me measured OK. Actually better than these 804s… again perhaps faulty memory. They replaced a Bose Lifestyle 3, so definitely an upgrade. I have absolutely no doubt that B&W could make a very expensive, very beautiful flat sounding speaker. Why they don’t is beyond me. It proves to me that people will take weeks researching the best fitting $30 tshirt, but think nothing of spending $8k on speakers.
 
I'm not sure that's the problem.


With the smaller 805S, there are cancellation issues in the crossover area, but no 5 kHz dip even though it's using the same tweeter and cabinet design as the 804S.

It seems like the dip only occurs with speakers that have the FST midrange.

702 S2 (FST midrange and tweeter on top):
View attachment 370788
View attachment 370938
View attachment 370939


705 S3 (Tweeter on top, but no FST midrange):
View attachment 370943
View attachment 370941
View attachment 370942


I did a few more measurements today, at 30cm, in front of the phase plug (on the FST midrange).

View attachment 370793

The result was as expected. A huge dip.

View attachment 370791

I then blocked the tweeter using a piece of cloth and a rubber band (with the tweeter grille on ;) ).

View attachment 370796

Finally, I tried blocking the midrange instead (with a piece of acoustic ceiling tile).

View attachment 370804

The tweeter response is uneven (measured at an angle), but the 5 kHz dip is gone.

View attachment 370797

All three measurements. At this distance and angle, the tweeter and mid cancel each other out at 4.2 kHz:

View attachment 370944


Another measurement, at 50cm:

Blue = Tweeter axis, nothing blocked
Red = Acoustic ceiling tile in front of the midrange

View attachment 370803


Just for fun, I compared the 804S to Revel F208.

I know measuring at midrange axis, and at 30cm is unusual, but I wanted to see how the F208 performs in comparison.

F208: +/- 2.5 dB (+/- 2dB up to 10 kHz)
804S: +/- 11.8 dB ( :) )

View attachment 370816

View attachment 370946
What I'm getting from this is they built the crossover specifically to cancel at 5K so the excess off-axis energy would balance on-axis?

So definitely intentional. I guess the idea is to get a relatively balanced sound in-room with treble getting more reflected than direct. Not the craziest thing I ever heard... but pretty questionable in terms of hi-fi orthodoxy. Although, I do think it took some skilled engineering to get that to work, even if the concept seems disagreeable.

@Ageve what's your take, having actually listened to these things?
 
What I'm getting from this is they built the crossover specifically to cancel at 5K so the excess off-axis energy would balance on-axis?

So definitely intentional. I guess the idea is to get a relatively balanced sound in-room with treble getting more reflected than direct. Not the craziest thing I ever heard... but pretty questionable in terms of hi-fi orthodoxy. Although, I do think it took some skilled engineering to get that to work, even if the concept seems disagreeable.

@Ageve what's your take, having actually listened to these things?
There does seem to be legit engineering involved with their cabinet designs and reducing resonances.
 
What I'm getting from this is they built the crossover specifically to cancel at 5K so the excess off-axis energy would balance on-axis?

So definitely intentional. I guess the idea is to get a relatively balanced sound in-room with treble getting more reflected than direct. Not the craziest thing I ever heard... but pretty questionable in terms of hi-fi orthodoxy. Although, I do think it took some skilled engineering to get that to work, even if the concept seems disagreeable.

You may be right.

I applied a 5 dB boost at 5 kHz, and a downward slope, and then measured at 5 positions around my listening chair (3m).

The top curves are without EQ:

804s eq vs no eq.png



It responds well to EQ, and boosting 5 kHz causes a peak at listening distance.

This is what the same measurements look like with a 3ms window (room reflections removed).

The top curves are without EQ:

804s 5 list pos 3ms.png


@Ageve what's your take, having actually listened to these things?

They actually sound ok. A bit too bright, and the midrange can sound a bit muffled at times. The bass is really good, with low distortion and extension down to 30Hz in room. Overall, the sound is a bit "safe". It won't offend anyone. ;)
 
You may be right.

I applied a 5 dB boost at 5 kHz, and a downward slope, and then measured at 5 positions around my listening chair (3m).

The top curves are without EQ:

View attachment 371255


It responds well to EQ, and boosting 5 kHz causes a peak at listening distance.

This is what the same measurements look like with a 3ms window (room reflections removed).

The top curves are without EQ:

View attachment 371256



They actually sound ok. A bit too bright, and the midrange can sound a bit muffled at times. The bass is really good, with low distortion and extension down to 30Hz in room. Overall, the sound is a bit "safe". It won't offend anyone. ;)
Pretty interesting! Thanks for the follow-up.

To me this sort of seems like the physical embodiment of a "stereo widener" VST effect. I think it's interesting that they seem to have employed good ( or at least skilled depending on your POV) engineering, but came up with an on-axis response that makes most people at ASR wince. I guess this is a good example of "Can speakers measure bad but sound good?". (or at least okay?)
 
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