What do you think about the B+W 705 S2?

[speakerman39]

Joseph Audio uses "infinite slope" crossovers that start off with 100 dB/octave slopes. They are quite complex and involve interactions between adjacent inductors. It's pretty much the exact opposite of B&W's approach on their more mainstream speakers.

Thanks Dennis for the info. I read a while back a review of Joseph Audio that mentioned that they use 1st order X-overs most of the time. When I get the time, I will try to find that specific review. Not exactly sure what publication that I read that in. May take me some time to find. However, as always Dennis thanks for bringing that to my attention.


Cheers,

Phil

 

[Dennis Murphy]

Thanks Dennis for the info. I read a while back a review of Joseph Audio that mentioned that they use 1st order X-overs most of the time. When I get the time, I will try to find that specific review. Not exactly sure what publication that I read that in. May take me some time to find. However, as always Dennis thanks for bringing that to my attention.


Cheers,

Phil

Never say never. But I would be quite surprised. The infinite slope crossover is their trade mark.

 

[zieglj01]

I read a while back a review of Joseph Audio that mentioned that they use 1st order X-overs most of the time. When I get the time, I will try to find that specific review. Not exactly sure what publication that I read that in. May take me some time to find. However, as always Dennis thanks for bringing that to my attention.

2 different applications
http://www.theabsolutesound.com/articles/joseph-audio-prism/

https://www.stereophile.com/content/joseph-audio-perspective-loudspeaker

 

[Dennis Murphy]

2 different applications
http://www.theabsolutesound.com/articles/joseph-audio-prism/

https://www.stereophile.com/content/joseph-audio-perspective-loudspeaker

I wonder why they dropped the original slopes. The new ones aren't nearly as steep (though steeper than traditional LR 4th order), and the breakup mode of the magnesium woofer isn't suppressed as much as it would be with a simple lcr trap.

 

[speakerman39]

2 different applications
http://www.theabsolutesound.com/articles/joseph-audio-prism/

https://www.stereophile.com/content/joseph-audio-perspective-loudspeaker

I see you post this to make your point. I have read that they, albeit Joseph Audio, used 1st order X-overs. Very busy right now and can not look for it. It has been a good while since I read that. However, I will do my best to find the article I am referring to. Just a bit stressed dealing with my daughter right now. Hope you all understand.


Cheers,

Phil

 

[speakerman39]

I wonder why they dropped the original slopes. The new ones aren't nearly steep (though steeper than traditional LR 4th order), and the breakup mode of the magnesium woofer isn't suppressed as much as it would be with a simple lcr trap.

Dennis it is showing 100dB/octave slopes on my end. Are you not seeing that? I am dealing w/some personal issues right now and will try to find the article that mentions the 1st order X-overs. Will get back to you on it. But, I am most certain it was Joseph Audio.


Cheers,

Phil

 

[speakerman39]

Never say never. But I would be quite surprised. The infinite slope crossover is their trade mark.

Dennis, I think I have it wrong. I emailed Joseph Audio regarding 1st order X-overs. But, after looking over their website it looks to be all Infinite Slope X-overs. As such, it must not have been Joseph Audio. But, I do know that I read about the "less is more" approach. Could have sworn it was Joseph Audio. Therefore, I stand corrected. However, I do think the review was from the mid-2000's. Now my curiosity is piqued more than ever. Thanks for keeping me from misinforming. What would we do w/o you?


Cheers,

Phil

 

[Dennis Murphy]

Dennis it is showing 100dB/octave slopes on my end. Are you not seeing that? I am dealing w/some personal issues right now and will try to find the article that mentions the 1st order X-overs. Will get back to you on it. But, I am most certain it was Joseph Audio.


Cheers,

Phil

I was looking at the second link. The slopes start out steep but taper off with frequency. That's curious because it's best practice to get the magnesium breakup mode as far down as possible. Anyhow, all of the Joseph Audio speakers I've heard have been excellent. You do pay top dollar, though.

 

[Bad Kitty]

That gaping dip of the 704 S2 is frightening. Between 1k and 3.5k that dip causes swings of 13 dB!! And yet, B&W claims on their web site that the speaker's FR is "48Hz to 28kHz +/- 3 dB. What a crock.

And if the 704 S2 is that bad, the 705 S2 can't be any better.

 

[Bad Kitty]

B&W is known for not measuring very flat. However, the CM1 S1's still sounded very good in my small room.

Decades of research by Dr. Floyd Toole and Dr. Sean Olive at both the NRCC in Canada and at Harman's extensive facilities in Northridge, CA have shown that there is a .86 correlation between flat on and off axis frequency response and listener preference in loudspeakers. Their results in double blind testing for decades is so predictable that they know how a speaker will fare just by looking at it's measurements.

Anyone interested in what I just said should read Dr. Toole's book, 3rd edition. But first, watch this fascinating Youtube video of a lecture he gave.

 

[zieglj01]

I wonder why they dropped the original slopes. The new ones aren't nearly as steep (though steeper than traditional LR 4th order), and the breakup mode of the magnesium woofer isn't suppressed as much as it would be with a simple lcr trap.

A mystery to me why they changed -- it would be interesting to know why. However, still would like to hear some of there speakers.

 

[speakerman39]

I was looking at the second link. The slopes start out steep but taper off with frequency. That's curious because it's best practice to get the magnesium breakup mode as far down as possible. Anyhow, all of the Joseph Audio speakers I've heard have been excellent. You do pay top dollar, though.

Dennis, I am seeing that Dyn Audio uses 1st order X-overs quite frequently. Perhaps, it was a Dyn Audio review that I read,no? Who knows as it was in the upper-middle 2000's from what I remember. Anyways, reading that there is a lot more to a 1st order X-over than a simple cap and coil. The Special Forty looks very impressive to say the least. It is also pricey as well. Cross-over design can get real complex real fast. But, I find it fascinating.


Cheers,

Phil

 

[speakerman39]

Decades of research by Dr. Floyd Toole and Dr. Sean Olive at both the NRCC in Canada and at Harman's extensive facilities in Northridge, CA have shown that there is a .86 correlation between flat on and off axis frequency response and listener preference in loudspeakers. Their results in double blind testing for decades is so predictable that they know how a speaker will fare just by looking at it's measurements.

Anyone interested in what I just said should read Dr. Toole's book, 3rd edition. But first, watch this fascinating Youtube video of a lecture he gave.

Yeah, I have seen this video several times. Have even viewed his book. Plan to buy my own copy as soon as funds allow. Vance D. also has a book out, but found it a bit difficult to get much out of it. Might get around to taking another look at it though.

Every B&W speaker that I have ever heard sounded very good to me. However, I would still opt for the BMR's and save $700 myself. Others may think otherwise and that is perfectly fine too. To each their own I always say.



Cheers,

Phil

 

[Dennis Murphy]

Dennis, I am seeing that Dyn Audio uses 1st order X-overs quite frequently. Perhaps, it was a Dyn Audio review that I read,no? Who knows as it was in the upper-middle 2000's from what I remember. Anyways, reading that there is a lot more to a 1st order X-over than a simple cap and coil. The Special Forty looks very impressive to say the least. It is also pricey as well. Cross-over design can get real complex real fast. But, I find it fascinating.


Cheers,

Phil

Right--Dynaudio, along with Vandersteen, are advocates of true 1st or acoustic slope crossovers. But as you noted, that's not a "less is more" situation. It usually takes a very complicated crossover to achieve 1st order slopes across a wide enough range (over 2 octaves) to maintain phase coherence on the listening axis. And that doesn't just mean the adjacent drivers are in phase with one another. A 4th order Linkwitz-Rile will give you that result. The drivers have to be at the exact same point in the music. With a LR 4th order, the drivers are one cycle apart. Can you hear that? Not according to Floyd Toole.

 

[Dennis Murphy]

That gaping dip of the 704 S2 is frightening. Between 1k and 3.5k that dip causes swings of 13 dB!! And yet, B&W claims on their web site that the speaker's FR is "48Hz to 28kHz +/- 3 dB. What a crock.

And if the 704 S2 is that bad, the 705 S2 can't be any better.

Well, I believe the 705 sells for the same price as the 704, but has fewer drivers and a much smaller cabinet. So I have to assume something is upgraded in the 705.

 

[speakerman39]

Dennis here is an article on the Special Forty that I find fascinating. For what I garner, Dyn Audio specifically engineers drivers that can be used w/1st order X-overs. Find that to be rather impressive. Hope to hear some Dyns in the very near future. More specifically, I am more interested in the Emit M10's and/or the Emit M20's. They both are more in my price range......LOL!!!!!


https://www.dynaudio.com/dynaudio-academy/2017/june/what-s-inside-the-special-forty



Here are the Emit M10's/M20's:


https://www.crutchfield.com/p_345M10B/Dynaudio-Emit-M10-Black-Satin.html


https://www.crutchfield.com/p_345M20B/Dynaudio-Emit-M20-Black-Satin.html



Cheers,

Phil

 

[Art Vandelay]

That gaping dip of the 704 S2 is frightening. Between 1k and 3.5k that dip causes swings of 13 dB!! And yet, B&W claims on their web site that the speaker's FR is "48Hz to 28kHz +/- 3 dB. What a crock.

And if the 704 S2 is that bad, the 705 S2 can't be any better.

Single plane measurements performed at close distance should always be treated with some caution. What matters most in typical domestic listening environments is a speaker's power response, or what Harmon refers to as "Sound Power". That said, it's apparent that B&W deliberately engineer a dip in the power response in the 2-3kHz region, although it's done to a lesser extent in the 800 series. Some people refer to this as their 'house sound' but my guess is that the slight departure from flat is in part a means of compensating for the non linearity of the human ear, given that most people will be listening at levels 10-20dB below 'live'. Whether this is good, bad, right or wrong etc is a matter of opinion of course.

Fwiw, the decision by B&W to use simpler crossovers was based on improved transient response, and the subjective benefits were deemed to outweigh the subjective downside of a less even lateral and vertical polar response.

 

[shadyJ]

Single plane measurements performed at close distance should always be treated with some caution. What matters most in typical domestic listening environments is a speaker's power response, or what Harmon refers to as "Sound Power". That said, it's apparent that B&W deliberately engineer a dip in the power response in the 2-3kHz region, although it's done to a lesser extent in the 800 series. Some people refer to this as their 'house sound' but my guess is that the slight departure from flat is in part a means of compensating for the non linearity of the human ear, given that most people will be listening at levels 10-20dB below 'live'. Whether this is good, bad, right or wrong etc is a matter of opinion of course.

Fwiw, the decision by B&W to use simpler crossovers was based on improved transient response, and the subjective benefits were deemed to outweigh the subjective downside of a less even lateral and vertical polar response.

Sound Power is definitely not the curve that any loudspeaker would want to set as a primary performance goal. It's more like how a speaker would measure in a reverberant chamber. Harman uses it because it can give good performance predictions in rooms below the transition frequency, since it is like an omnidirectional metric, i.e., it is good for examining the bass response, but not mids or treble unless the speaker is truly omnidirectional throughout its entire bandwidth.

 

[Art Vandelay]

With a LR 4th order, the drivers are one cycle apart. Can you hear that? Not according to Floyd Toole.

I was once of that view too but having heard a few demos of phase / time correction I'm now more of the view that it is 'perceived' and definitely preferred when the spectrum is time and phase coherent.

My take on it is that time and phase coherence of the primary wavefront results in a more life-like presentation where everything seems to snap into place and focus. Of course it can't be readily described in usual terms such as 'tone' or 'timbre' etc, and is not related to neutrality or accuracy in the strict sense, but to a large extent I think it's what still separates the live performance from (even) the best high fidelity systems.

 

[Good4it]

All this very confusing to me. Maybe I should just trust Dennis.