Evidence-based Speaker Designs

[maty]

Revel Performa3 F206

https://www.soundstagehifi.com/index.php/equipment-reviews/766-revel-performa3-f206-loudspeakers

https://www.soundstagenetwork.com/i...&catid=77:loudspeaker-measurements&Itemid=153

Revel Performa3 F208

https://www.stereophile.com/content/revel-performa3-f208-loudspeaker

https://www.stereophile.com/content/revel-performa3-f208-loudspeaker-measurements

Harbeth Monitor 40.1

https://www.stereophile.com/standloudspeakers/1008har/index.html

https://www.stereophile.com/content/harbeth-m401-loudspeaker-measurements

 

[maty]

From http://highfidelity.pl/@main-405&lang=en, I have optimized the Revel Performa3 F206 crossover. I think is always interesting to see the components.

 

[Juhazi]

^I don't believe that baffle width is the explanation of differences between Revels and Harbeth. It comes more from high xo and sharp baffle edges of Harbeth.

A brilliant speaker with a relatively wide (14") and flat baffe is Magico S5 https://www.stereophile.com/content/magico-s5-mkii-loudspeaker-specifications
Directivity responses in Stereophile are normalized to 0¤

 

[SIY]

How do they look at wider angles? 30 degrees is not adequate to determine how the speaker will act in a room.

 

[andreasmaaan]

How do they look at wider angles? 30 degrees is not adequate to determine how the speaker will act in a room.

Also good.

 

[SIY]

Also good.

Many thanks!

 

[Cosmik]

Greene’s statement doesn’t directly accord with my understanding of Toole’s research. It’s been a while since I read Toole, but IIRC the findings were that speakers with a flat axial response and constant directivity or downward-sloping power response were preferred. There was no specific finding regarding preferred baffle width to my knowledge.

Revel speakers are all “narrow”-baffle too FWIW.

Isn't the point that a wide baffle aids you in controlling dispersion to a lower frequency than you get with a narrow baffle? For sure, if the only speakers you test are narrow, people are going to prefer the ones with most constant or 'smoothest' change in dispersion with frequency. But the ideas person *knows* what a wider baffle does before they have even tested any speakers.

 

[svart-hvitt]

Isn't the point that a wide baffle aids you in controlling dispersion to a lower frequency than you get with a narrow baffle? For sure, if the only speakers you test are narrow, people are going to prefer the ones with most constant or 'smoothest' change in dispersion with frequency. But the ideas person *knows* what a wider baffle does before they have even tested any speakers.

Any thoughts on baffle width and soffit mounting?

 

[Ron Texas]

We are all ideas persons. Not everyone has the same ideas. The overwhelming majority of speakers today have a small baffle. Is that all for WAF? Does it cost less to manufacture a narrow floor standing speaker with three 6.5" low frequency drivers instead of a speaker with a single low frequency driver capable of moving the same amount of air?

 

[MattHooper]

I just came back from auditioning a narrow profile speakers against some Harbeth SuperHL5 plus speakers (they were essentially side-by-side, the speaker cable switched between each). I also owned the Harbeths at one point. My consistent impression of the Harbeth sound (in the SuperHL5plus and up range) is one that sounds *particularly* rich and full. Vs thin and anemic or reductive. The same seemed true in comparing the Harbeth right against the narrow profile speakers that were spec'd very similarly for bass response.

I also found the same impression from the Devore 0/96 and 0/95 speakers - their distinctive design feature being big 10" drivers woofer and a tweeter, on a squat, wide-baffle design. The Devores sound even more "full/filled out" than the Harbeths. Compared to slim floor standing speakers rated with the same bass range (and sounding audibly similar in bass reach) the Devore speakers just sound huge, saxophones, drums etc just sound more full bodied and life-sized.

In wondering why it's hard not to think about the wide baffle design (and maybe the big drivers). I've read that the wide baffle design focuses more of the sound toward the listener rather than "losing" it to the sides, hence the sensation of more/full sound. That sounds fairly intuitive in a naive way. But I'm wondering if there is anything to this, and if not, what else would explain the apparent tendency of those wide-baffle/bigger driver speakers from sounding bigger, fuller than similar-spec slim floor standing speakers.

?

 

[Bjorn]

Wide baffle isn't the only way to deal with baffle step, thus have "controlled directivity" lower in frequency. The CBT speaker for instance has built in baffle step compensation, hence has "controlled directivity" low in frequency despite of a very narrow cabinet.

But for a "normal" front firing speaker, the width of the cabinet will decide when baffle step kicks in. I have a speaker design I'm working on now that has controlled directivity both horizontally and vertically between approximately 400/500 Hz and 7KHz and with no vertical phase issues at all. The cabinet is 50 cm wide. Making it wider would move the baffle step lower in frequency, but I felt 50 cm was as wide as I could go and still being able to reach a market. Few can live with a very wide speaker and that's why most speakers are made narrow.

 

[Ilkless]

Wide baffle isn't the only way to deal with baffle step, thus have "controlled directivity" lower in frequency. The CBT speaker for instance has built in baffle step compensation, hence has "controlled directivity" low in frequency despite of a very narrow cabinet.

But for a "normal" front firing speaker, the width of the cabinet will decide when baffle step kicks in. I have a speaker design I'm working on now that has controlled directivity both horizontally and vertically between approximately 400/500 Hz and 7KHz and with no vertical phase issues at all. The cabinet is 50 cm wide. Making it wider would move the baffle step lower in frequency, but I felt 50 cm was as wide as I could go and still being able to reach a market. Few can live with a very wide speaker and that's why most speakers are made narrow.

The poster you replied to (and a few others) seem to have used Greene's quote to suggest even a narrow baffle speaker with BSC will for some reason sound off, purely due to the baffle configuration. There are other reasons incidental to the narrow baffle that may caused the purported "thin" sound, like small-diameter drivers running into compression, or hitting Xmax, or such speakers typically having a limited internal volume and high port tuning etc etc, but these are not intrinsic to narrow baffle design, so long as optimal BSC is present.

 

[Bjorn]

Yes, I agree. Narrow cabinet isn't the only cause of "thin sound". Besides what you're mentioning, it will also depend on baffle step compensation be used. However, there's no doubt that a wider cabinet have several benefits for a traditional speaker. And so does using bigger woofers.

Personally I shy away from using 6.5" woofers in a 2-way or 3-way design. I've yet to hear a 6.5" woofer that does not sound compressed, something that's very obvious when you compare it to a larger woofer. While you can add several drivers to compensate for that, in most designs that will introduce other weaknesses.

 

[Cosmik]

Baffle step compensation is just a compromise: EQ'ing the speaker to best mask uneven dispersion versus frequency. I use it on my (wider than average) speakers certainly, and I do this without any other form of 'room correction'. I implement it as a curve whose corner frequency and shape is pre-calculated from the driver's baffle width but whose depth is room and position-dependent and set by ear - just a single variable to adjust. (If it didn't sound any good I would look for something else! ). The direct sound remains linear phase after this adjustment.

To the exclusively frequency domain-thinking person, it makes an imperfect speaker perfect because - maybe - EQ can make some frequency response curves flat or fit your 'target'. But a speaker that radiates in all directions at some frequencies but not at others is still a strange-sounding transducer in both frequency and time domains - and at narrow baffle widths the effect is straying right up into the mid range so can't be dismissed as benign 'minimum phase' etc.

In order to verify this - or dismiss it - you could run listening tests, but there are so many variables that you would never get a definitive answer. As I say, I like the R.E.G./Grimm approach which is to bypass the 'evidence' stage altogether.

 

[Bjorn]

Baffle step compensation is just a compromise:

Oh, absolutely. Baffle step compensation is in most cases better than nothing, but can't compare with avoiding it. While we can minimize the lack of controlled directivity with room treatment, it's always best to have a speaker that measures the same off-axis as on-axis. Trying to fix something later will always involve a compromise.

 

[DDF]

Isn't the point that a wide baffle aids you in controlling dispersion to a lower frequency than you get with a narrow baffle?

Different baffle widths result in the power response hole landing in different frequency ranges. Heres an "evidence based" technical analysis I performed on Grimms LS1 wide baffle, comparing its theoretical power response difference vs a narrow baffle

https://www.diyaudio.com/forums/mul...ros-cons-wide-baffles-study-grimm-ls-1-a.html

 

[maty]

Talking about wide speakers... Tony Gee from Netherlands:

Plutone

http://www.humblehomemadehifi.com/Plutone.html

(W x H x D) • 325 x 580 x 230 mm

Cheaper, Twenty Five

http://www.humblehomemadehifi.com/Twenty-Five.html

(W x H x D) • 360 x 790 x 270 mm

 

[Cosmik]

Different baffle widths result in the power response hole landing in different frequency ranges. Heres an "evidence based" technical analysis I performed on Grimms LS1 wide baffle, comparing its theoretical power response difference vs a narrow baffle

https://www.diyaudio.com/forums/mul...ros-cons-wide-baffles-study-grimm-ls-1-a.html

Yes, but I don't really know what a "power hole" is. If the aim of a speaker is to produce a constant amount of power for all frequency ranges during a time window when collected in buckets placed at the listener's chair, then maybe it means something and evidence can be produced thereof. But I think that a speaker should do more than that.

There are many ways to achieve that equal slop level in all the buckets, but few that maintain a coherent relationship between the levels as the buckets are moved around in the room and which don't give the game away in terms of phase, delay, frequency-dependent reverberation, etc. The wider baffle makes the levels more equal at the listener's chair *and* more stable/coherent with movement.

Instead of the composite symphony orchestra being passed through a frequency-dependent 'characteristic' (involving amplitude, phase, delay, reverberation - even though EQ has achieved a target 'bucket-based' frequency response at some location) it is passed through a more frequency-independent 'characteristic' which is less likely to 'give the game away'.

 

[Ron Texas]

I am having trouble buying into claims of small speakers and narrow towers sounding thin while wide baffle speakers sound full (or fat). Listening tests mentioned here are likely heavily biased. It looks a bit too much like the technological throwback thing many audiophiles suffer from. Tubes are better than solid state, vinyl beats digital, and even multibit DAC's are believed to be better than delta sigma. Over the years I have owned AR's, Advents and Snell E III's. I don't remember them being inherently better than Phase Tech 60's, PSB bookshelf's, B&W 685 S2's, 683 S2's or most recently LS50's. If anything the small baffle speakers threw a better sound stage with instruments placed more distinctly. That's my opinion after 50 years of this hobby.

A few weeks ago the rage here was DSP controlled active speakers. Now it's large baffles. What will it be in March?

 

[Kal Rubinson]

I just came back from auditioning a narrow profile speakers against some Harbeth SuperHL5 plus speakers (they were essentially side-by-side, the speaker cable switched between each). I also owned the Harbeths at one point. My consistent impression of the Harbeth sound (in the SuperHL5plus and up range) is one that sounds *particularly* rich and full. Vs thin and anemic or reductive. The same seemed true in comparing the Harbeth right against the narrow profile speakers that were spec'd very similarly for bass response.

It is hard to accept as reliable this un-blinded comparison given the visual influence on the listener. Also, even if one accepts the described audible dichotomy between the two speakers, they afford no relationship to accuracy, just personal preferences as revealed by the chosen adjectives.