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narrow and wide baffles and imaging

According to all the "professional" audio reviews that I've read over the last several years, narrow baffles are crucial to creating that so-desired pin-point imaging.

However, over the last few weeks, I've had the opportunity to audition Harbeth 40.2, Spendor Classic 100, Audio Note AN-E, and Devore O/93.  None of these had deficient imaging; indeed I would go so far as to say that it was good to very good.

So, what gives?  I'm forced to conclude that modern designs, 95% of which espouse the narrow baffle, are driven by aesthetic/cosmetic considerations, rather than acoustical ones, and the baffle~imaging canard is just an ex post facto justification.

I can understand the desire to build speakers that fit into small rooms, are relatively unobtrusive, and might pass the SAF test, but it seems a bit much to add on the idea that they're essentially the only ones that will do imaging correctly.



128x128twoleftears
audiokinesis
2,753 posts
 

@twoleftears wrote:

"So what we need is a 19" front baffle?"

Maybe even wider, depending on driver diameters and crossover points!

That being said, I think a small baffle with large round-overs would image extremely well, assuming all of its other ducks are in a row.

The venerable and magnificent Snell Acoustics Type A used a wide baffle that was virtually one big round-over on both sides and on the top (of the front baffle), and its imaging was superb.

I think large-diaphragm panel speakers avoid significant edge diffraction by virtue of their inherent directivity.

The approach I embrace is to use a compression driver on a low-diffraction waveguide whose radiation is fairly narrow in the horizontal plane (-6 dB at 45 degrees to either side of the centerline, falling to about -20 dB at 90 degrees, or towards the cabinet edge). The woofer has a large enough diameter that its radiation pattern is essentially the same as the waveguide in the crossover region. I don’t claim that this is necessarily the best-imaging format, but I believe it does enough other things well to be competitive overall.

I have NOTHING against superb imaging, and I think I know how to get it (time coherence and application of the principles I described above), but it is not my top priority. Imo loudspeaker design is a juggling of compromises, and anyone who says differently is in marketing.

@tomic601 wrote:

"the big baffle also honks up frequency response....period..."

How so?

fsonicsmith's avatar
fsonicsmith
967 posts
 
Imo loudspeaker design is a juggling of compromises, and anyone who says differently is in marketing.
I possess a fraction of your technical knowledge, a tiny fraction, but this is my viewpoint too. But just to expand upon that, the people that have a hard time accepting this reality are the ones who equate exotic driver materials, driver shapes, enclosure materials, enclosure shapes, crossover configurations, crossover components, et al to "the best". I read S'Phile these days for only one reason; I love the tension between the tech weenies (JA, MF, KR) and the luddites (AD, HR, SG, KM). This thread is about baffle size but barring a dipole, large baffle speakers tend to have resonant cabinets. One approach is to try to eliminate all resonance and another is to play to the resonance. Again, it boils down to an effort to change the real world vs. an accommodation of the real world, or swimming upstream vs. downstream. One can validly argue that those that fight the current (pun) by swimming upstream are the ones who innovate and create new concepts. I accept that. But with loudspeakers, where has that gotten us? 98% of the "cutting edge" loudspeaker designs boil down to marketing BS. And now I am really getting OT, but the same applies to cabling, amplification, and all else other than digital technology. 
tomic601's avatar
tomic601
13,111 posts
 
 @audiokinesis  reflected wave off baffle creates constructive and destructive interference, seen as amplitude.....
tomic601's avatar
tomic601
13,111 posts
 
agree that real engineering is about managing the trade space...however IF we are interested in moving forward instead of creating new flavors, perhaps we can agree that lower distortion is better ?
audiokinesis
2,753 posts
 

@tomic601 wrote: "reflected wave off baffle creates constructive and destructive interference, seen as amplitude....."

A wave travelling along a surface, parallel to that surface, does not reflect off of it. However it can diffract at the edge. The amplitude disturbance caused by diffraction, in and of itself, is imo not a big deal. It is only present in the first-arrival sound so its subjective impact is relatively minor in most cases. However what IS a big deal is, the time delay. The ear is often pretty good at overlooking a distortion that occurs at the exact same time as the signal, but usually quite poor at ignoring a distortion that occurs even slightly later in time. This has to do with a psychoacoustic phenomenon called "masking" which I can come back to if you are interested.

Tomic601 also said, "IF we are interested in moving forward instead of creating new flavors, perhaps we can agree that lower distortion is better?"

I think we should try to figure out which distortions matter the most to the ears and prioritize accordingly. "Lower measured distortion" does not necessarily correspond to "lower perceived distortion". The latter is what matters in my opinion.

Duke

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