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.
@tomic601 said, "much harder to figure out with reliability psychoacoustics than the more or less well understood physics... "
Psychoacoustics is fascinating, in my opinion, in part because much of it is counter-intuitive.
Sounds like you already have a good background in acoustics (you are absolutely correct that the front baffle is a 180 degree horn!!). You might enjoy Floyd Toole’s book "Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms." His book is basically all about answering the question, "what really matters?"
great thread has me reading some old and new papers and thinking about ( anything is possible with a third Margarita and some good Jazz ) brushing up on my partial differential equations......
well
maybe not....
can we agree humans can hear + / - 5 db ? 1956 paper, Olsen.... time to get tge old Focal fiberglass spheres out......
Duke: hence my blackart comment... much harder to figure out with reliability psychoacoustics than the more or less well understood physics... Werner H not withstanding.... perhaps it is useful to think of the large baffle as a 180 degree Horn.... and in a two way with crossover overlap easy to see effects of both waves and the baffle... but an area of violent agreement is the weighted trade space for attacking distortion.... Dr Ottola got us headed down one right path there... some very simple - like 5 parts in circuit path SS amp outperform tubes in some of the ear is more sensitive areas..... so that designer understands how we hear and attacks the sensitive stuff first. best to you Duke
@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.
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 ?
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.
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..."
I know Shakey Graves. (Not exactly a fan, but he got on my radar due to some recommendation).
As I've mentioned, I found the 0/96 and 0/93 imaging pretty good, even if not pin-point. I also really got yet another reminder of the importance of speaker positioning. As you know the Devores generally have a big, rich sound. But at one point while moving them around during my audition the dealer had them closer together, and really toed in heavily. At that point that richness and image size practically disappeared into a small, squeezed sound! Once we spread them out enough again, and aimed them right, then they did that Devore thing with big rich images and weight.
tangramca,
Yeah, if you are wedded to the most pin-point imaging the Devores are the wrong direction. That said, I'm still surprised they didn't turn your crank at all, given the genres you mentioned are particularly suited to the Devores IMO.
@prof I had become accustomed and enamored with the pinpoint imaging of the Focals (which may be a bit much for some) and I found the Devores to be less pinpoint. I mostly listen to rock, folk rock and funk. The albums I demo’ed that I was quite familiar with were less satisfying than I had hoped for from the O96’s. I really wanted to like them but we didn’t click.
The Devore O/93's do a strange thing in my room-with the right cabling and placement they throw out a wide wall of sound way beyond and above the confines of the boxes-when the recording has it. But what they don't do is provide pin-point placement anywhere within the wall of sound. I don't expect a single person who reads this thread to be familiar with Shakey Graves or his latest release "Can't Wake Up" but I can't think of a single recording that better reflects this weird dichotomy. It is not at all unusual for me to look around in my listening room thinking that someone must be calling me from behind because a sound I am not familiar with comes from "out of nowhere" as I get accustomed to this new recording, but if I play, for example, the excellently recorded Madeleine Peyroux "Careless Love", I don't "see" her singing in front of me the way my old B&W 805 standmounts would have defined her. If I play the old chestnut "The ARC Choir" from Mapleshade through my digital rig, the choir is wide and high but the individual singers are not defined with the specificity that I know is there in the recording. I am happy with them, but they have their trade-offs.
I've had a pair of very skinny (about 5.5 inches wide) Silverline Prelude speakers for years and they image amazingly well, in fact much better than various other tower speakers I've owned. However, they were retired to make way for a pair of Klipsch Heresy IIIs that image even better, with an amazingly well defined soundstage...and although they sit on the floor pointed up at what seems to be the exact angle my ears require, the image doesn't seem to originate from the floor and the image height seems like it's coming from a speaker at ear level. About 9 feet from my head, and 6 feet apart with some toe in seems to work best. These have horn mids and tweets which I imagine blow right by the baffle, and the 12" bass speaker covers most of the width of the cabinet so it's its own baffle...the whole thing baffles me, but I like it. It's good.
I auditioned Devore O96’s when I was looking to upgrade. System was very good and listening room was in an old house with plaster walls and high ceilings. I was ready to be dazzled but in the 45 minutes I listened, the number one disappointment was the imaging. Granted, I was coming from Focal Electra standmounts but nowhere in the reviews had there been anything but gushing praise for the Devores. I value good imaging in my speakers so this was a dealbreaker for me. I purchased Totem Element Metals instead, which image almost as good as the Focals. So in, my mind, I have a bias towards narrow baffles imaging better than wide baffles. I am sure this is a gross stereotyping but still...
Imo the Precedence Effect explains many observations made about correlations between imaging precision and baffle width, in particular those posted by @shadorne on the previous page.
The Precedence Effect kicks in at about .68 milliseconds, which corresponds to the time it takes for a sound wave to travel about 9 inches, which in turn correlates with the distance around the head from one ear to the other. We get our primary directional cues from that first .68 milliseconds, after which the ear/brain system suppresses directional cues from reflections.
So any reflections occurring within those first .68 milliseconds will degrade imaging, and in general the closer to that .68 millisecond threshold, the worse the degradation. This is because as we approach .68 milliseconds, we are approaching the interaural time delay that would correspond to a sound coming from one side or the other.
So, the wider the baffle the worse the imaging (ignoring the potential improvement from round-overs) until the baffle edge is more than 9 inches away from the driver's edge. Then imaging abruptly improves.
A round-over can mitigate edge diffraction, but it must have a large enough radius to be effective, at least 1/2 wavelength and preferably 1 wavelength. The ear is most sensitive to diffraction at about 4 kHz, and at 4 kHz a wavelength is about 3.4 inches. That's a pretty big round-over! Point being, small round-overs probably don't do much.
Driver directivity can reduce the amount of energy that sees the cabinet edge in the first place, but care must be taken to not do more harm than good in the pursuit of increased directivity.
Yes, the IRS V had a very large baffle. But Arnie Nudell, physicist that he was, curved it back to minimize the effects of diffraction.
It was also to re-enforce the bottom of the midrange so it could be xover (mated up) to the bass towers without a big hole in the upper bass/lowermids. as they were yet to bring out the much larger LEMIM low mid/bass driver that’s use in the IRS Beta a far better imaging speaker, with no baffle.
Notice that there's no attempt to take advantage of what could be the total internal volume; the enclosure remains a box, and the front and rear baffles, as far as I can see, don't even join up at the sides.
you’ve concluded your individual experience trumps that data
Yes, certainly. Your data does reveal differences between the two generations of L-EMIMs, but you haven’t shown any correlation between that data and actual, real-world performance or the defect "rattling" hearsay that you repeat. So yes, the experience I’ve had over decades of use, combined with confirmed first-hand reports from other users, trumps your hearsay and "data" acquired from other sources.
If my L-EMIMs suddenly start rattling next week, I’ll be sure to let you know.
I provided a technical basis to support my contention which you chose to ignore ...
I didn’t ignore your "technical basis" at all, I just don’t think it supports your claim that Infinity L-EMIMs are prone to "rattling." Instead, I provided the results of about 30 years of first-hand experience, as opposed to your remark:
All I can say is i’ve read several reports from other owners
In fact, in all my conversations with other IRS Beta owners, I've never heard the complaint you cite. If the Beta has a weak link, most think it's the EMIMs, not the L-EMIMs. That's why I have spares - although I haven't needed them.
All I can say is i’ve read several reports from other owners who have
experienced this behaviour at high volumes. With the Beta’s ...
There are a lot of poorly maintained, poorly modified and even abused Infinity IRS Beta systems out there, so there's nothing you might read that would surprise me. I bought my Beta system new and haven't had any of these issues. That's not to say that I haven't had issues, of course - the system is about 30 years old - but it plays loud with aplomb, and has actually been quite serviceable.
Re: the IRS-Beta’s ... I don’t think the narrow wood frame
of the mid/high panels was completely adequate to tame the resonance of
the dual L-Emim drivers as they would ’rattle’ at high volumes.
Huh? I've never detected any rattling at all with the IRS Beta system, with the exception of when the woofers need to be re-foamed.
The problem that I had with the
imaging of the IRS Betas that my friend had was that each frequency
range came from a different height. Maybe his listening seat was too
close, but it used to drive me crazy. Very cool plasma tweeters, by the
way!
The IRS Beta system is highly adjustable, which is a double-edge sword. On the one hand, it makes it possible to achieve excellent results in rooms with very different characteristics. On the other hand, it makes them easy to setup incorrectly, and it sounds like that's what happened with your friend's system. The Beta system used planar tweeters, not plasma. It looks like your friend's system was modified.
"No matter how you cut the cake, big baffles aren't good if they're anything resembling flat with corners. "
That's not necessarily true. The size of the driver and the frequency range from the driver is more important since that determines the wavelength and for high/mid frequencies the wavelength is not long enough to be affected by the (large) baffle size. Low frequencies with longer wavelength behave completely differently.
one of the reasons i like to own several speakers w widely divergent design philosophy but from competent designers....
Same here.
I own Thiel and love the first order/time/phase coherence aspect of the design.
But I also enjoy owning diverging designs. Right now I have speakers from Waveform (very "NRC" in approach), Spendor, Hales, and most divergent...MBL Radialstrahler speakers.
No speaker I've ever heard "does everything" for me, and I like the things one speaker may do that another doesn't. Also helps with not getting bored.
Yes, the IRS V had a very large baffle. But Arnie Nudell, physicist that he was, curved it back to minimize the effects of diffraction.
Also, the note that the mids and tweeters are right next to one another, producing something close to a coherent line, and they covered a wide frequency range, with only the deep bass, which is hard to localize, produced by the separate woofer towers. By comparison, line sources like Maggies or Apogees have more separation between the drivers, smearing the image laterally.
Paradoxically, it’s the wide baffle of the IRS that makes the extended frequency range of the line possible, by better supporting the bass.
The problem that I had with the imaging of the IRS Betas that my friend had was that each frequency range came from a different height. Maybe his listening seat was too close, but it used to drive me crazy. Very cool plasma tweeters, by the way!
Well you must know something that Arnie Nudell (rip), Paul McGowan and Bill LeGall don’t...
Just going by what I personally hear and read about. Good small two ways on open stands always have great image. Audio Phyic's speakers very narrow baffle great imaging. The IRS Beta (no baffle) to me was a master at imaging. And the Infinity Prelude design is reviewed as an imaging master. All these and my own experience with my friends Amati's v his Stradivarius. Another with Wilson Alexia. My own ELS's all say to me, little or no baffle is best for imaging.
And to top it all of placement, nothing between the speakers or close to the side wall for good side to side and outside imaging. And well out from the back wall for good front to back depth perception EG: equipment racks, tv, even the back wall ect. My system friends say has a holographic image you see and hear that you feel you can walk into and/or reach out and touch, because of the above.
I've read through this thread and so far Bache and johnk are the 2 that have responded to the question at hand. Driver selection matters along with the baffle size In frequency bumps or dips, even the driver frame combined with the material that the baffle is made from can cause diffraction loss... Next, If the baffle starts getting thinner, you might have to deal with Baffle Step Compensation as johnk eluded to as (BSC). Overall, there is no reason that you cannot have a wide or narrow speaker that are imaging champs.
The baffle is part of the over all design too small like many designs today requires BSC in networks and thus is inferior to those with proper sized baffles that do not require correction in network
Yes you can have a big baffle still with no box, as the IRS V has, but the Beta is truly baffle’less, as are the Plasma’s as are most ESL’s. The moment you ad "wings", you make a baffle and it re-enforces the sound but will also screw up the image compared to no baffle. That’s why very narrow speakers such as the Audio Physics image like there’s no tomorrow. https://www.google.com.au/search?q=audio+physic+speakers&source=lnms&tbm=isch&sa=X&v...
The Infinity Prelude also had a good rep for imaging well. https://www.stereophile.com/content/infinity-composition-prelude-p-fr-loudspeaker "
I could hear precisely where each instrument or voice was in the soundstage, and images were highly focused, tight, and compact, making the presentation sound like a collection of individual instruments in three-dimensional space. There was also a remarkable stability and tangibility to the images, further heightening the impression of instruments before me."
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