Redirected from: EnABL - Listening impressions & techniques
Hi,
I haven't looked at this thread for some years now and I can't see myself reading all of it to find the word "holes".
I have a question, though, brought about by a need in one of my speaker boxes. When talking about baffle (diffraction or what not) treatments, has anyone experimented with a pattern of holes instead of bumps, i.e. intaglio instead of embossed? Around a driver, say.
Thanks,
Jacques
Hi,
I haven't looked at this thread for some years now and I can't see myself reading all of it to find the word "holes".
I have a question, though, brought about by a need in one of my speaker boxes. When talking about baffle (diffraction or what not) treatments, has anyone experimented with a pattern of holes instead of bumps, i.e. intaglio instead of embossed? Around a driver, say.
Thanks,
Jacques
Thanks Dave
I'm not particularly interested in technical details at this point. I should be able to figure them out if needed. Thus the "or what not". What I AM interested in at this point is whether anyone has ever attempted this and to what (subjective) effect.
No desire to cross swords at this junction either, but I don't think I have (or have supplied) enough information for a conclusion such as the one you seem to suggest, that "it can only make the response worse". I'm also not interested in addressing baffle edge diffraction as such.
Any experiences, anyone?
Jacques
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I've tried to avoid the imbroglio into which the technical conversations on this subject have "evolved", but have been listening to treated drivers almost exclusively for the past 4 or so years.
So far the only treatment of which I'm aware to baffles and other enclosure panels have involved the application of patterns by addition of paint or thin vinyl - it's so much easier to experiment by moving painted or stick-on bumps than would be the case with divots.
In fact one of several pairs of enclosures that I have for a Fostex FE127E design has an application of EnABL, done by Bud. This is an already fairly low diffraction design, and the pattern seems to aid even further in box "getting out the way"
Indeed, tuxedocivic. That kind of thing. Or any kind of thing for that matter. I'm not going to use the words "boundary layer" because I've witnessed what happens when one does. Aircraft wings have little pin-like protuberances on them, for instance, but those, rather obviously, protrude from the surface. I have little idea how or why (or indeed if) EnABL works. The support seems to be overwhelming and I'm certainly not going to assume some kind of psychological explanation for this, as many seem to do. The point is that one person's dented surface might be another's protrusions. B&W have something like that going on in their ports, not? (Though, conceivably, for specific reasons.)
Intaglio whatever
so why imply or worry about "technical" things if you don't want "technical" answers???
Intaglio...Imbroglio... I get it!!
clever...😀😉
so why imply or worry about "technical" things if you don't want "technical" answers???
Intaglio...Imbroglio... I get it!!
clever...😀😉
Thanks, chrisb.
I'm in agreement. The thing is that these "dots" sometimes have a bit of an aesthetic impact one might want to avoid on spousal grounds, amongst others. Perhaps dimples would charm more, all other things being the same. (Let's not pursue this metaphor too far..) B&W might even have noticed this.
(I promise I'll try not to use the B-name anymore.)
I might be framing myself as an EnABL heretic here. Please forgive me. It's not the intention.
J
I'm in agreement. The thing is that these "dots" sometimes have a bit of an aesthetic impact one might want to avoid on spousal grounds, amongst others. Perhaps dimples would charm more, all other things being the same. (Let's not pursue this metaphor too far..) B&W might even have noticed this.
(I promise I'll try not to use the B-name anymore.)
I might be framing myself as an EnABL heretic here. Please forgive me. It's not the intention.
J
You'd need to do some substantial changes to hear a difference, little modifications like EnABL, holes, bumps and such have absolutely no audible effect.
Even strong edge diffraction is not immediately audible, it certainly is measurable, but I'm yet to confirm it's audibility.
Even strong edge diffraction is not immediately audible, it certainly is measurable, but I'm yet to confirm it's audibility.
Certainly the use of an EnABL pattern made of holes has been discussed particularily in reference to OBs. One could even have a cascade of a number of rows with shrinking holes as you move inward. Besides any benefit from EnABL, i think that it would tend to make the edge of the baffle "fuzzy". Fuzzy was the idea behind the Karlson slot in the iBIBk, in that case, to make the length fuzzy with a hopeful smoothing of the ripple inherent in a BIB.
dave
dave
Thanks Dave. Just as I'm about to give up because of the endless pontifications and strong statements, an actual answer. It's always a good idea just to try something if you're wondering about it, I think, but it's nice to hear that someone else has actually wondered about the same thing. Or, better, done it.
There's a lot to be said for "fuzzy" it seems, mathematically or otherwise.
Either simply cut/drilled into the baffle or treated, I assume. (I just had an entirely horrible idea: little worm holes stuffed with cotton wool. Nasty...)
J
There's a lot to be said for "fuzzy" it seems, mathematically or otherwise.
Either simply cut/drilled into the baffle or treated, I assume. (I just had an entirely horrible idea: little worm holes stuffed with cotton wool. Nasty...)
J
Two things come to mind, but first, what is this problem with only one of your boxes?
First to mind are some experiments that Vic Tiscareno performed on the face plate of the tweeters he was buying from china (for AudioPrism). These were bare corrugated aluminum ribbons about 2 inches in length, The bezel was, to memory, about 4 inches wide and perhaps 3 inches tall. The drilled dimples were 1/4 inch in diameter and applied across the entire surface. They did succeed in removing the pinched edgy character to the high frequencies but did not make any other audible changes,
Second to mind is finding the problems and dealing with them directly. We have been using a direct application of light radial tapping on the surface of drivers of all types to discover their local resonant characteristics. The tap has an initial strike, a "tone" and a decay direction. If only the "tone" changes as you move across the surface point of interest this can be ignored. If the decay changes it's direction as you move across the surface point of interest this indicates a need for a pattern ring set at the mid point of this area. If the initial strike disappears this indicates a subduction and the beginning of a Raleigh wave zone. For cones this means two ring sets, one at the onset and one at it's end, across a radial distance. It also means applying damping material on the backside of the cone between these two ring sets.
The above are subtle, require a quiet environment and a significant effort to hear. Once you "get it" it becomes easy to find the problem areas. The reason I mention this is that these areas extend beyond the driver out onto the box surface. With or without the driver installed, though the driver does add to the number needed, the locations needed without the driver do not change. So, you can find these problems with direct empirical experimentation. However, I can't guarantee they will address your problem.
I would recommend using clear, self adhesive, peal-able pantry shelf covering plastic to make blocks with and use those as an experimental tool. Then drill the dimples at each block location center, remove the blocks and see what you have. At worst you will have begun the drilling process and discovered that the above is all nonsense, At best you will have satisfied the need with the least number of dimples.
Bud
First to mind are some experiments that Vic Tiscareno performed on the face plate of the tweeters he was buying from china (for AudioPrism). These were bare corrugated aluminum ribbons about 2 inches in length, The bezel was, to memory, about 4 inches wide and perhaps 3 inches tall. The drilled dimples were 1/4 inch in diameter and applied across the entire surface. They did succeed in removing the pinched edgy character to the high frequencies but did not make any other audible changes,
Second to mind is finding the problems and dealing with them directly. We have been using a direct application of light radial tapping on the surface of drivers of all types to discover their local resonant characteristics. The tap has an initial strike, a "tone" and a decay direction. If only the "tone" changes as you move across the surface point of interest this can be ignored. If the decay changes it's direction as you move across the surface point of interest this indicates a need for a pattern ring set at the mid point of this area. If the initial strike disappears this indicates a subduction and the beginning of a Raleigh wave zone. For cones this means two ring sets, one at the onset and one at it's end, across a radial distance. It also means applying damping material on the backside of the cone between these two ring sets.
The above are subtle, require a quiet environment and a significant effort to hear. Once you "get it" it becomes easy to find the problem areas. The reason I mention this is that these areas extend beyond the driver out onto the box surface. With or without the driver installed, though the driver does add to the number needed, the locations needed without the driver do not change. So, you can find these problems with direct empirical experimentation. However, I can't guarantee they will address your problem.
I would recommend using clear, self adhesive, peal-able pantry shelf covering plastic to make blocks with and use those as an experimental tool. Then drill the dimples at each block location center, remove the blocks and see what you have. At worst you will have begun the drilling process and discovered that the above is all nonsense, At best you will have satisfied the need with the least number of dimples.
Bud
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Thanks Bud for a detailed and informative answer.
I'll need to chew on this for a while, and perhaps read a bit more on the subjects involved. Just a misunderstanding: there's nothing "wrong" with only one of my speakers. It's a new speaker (type) I'm designing and I'm expecting to run into a number of problems. In all likelihood all of what I've built might benefit from some treatment or another. (This is quite probably a very general statement.) In other words, my posting is preemptive, not remedial. Once I run into these problems, I'll make sure I relate them here.
One thing evident from your and Dave's posts is that solutions are specific, not general. And that symmetry/aesthetics and fuzziness/specificity don't always go together. But that's in a way what you're saying in your Tsong Ko Pa quotation, isn't it? Clearly one would like some form of symmetry, otherwise we'd all have "rock speakers" or the like in our homes. (there's a thought..) I've seen you expand on the tapping theme somewhere; maybe I should go look for that and read. I like tapping on things anyway - you'll frequently find me tapping on wood samples at wood merchants, drawing weird stares.
Either way, thanks again.
Let me go DO something.
J
I'll need to chew on this for a while, and perhaps read a bit more on the subjects involved. Just a misunderstanding: there's nothing "wrong" with only one of my speakers. It's a new speaker (type) I'm designing and I'm expecting to run into a number of problems. In all likelihood all of what I've built might benefit from some treatment or another. (This is quite probably a very general statement.) In other words, my posting is preemptive, not remedial. Once I run into these problems, I'll make sure I relate them here.
One thing evident from your and Dave's posts is that solutions are specific, not general. And that symmetry/aesthetics and fuzziness/specificity don't always go together. But that's in a way what you're saying in your Tsong Ko Pa quotation, isn't it? Clearly one would like some form of symmetry, otherwise we'd all have "rock speakers" or the like in our homes. (there's a thought..) I've seen you expand on the tapping theme somewhere; maybe I should go look for that and read. I like tapping on things anyway - you'll frequently find me tapping on wood samples at wood merchants, drawing weird stares.
Either way, thanks again.
Let me go DO something.
J
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