Right on both thoughts, I'd think. You need a good woofer in the usual way you define "good woofer."
But I'm waiting to learn how Calvin does his prime-importance matching for directivity of a cone and an ESL.
Hi,
You might want to reread #53, see earlier post of mine about my systems, or take a look at the former ML Statement II. It´s already all there for quite a time.
jauu
Calvin
You might want to reread #53, see earlier post of mine about my systems, or take a look at the former ML Statement II. It´s already all there for quite a time.
jauu
Calvin
In addition, the lower the cross over the less the stereo effect. At some point you really don't need a sub-woofer in/at both pannels, just one in the middle will handle the low end just fine.
Maybe I'm completely tone deaf, but to my ears as long as the pannels give all the higher order overtones, the ear-brain connection can extract the stereo effect from sub-woofers crossed over as high as 200 Hz. That is, while the sub may take over the 98% of the power of the string bass, the pannels reproduce the plucks and sliding finger movements to key in where the bass is comming from.
I've crossed over to a mixed bass at 140 Hz for many years, including with the sub miles off to the left of the left speaker. No localization shortcomings. Today, I have added horsepower to my Dayton-Wright amp and so can move them down to a 110 Hz crossover, but still with no signal to them at the low frequencies where the D-Ws are poor.
About that post #53, how stupid of me not to have thought of a dipole kind of woofer to match in directivity, rather crudely, a dipole kind of ESL middle. I wonder why I didn't think of it? I wonder why almost nobody ever thinks of it? Actually, I have some suspicions about why almost nobody ever thinks of dipole bass... something to do with high school physics maybe.
But then, a careful person like Calvin (and post #53 does show his design sophistication) and a high crossover at the bottom end of the woofer, like 200 Hz to sub or subs as Mitch mentions....hmmm, possible.....
So we've established there are ways to sort of match directivities (not just dipoling as Calvin suggests, but that does seem the most natural approach). Next we need to establish how much it might matter to match directivities and is that value worth the other compromises both audible and otherwise (like having 10 foot tall woofers as Calvin seems to recommend)?
Yes, directivity influences sound in a room. But is the gap in directivities and the extent of the gap important or not so important and worth other compromises?
About that post #53, how stupid of me not to have thought of a dipole kind of woofer to match in directivity, rather crudely, a dipole kind of ESL middle. I wonder why I didn't think of it? I wonder why almost nobody ever thinks of it? Actually, I have some suspicions about why almost nobody ever thinks of dipole bass... something to do with high school physics maybe.
But then, a careful person like Calvin (and post #53 does show his design sophistication) and a high crossover at the bottom end of the woofer, like 200 Hz to sub or subs as Mitch mentions....hmmm, possible.....
So we've established there are ways to sort of match directivities (not just dipoling as Calvin suggests, but that does seem the most natural approach). Next we need to establish how much it might matter to match directivities and is that value worth the other compromises both audible and otherwise (like having 10 foot tall woofers as Calvin seems to recommend)?
Yes, directivity influences sound in a room. But is the gap in directivities and the extent of the gap important or not so important and worth other compromises?
Now we're getting back on track.
Mitch> You have a very interesting point. Using only one woofer would definately make it easier not to say way cheaper as well.
bentoronto> Crossing at 140Hz would make my choice of sub an easy one, I'd go with a TH.
Maybe I should turn the tables? How wide/big need the panels be to cross at 150Hz and still retaining a good sensitivity?
Mitch> You have a very interesting point. Using only one woofer would definately make it easier not to say way cheaper as well.
bentoronto> Crossing at 140Hz would make my choice of sub an easy one, I'd go with a TH.
Maybe I should turn the tables? How wide/big need the panels be to cross at 150Hz and still retaining a good sensitivity?
There is a current very productive discussion of center channels (real, not phantom) and mono an putting L and R speakers close together elsewhere on the loudspeaker forum. Might give you some ideas and no need to be totally locked into conventional stereo layouts.
Well, even with a 24 dB/8ave electronic crossover, "150 Hz" means the ESL has to tolerate inputs (and you tolerate the outputs from the ESL) down to an octave or so below. That's optimistic.
Start with a little two-panel pair of tweeters coming in at 1kHz in a two-way system. If the ESLs tweet high powerfully, add a mixed bass sub. Most of the ESL benefits without stress and frustration.
I think I mentioned earlier that Roger Sanders' latest Eros "C" hybrid speaker is crossed over at 172hz but I neglected to mention that he had to use a 48db/oct slope with a shelving circuit and some fairly powerful amps to go that low and make it work.
Hi,
Ben, I´m not taking such comments to ridicule me. Comparing Your expertise in this matter with mine, I´m quite confident, I need not hide.
Almost every ESL works as dipolar radiator. Maybe You missed out on this small but important information. 🙄
If You knew Your school physics You need not wonder about the idea of an dipole as midbass or even as subwoofer.
jauu
Calvin
Ben, I´m not taking such comments to ridicule me. Comparing Your expertise in this matter with mine, I´m quite confident, I need not hide.
Almost every ESL works as dipolar radiator. Maybe You missed out on this small but important information. 🙄
If You knew Your school physics You need not wonder about the idea of an dipole as midbass or even as subwoofer.
jauu
Calvin
Calvin> Do you know a suitable driver you could mention? I'd like to run a simulation or two and I don't know what to look for in a Dipole bass driver? Perhaps a 10" or something in that general area?
CharlieM> Thats harsh, 48dB filters... ouch.
At the momet I'm thinking a 12"x48" panel is looking pretty good. Big enough to useful but not too big a beast.
CharlieM> Thats harsh, 48dB filters... ouch.
At the momet I'm thinking a 12"x48" panel is looking pretty good. Big enough to useful but not too big a beast.
Calvin - sometimes the difference between "humorous nudge" and "ridicule" are not clear enough and so I am sorry if I failed in that respect. My comments that I was stupid not to have thought of dipole bass, few people think of it, and the high-school physics issue of wave length, are meant to critique the notion of using dipole bass since they are meant to be true and almost self-evident (at least to most people).
When I wrote anyone can see from your design you are sophisticated... well, if you take that - seemingly true - statement as if it were some kind of reversal-sarcasm.... well, some people can take construe ANY statement as if meant in reversal-sarcasm, like "Jack is a nice fellow". At least for me, easy enough to believe BOTH (a) Calvin's dipole bass proposal is probably not worth a second thought and (b) Calvin has designed a sophisticated dipole bass.
Just for the record, I liked cone dipoles long before becoming involved with ESLs. In 1967, I had of pair of Bozak speakers with their classic aluminum-and-latex drivers running quasi-dipole. Even tried hanging a 12 inch cone driver from a string from the ceiling. Nice open sound, and reminiscent of the Leslie speaker in an electric organ (it rotates too, ha ha). But not much bass.
Oh yes, about that 12 inch driver hanging from a string. I taped a lovely toroid inductor to the back of the magnet and wired in series, maybe a nice fraction of a Henry, and a resistor or two. Yup, got a little bass. Nice open sound.
Engineering Design Note: for those who think I was violating some principle of Newton's, the toroid coil added mass to the frame so the cone did more of the shaking, not the frame.
Engineering Design Note: for those who think I was violating some principle of Newton's, the toroid coil added mass to the frame so the cone did more of the shaking, not the frame.
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Bentoronto:
Can you clarify your concerns about matching the directivity of an ESL panel to that of a OB dynamic woofer? I don't see why it should be difficult to match them at frequencies in the 100 - 400 Hz range. To a first approximation (neglecting the effects of the woofer's magnet, spider, frame etc. behind the woofer cone) a vertical array of 8" woofers and an 8" wide ESL panel whose height is similar to that of the array ought to have similar directivity at frequencies where both systems can be approximated as pistonic. Or am I missing something?
I second Calvin's assertion that matching the directivity patterns matters. A point-source monopole's loudness will drop off much more quickly with increasing distance than will a quasi-line source ESL. When combining a point source and a line source you can match their outputs at one distance from the speakers but their outputs won't match at other distances. If, instead, the bass is generated by a vertical array of dynamic woofers, and that array's dimensions match that of a vertical ESL, then it should be possible to do a much better job of making the outputs match at a wide variety of distances and angles. That also ensures that the sounds reflected from room boundaries and directed toward the listener ought to match up better as well.
From this point of view the "all there is is good bass or bad bass" argument doesn't seem to me to capture some important features.
On the other hand, once the wavelengths get so long (the frequencies get so low) that room resonances dominate bass response, then I would think that the details of the directivity pattern or Q of the source of the low frequencies would matter less. What matters then is the response of the combined source-room system. In other words, a low Q bass system can excite a high Q room resonance and result in boomy bass even though the bass system's response, taken in isolation, does not suffer from serious resonance problems.
Few
Can you clarify your concerns about matching the directivity of an ESL panel to that of a OB dynamic woofer? I don't see why it should be difficult to match them at frequencies in the 100 - 400 Hz range. To a first approximation (neglecting the effects of the woofer's magnet, spider, frame etc. behind the woofer cone) a vertical array of 8" woofers and an 8" wide ESL panel whose height is similar to that of the array ought to have similar directivity at frequencies where both systems can be approximated as pistonic. Or am I missing something?
I second Calvin's assertion that matching the directivity patterns matters. A point-source monopole's loudness will drop off much more quickly with increasing distance than will a quasi-line source ESL. When combining a point source and a line source you can match their outputs at one distance from the speakers but their outputs won't match at other distances. If, instead, the bass is generated by a vertical array of dynamic woofers, and that array's dimensions match that of a vertical ESL, then it should be possible to do a much better job of making the outputs match at a wide variety of distances and angles. That also ensures that the sounds reflected from room boundaries and directed toward the listener ought to match up better as well.
From this point of view the "all there is is good bass or bad bass" argument doesn't seem to me to capture some important features.
On the other hand, once the wavelengths get so long (the frequencies get so low) that room resonances dominate bass response, then I would think that the details of the directivity pattern or Q of the source of the low frequencies would matter less. What matters then is the response of the combined source-room system. In other words, a low Q bass system can excite a high Q room resonance and result in boomy bass even though the bass system's response, taken in isolation, does not suffer from serious resonance problems.
Few
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Hi,
having read and reread and reread the thread and taken the help of an online translator I got the impression, that I misinterpreted Ben´s words.
It sometimes is a mercy and sometimes a burden that language leaves room for interpretation. Sorry for that.
This is a list of threads in which I explained what for and why I use dipole basses.
http://www.diyaudio.com/forums/planars-exotics/95324-diy-esl-suggestions-thread.html
http://www.diyaudio.com/forums/planars-exotics/124282-carver-tfm-amps-esls.html
@MarkusG
Mr. Linkwitz explains in depth the theory of dipole basses on his website. He likes to use the peerless XXLS drivers. He focuses on the H-frame cabinet stile and rather low Q-drivers. Mr. Ridtahler of whom I learned how to design dipoles built probabely the most compact folded dipole bass and prefers rather mid to high Qed drivers (needs less equing).
There are other cabinet styles popssible, each with its distinct behaviour.
- The small folded dipole (Ripol):
...lowers the Fs of the driver considerably, which allows of use drivers with a stiffer spider and higher fs. This is good for the behaviour of the system under large signal/large excursion or overdrive conditions. But the 2 or 3 chambers of the cabinet resonate (similar to a TL) and restrict the upper frequency limit and must be notched. The larger the driver, the larger the chambers, the lower the upper bandwidth limit. Drivers like the affordable Peerless SLS-series work exceptionally well in these small dipole casings, especially the SLS10 (they sound terrible in TLs and seemingly every other compartment). One very desirable feature of the SLS-series is their very progressive suspension, which allows to drive the systems very hard without risk of destruction.
The small SLS10-dipole should not play higher than ~200Hz.
- The H-frame:
...is extensively written about and analyzed on SLs site. The Fs-drop of the drivers is neglectable here. Since the drivers don´t experience any external spring mechanism, they tend to show large excursions at already low power inputs. The spider needs to be of the rather soft type but with a strong progression in stiffness towards the excursion limit. Its size, looks and the choice of drivers is not to my taste and I think its a case where theory and praxis are not overly happy with each other.
- Open Baffles:
...are the easiest to build, just a large flat sheet of cardboard. No Fs-reduction with these and the same factors apply to them as to the choice of H-frame drivers. Size -and I mean the ´visible´ sitze- is the largest of all dipoles. No distinct advantages against smaller forms.
Folded open Baffle in a U or A-shape:
..the U-shape just reduces the optical size of the open Baffle. Depending on the depth of the backwards folded parts of the baffle a chamber resonance develops which reduces the upper bandwidth limit.
...the A-shape folds the sides even more to the inside. A chamber develops with a bandwidth limiting resonance, the lower in frequnency the deeper the dimension of the casing is. Also the Fs of the driver sinks a few Hz, which allows for drivers with slightly elevated Fs-values and better large signal behaviour. Using 6.5" to 7" drivers the A may take less floor space than a sheet of DIN A4 paper with an upper bandwidth limit around ~300Hz. The lower bandwidth limit could be around 35Hz, but very probabely needs some electronic equing.
My favourites are the Ripol and the A-shape. The tiny cabinets simply look sexy 😉 The small dimensions and the favourable Fs-reduction make stacking of a multitude of dipoles more paracticable and optically tolerable than with any other dipole. Multiple smaller drivers with higher Fs values can still produce deep bass in an outstanding quality and provide for a large dynamic range.
Nowadays my small system looks like this:
jauu
Calvin
having read and reread and reread the thread and taken the help of an online translator I got the impression, that I misinterpreted Ben´s words.
It sometimes is a mercy and sometimes a burden that language leaves room for interpretation. Sorry for that.
This is a list of threads in which I explained what for and why I use dipole basses.
http://www.diyaudio.com/forums/planars-exotics/95324-diy-esl-suggestions-thread.html
http://www.diyaudio.com/forums/planars-exotics/124282-carver-tfm-amps-esls.html
@MarkusG
Mr. Linkwitz explains in depth the theory of dipole basses on his website. He likes to use the peerless XXLS drivers. He focuses on the H-frame cabinet stile and rather low Q-drivers. Mr. Ridtahler of whom I learned how to design dipoles built probabely the most compact folded dipole bass and prefers rather mid to high Qed drivers (needs less equing).
There are other cabinet styles popssible, each with its distinct behaviour.
- The small folded dipole (Ripol):
...lowers the Fs of the driver considerably, which allows of use drivers with a stiffer spider and higher fs. This is good for the behaviour of the system under large signal/large excursion or overdrive conditions. But the 2 or 3 chambers of the cabinet resonate (similar to a TL) and restrict the upper frequency limit and must be notched. The larger the driver, the larger the chambers, the lower the upper bandwidth limit. Drivers like the affordable Peerless SLS-series work exceptionally well in these small dipole casings, especially the SLS10 (they sound terrible in TLs and seemingly every other compartment). One very desirable feature of the SLS-series is their very progressive suspension, which allows to drive the systems very hard without risk of destruction.
The small SLS10-dipole should not play higher than ~200Hz.
- The H-frame:
...is extensively written about and analyzed on SLs site. The Fs-drop of the drivers is neglectable here. Since the drivers don´t experience any external spring mechanism, they tend to show large excursions at already low power inputs. The spider needs to be of the rather soft type but with a strong progression in stiffness towards the excursion limit. Its size, looks and the choice of drivers is not to my taste and I think its a case where theory and praxis are not overly happy with each other.
- Open Baffles:
...are the easiest to build, just a large flat sheet of cardboard. No Fs-reduction with these and the same factors apply to them as to the choice of H-frame drivers. Size -and I mean the ´visible´ sitze- is the largest of all dipoles. No distinct advantages against smaller forms.
Folded open Baffle in a U or A-shape:
..the U-shape just reduces the optical size of the open Baffle. Depending on the depth of the backwards folded parts of the baffle a chamber resonance develops which reduces the upper bandwidth limit.
...the A-shape folds the sides even more to the inside. A chamber develops with a bandwidth limiting resonance, the lower in frequnency the deeper the dimension of the casing is. Also the Fs of the driver sinks a few Hz, which allows for drivers with slightly elevated Fs-values and better large signal behaviour. Using 6.5" to 7" drivers the A may take less floor space than a sheet of DIN A4 paper with an upper bandwidth limit around ~300Hz. The lower bandwidth limit could be around 35Hz, but very probabely needs some electronic equing.
My favourites are the Ripol and the A-shape. The tiny cabinets simply look sexy 😉 The small dimensions and the favourable Fs-reduction make stacking of a multitude of dipoles more paracticable and optically tolerable than with any other dipole. Multiple smaller drivers with higher Fs values can still produce deep bass in an outstanding quality and provide for a large dynamic range.
Nowadays my small system looks like this:
An externally hosted image should be here but it was not working when we last tested it.
[URL="http://a.imageshack.us/img689/940/eslfront02.jpg"]http://a.imageshack.us/img689/940/eslfront02.jpg http://a.imageshack.us/img689/940/eslfront02.jpg 
An externally hosted image should be here but it was not working when we last tested it.
http://a.imageshack.us/img201/543/eslback02.jpg 
An externally hosted image should be here but it was not working when we last tested it.
http://a.imageshack.us/img695/9049/eslside01.jpg 
An externally hosted image should be here but it was not working when we last tested it.
http://a.imageshack.us/img824/6960/eslside02.jpg
jauu
Calvin
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Hi Calvin,
I dare not call your small system a small one at all. They look awesome and mighty. 🙂
Wachara C.
I dare not call your small system a small one at all. They look awesome and mighty. 🙂
Wachara C.
Calvin> 
Those are some awsome looking speakers you have there.
A-shaped OB and Ripoles are new to me and I haven't got a clue how to do simulations. I guess I have some reading to do.
I'd love to pick your brain for the little details on your build but I'll try and restran myself.
You've done exactly what I want to do but don't know how to? (At least as far as the ESL goes.)
Those are some awsome looking speakers you have there.A-shaped OB and Ripoles are new to me and I haven't got a clue how to do simulations. I guess I have some reading to do.
I'd love to pick your brain for the little details on your build but I'll try and restran myself.
You've done exactly what I want to do but don't know how to? (At least as far as the ESL goes.)
Hi,
well there´s small and then there´s small 😉
I call it the small one (esl), because there´s still my ´Mr. Big´(ESL) that features a panel with double the membrane area (150x40cm), a bass tower with 8pcs of 7"-drivers and a side-gated 75cm-globe subwoofer featuring two 15" superlongthrow drivers.
The esl is also perfectly happy with smaller room sizes from 20m² up and shorter recommendd listening distances. For rooms of more than 30m² I´d recommend an additional subwoofer. The big ESL needs room space of min. 40m².
The esl is app. 130cm high. This is a height which You don´t recognize easily and which You tend to ´overlook´. The Big one reaches 160cm, a height that one recognizes as obstacle ín one´s way. Luckily the thinness in appearance of the solid bass tower dominates the impression, while the wider panel makes a lightweight and smaller impression because of its transparency and little depth. If You had a typical speaker system of these demensions standing around it truly would look heavy, plump and ugly.
The system can also be called small because the dimensions are indeed small compared to a typical speaker with a similar driver number count and performance. And its alot smaller than earlier evolutions which You can also find pics of in this forum. The bass tower occupies less space than a sheet of DIN A4 paper. Its 21cm wide, 15cm deep and 125cm high (150cm the Big).
So the bass tower has similar width and heigth of a lot of other speakers, but less depth. The curved panel is 125x25cm in size, embraced by a very thin frame that is a roughly triangular shaped profile of 12*50mm crosssection. The massive aluminium base could hardly be made smaller than it is. Only the third foot protrudes from the speaker´s backside footprint shape for stable standing reasons. Practically the only way to reduce size would mean smaller sized bass drivers, a smaller number of bass drivers and a smaller panel. Since it is not intended as a bookshelf system but a free standing system, with its height just below the optical perception treshold, smaller dimensions wouldn´t help to reduce optical size impression much, but it would mean to give up on a good part of this system´s sonic qualities.
Lastly I call it small, because of the sonic capabilities of this system. Its a system I don´t fear at all to be compared against famous ´flagships´ which are typically a lot larger in size.
Of course...compared to a headphone -I´m so sorry I still haven´t found time to build the HP, Wachara- it´s dimensions are slightly larger. 😀
@MarkusG
thanks alot. As a speaker designer I´m happy with the technical and acoustical end result. But it´s even more pleasing to hear a ´I like it´ because industry design is not my field of expertise. I´m no architect or industry designer. To me as technocratical person the world is rather a straight line rather than a curve. The concept of a lightly drawn curvature is simply not locked into my genes 🙄 With both systems only the vertical lines are straight. Basically all horizontal lines are bows and curves. So it took me ages -of felt time- till the system looked as it looks now. It taught me a lot about size- space and area-relations and how much difference just one small line can make. As You might see this system strictly follows the rule of form-follows-function which I learned often -but not necessarily- leads to a design that pleases many people´s feelings or emotions.
Somehow funny, but hardly anone who inspected the system noticed that it is indeed a fullrange open baffle/dipole system, i.e that the bass is not a closed box design. They wondered about the small footprint and small cabinet volume of the bass and were astonished about the sonical qualities of it. Just few noticed that the cloth covering the open backside of the bass tower is just an optical barrier.
Anyway these systems represent just one of several possible concepts. But to me its one of the straightest and most stringent acoustical concepts to follow if You aim for the very top. And it has proven its qualities since MartinLogan presented its famous StatementII to the public, which I admire because of its conceptual beauty. You can use it as a suggestion for own designs or follow other conceptual ideas.
If You build such a system You should be aware though that it might lead to a chain of new experiences along which You will put every device in Your chain under proof. You may come to recognize that OP-amped devices and most global feed-back amps don´t sound natural or authentic but artificial. You may come to realize that the speaker is no longer the weakest link in Your chain. 😉
jauu
Calvin
well there´s small and then there´s small 😉
I call it the small one (esl), because there´s still my ´Mr. Big´(ESL) that features a panel with double the membrane area (150x40cm), a bass tower with 8pcs of 7"-drivers and a side-gated 75cm-globe subwoofer featuring two 15" superlongthrow drivers.
The esl is also perfectly happy with smaller room sizes from 20m² up and shorter recommendd listening distances. For rooms of more than 30m² I´d recommend an additional subwoofer. The big ESL needs room space of min. 40m².
The esl is app. 130cm high. This is a height which You don´t recognize easily and which You tend to ´overlook´. The Big one reaches 160cm, a height that one recognizes as obstacle ín one´s way. Luckily the thinness in appearance of the solid bass tower dominates the impression, while the wider panel makes a lightweight and smaller impression because of its transparency and little depth. If You had a typical speaker system of these demensions standing around it truly would look heavy, plump and ugly.
The system can also be called small because the dimensions are indeed small compared to a typical speaker with a similar driver number count and performance. And its alot smaller than earlier evolutions which You can also find pics of in this forum. The bass tower occupies less space than a sheet of DIN A4 paper. Its 21cm wide, 15cm deep and 125cm high (150cm the Big).
So the bass tower has similar width and heigth of a lot of other speakers, but less depth. The curved panel is 125x25cm in size, embraced by a very thin frame that is a roughly triangular shaped profile of 12*50mm crosssection. The massive aluminium base could hardly be made smaller than it is. Only the third foot protrudes from the speaker´s backside footprint shape for stable standing reasons. Practically the only way to reduce size would mean smaller sized bass drivers, a smaller number of bass drivers and a smaller panel. Since it is not intended as a bookshelf system but a free standing system, with its height just below the optical perception treshold, smaller dimensions wouldn´t help to reduce optical size impression much, but it would mean to give up on a good part of this system´s sonic qualities.
Lastly I call it small, because of the sonic capabilities of this system. Its a system I don´t fear at all to be compared against famous ´flagships´ which are typically a lot larger in size.
Of course...compared to a headphone -I´m so sorry I still haven´t found time to build the HP, Wachara- it´s dimensions are slightly larger. 😀
@MarkusG
thanks alot. As a speaker designer I´m happy with the technical and acoustical end result. But it´s even more pleasing to hear a ´I like it´ because industry design is not my field of expertise. I´m no architect or industry designer. To me as technocratical person the world is rather a straight line rather than a curve. The concept of a lightly drawn curvature is simply not locked into my genes 🙄 With both systems only the vertical lines are straight. Basically all horizontal lines are bows and curves. So it took me ages -of felt time- till the system looked as it looks now. It taught me a lot about size- space and area-relations and how much difference just one small line can make. As You might see this system strictly follows the rule of form-follows-function which I learned often -but not necessarily- leads to a design that pleases many people´s feelings or emotions.
Somehow funny, but hardly anone who inspected the system noticed that it is indeed a fullrange open baffle/dipole system, i.e that the bass is not a closed box design. They wondered about the small footprint and small cabinet volume of the bass and were astonished about the sonical qualities of it. Just few noticed that the cloth covering the open backside of the bass tower is just an optical barrier.
Anyway these systems represent just one of several possible concepts. But to me its one of the straightest and most stringent acoustical concepts to follow if You aim for the very top. And it has proven its qualities since MartinLogan presented its famous StatementII to the public, which I admire because of its conceptual beauty. You can use it as a suggestion for own designs or follow other conceptual ideas.
If You build such a system You should be aware though that it might lead to a chain of new experiences along which You will put every device in Your chain under proof. You may come to recognize that OP-amped devices and most global feed-back amps don´t sound natural or authentic but artificial. You may come to realize that the speaker is no longer the weakest link in Your chain. 😉
jauu
Calvin
Last edited:
Calvin -
Measurements? Data?
After some time on the Geddes thread, glad to see Calvin's excellent restraint in promoting his products. I had a look at the website but would like to ask what are the price(s) for these speakers?
Footnote: each Dayton-Wright speaker is very roughly 8000 sq cm membrane. The 1:100 step-up transformers weigh, just guessing, about 30 lbs each. I drive them with an amp clipping at 350 watts/ch into 4 ohms.
Measurements? Data?
After some time on the Geddes thread, glad to see Calvin's excellent restraint in promoting his products. I had a look at the website but would like to ask what are the price(s) for these speakers?
Footnote: each Dayton-Wright speaker is very roughly 8000 sq cm membrane. The 1:100 step-up transformers weigh, just guessing, about 30 lbs each. I drive them with an amp clipping at 350 watts/ch into 4 ohms.
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Hi,
Ahh prices....I don´t know ..... probably either beyond belief, or beyond honorable DIYer´s budget ?? 😉
I don´t think that the forum appreciated such infos from me as an person involved in the design. The intention is to show what can be done and how...to share ideas and knowledge .... and enjoy the times here. All of that can´t be paid with money. 🙄
I´d be willing to give more infos on request on a PN level, as anybody interested may contact any manufacturer or dealer of his choice.
jauu
Calvin
Ahh prices....I don´t know ..... probably either beyond belief, or beyond honorable DIYer´s budget ?? 😉
I don´t think that the forum appreciated such infos from me as an person involved in the design. The intention is to show what can be done and how...to share ideas and knowledge .... and enjoy the times here. All of that can´t be paid with money. 🙄
I´d be willing to give more infos on request on a PN level, as anybody interested may contact any manufacturer or dealer of his choice.
jauu
Calvin
The scales are falling from my eyes. And now I understand why Calvin kept on emphasizing he was talking about a mid/woofer crossover not working with a subwoofer.
Returning to Markus' thread, crossover point is quite important. I know that is odd to say since every Hz-point has been used by somebody at some time. With ESLs, you do have the opportunity to run a quite wide-band mid and thereby have nearly all of the core sound from one driver source.
A rather bad place to make the break is in the region say roughly 200-500 Hz where a lot of music resides, the ear is sensitive, and long chapters of Toole's book address reflections and speaker configurations which come into play. It can and it has been done but it comes with a problems.
But the reality of making biggish DIY ESLs comes home to roost and nests right around there...not to mention otherwise beautiful units that Calvin sells. Very great effort is needed to push ESLs down lower in cut off.
If you find yourself dividing between speakers in that ear-sensitive region, then Calvin's recommendation about about taking care with dispersion and matching dipole to dipole may well be spot-on. Fortunately, nobody is forced to make that painful compromise if they don't make their division in that region. Even in that region, there are lots of design criteria to consider besides directivity, but Calvin may have a point.
Calvin's general absolutist urgings about matching dipole to dipole may well be applicable to that crossover region. But it is of less or no importance at frequencies below roughly 150 and above roughly 2000. At low frequencies, directivity isn't much of an issue although there are bound to be golden-eared people who think otherwise and who can tell the difference between open sound and closed sound from 100 yards away.
At high frequencies, ESL are less dipolar and forward beaming becomes the problem. Calvin (and as a widely shared opinion) may well be correct about matching (or at least correctly working with) directivity factors. But a solution which is not likely to be sound is to have a cone dipole to "match" an ESL dipole at high frequencies.
And for a beginner's ESL with a crossover at 1000 Hz, as I have been urging, it is anybody's guess what to do!
Returning to Markus' thread, crossover point is quite important. I know that is odd to say since every Hz-point has been used by somebody at some time. With ESLs, you do have the opportunity to run a quite wide-band mid and thereby have nearly all of the core sound from one driver source.
A rather bad place to make the break is in the region say roughly 200-500 Hz where a lot of music resides, the ear is sensitive, and long chapters of Toole's book address reflections and speaker configurations which come into play. It can and it has been done but it comes with a problems.
But the reality of making biggish DIY ESLs comes home to roost and nests right around there...not to mention otherwise beautiful units that Calvin sells. Very great effort is needed to push ESLs down lower in cut off.
If you find yourself dividing between speakers in that ear-sensitive region, then Calvin's recommendation about about taking care with dispersion and matching dipole to dipole may well be spot-on. Fortunately, nobody is forced to make that painful compromise if they don't make their division in that region. Even in that region, there are lots of design criteria to consider besides directivity, but Calvin may have a point.
Calvin's general absolutist urgings about matching dipole to dipole may well be applicable to that crossover region. But it is of less or no importance at frequencies below roughly 150 and above roughly 2000. At low frequencies, directivity isn't much of an issue although there are bound to be golden-eared people who think otherwise and who can tell the difference between open sound and closed sound from 100 yards away.
At high frequencies, ESL are less dipolar and forward beaming becomes the problem. Calvin (and as a widely shared opinion) may well be correct about matching (or at least correctly working with) directivity factors. But a solution which is not likely to be sound is to have a cone dipole to "match" an ESL dipole at high frequencies.
And for a beginner's ESL with a crossover at 1000 Hz, as I have been urging, it is anybody's guess what to do!
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I think that sums it up pretty good.
However you do it there are compromises.
Crossing @ 150Hz will demand some serious big panels and you risk sensitivity/need some serious amplifiers.
Crossing @ 200-500Hz is more doable but arguably it may sound iffy if not done right.
Crossing @ +300Hz will put us in the midrange where our ears are the most sensitive
To me it looks like a 250-300Hz cross will encompass the least audiable compromises and still let you get away with a reasonably sized panel?
bentoronto> The only thing I can't really understand is why you propose crossing at 1kHz? It's right at the ears most sensitive area? It's hard to build a good two-way system? At least it's hard to get a bass with some slam and a good sonic match?
I have one small OT question...
Is it ok to use foam tape for D/S spacing? (Mylar -> Perf metal) Will it hold when one heat shinks the diaphragm? What kind of tape is preferred? (There are many materials to be found?)
However you do it there are compromises.
Crossing @ 150Hz will demand some serious big panels and you risk sensitivity/need some serious amplifiers.
Crossing @ 200-500Hz is more doable but arguably it may sound iffy if not done right.
Crossing @ +300Hz will put us in the midrange where our ears are the most sensitive
To me it looks like a 250-300Hz cross will encompass the least audiable compromises and still let you get away with a reasonably sized panel?
bentoronto> The only thing I can't really understand is why you propose crossing at 1kHz? It's right at the ears most sensitive area? It's hard to build a good two-way system? At least it's hard to get a bass with some slam and a good sonic match?
I have one small OT question...
Is it ok to use foam tape for D/S spacing? (Mylar -> Perf metal) Will it hold when one heat shinks the diaphragm? What kind of tape is preferred? (There are many materials to be found?)
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