Back to back , But not really 🙂 it is like me sandwich esl thread , the stats are in phase resulting in higher surface area since Mylar is acoustically transperant. To a certain point , using 2 x 3 micron foils acts like one twice as large 6. Micron film in the 18khz band. You gain 6 dB 🙂
I bought me some audiostatic trannies to do the same with low frequencys as I did in the thread 🙂 but I don't have enough time yet for all these cool things to try 🙂 Are you sure the quads where ok ? There should not be a plastic rattle sound hehe , the stators are looking screwed and are in need of refurb if you ask me
One funny side note esl 63 uses 2. Times 3 micron foil as dust screen , sound is not really affected by it (unless it is floppy an you hear plastic foil flaping)
I bought me some audiostatic trannies to do the same with low frequencys as I did in the thread 🙂 but I don't have enough time yet for all these cool things to try 🙂 Are you sure the quads where ok ? There should not be a plastic rattle sound hehe , the stators are looking screwed and are in need of refurb if you ask me
One funny side note esl 63 uses 2. Times 3 micron foil as dust screen , sound is not really affected by it (unless it is floppy an you hear plastic foil flaping)
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I will have to take a look at that thred.
Not sure ther was any increase in sens from the dual diaphragm bass panel ( similar to the dual woofers in a isobarric arraingment) he mentioned that it was more of a way to increase the mass w/o the resonant effects in the midrange. In other words it was a 4 micron film wich is suposed to sound noticably better in mids than the 12 micron, but with two back to back in phase the total mass overcomes the overdamped situation due to the mass of air damping the very low mass 4 micron film.
The Quads I heard were new units in a audio store in NYC. It was not at all a rattle. It was a plastic sounding coloration. As said I was trained to hear it through many proto developments of my own of low mass plainer diaphragms. I would hear it in 12 micron film diaphragms but not in 6 micron film.
Not sure ther was any increase in sens from the dual diaphragm bass panel ( similar to the dual woofers in a isobarric arraingment) he mentioned that it was more of a way to increase the mass w/o the resonant effects in the midrange. In other words it was a 4 micron film wich is suposed to sound noticably better in mids than the 12 micron, but with two back to back in phase the total mass overcomes the overdamped situation due to the mass of air damping the very low mass 4 micron film.
The Quads I heard were new units in a audio store in NYC. It was not at all a rattle. It was a plastic sounding coloration. As said I was trained to hear it through many proto developments of my own of low mass plainer diaphragms. I would hear it in 12 micron film diaphragms but not in 6 micron film.
Correct me if I am wrong, but a sandwich dual diaphragm panel will have increased mass more than 2x the individual diaphragms, due to the air mass trapped between them.
Hi,
the dual diaphragm system can be a real improvement in a couple of ways:
- increased efficiency of up to +6dB for ka values of up to 4 iIrc (and depending on the membranes distance).
- counters acoustic phase cancellation --> less electronic equalization --> increase in >6dB of dynamic range.
- base resonance remains nearly unchanged in frequency and Q ... still mostly dominated by membrane dimensions and amount of tension.
- capacitance and hence impedance remains almost unchanged --> same audio tranny can be used.
- lower sensitivity of coating to environmental conditions --> improved ageing
- alot more blood sweat and tears when building curved panels .... with flat panels its just a bit more effort.
jauu
Calvin
ps: I assume adding Supra-onions to a Quad will not lead You on the path to Endor 😉
the dual diaphragm system can be a real improvement in a couple of ways:
- increased efficiency of up to +6dB for ka values of up to 4 iIrc (and depending on the membranes distance).
- counters acoustic phase cancellation --> less electronic equalization --> increase in >6dB of dynamic range.
- base resonance remains nearly unchanged in frequency and Q ... still mostly dominated by membrane dimensions and amount of tension.
- capacitance and hence impedance remains almost unchanged --> same audio tranny can be used.
- lower sensitivity of coating to environmental conditions --> improved ageing
- alot more blood sweat and tears when building curved panels .... with flat panels its just a bit more effort.
jauu
Calvin
ps: I assume adding Supra-onions to a Quad will not lead You on the path to Endor 😉
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Calvin could u explain
"counters acoustic phase cancellation --> less electronic equalization --> increase in >6dB of dynamic range."
Im struggling to see how two diaphragms close together would have any effect in low freq. cancilation of dipoles
"counters acoustic phase cancellation --> less electronic equalization --> increase in >6dB of dynamic range."
Im struggling to see how two diaphragms close together would have any effect in low freq. cancilation of dipoles
Hi.
it functions because each of the thin diaphragms is acoustically transparent and as long as there's an layer of air between, soundwaves can develop which add up.
The effect has a lowpass character.
Acoustic phase cancellation on the other hand has a highpass character that requires electronic equalization.
The equalization distracts from the possible dynamic range in that it increases the driving power and the diaphragm excusion
When You choose all parameters well both effects nearly cancel within the working range, resulting in a quite linear amplitude response down to the point where the phase cancellation would reach -6dB, without the need of electronic equalizing.
jauu
Calvin
it functions because each of the thin diaphragms is acoustically transparent and as long as there's an layer of air between, soundwaves can develop which add up.
The effect has a lowpass character.
Acoustic phase cancellation on the other hand has a highpass character that requires electronic equalization.
The equalization distracts from the possible dynamic range in that it increases the driving power and the diaphragm excusion
When You choose all parameters well both effects nearly cancel within the working range, resulting in a quite linear amplitude response down to the point where the phase cancellation would reach -6dB, without the need of electronic equalizing.
jauu
Calvin
I do must add , adding membranes will increase resonance. but this is usually not a problem since you get low pretty easy. it is a problem when you handle very small DS spacings stability tend to be a problem. at least if you want to have a small panel wiith HIGH HV multiple membranes and low resonance 🙂 but maybe i wanted to much of everything 🙂 in bigger panels and greater DS spacing this should not be a major isue. and as calving metnioned you gain 6dB every tiem you double. from 1 to 2 +6dB 2 to 4 +6 dB, and 12 db is allot of power and allot of stepup not needed. so a 150 stepup could be halved, and then halved to get the same volume. it worked well woth my tiny panels, but should be even beter with the bass panels since the distance between panels is no isue here since wavelengths are so huge you could stack 8 if you wanted. except that the top and will be crap 🙂 and resonance is going up up up
Thanks Calvin
WrineX, I dont understand how the resonance increase? Seems to me we have 2X mass but 1/2 compliance wich should give same resonant freq.
WrineX, I dont understand how the resonance increase? Seems to me we have 2X mass but 1/2 compliance wich should give same resonant freq.
For ESLs, resonance is almost always at low enough freqency that wavelength is much larger than the panel's smallest dimension. (ie ka<<1) That being the case the moving mass is almost entirely made up of the airload, the diaphragm mass is very small in comparison. A single diaphragm has an airload due to radiation impedance on each side. When you space two diaphragms very close together, the net airload from radiation impedance is still the same so the moving mass should be unchanged. With 1/2 the compliance you might expect to see the resonance increase by a factor of 1.414. In practice, due to the mass of the air layer between the diaphragms and the small contribution from the diaphragms themselves, resonance usually increases about 20% when typical ESL panels are placed one behind the other.
More details on LF behavior when stacking ESLs:
http://www.diyaudio.com/forums/planars-exotics/226890-my-acoustat-panel-experiment.html#post3309417
More details on HF behavior when stacking ESLs: (including spreadsheet calculator)
sandwich esl ?Yummie - post#25
sandwich esl ?Yummie - post#48
Bolserst nice I kne it went up but did not know it was 1,4 good to know, and the piece about the x max in the linked post is also helpfull. So in the end max output will stay the same but increased efficiency. , so this could be nice for all the. Tube guys 🙂
I'm taking advantage of our hearing being MUCH less discriminating in the bass, so a magnetic woofer is passable, esp once one goes active xo there to allow its amp to keep control of it. This divide & conquer approach also permits me to use a small class A amp on the ESL, while any old (but big) amp will suffice for the bass.
The ESL hybrid ML Ascenti f.ex. has the basics right and is a bargain at under $1500 used, while still being a narrow 13 inches wide, so they don't look like a pair of tombstones.
Attachments
yeah thats another option. but that is hardly a challenge to use such big panels for only 300hz and up. although the high end still has shitty dispersion. since bedning the panel does not mean it has dispersion with the same angle the panel has. what you do get is more distortion. since the mylar is is never nicely in between the stators.
Hi,
Certainly the ML doesn't have one of the most aspects right, which is why their basses never integrate seamless and which is the single most named reason of fans of fullrangers that they still think that FRs are superior.
Working range and transformer quality to name just two, are more decicive for the Q of pro or con than the fact flat vs curved.
When built precisely and the parameters are chosen well, the increase of THD is restricted to the lowest frequencies and some membrane excursion -where it still is rather irrelevant for the sonic impression- but doesn't count at all for hybrid panels crossed over high enough.
Also, even in the most practical praxis will a ESL disphram always find itself nicely trapped between the stators 😛 😀
Of course what You meant is that it were centered between the stators.
This condition applies to a flat unenergized panel on the workbench.
But as soon as You apply the bias voltage the membrane will be offset to one of the stators, regardless of the stator shape.
Peter Baxandall prooved in his papers that this offset (dc condition) doesn't affect the linearity of the drive, but just subtracts from the maximum SPL that the panel can put out.
Now he didn't take the spring forces due to that offset -though they introduce a linear distortion source- into his (ac) calculations, probabely because he assumed them to be negligable for the expected excursion levels anyway.
It doesn't really matter for THD in praxis wether the panel is curved or flat.
In fact adds the curvature a high degree of rigidity to the panel structure.
A flat panel will rattle far more under the same conditions .... which introduces THD.
That's why all decent flat panels have some means to stiffen the whole assembly.
A curved panel though requires more attention and precision and means generally more effort to build .... hence its costier than a flat panel. 😉
jauu
Calvin
Well, change it to 'some basics rihüght' and I agree 😉
Certainly the ML doesn't have one of the most aspects right, which is why their basses never integrate seamless and which is the single most named reason of fans of fullrangers that they still think that FRs are superior.
In theory You may get higher distortion, yes, but in praxis THD depends on quite a few more factors.
Working range and transformer quality to name just two, are more decicive for the Q of pro or con than the fact flat vs curved.
When built precisely and the parameters are chosen well, the increase of THD is restricted to the lowest frequencies and some membrane excursion -where it still is rather irrelevant for the sonic impression- but doesn't count at all for hybrid panels crossed over high enough.
Also, even in the most practical praxis will a ESL disphram always find itself nicely trapped between the stators 😛 😀
Of course what You meant is that it were centered between the stators.
This condition applies to a flat unenergized panel on the workbench.
But as soon as You apply the bias voltage the membrane will be offset to one of the stators, regardless of the stator shape.
Peter Baxandall prooved in his papers that this offset (dc condition) doesn't affect the linearity of the drive, but just subtracts from the maximum SPL that the panel can put out.
Now he didn't take the spring forces due to that offset -though they introduce a linear distortion source- into his (ac) calculations, probabely because he assumed them to be negligable for the expected excursion levels anyway.
It doesn't really matter for THD in praxis wether the panel is curved or flat.
In fact adds the curvature a high degree of rigidity to the panel structure.
A flat panel will rattle far more under the same conditions .... which introduces THD.
That's why all decent flat panels have some means to stiffen the whole assembly.
A curved panel though requires more attention and precision and means generally more effort to build .... hence its costier than a flat panel. 😉
jauu
Calvin
Yes, I was arguing from ignorance when complaining about the horizontal dispersion of the Quad 57s. Quad rebuilder Kent McCollum tells me that the 57s have a perfectly fine 70 degree horizontal dispersion; it’s the 15 degree vertical that causes the beaming.
But is the beaming across the Quad’s entire frequency range or mainly in the HF range? I presumed that it was in the highs, and that’s the only reason why I had proposed the idea of using wider dispersion tweeters-to eliminate the beaming, not to gain HF extension. And if not ribbons then perhaps something like Mundorf AMTs https://www.madisoundspeakerstore.c...rf-amt25d6.1-r-dipole-air-motion-tweeter-amt/
I am also aware that the 57’s beaminess was eliminated in the 63s. But though I still have had no chance yet to hear either Quad model, my somewhat ridiculous search for a consensus among Quad owners (older models) seemed to show that most preferred the 57s. So I reasoned that if it’s was to be the 57s then look for solution for its HF range beaming. But if it’s the 57’s entire frequency response that’s beamy then adding tweeters would hardly help at all.
Better to put the 57s up on stands, 14 to 18” and titled accordingly. Kent said that will solve almost all of the beaming problem. But I’ve read that the Arcici stands can damage the Quad’s wooden frames. What stands might you recommend? And do they offer tilt adjust?
Of course, even I know that ESLs perform poorly in the bass department. To that end please see my post http://www.diyaudio.com/forums/subw...nopole-servo-subs-compatible.html#post4953530
Indeed, my biggest problem is that for health reasons I can’t do air traveling; many people and places I will never be able to visit. So things like RMAF, Axpona or take a kind member’s offer to hear his ESLs hundreds of miles from Long Island are not possible. But might one of your clients in NYC allow to hear their Quads? 57s? 63s? 989s? 2805s? 2905s? A chance to finally hear even just one of those models and just a train ride away would be a blessing-my first ESL session ever.
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