I am realy interested in the point source technology used in quad esl's. Is point source the reason quads sound good? Link explaining delay rings:
http://www.euronet.nl/users/temagm/audio/esl63.htm
I have a few questions about them.
1. Are the bass panels last in the delay line?
2. Where could i get delay coils?
3. What is the delay between rings?
4. Won't some frequancys sound delayed? Or is the delay so short that there is not enoungh time to notice?
5. Is the different ring thicknesses for different frequencys? If they are why are they aranged in that order?
How could this idea be inproved upon?
thanks
http://www.euronet.nl/users/temagm/audio/esl63.htm
I have a few questions about them.
1. Are the bass panels last in the delay line?
2. Where could i get delay coils?
3. What is the delay between rings?
4. Won't some frequancys sound delayed? Or is the delay so short that there is not enoungh time to notice?
5. Is the different ring thicknesses for different frequencys? If they are why are they aranged in that order?
How could this idea be inproved upon?
thanks
As it is christmas holiday anyway, I suggest you do some reading 
Most answers to your questions can be found in these articles:
-Peter Baxandall wrote an excellent article on esl theory which also contains a wealth of detailed information on the Quad 57/63 models.
-You may also want to read the original papers from Peter Walker. Here is one to start with, a zillion others can be found all over the internet. Quadesl.org is a good starting point.
Btw I don't agree with you that the Quads are very good sounding esl's
But that's a matter of personal taste I guess..
Most answers to your questions can be found in these articles:-Peter Baxandall wrote an excellent article on esl theory which also contains a wealth of detailed information on the Quad 57/63 models.
-You may also want to read the original papers from Peter Walker. Here is one to start with, a zillion others can be found all over the internet. Quadesl.org is a good starting point.
Btw I don't agree with you that the Quads are very good sounding esl's
But that's a matter of personal taste I guess..
Simulations
I have been trying to simulate the delay line to get some idea of how effective it is at producing the "pulsating sphere" that Quad talked about in their marketing literature.
The problem I am running into is that I don't have any data on the coils. I'd bust open one of my speakers, but since I rebuilt them, getting at the boards with the coils is a major PITA. Does anyone have a loose coil sitting around? I have a quality LCR bridge that I can use to do some tests so I can develop a decent model.
In my initial playing around I tried simulating the coils (actually air core transformers with a shorted secondary, per the schematic). The results are not encouraging. The shorted coil makes the whole thing look like a smaller inductance. That is the opposite of what is needed based on my simulations of the entire delay line circuit, where I can't seem to get more than about 20 us delay between adjacent segments of the speaker, which seems too small to me.
I'll post some of the circuits and results when I reboot to windoze. I sure wish LT would come up with a linux version of SwitcherCAD! Maybe I'll try running it in wine...
I_F
I have been trying to simulate the delay line to get some idea of how effective it is at producing the "pulsating sphere" that Quad talked about in their marketing literature.
The problem I am running into is that I don't have any data on the coils. I'd bust open one of my speakers, but since I rebuilt them, getting at the boards with the coils is a major PITA. Does anyone have a loose coil sitting around? I have a quality LCR bridge that I can use to do some tests so I can develop a decent model.
In my initial playing around I tried simulating the coils (actually air core transformers with a shorted secondary, per the schematic). The results are not encouraging. The shorted coil makes the whole thing look like a smaller inductance. That is the opposite of what is needed based on my simulations of the entire delay line circuit, where I can't seem to get more than about 20 us delay between adjacent segments of the speaker, which seems too small to me.
I'll post some of the circuits and results when I reboot to windoze. I sure wish LT would come up with a linux version of SwitcherCAD! Maybe I'll try running it in wine...
I_F
I measured them long ago. As far as I know, the coils are around 4H.
You also need the capacity of the segments:
Capacity of the inner 6 rings is around 11 pF. The next one is 45pf, the most outer one is 72pf.
Bass pannels are 360pf total.
The shorted turn is to dampen the line, which is calculated exactly so the signal won't reflect back at the end. You can simulate that by placing a resistor in series with the shortened turn.
There is some more info about the coils in the Baxandall article if I remeber well.
You also need the capacity of the segments:
Capacity of the inner 6 rings is around 11 pF. The next one is 45pf, the most outer one is 72pf.
Bass pannels are 360pf total.
The shorted turn is to dampen the line, which is calculated exactly so the signal won't reflect back at the end. You can simulate that by placing a resistor in series with the shortened turn.
There is some more info about the coils in the Baxandall article if I remeber well.
Btw, the capacitances mentioned are measured directly on teh panels, also without wiring capacitance.
Also there is signifant capacitance in between the rings. The small 10p caps are there to compensate for them. Better omit them in simu.
The source the line is driven from (stepup trannie) is important as well, the transformers have a remarkable high dc resistance (several kohm, don't have the accurate number where I can find them...)
Also there is signifant capacitance in between the rings. The small 10p caps are there to compensate for them. Better omit them in simu.
The source the line is driven from (stepup trannie) is important as well, the transformers have a remarkable high dc resistance (several kohm, don't have the accurate number where I can find them...)
point or line what do you really want?
Remember that with a point source you have a panel that radiates hemispherical wave fronts. That means that you are exciting all the room modes especially consider the floor, ceiling as well as wall bounce. With a line source you no longer have to worry about floor and ceiling bounce and your wall bounce can be controlled. Just some food for thought.
Some years ago I co designed a point sourch panel speaker that was magnetically driven. All of our first designs were line source but we went to market with a point source version. For what it is worth we never had a point source panel that could touch our line source versions in terms of 3-D holographic image quality, not even close. Long story as to why we went with the point but it was not because it was better. Regards Moray James.
Remember that with a point source you have a panel that radiates hemispherical wave fronts. That means that you are exciting all the room modes especially consider the floor, ceiling as well as wall bounce. With a line source you no longer have to worry about floor and ceiling bounce and your wall bounce can be controlled. Just some food for thought.
Some years ago I co designed a point sourch panel speaker that was magnetically driven. All of our first designs were line source but we went to market with a point source version. For what it is worth we never had a point source panel that could touch our line source versions in terms of 3-D holographic image quality, not even close. Long story as to why we went with the point but it was not because it was better. Regards Moray James.
Here are some simulation results
I put them here so they'll have a permanent home:
http://mark.rehorst.com/Quad_ESL-63/index.htm
I_F
I put them here so they'll have a permanent home:
http://mark.rehorst.com/Quad_ESL-63/index.htm
I_F
In the Baxandall document linked above (I think copied from 'The Loudspeaker and Headphone Handbook' edited by John Borwick.) he presents a simplified single ended schematic just containing the panel capacitances and with inductor values of 18H. Figure 3.44 in my copy of the Third Edition. I would expect this to be a good basis for simulation.
The actual inductors are apparently 3H, the delay per section is 20uS. The DC resistance of the output transformer secondaries is about 3.1K (each).
Paul
The actual inductors are apparently 3H, the delay per section is 20uS. The DC resistance of the output transformer secondaries is about 3.1K (each).
Paul
Hi,
as Moray pointed out, one might have better results with a line source than with a point source.
Besides featuring very clever ideas, the Quads are still production cost optimized products. As a result I see some compromises that lead imo to the fact, that the ESL63 doesn´t really work as it is intended to!
Every ring of the diaphragm should be mechanically decoupled from it´s neighbouring rings. Otherwise there will be resonances and bending waves with increased distortion and narrower distribution than predicted!!?? There is a Patent dating from 1930 (!!) which describes exactly what the ESL63 does, or is intended to do.
And I´m with maudio: What is all the fuss about such a dull sounding speaker...no bass, no highs, no dynamics...every 63 I heard sounded as if a blanket were thrown over the speaker.
jauu
Calvin
as Moray pointed out, one might have better results with a line source than with a point source.
Besides featuring very clever ideas, the Quads are still production cost optimized products. As a result I see some compromises that lead imo to the fact, that the ESL63 doesn´t really work as it is intended to!
Every ring of the diaphragm should be mechanically decoupled from it´s neighbouring rings. Otherwise there will be resonances and bending waves with increased distortion and narrower distribution than predicted!!?? There is a Patent dating from 1930 (!!) which describes exactly what the ESL63 does, or is intended to do.
And I´m with maudio: What is all the fuss about such a dull sounding speaker...no bass, no highs, no dynamics...every 63 I heard sounded as if a blanket were thrown over the speaker.
jauu
Calvin
http://user.tninet.se/~wea635n/mt_audio_design/mt_audio_archives/esl_repair_shop.htm
"och dom er svenska"
And they are swedish
"och dom er svenska"
And they are swedish
Possibly Quad themselves sell dustcover repair kits and new 'stockings', another source is One Thing Audio, http://www.onethingaudio.com/OTA/9152-OTA-MAIN.htm
Paul
Paul
I don't know if I'd be quite so harsh describing the Quads. they are what I'd call "polite" speakers. If you listen to a lot of badly recorded material (how come the best performances are the worst recorded?), then the quads are a very nice choice and make all music at least listen-able.
To me, the 57's are nicer than the 63's. The 63's tried to get better dispersion and better frequency extremes but at the expense of the magical midrange which is the Quad selling point.
If my DIY ESL's are representative, then it's not too hard to better the speaker yourself. My DIY ESL's are better than the 57's and 63's in every way except for dispersion (which is a good thing too).
Sheldon
To me, the 57's are nicer than the 63's. The 63's tried to get better dispersion and better frequency extremes but at the expense of the magical midrange which is the Quad selling point.
If my DIY ESL's are representative, then it's not too hard to better the speaker yourself. My DIY ESL's are better than the 57's and 63's in every way except for dispersion (which is a good thing too).
Sheldon
A cautionary tale:
With all this discussion about the ESL-63 sounding “polite” or even dull, let me say that I too have heard this speaker sound pretty darned unimpressive in too many settings.
But chameleon that it is, it can also sound closer to reality than any commercial speaker I’ve heard to date (I include the newer versions with the 63 here, the 2805, etc.). I always prefer this speaker far from walls, which reduces excessive mid-bass warmth. The speaker does well when lifted off the floor. And it needs to be listened to dead-on axis. It really is a one-person speaker, unfortunately. Dispersion is not very wide in the top few octaves, despite the pseudo-point source design concept.
Finally, and really the point I wanted to make: the ESL-63s truly come alive when listened to “naked”. It seems that the metal grills (particularly the older ones, granted), and the fabric sock contribute to both high frequency losses and also to HF reflections that blur detail. The thin Mylar dust covers add some coloration too, but I leave those in place to keep dust out of the elements. These parts were commercial compromises for appearance, safety and reliability. The cloth sock is easy to roll down. The metal grills can then be removed, but they do contribute to the stiffness of the frames, so the frames become “floppier” for want of a better word. Some folks, such as “I_Forgot”, have even built new, sturdier frames for naked Quads. When listened to “naked” (the speaker, not necessarily the listener), there is an immediacy and focus that it hard to describe. The Quads don’t then sound necessarily brighter, but they do sound cleaner and reveal more detail.
Most planar ESLs, even curvilinear ones, will generally sound too bright unless steps are taken to equalize for the rising response due to the directivity index of drivers whose dimensions exceed audio wavelengths. The additional “air” and “edge” may be impressive in the short term when compared to a more neutral speaker like the ESL-63. But it’s not true to music. I’m not saying that a diligent DIY design can’t compete with the Quads, but the Quad, for me, serves as reference design, something to which to aspire taking all parameters in balance. It’s only too easy to fall for the sound of a DIY ESL with exaggerated detail. Been there, done that…
With all this discussion about the ESL-63 sounding “polite” or even dull, let me say that I too have heard this speaker sound pretty darned unimpressive in too many settings.
But chameleon that it is, it can also sound closer to reality than any commercial speaker I’ve heard to date (I include the newer versions with the 63 here, the 2805, etc.). I always prefer this speaker far from walls, which reduces excessive mid-bass warmth. The speaker does well when lifted off the floor. And it needs to be listened to dead-on axis. It really is a one-person speaker, unfortunately. Dispersion is not very wide in the top few octaves, despite the pseudo-point source design concept.
Finally, and really the point I wanted to make: the ESL-63s truly come alive when listened to “naked”. It seems that the metal grills (particularly the older ones, granted), and the fabric sock contribute to both high frequency losses and also to HF reflections that blur detail. The thin Mylar dust covers add some coloration too, but I leave those in place to keep dust out of the elements. These parts were commercial compromises for appearance, safety and reliability. The cloth sock is easy to roll down. The metal grills can then be removed, but they do contribute to the stiffness of the frames, so the frames become “floppier” for want of a better word. Some folks, such as “I_Forgot”, have even built new, sturdier frames for naked Quads. When listened to “naked” (the speaker, not necessarily the listener), there is an immediacy and focus that it hard to describe. The Quads don’t then sound necessarily brighter, but they do sound cleaner and reveal more detail.
Most planar ESLs, even curvilinear ones, will generally sound too bright unless steps are taken to equalize for the rising response due to the directivity index of drivers whose dimensions exceed audio wavelengths. The additional “air” and “edge” may be impressive in the short term when compared to a more neutral speaker like the ESL-63. But it’s not true to music. I’m not saying that a diligent DIY design can’t compete with the Quads, but the Quad, for me, serves as reference design, something to which to aspire taking all parameters in balance. It’s only too easy to fall for the sound of a DIY ESL with exaggerated detail. Been there, done that…
If I may add to Brian Beck's comment on ESL 63.
I could not agree more with him regarding the ESL 63.
I have the ESL 63 US monitor and I listen to them completely butt naked, that is no grill, no cloth, no dust cover. I do keep them completely cover with dark trashbag when not in use - This drives my wife totally mad when ever she walks past them. They are elevated off the floor about 13inches. The ESL 63 is indeed a one man speaker despite comments about its wider dispersion. A few inches away from the sweet spot and the imaging is gone. In the sweet spot is is very musical and neutral.
One drawback of the ESL63 is their reliabity. I have had to repair 3 panels already and will anticipate repairing more in the future. I live on the west coast and do not suffer as much of a humidity problem but they still fail easily.
To Brian,
I have been thinking about stacking the 63's like Stewart Penkerth did. Have you tried this or can you commenet on +/- of this. Thanks.
I could not agree more with him regarding the ESL 63.
I have the ESL 63 US monitor and I listen to them completely butt naked, that is no grill, no cloth, no dust cover. I do keep them completely cover with dark trashbag when not in use - This drives my wife totally mad when ever she walks past them. They are elevated off the floor about 13inches. The ESL 63 is indeed a one man speaker despite comments about its wider dispersion. A few inches away from the sweet spot and the imaging is gone. In the sweet spot is is very musical and neutral.
One drawback of the ESL63 is their reliabity. I have had to repair 3 panels already and will anticipate repairing more in the future. I live on the west coast and do not suffer as much of a humidity problem but they still fail easily.
To Brian,
I have been thinking about stacking the 63's like Stewart Penkerth did. Have you tried this or can you commenet on +/- of this. Thanks.
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