Happy Holidays All,
Well I have successfully constructed a great many ESL panels, and have even was able to stretch the 6uM mylar to over 2.5% elongation consecutively without any issues. I am utilizing an electronic crossover and the music sounds near perfect....and that's where the questions begin. It seems that if I run these panels below 140 bass slapping is present.
The question... Is it possible to develop an ESL which will not slap?
I am considering making a test panel using .125 thickness 3m double sided tape (instead of the .060, and quadrupling the voltage as the inverse square law would suggest, would someone care to surmise the quality of sound which can be realized with this hypothetically?
Will this distance prevent slapping from occurring, could increased Bass be produced below 140, would the High frequencies be reduced?
Has anyone built perforated panels using D/S spacing of .125?
Thanks In advance,
Doc/Jerry
Well I have successfully constructed a great many ESL panels, and have even was able to stretch the 6uM mylar to over 2.5% elongation consecutively without any issues. I am utilizing an electronic crossover and the music sounds near perfect....and that's where the questions begin. It seems that if I run these panels below 140 bass slapping is present.
The question... Is it possible to develop an ESL which will not slap?
I am considering making a test panel using .125 thickness 3m double sided tape (instead of the .060, and quadrupling the voltage as the inverse square law would suggest, would someone care to surmise the quality of sound which can be realized with this hypothetically?
Will this distance prevent slapping from occurring, could increased Bass be produced below 140, would the High frequencies be reduced?
Has anyone built perforated panels using D/S spacing of .125?
Thanks In advance,
Doc/Jerry
I have never noticed this problem with Quad ESL57's, either. I recommend always run 57's with a suitable amplifier, in my case Quad 303 Quad ESL & ESL63 Information
Cheers / Chris
Cheers / Chris
You also should consider (if you haven't yet) some damping of the fundamental resonance. Fine mesh glued on the stator, speaker grill cloth, silicone dots on the mylar, these are things which has been used succesfully used.
Without damping there will be a high Q resonance with a large associated excursion and uncontrolled sound. As an untamed resonancepeak can be around 15 dB, it sure will ' eat up' excursion limits.
Without damping there will be a high Q resonance with a large associated excursion and uncontrolled sound. As an untamed resonancepeak can be around 15 dB, it sure will ' eat up' excursion limits.
Hi,
well, it all depends on which quality You are content with, doesn´t it?
Constructed as open baffle system, the tendency to flap always remains. Putting a panel into a cabinet on the other hand creates different but similarly serious issues.
A ESL offers no first class bass compared to the qualities a dynamic driver bass may offer. At least, I haven´t heard of just one ESL with truely outstanding bass qualities.
If the panel is constructed as Fullranger, You have to accept compromises in the midhighs. The required higher voltage and power demands don´t come for free. Damping felt mats and such stuff, needed to mechanically control high-Q resonance, don´t perform linear, neither in the amplitude domain nor in the frequency domain and certainly remain audible in the mid-highs.
If the panel is constructed as a pure bass panel, You can optimize certain parameters, but it still is clearly inferior to a dynamic bass system. The mechanical losses inherent to a dynamic driver, that control it´s performance to a large extent, are much smaller. They would have to be supplied for by the design itself, by some form of mechanical means or by some form of external control circuitry.
Still though serious issues of the electrostatic principle will be left unsolved.
For example the lower force-per-unit-area-relation, or the low mass membrane, which discludes typical boxes as cabinets. Not to mention the vast levels of driving signal voltage and power demand.
A bass ESL performs inferior compared to a dynamic bass on nearly each and every aspect such as:
- size
- dynamic range
- power demand
- drive requirements an on the amplifier
- demand of room floor space
- distortion
- low and lowest frequency performance
- kickbass performance
- lower mids performance
- probabely even costing more than a decent dynamic bass system
jauu
Calvin
well, it all depends on which quality You are content with, doesn´t it?
Constructed as open baffle system, the tendency to flap always remains. Putting a panel into a cabinet on the other hand creates different but similarly serious issues.
A ESL offers no first class bass compared to the qualities a dynamic driver bass may offer. At least, I haven´t heard of just one ESL with truely outstanding bass qualities.
If the panel is constructed as Fullranger, You have to accept compromises in the midhighs. The required higher voltage and power demands don´t come for free. Damping felt mats and such stuff, needed to mechanically control high-Q resonance, don´t perform linear, neither in the amplitude domain nor in the frequency domain and certainly remain audible in the mid-highs.
If the panel is constructed as a pure bass panel, You can optimize certain parameters, but it still is clearly inferior to a dynamic bass system. The mechanical losses inherent to a dynamic driver, that control it´s performance to a large extent, are much smaller. They would have to be supplied for by the design itself, by some form of mechanical means or by some form of external control circuitry.
Still though serious issues of the electrostatic principle will be left unsolved.
For example the lower force-per-unit-area-relation, or the low mass membrane, which discludes typical boxes as cabinets. Not to mention the vast levels of driving signal voltage and power demand.
A bass ESL performs inferior compared to a dynamic bass on nearly each and every aspect such as:
- size
- dynamic range
- power demand
- drive requirements an on the amplifier
- demand of room floor space
- distortion
- low and lowest frequency performance
- kickbass performance
- lower mids performance
- probabely even costing more than a decent dynamic bass system
jauu
Calvin
Thank you all for your comments and suggestions.
Moray James- I segment my 15x48" panels along the long axis with 3 spacers at 3 3/4".
M.J. Dijkstra-I forgot to mention I do run a separate sub and do not rely on the ESL for bass, essentially I do dampen low frequencies on my PC EQ.
It certainly sounds like it is "give and take with every aspect of an open baffle design" , by designing for bass you sacrifice the highs, and if you construct a mid/high panel your panels may be subject to slapping.
Beun- do you run your ESL at full range, do you use a parametric EQ or a electronic crossover? How large are your ESL panels?
Calvin, thanks for you explanation as always.
Jerry
Moray James- I segment my 15x48" panels along the long axis with 3 spacers at 3 3/4".
M.J. Dijkstra-I forgot to mention I do run a separate sub and do not rely on the ESL for bass, essentially I do dampen low frequencies on my PC EQ.
It certainly sounds like it is "give and take with every aspect of an open baffle design" , by designing for bass you sacrifice the highs, and if you construct a mid/high panel your panels may be subject to slapping.
Beun- do you run your ESL at full range, do you use a parametric EQ or a electronic crossover? How large are your ESL panels?
Calvin, thanks for you explanation as always.
Jerry
If you tensioned the mylar to 2.5% elongation I suspect what you thought was mylar is something else or, if it is mylar, it went beyond it's yield strength, and you have less tension than you think. I just recently made some cells and could never get much more than 1.8% elongation before it gave out.
I don't think 2.5% elongation exceeds the tensile strength of 6uM hosphenstaf C, however I do see your point if that were the case.
I was stretching at 1.5% with good results however, the increase of tension has an improved response and dynamics over that of a less stretched panel.
To achieve this tension you need a well made jig, and secure the mylar with double sided tape.
I was stretching at 1.5% with good results however, the increase of tension has an improved response and dynamics over that of a less stretched panel.
To achieve this tension you need a well made jig, and secure the mylar with double sided tape.
Doc,
I have made several speakes in the following sizes:
1) The big one, 3'3" x 6'6"
2) The WAF one 2' x 5'
3) The tall one 30" x 82"
All of them are more or less full range and go at least down to 80Hz. All are curved in the horizontal plane (like ML) but the segmentation runs vertical and as mentioned is never wider than 4 or 5" or so.
I could run them full range and have done so in the past but currently I run them with a highpass at around 60-80Hz depending on the size of the speaker and cross them over to a sub.
When your tension is sufficient it is impossible for the membrane to slap when your width is not more then 4" and the pacing is 1/8". At 1/16th maybe, but transformer saturation sounds more logical and I can tell you it sounds really nasty
I have made several speakes in the following sizes:
1) The big one, 3'3" x 6'6"
2) The WAF one 2' x 5'
3) The tall one 30" x 82"
All of them are more or less full range and go at least down to 80Hz. All are curved in the horizontal plane (like ML) but the segmentation runs vertical and as mentioned is never wider than 4 or 5" or so.
I could run them full range and have done so in the past but currently I run them with a highpass at around 60-80Hz depending on the size of the speaker and cross them over to a sub.
When your tension is sufficient it is impossible for the membrane to slap when your width is not more then 4" and the pacing is 1/8". At 1/16th maybe, but transformer saturation sounds more logical and I can tell you it sounds really nasty
Beun,
Let me first begin by saying wow!
And before I lose my focus by asking how do you stretch your mylar?, I will stick to the questions with regards to the thread....I am using 1/16th thick spacing material I am certain that nasty yet predictable sound is slapping (never present above 140hz. I however believed that the 1/16th spacing is referred to as full range. If I were to use 1/8th spacing and 4x bias voltage would this provide a full range from the ESL, an (yes I would still need to utilize my Sub), but can this D/S of 1/8" .0125 produce a full range without that low frequency slap?
and lastly, what thickness mylar do you use, and stretching method do you use...% elongation?
Also, can you post the schematics for the high-pass filter?
Thanks and Happy New Years,
Doc
Let me first begin by saying wow!
And before I lose my focus by asking how do you stretch your mylar?, I will stick to the questions with regards to the thread....I am using 1/16th thick spacing material I am certain that nasty yet predictable sound is slapping (never present above 140hz. I however believed that the 1/16th spacing is referred to as full range. If I were to use 1/8th spacing and 4x bias voltage would this provide a full range from the ESL, an (yes I would still need to utilize my Sub), but can this D/S of 1/8" .0125 produce a full range without that low frequency slap?
and lastly, what thickness mylar do you use, and stretching method do you use...% elongation?
Also, can you post the schematics for the high-pass filter?
Thanks and Happy New Years,
Doc
Doc,
It is hard from afar to disagree with your listening experience but unfortunately the true cause of the sound is hard to determine. The reason is that at higher frequencies the membrane excursion is indeed going to be less, unfortunately at higher frequencies the transformer is also less likely to go into saturation. With a sufficient amount of tension it is in my opinion unlikely that the membrane will ever hit the stators even at 1/16th spacing, at 1/8th spacing I have never seen it happen.
When you have a scope you could do some measurements directly at the primary side of the transformer using a 4 Ohm resistor between your amp and the primary. Significant distortion of the signal would indicate transformer saturation. Which transformer are you using by the way and how high is your bias voltage. Also when doubling the spacing you can only double the HV-bias otherwise you will start to ionize the air.
Currently I use a bass management unit with just a 6db slope on the high pass. When you have measured the panel+transformer impedance at low frequencies (mine is around 50 Ohms) you can use a simple series cap of around 60uF to create a 60Hz high-pass.
I built my panels a bit differently as usual except for the curved design I also use 0.5mil/25um metalized mylar. I have never measured much of a difference in the high frequency response and the thicker stuff is much easier to work with. I use a manual stretching method and measure the resonance to check matching between two panels. The elongation is somewhere between 0.5 and 1%.
Personally I like the curved design for several reasons:
1) It provides mechanical strength
2) It gives a better dispersion and a much wider sweet spot
In contrast to ML which only used vertical tension I use an even horizontal and vertical tension leading to a piecewise linear curve instead of ML's smooth curve.
It is hard from afar to disagree with your listening experience but unfortunately the true cause of the sound is hard to determine. The reason is that at higher frequencies the membrane excursion is indeed going to be less, unfortunately at higher frequencies the transformer is also less likely to go into saturation. With a sufficient amount of tension it is in my opinion unlikely that the membrane will ever hit the stators even at 1/16th spacing, at 1/8th spacing I have never seen it happen.
When you have a scope you could do some measurements directly at the primary side of the transformer using a 4 Ohm resistor between your amp and the primary. Significant distortion of the signal would indicate transformer saturation. Which transformer are you using by the way and how high is your bias voltage. Also when doubling the spacing you can only double the HV-bias otherwise you will start to ionize the air.
Currently I use a bass management unit with just a 6db slope on the high pass. When you have measured the panel+transformer impedance at low frequencies (mine is around 50 Ohms) you can use a simple series cap of around 60uF to create a 60Hz high-pass.
I built my panels a bit differently as usual except for the curved design I also use 0.5mil/25um metalized mylar. I have never measured much of a difference in the high frequency response and the thicker stuff is much easier to work with. I use a manual stretching method and measure the resonance to check matching between two panels. The elongation is somewhere between 0.5 and 1%.
Personally I like the curved design for several reasons:
1) It provides mechanical strength
2) It gives a better dispersion and a much wider sweet spot
In contrast to ML which only used vertical tension I use an even horizontal and vertical tension leading to a piecewise linear curve instead of ML's smooth curve.
Stop selling - you've SOLD ME!
Full range it is!!!
But they are easier to build... from what I heard anyway... I don't know.
Creating some panels by the way... in blazing red polyurethane glory. Have a great new year everyone!!
Full range it is!!!
But they are easier to build... from what I heard anyway... I don't know.
Creating some panels by the way... in blazing red polyurethane glory. Have a great new year everyone!!
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