Hi,
have a look at #16 of http://www.diyaudio.com/forums/planars-exotics/81670-mylar-roller-buy-what-real-uses-2.html#post946729 "link"
The mass-related difference between 12µm and 3.5µm at 20kHz was just 5dB (not taken into account the larger capacitance hence lower bandwidth limit of the larger panel and not taking into account the weight increase by the membrane coatings). The difference between 12µm and 6µm or 6µm to 4µm will be less. Below 6µm no significant mass related effects will occur within the audio bandwith limits. I would´t go thinner than 5-6µm for a FR panel and no thinner than 3µm for a hybrid panel.
The thinner the membrane material the higher the percentage weight of coating. The thinner the membrane material the thinner and lighter the coating should be. At 3.5µm the behaviour of the coated diaphragm is to a considerable percentage determined by the coatings characteristics. A coating obviously should be thinner than 1µm with such a thin material.
Spraying on a coating will result in larger dry thickness. Wiping produces lower thickness.
jauu
Calvin
have a look at #16 of http://www.diyaudio.com/forums/planars-exotics/81670-mylar-roller-buy-what-real-uses-2.html#post946729 "link"
The mass-related difference between 12µm and 3.5µm at 20kHz was just 5dB (not taken into account the larger capacitance hence lower bandwidth limit of the larger panel and not taking into account the weight increase by the membrane coatings). The difference between 12µm and 6µm or 6µm to 4µm will be less. Below 6µm no significant mass related effects will occur within the audio bandwith limits. I would´t go thinner than 5-6µm for a FR panel and no thinner than 3µm for a hybrid panel.
The thinner the membrane material the higher the percentage weight of coating. The thinner the membrane material the thinner and lighter the coating should be. At 3.5µm the behaviour of the coated diaphragm is to a considerable percentage determined by the coatings characteristics. A coating obviously should be thinner than 1µm with such a thin material.
Spraying on a coating will result in larger dry thickness. Wiping produces lower thickness.
jauu
Calvin
I have to do some measurements today after i have gotten the panel up and ready. 5dB difference between 12µm and 3,5µm is quite small, smaller than I expected. Maybe the bigger difference I saw was due to the aluminum coating.
I'm a bit afraid how high Q value of the panel resonance is going to be with 3,5µm membrane. When I excite the panel with hand claps or of "beatbox bass", the thinner membrane resonates somewhat lower than the 6µm panel, but also longer, which - I presume - indicates higher Q. However the thinner membrane is not currently between the stators like the 6µm, this might affect it's damping because the air mass/flow resistance surrounding it is smaller and the membrane can resonate more freely. I would still presume the Q will be higher because the tension is not as high.
I'm a bit afraid how high Q value of the panel resonance is going to be with 3,5µm membrane. When I excite the panel with hand claps or of "beatbox bass", the thinner membrane resonates somewhat lower than the 6µm panel, but also longer, which - I presume - indicates higher Q. However the thinner membrane is not currently between the stators like the 6µm, this might affect it's damping because the air mass/flow resistance surrounding it is smaller and the membrane can resonate more freely. I would still presume the Q will be higher because the tension is not as high.
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Hi,
why is it less than expected? The mass related effect drops the amplitude response by -6dB/oct. With all films of 12µm and less the -3db popint is well above 10kHz. So I´d expect no more 6dB difference in any case. The amplitude drop because of the voltage divider action of the Audio-trannies copper resistance and transformed lowimpedance value in the highest octave will be of greater impact. Maybe You also changed something else like Bias voltage. More charge on the diaphragm will result in more force per area on the diaphragm, hence a shift of mass-related amplitude drop towards higher freqs.
Regarding Q: Yes, a lower Fs coincides with a larger Q. The only measurements against it are mechanical damping with flow resistances and electrical notch filtering.
jauu
Calvin
why is it less than expected? The mass related effect drops the amplitude response by -6dB/oct. With all films of 12µm and less the -3db popint is well above 10kHz. So I´d expect no more 6dB difference in any case. The amplitude drop because of the voltage divider action of the Audio-trannies copper resistance and transformed lowimpedance value in the highest octave will be of greater impact. Maybe You also changed something else like Bias voltage. More charge on the diaphragm will result in more force per area on the diaphragm, hence a shift of mass-related amplitude drop towards higher freqs.
Regarding Q: Yes, a lower Fs coincides with a larger Q. The only measurements against it are mechanical damping with flow resistances and electrical notch filtering.
jauu
Calvin
Without knowing the volatiles content of both materials, I would not assume that equal quantities of Licron Crystal and Staticide 6300 would give equivalent wipe-on thickness or resistance. Licron Crystal is formulated for spray application with just over 98% volatile solvents. Does anyone know the percentage of volatiles in Staticide 6300?
BTW, Licron Crystal + shipping costs about $50 dollars for an 8-oz aerosol can and that's only enough to spray about 3 sets of panels. If it takes only a few drops of Staticide to coat a panel, then the cost per panel would be much, much less with the Staticide.
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Here's a near field (mic 30-40cm away) response with 0.6R series resistor and 280Hz 1st order passive line level crossover (12nF series cap). I think I used 0.3R in previous measurements because it gives more HF.
I think the 3,5 gives more HF response, but I have to measure some more, luckily I have the other panel with 6µm so I can make a direct comparison.
Bass goes deeper due to lower resonances just as I thought, and is actually less peaky than before. It also sounds better, better controlled I would say. When listened up close it sounds nicer because the resonances are lower.
The coating is clearer with one layer, and I did not lose any efficiency by doing that.
One can hear everything that is on the record. There is a difference in favor of 3,5µm, it adds more resolution and ever so slightly more a feeling of speed and pin point sharpness to MF and HF transients. ZAP!
The only concern I have is that this panel leaks a bit more than the other, the blink rate is approx. double. I was quite through in cleaning. It could be the tape, I used black duct tape sealing the sides, I don't know it's surface's and glue's features. Maybe electrical PVC tape would have been better. I will monitor the blink rate, sometimes it settles in couple of days.
An externally hosted image should be here but it was not working when we last tested it.
I think the 3,5 gives more HF response, but I have to measure some more, luckily I have the other panel with 6µm so I can make a direct comparison.
Bass goes deeper due to lower resonances just as I thought, and is actually less peaky than before. It also sounds better, better controlled I would say. When listened up close it sounds nicer because the resonances are lower.
The coating is clearer with one layer, and I did not lose any efficiency by doing that.
One can hear everything that is on the record. There is a difference in favor of 3,5µm, it adds more resolution and ever so slightly more a feeling of speed and pin point sharpness to MF and HF transients. ZAP!
The only concern I have is that this panel leaks a bit more than the other, the blink rate is approx. double. I was quite through in cleaning. It could be the tape, I used black duct tape sealing the sides, I don't know it's surface's and glue's features. Maybe electrical PVC tape would have been better. I will monitor the blink rate, sometimes it settles in couple of days.
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You are missing the point,
6300 is water based, easier to dilute and to smear which makes it superior to Licron, based on spirits/solvents which are to dry in a matter of seconds.
Nothing comes free - yes it has limited life, once opened, if purchased in bulk, say bottles.
Aerosol flavor of 6300 is called 6500 - so there is no real "opening", bingo!
Price wise they are about the same: $32 up for canned option. Can be air shipped!
I've measured 6300 resistivity and doubt 3 drops figure for a full size panel... what size are the drops in question?
Really thin coating is more fragile... so unless you are trying to confuse bats with your speaker it's better to stay with reasonably thick coating.
Licron Crystal doesn't appear to be completely humidity and temperature independant. I lost ~3dB of sensitivy when the temp of the room dropped from 28deg to 22deg, and humidity dropped from 60% to 45% (I left the window open for the night. Also the neon lamp blinks now much slower.
This makes the subwoofer volume setting little tricky, I will have to make some presettings that will be loaded depending on the temperature and humidity conditions. Or buy an air conditioner.
This makes the subwoofer volume setting little tricky, I will have to make some presettings that will be loaded depending on the temperature and humidity conditions. Or buy an air conditioner
.F21 SUPER PROTECTANT on my panels from Turtle wax $299.US for over 10oz has more output than any other i have had in 10years. How can this be, what world make this have more output than others??
Nothing well over come Humidity...Acousta panels, SL panels ML panels.. all drop output....but this F21 after 5 days setup great...best i have found an well last...Goodluck
Nothing well over come Humidity...Acousta panels, SL panels ML panels.. all drop output....but this F21 after 5 days setup great...best i have found an well last...Goodluck
I was going to try the F21 stuff when it got mentioned.
But I don't recall anyone stating that it actually worked or for how long, maybe I missed it somewhere.
This is very interesting!
I will have to keep a note on the Licron Crystal for this when the winter comes as I will be building some new panels shortly, atleast before fall anyhow.
I never had my panels running long enough to tell if there was any changes due to humidity.
But keeping this in mind I did try breathing on them to see if any change would occur and I didn't notice anything at the time.
Being that my panels are so small I did have a generous amount of coating on them for their size.
I think from Techspray's info it is not supposed to change.
Although they specify a fairly wide range of resistance of 10^6 to 10^9 ohms per square.
It does say on the can "Humidity Independent" !!!
I will have to see if I can find any more info on this.
jer
But I don't recall anyone stating that it actually worked or for how long, maybe I missed it somewhere.
This is very interesting!
I will have to keep a note on the Licron Crystal for this when the winter comes as I will be building some new panels shortly, atleast before fall anyhow.
I never had my panels running long enough to tell if there was any changes due to humidity.
But keeping this in mind I did try breathing on them to see if any change would occur and I didn't notice anything at the time.
Being that my panels are so small I did have a generous amount of coating on them for their size.
I think from Techspray's info it is not supposed to change.
Although they specify a fairly wide range of resistance of 10^6 to 10^9 ohms per square.
It does say on the can "Humidity Independent" !!!
I will have to see if I can find any more info on this.
jer
Could it be that "humidity independent" could be translated that at ~100% air humidity it's surface resistivity is 10^6 and at ~0% it 10^9 (our ESL's very light layers could have higher than the specified range)... Total "independcy" might be a bit overstated, it could mean that the stuff works at every humidity, but is not completely independent of it's effect.
I don't know how the temperature affects conductivity and surface resistivity. At least it reduces dielectris strenght of insulators. In metals higher temperature rises the resistance... It might be that the effect I experienced was only from the change in air humidity and the temperature change had no part in it.
I don't know how the temperature affects conductivity and surface resistivity. At least it reduces dielectris strenght of insulators. In metals higher temperature rises the resistance... It might be that the effect I experienced was only from the change in air humidity and the temperature change had no part in it.
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Before you pin the humidity dependent sensitivity change on the Lycron coating you might consider the rest of you panel as well.
Do you know the bulk resistivity for the coating you used on your stators? If stator insulation is too high, charge will collect on it's surface over time and reduce the sensitivity of your ESL. This is more of a problem in low humidity environment. When humidity is higher, the charge leaks away more easily.
You can verify if this is what is going on by playing the panels for a while in a low humidity environment. Then, remove the HV supply and short the diaphragm connection to the CT of your transformer to discharge the diaphragm. Now, remove the short between the diaphragm connection and CT, and try playing music or test signals thru the panel again. If your stator insulation is retaining charge you will hear output. If you have measurement equipment, you will see that that phase of the impulse response is inverted compared to when the HV supply is hooked up.
I know I had already posted this in another thread, but Strickland experienced charge retention problems when he was experimenting with different types of insulation for the Acoustat stator wires like PE/Teflon. The fix was to switch back to the Janszen patent recommendation of PVC which has lower bulk resistivity.
“…Strickland told me once that he'd seen lab speakers that actually played louder after power down of the bias supply than before (for a while anyway), and sometimes he observed audio phase reversals at that time too. This was all with PE before he switched to nice leaky PVC. Weird science…”
http://www.diyaudio.com/forums/planars-exotics/58407-insulated-vs-bare-metal-stators.html#post658044
This issue of highly resistive stator coatings playing louder in humid conditions was also mentioned briefly in the Acoustat White Paper:
http://www.audiocircuit.com/A-PDF/AA-Brands/A/Acoustat-ACO/GEN-John_Strickland_-A-EN2-941-ACO.pdf
http://www.integracoustics.com/MUG/MUG/tweaks/acoustat/technology.pdf
Do you know the bulk resistivity for the coating you used on your stators? If stator insulation is too high, charge will collect on it's surface over time and reduce the sensitivity of your ESL. This is more of a problem in low humidity environment. When humidity is higher, the charge leaks away more easily.
You can verify if this is what is going on by playing the panels for a while in a low humidity environment. Then, remove the HV supply and short the diaphragm connection to the CT of your transformer to discharge the diaphragm. Now, remove the short between the diaphragm connection and CT, and try playing music or test signals thru the panel again. If your stator insulation is retaining charge you will hear output. If you have measurement equipment, you will see that that phase of the impulse response is inverted compared to when the HV supply is hooked up.
I know I had already posted this in another thread, but Strickland experienced charge retention problems when he was experimenting with different types of insulation for the Acoustat stator wires like PE/Teflon. The fix was to switch back to the Janszen patent recommendation of PVC which has lower bulk resistivity.
“…Strickland told me once that he'd seen lab speakers that actually played louder after power down of the bias supply than before (for a while anyway), and sometimes he observed audio phase reversals at that time too. This was all with PE before he switched to nice leaky PVC. Weird science…”
http://www.diyaudio.com/forums/planars-exotics/58407-insulated-vs-bare-metal-stators.html#post658044
This issue of highly resistive stator coatings playing louder in humid conditions was also mentioned briefly in the Acoustat White Paper:
http://www.audiocircuit.com/A-PDF/AA-Brands/A/Acoustat-ACO/GEN-John_Strickland_-A-EN2-941-ACO.pdf
http://www.integracoustics.com/MUG/MUG/tweaks/acoustat/technology.pdf
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How long the stator coating can hold the charge if I test it by unplugging the bias supplies for a perioid of time and then measure again the sensitivity. Would 2 hours be enough?
I have always had very small output with uncharged membrane. Should the output go completely away if the stator coating is not charged at all?
I have always had very small output with uncharged membrane. Should the output go completely away if the stator coating is not charged at all?
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In low humidity conditions, highly resistive stator coatings can hold charge for 12+ hours.
Yes, the output should go completely away with an uncharged diaphragm if the stator insulation is not storing charge.
If your stator coating is retaining charge, you will notice that when you disconnect the HV supply with music or test signal playing, the output will reduce in level overtime till it reaches zero output. Then, it starts ramping up in level. If you look at test signals, you will see that phase of output is now reversed.
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Ok, I will test it by unplugging other speaker for the night, plug again in the morning and see if the stereo image is still at the center. As small as 1dB difference is quite clear, the vocalist moves away from the center. If there is an audible difference, I will try to quantify it. The 45% is not very low humidity, but it's a cheap meter and I don't know if it's accurate (should be +/- 5% accurate according to specs).
edit. By the way would the increased charge in the stator coating affect the neon lamp blinking speed so much that it's reduced to 1/4 of the previous speed?
edit. By the way would the increased charge in the stator coating affect the neon lamp blinking speed so much that it's reduced to 1/4 of the previous speed?
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The long term blinking speed of the neon lamp is related to leakage currents.
Leakage currents can be thru/over the frame and adhesives, or thru the air-gap if the HV level is set near the air ionization threshold.
Lower humidity will reduce the leakage current for both these contributors.
However, the leakage currents thru/over the frame tend to dominate when you use long copper charge rings.
So the reduced blink rate and reduced sensitivity may both be caused by reduced humidity.
But, they may not be directly related.
Needing instruction to open the ML ES panel for re-coating
Hello Folsk,
I would re-coat my old Sequel II ES panel, so I need to open my Martin Logan Sequel II panels.
Anybody out there is willing to give me precise instruction to correctly separate the back stator from the front stator without tearing the diaphragm film?
I never did it before and I have fear to damage something.
I also would appreciate if you could suggest me the best coating product for these Martin Logan ES panels that have an ITO surface treatment also.
Many thanks in advance!
Kind regards,
Andrea
Hello Folsk,
I would re-coat my old Sequel II ES panel, so I need to open my Martin Logan Sequel II panels.
Anybody out there is willing to give me precise instruction to correctly separate the back stator from the front stator without tearing the diaphragm film?
I never did it before and I have fear to damage something.
I also would appreciate if you could suggest me the best coating product for these Martin Logan ES panels that have an ITO surface treatment also.
Many thanks in advance!
Kind regards,
Andrea
I dont know how to open the panels, google it.
But I can provide you (at self cost) with the original M-L film, if you need it.