I can vouch for the 16 KHz issue with 6um Mylar. My newly made ESLs have rolloff right around 16khz. The rolloff is actually quite steep.
The good news is that I have corrected it via PEQ (I am using the Minidsp PWR-ICE250 for my hybrid floorstanders) and the results are fantastic. I would recommend a decent Mic and REW to measure allow for proper correction.
The good news is that I have corrected it via PEQ (I am using the Minidsp PWR-ICE250 for my hybrid floorstanders) and the results are fantastic. I would recommend a decent Mic and REW to measure allow for proper correction.
I've been following your speaker build thread... if you've finished those speakers, I would to see some more pics.
I will definitely post pics when they are finished. At the moment I have the ESL panels finished and I have successfully tested all of the electronics:
HV supply (your design)
Step up xformers (4x for 150:1)
Amps (Minidsp PWR-ICE250....the are fantastic, the built in DSP is awesome for powered speakers like this)
Woofers (Dayton Reference Series 10")
I am currently waiting on material to build the cabinets. They will be mostly solid mahogany. I will of course use some plywood and MDF on the woofer enclosure.
Anyone want to hear a story on my first esl wire attempt and everything that could possibly go wrong. if okay with Charlie
I would be very interested!!
Anyone want to hear a story on my first esl wire attempt and everything that could possibly go wrong. if okay with Charlie
Yeah, lay it on us. Maybe I can add to your list before I'm done with mine.
I may be finished with the panels this week.
And I've been giving some more thought to making the dispersion selectable. I found a couple of rotary switches for dirt cheap on Ebay that might work... multi-pole Soviet military types with ceramic wafers and silver contacts. Perhaps submerge the switch in oil to contain the voltage.
I'm thinking the simplist way would be to leave the resistors in the circuit, add a jumper wire across each resistor and use the switch to open and close the jumpers.
Wouldn't this work?
And I've been giving some more thought to making the dispersion selectable. I found a couple of rotary switches for dirt cheap on Ebay that might work... multi-pole Soviet military types with ceramic wafers and silver contacts. Perhaps submerge the switch in oil to contain the voltage.
I'm thinking the simplist way would be to leave the resistors in the circuit, add a jumper wire across each resistor and use the switch to open and close the jumpers.
Wouldn't this work?
Last edited:
Take a look at these, see attach. About two times larger. I would of talked to radio ham guys on that matter, they do switch antennas and the like at rather high potentials.
https://www.surplussales.com/RF/rfcerrot_1.html
There are really good reed relays 7kV rated but it might not be the cheapest solution whatsoever. What the point of such a thing? Tuning on the fly?
Problem with oil is a dirt accumulating on conductors under potential, like a dust on CRT. Not mentioning the mess. Do not forget to make dielectric drive shaft extension and use plastic knob.
Dust proof box together with decent coating on rotary switch plates and tidy round solder blobs at soldering joints should work as well. No on the fly switching though.
Edit: On the other hand the potential between the sections is relatively low. Silver contact is not good either - Ag likes to migrate, whiskers to be exact.
Last edited:
Thanks for the tip on those high-V switches but I can’t spend that much money. I’ve already purchased the Soviet military switches so I’ll give them a go and if they don’t work out I can always just rig some plug connectors (not convenient but would work). I plan to submerge and seal the switches in an oil bath such that only their actuator shafts are exposed. And of course-- no switching under load!
My current flat panel ESL’s are quite magical in their tightly focused sweet spot but they aren’t much good for entertaining guests. Yet, I don’t want to compromise their pristine purity and magical imaging, which I doubt any wide dispersion speaker could match. So, for my new panels, I want to have it both ways… that is; narrow dispersion for solo listening and wide dispersion when entertaining guests.
So the plan is to have selectable narrow and wide dispersion modes for the panels and dedicated EQ curves for each mode using the memory settings in my digital EQ.
My current flat panel ESL’s are quite magical in their tightly focused sweet spot but they aren’t much good for entertaining guests. Yet, I don’t want to compromise their pristine purity and magical imaging, which I doubt any wide dispersion speaker could match. So, for my new panels, I want to have it both ways… that is; narrow dispersion for solo listening and wide dispersion when entertaining guests.
So the plan is to have selectable narrow and wide dispersion modes for the panels and dedicated EQ curves for each mode using the memory settings in my digital EQ.
Yes this will work. How quickly are you needing to switch between the two modes?
I just used a shorting bar with alligator clips to attach to each segment.
I could imagine a round bar that would click into a row of fuse holder type connectors...might be a cleaner setup.
What are the unsupported dimensions of your diaphragm?
Is the HV bias applied? Resonance will drop with increased HV bias.
http://www.diyaudio.com/forums/plan...agm-resonance-change-hv-bias.html#post1884466
If you don't have measurement equipment, you can determine resonance by player a slow sinewave sweep(from 20Hz up) thru a woofer placed a few inches from the diaphragm. It will be really obvious when you hit the diaphragm resonance as you will hear the diaphragm start moving in sympathy with the woofer.
If you don't have a signal generator, here is a website where you can download a simple signal generator called "Tone" to drive your woofer amplifier from your computer. Click on sinusoid and then the play button at the top. There are two sliders at the bottom that let you change the frequency.
Tolvan Sofware
Last edited:
Hi,
What thickness of coating are you using? I have done multiple trials of 6 vs 2um film and did not observe a steep roll of from 16 kHz. I have lost measurements data but I recall the difference was perhaps in the order of 1-2 db at 20 kHz. Since i don't hear at all above 16 kHz... No concerns for me
Also a subjective opinion. A thermally annealed 6u membrane sounded very neutral compared to a mechanically stretched either 6u or 2u. Quite weird, but trying to heat-treat 2u membrane has lead to very inconsistent results. Every time I repeated the operation, and frequency response was changing, sometimes showing wave-like visual pattern.
Cheers
Lukas.
Last edited:
Doesn't have to be quick, just easily reconfigurable. I like the idea of a shorting bar bridging fuse clips... very clean.
I have ordered a couple of these switches to try:
Ceramic Rotary Switch 8 Pole 2 Positions NOS Lot of 1 | eBay
5.3" max span between diaphragm supports (.062 d/s)
Thanks, I will check that out
I'm still working on the stators... it will be a while.
Hi,
What thickness of coating are you using? I have done multiple trials of 6 vs 2um film and did not observe a steep roll of from 16 kHz. I have lost measurements data but I recall the difference was perhaps in the order of 1-2 db at 20 kHz. Since i don't hear at all above 16 kHz... No concerns for me
Also a subjective opinion. A thermally annealed 6u membrane sounded very neutral compared to a mechanically stretched either 6u or 2u. Quite weird, but trying to heat-treat 2u membrane has lead to very inconsistent results. Every time I repeated the operation, and frequency response was changing, sometimes showing wave-like visual pattern.
Cheers
Lukas.
Hi Bazukaz,
I know it is mentioned before and many times but be careful with the simple conclusion " I cannot hear above ( a constant sine wave ) of 16kHz so it doesn't matter what happens above that. IT DOES and you hear it too.
Edmund
Hi phazer99,
Well I guess this discussion -audible or not- is well known.
There are some experiments documented and one such test is about two person's where tested and one could hear to about 12000Hz the other to 10.000Hz or so , I don't have the exact figures but that doesn't matter for the explanation. The testing was done with a gliding tone.
Then the test persons where listening to reproduced music and and random times a filter was applied far above what both test persons could hear according the audio test.
Guess what, both test persons where able to exactly tell when the filter was ON and OFF.
There are many discussions about this and why it is like it is, and what's the use of SACD or HD-PCM audio but as long as I can clearly tell the difference between the best audio system in the world and for instance -real cymbals- , I wouldn't start with neglecting high frequencies.
Edmund
Well I guess this discussion -audible or not- is well known.
There are some experiments documented and one such test is about two person's where tested and one could hear to about 12000Hz the other to 10.000Hz or so , I don't have the exact figures but that doesn't matter for the explanation. The testing was done with a gliding tone.
Then the test persons where listening to reproduced music and and random times a filter was applied far above what both test persons could hear according the audio test.
Guess what, both test persons where able to exactly tell when the filter was ON and OFF.
There are many discussions about this and why it is like it is, and what's the use of SACD or HD-PCM audio but as long as I can clearly tell the difference between the best audio system in the world and for instance -real cymbals- , I wouldn't start with neglecting high frequencies.
Edmund
I choose to believe that sounds above 20 kHz (well more like 15 kHz in my case) are not important in sound reproduction until I read some convincing proof of the opposite. To quote Wikipedia page for SACD:
In September 2007 the Audio Engineering Society published the results of a year-long trial, in which a range of subjects including professional recording engineers were asked to discern the difference between SACD and a compact disc audio (44.1 kHz/16 bit) conversion of the same source material under double blind test conditions. Out of 554 trials, there were 276 correct answers, a 49.8% success rate corresponding almost exactly to the 50% that would have been expected by chance guessing alone.
Hi,
It is difficult to draw any conclusions without knowing under what conditions the tests have been carried out.
The slope of filter and it's effects on different frequencies is not known.
Even if the filtering did not affect hearing range of persons examined, possible effects of intermodulation distortion from higher frequencies is likely.
Below is a link to a summary of experiments that were carried out regarding to listening tests and mixed frequencies with content above 20 kHz.
The conclusion is that the most likely such frequencies are heard indirectly, likely through intermodulation.
Audibility of Components Above 22 kHz in a Harmonic Complex Tone: ingentaconnect
The hints to the possibility that a speaker with very extended high frequency response may sound even worse under some circumstances.
Regards,
Lukas.
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.