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I cant reach above 15Khz on my planars
I cant reach above 15Khz on my planars
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Old 3rd May 2017, 06:45 AM   #31
WrineX is offline WrineX  Netherlands
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Hi bolserst thanks again for a the work you put in your replies !!! You've been a great help so many times where I/ and I guess others get stuck!

I looked at some responses of the cheap capsules to and noticed the same the curve you post are plots of the mic itself ? When used as call it will end up as mirrored? I mean positive values will be negative to compensate ? I looked at my cal and all numbers up high where the peak is are positive numbers. So according to you dashed red line 17 kHz should -5db so when used as call it will add 5 dB ?? Or am I doing it wrong ?

bolserst do you have a cal file if the red line I might be able to try?


Last question, if I just buy a crappy EMC 8000or slightly better could I let it be calibrated somewhere and have a bit more trusty measurements ?

Last edited by WrineX; 3rd May 2017 at 06:48 AM.
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Old 3rd May 2017, 06:51 AM   #32
WrineX is offline WrineX  Netherlands
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Quote:
Originally Posted by bolserst View Post
Thanks for sharing your experience. I've often wondered about this aspect of planar magentics where there is often a significant portion of undriven diaphragm area that is just "along for the ride".

I think we all wondered about that , my etched membranes have extra traces I called filler traces between traces there are useless traces to fill everything. I did this to most of my amt as well. I've seen it in commercial amt to like the one from Martin Logan.

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Originally Posted by lowmass View Post
well I wouldnt say all your past work is useless. There maybe an issue with measurment accuracy BUT not nessasarily measurment indication. Meaning that if there is a response upset the system may not be telling you exactly whats going on but its still telling you enough to know basically whats going on.
Most of the time we are trying to overcome a basic problem and just getting ballpark indication of it is enough to goto work on the issue. This is perhaps 90% of the work. from there if we want to refine things to some higher degree then of course we may need calibrated instruments.
The vast magority of your work is still useful info if interpreted well.
Not useless that's true but for instance: I made some rubanoides and stopped working on it since it drops at 15 kHz thought it was hefty phase problems , I was busy with the stacked esl panels but stopped working on it since it dropped at 15 kHz to early and thought it was the weight or phase issues. Now the same for the planars. My goal every time was to create something that could play from midrange to high frequency 18-20 kHz as goal. The midrange and upper mid range was never a problem. But the amount of scrapped designs an tries to reach 20 kHz or smooth the huge hump are countless. I may have trown many random designs that should meausure rather good. So of course I learned allot of skills , materials and such and what certain things do ,but I never ended up after 3 years with a design I was feeling good enough about to finally build something with not wasted time I enjoyed myself to and lost loads of money on materials and I still have allot materials so if I can get a mic I can trust I hapilly start all over !!!! And will redo every idea that was not a complete fail in other departments , so everything will be going faster

Last edited by WrineX; 3rd May 2017 at 07:08 AM.
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Old 3rd May 2017, 12:26 PM   #33
lowmass is offline lowmass  United States
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Quote:
Originally Posted by bolserst View Post
Thanks for sharing your experience. I've often wondered about this aspect of planar magentics where there is often a significant portion of undriven diaphragm area that is just "along for the ride".
yep, if you draw a picture of magnet flux lines and then draw lines perpendicular to these to represent the force on the conductor its easy to see that although the force lines out over the magnets are not perpendicular to diaphragm, they are in a direction that does useful work. The only area thats not is a small area right at the center of each magnet.

BTW some of my designs have been single trace foil, but most have been multi trace designs. I found no magor difference in perf. However resurch in other areas has shown that the multi trace configuration may have some advantage in mid frequency damping. This effect tunable by trace size/#/mass/ etc etc
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Old 3rd May 2017, 06:04 PM   #34
WrineX is offline WrineX  Netherlands
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Nice low mass !!! I will try some of the trace theory with soon, I am taking a 2 hour journey now to pickup a isemcon emx 7150. index

Should at least be better then a umik even without cal file , looking good. It does not fix all my design or anything but gives me at least a way better insight. I hope especially in the upper freq
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Old 3rd May 2017, 06:19 PM   #35
lowmass is offline lowmass  United States
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Yea I remember years ago having trouble with a mic and no could afford a good one so I was actually thinking I would just make a ribbon mic. Never got around to it though
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Old 3rd May 2017, 11:50 PM   #36
WrineX is offline WrineX  Netherlands
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GOt the the new mic here a comparison


UMIK-1 vs Isemcon emx7150 both with cail file.



Pic 1 ferquency curve of a genelec 1019A at 30 cm

Pic 2 Distortion Umik-1
Pic 3 Distortion Isemcon emx7150

You can see the curve changed quit a bit smoother, which helps in terms of the 15Khz roll of i had. since with the umik it goes HIGH before it drops.
so you should level 15 Khz with the 15 Khz of the Isemcon emx7150, then the UMIK-1 would drop harder at 15 khz ... but another nice thing is if you look at distortion.

the Isemcon emx7150 is much more sensitive.
You can see clearly where the bass unit stops and the tweeter takes over in the same measurement, at around 2.1 Khz distortion from 0.099% skyrockets to 0.46% and so on. you can see the total noise floor increase, according to how much each unit is contributing to the total amount of output.

Distortion difference at 2.95khz

Isemcon emx7150 @ 2.95 Khz is 0.099% THD
uMIK-1 @ 2.95Khz 0.404% THD


I am looking forward to measuring the planars tomorrow. it might be nice it might be not but at least it is more honest i believe and i have more resolution.

the mic itself only differs around 1.66 dB at 10 hz . the rest from 20Hz - 20Khz differs max 0.8 dB. without calibration !

SAo im am impressed . there are also off mic calibration files and a file with measuring conditions like temperature etc , as well as ow much it differs at certain temperature differences .... way to much for me use but good it is there !

Letsssss Goooo
Attached Images
File Type: jpg isemcon curve.jpg (193.8 KB, 106 views)
File Type: jpg dist umik.jpg (237.8 KB, 107 views)
File Type: jpg dist isemcon.jpg (253.3 KB, 106 views)
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Old 4th May 2017, 07:49 PM   #37
WrineX is offline WrineX  Netherlands
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Here i measured the same ESL panel, (be it from a little further away.) with the new mic. looks slightly better.

Pic one old mic
Pic Two new mic

the 6dB per octave low roll of from 20khz and down is nicely visible. i did notice it is not exact 6 db more like 5. which cant be just fixes by a 6dB filter , i will end up short of high frequencies at 14 khz.

i used a crossover at 1.2 khz, and yeah its a different program somehow holm does not recognize my DAC input only output
Attached Images
File Type: png esl drop.png (31.3 KB, 88 views)
File Type: jpg only crossover.jpg (85.4 KB, 88 views)

Last edited by WrineX; 4th May 2017 at 07:52 PM.
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Old 6th May 2017, 06:28 PM   #38
bolserst is offline bolserst  United States
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Quote:
Originally Posted by WrineX View Post
… are plots of the mic itself ? When used as call it will end up as mirrored? I mean positive values will be negative to compensate ?...do you have a cal file if the red line I might be able to try?
Yes, the plots represent the response of the mic itself when measuring an acoustic sound field that has perfectly flat amplitude vs frequency. Yes, the correction the software applies when using the calibration data is the mirror image of the response. I will see about modifying your existing calibration file to something like the red line…should have it early next week for you to try.

Quote:
Last question, if I just buy a crappy EMC 8000or slightly better could I let it be calibrated somewhere and have a bit more trusty measurements ?
I think you probably have already figured this out, but it all depends on the quality of the calibration performed. The EMC 8000 is reasonably stable with time as long as you don’t accidently leave it locked in a car in the hot sun. So, if you get good calibration data for it, you will have trustworth measurements.

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Originally Posted by WrineX View Post
… im am impressed . there are also off mic calibration files and a file with measuring conditions like temperature etc , as well as ow much it differs at certain temperature differences ....
Can you post the calibration for your new mic? I would be interested to see how flat the response of the uncalibrated capsule is. Looks like it is providing a much flatter top octave measurement when calibrated than the UMIK.

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Originally Posted by WrineX View Post
Here i measured the same ESL panel, (be it from a little further away.) with the new mic. looks slightly better.
That looks a LOT better. -2.5dB down @ 20kHz vs -15dB.

Quote:
the 6dB per octave low roll of from 20khz and down is nicely visible. i did notice it is not exact 6 db more like 5. which cant be just fixes by a 6dB filter
If you look carefully, you will see that the slope is always 6dB, but there is a shift in the midrange due to the baffle effect of the spacer around the perimeter of the diaphragm. If you make your spacer wider or add an additional ring around it, you will notice the amplitude of the shift increase. If you somehow built an ESL with spacer width of only 1mm, there would be almost no shift noticeable. The frequency at which the shift occurs depends on the size of the panel; bigger panels have the shift at lower frequencies. The shift frequency also moves some when you start measuring very close to the panel.

When equalizing you use a 6dB slop filter + a very minor shelving filter to correct the shift.
Active Filters: 6 - Shelving highpass
Attached Images
File Type: png Wrinex_6dBslope_01.png (173.5 KB, 30 views)

Last edited by bolserst; 6th May 2017 at 06:37 PM.
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Old 6th May 2017, 09:39 PM   #39
WrineX is offline WrineX  Netherlands
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Quote:
Originally Posted by bolserst View Post
Yes, the plots represent the response of the mic itself when measuring an acoustic sound field that has perfectly flat amplitude vs frequency. Yes, the correction the software applies when using the calibration data is the mirror image of the response. I will see about modifying your existing calibration file to something like the red line…should have it early next week for you to try.


I think you probably have already figured this out, but it all depends on the quality of the calibration performed. The EMC 8000 is reasonably stable with time as long as you don’t accidently leave it locked in a car in the hot sun. So, if you get good calibration data for it, you will have trustworth measurements.


Can you post the calibration for your new mic? I would be interested to see how flat the response of the uncalibrated capsule is. Looks like it is providing a much flatter top octave measurement when calibrated than the UMIK.


That looks a LOT better. -2.5dB down @ 20kHz vs -15dB.


If you look carefully, you will see that the slope is always 6dB, but there is a shift in the midrange due to the baffle effect of the spacer around the perimeter of the diaphragm. If you make your spacer wider or add an additional ring around it, you will notice the amplitude of the shift increase. If you somehow built an ESL with spacer width of only 1mm, there would be almost no shift noticeable. The frequency at which the shift occurs depends on the size of the panel; bigger panels have the shift at lower frequencies. The shift frequency also moves some when you start measuring very close to the panel.

When equalizing you use a 6dB slop filter + a very minor shelving filter to correct the shift.
Active Filters: 6 - Shelving highpass
Nice ! You clarified allot again ! Good to know about filtering, , the panel in question had 15 mm wide spacer


I am in a train now but il post the cal file of the new mic when im home , uncalibrated the mic only drops 1 dB at 1 kHz Or so. I am really glad with the mic so far. IT opens up allot of possibilities of things i tried already without much succes. I can now redo. No problem since I like to fiddle around.


Bolserst don't spend any time on recreating the call I'll try to look up how to make one with the new mic and calibrate to that.but many thanks for offering to do it !!!!
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Old 6th May 2017, 09:42 PM   #40
WrineX is offline WrineX  Netherlands
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Here a response of a fast trown together tweeter driven by only 2 strips of rubber magnets in combination with 2 of the low panels crossed at 1.2 kHz. But it's all about the high end.

jeeej 20khz and beyond
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