I just measured my ESL57s (Mac+FuzzMeasure+Behringer ECM8000+MIC100):
Picasa Web Albums - fabien.lefebvre.fr
Is there a reference somewhere ?
.
Picasa Web Albums - fabien.lefebvre.fr
Is there a reference somewhere ?
.
Hi,
You don´t need to coat both sides of the diaphragm. That is just an effort without any gain whatsoever.
Regarding the measurement......as long as there are so many informations lacking about the setup no one could tell You anything seriously about it.
Which measurement distance? Position of the panel in the room? State of the panel, i.e with/without damping, with/without dust cover, etc.
The behaviour at 100Hz, 150Hz, 200Hz and 250Hz could be influenced by room modes/positioning.
jauu
Calvin
You don´t need to coat both sides of the diaphragm. That is just an effort without any gain whatsoever.
Regarding the measurement......as long as there are so many informations lacking about the setup no one could tell You anything seriously about it.
Which measurement distance? Position of the panel in the room? State of the panel, i.e with/without damping, with/without dust cover, etc.
The behaviour at 100Hz, 150Hz, 200Hz and 250Hz could be influenced by room modes/positioning.
jauu
Calvin
Measurements conditions are very standard: microphone located at one meter in front of the speaker. The room itself is rather small. The speakers are not that close to the walls nevertheless. At least 50cm away from them. There should be not that much reflections from the wall, due to the room itself and thanks to the measurement method (if the software is well done).
I understand that under 300Hz there will always be some doubts that the room and the measurement conditions may have influences results.
There is certainly already some useful information to extract from higher frequencies.
Your measurement looks more or less typical for an aged pair. Your bass panels show typical raised resonance from aging, the reason for it's reputation of being 'bass shy'.
See here Quad ESL Measurements for Quad ESL 57 measurements.
See here Quad ESL Measurements for Quad ESL 57 measurements.
Hello,
Thanks for this feedback. From what I saw on the site you mention, I understand that I should expect a resonance near 60Hz iso 100/110Hz.
This means both panels deserve to be re-built.
It reminds me that I read somewhere that aging stiffens the mylar which raises the resonant frequency.
What about the treble panels ? I think that they are as old as the bass ones, but is there something that can be seen on the measurement to confirm this ?
By comparison with other measurements, it seems that the peak frequency is lower on mines (~12kHz iso ~16kHz).
Unless the measuring system itself (MacBook dig out/ana in, Quad II) acts as a low pass.
All that can say on this measurement is that it is repeatable. I will do them again maybe with the microphone located at different distance.
The treble of one panel (orange on drawings) seems to lack sensitivity, which moves the stereo image. And it is rather slow to charge (1 or 2 hours) compared to the other one. Even letting it plugged does not change this feeling.
I made quite a lot of measurement with various (basic) soundmeters and white noise which confirms that it is less sensitive than the other one. Of 2dB I would say.
I take your point that re-building of bass panel should be considered first.
In that case you may have a problem.
It is normal for these panels to charge very slowly, some even improve after a full day. I keep them charged 24/7. So make sure they are both fully charged. To compare sensitivity I'd smooth the graphs as much as you can. And measure the treble panel from up close, say 10cm.
It is normal for these panels to charge very slowly, some even improve after a full day. I keep them charged 24/7. So make sure they are both fully charged. To compare sensitivity I'd smooth the graphs as much as you can. And measure the treble panel from up close, say 10cm.
I do keep them charged 24/7 as well most of the time. But sometimes I unplug them. One is very fast to recover, the other not. But few hours are enough for the lazy one.
In comparison, I just bought a second pair of ESL57 which is much much slower to charge.
To compare output levels with soundmeters, I did as suggested: get as close as possible to the panel itself with the soundmeter, in order to focus on one panel and not the entire speaker. Close = sticked to the grill.
Fabien,
your measurement indicates something strange. The fundamental resonance at about 100 Hz is far too high. Originally it was set to 55-60 Hz. The peak is to high.
I assume tensioning of the membrane is not appropriate. Too much tension and tension ratio length to width is mismatched.
Capaciti
your measurement indicates something strange. The fundamental resonance at about 100 Hz is far too high. Originally it was set to 55-60 Hz. The peak is to high.
I assume tensioning of the membrane is not appropriate. Too much tension and tension ratio length to width is mismatched.
Capaciti
This confirms that my bass panels need to be re-built. I never had the feeling they were so bad !
I just have to find some mylar now.
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