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Accelerometers to measure panel vibrations?
Accelerometers to measure panel vibrations?
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Old 14th December 2020, 09:18 AM   #11
scottjoplin is offline scottjoplin  Wales
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What's wrong with the old knuckle test?
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Old 14th December 2020, 09:24 AM   #12
MrKlinky is offline MrKlinky  United Kingdom
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What's wrong with the old knuckle test?
Arthritis...
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Old 14th December 2020, 09:35 AM   #13
larryldspkr is offline larryldspkr  Canada
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A stethoscope can be used to hear what the panel is doing or hear changes.

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Old 14th December 2020, 10:05 AM   #14
markbakk is offline markbakk  Netherlands
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Sorry to stray off-topic a little, but I have been think along these lines; using a two-piece brace supporting opposite walls with a visco-elastic material joining them and operating in shear.
I believe Earl Geddes and KEF both use this approach. The latter has nice BEM modeling on this in a white paper about the LS50.
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Old 14th December 2020, 10:25 AM   #15
gdan is offline gdan  Greece
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Accelerometers to measure panel vibrations?
If you are interested for an assembled and calibrated Accelerometer system, have a look here:

PCB and Front panel for Accelerometer preamplifier
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Old 14th December 2020, 01:24 PM   #16
Pano is online now Pano  United States
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Accelerometers to measure panel vibrations?
I have the contact mics and they work OK. As the frequency response is unknown, they are mostly used for comparison. The bass response is weak, which doesn't help. They come with adhesive on them, but it's meant to be semi-permanent. I removed that and used some very thin tape made for mounting photos. It isn't blameless, but the best I've found.

A few years back I talked with SY about using accelerometers for this sort of thing. He gave me some pointers, which I never put into practice. He also suggested MEMS microphones.
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Old 14th December 2020, 01:38 PM   #17
puppet is offline puppet  United States
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Accelerometers to measure panel vibrations?
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Originally Posted by head_unit View Post
But on the side panels...won't the coffee spill out?!?!
Step one, lay cabinet on its side.

Many here won't admit to, or forgot using this method to set engine points back in the day.
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Old 14th December 2020, 05:12 PM   #18
diyiggy is offline diyiggy
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...ash-tray sand on the surface to check... though visual checking only. One advantage : the sand moves mores where it vibrates the most, so countermeasure at the opposite side (fillets, bracing, damping) are easier to locate... maybe !
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Old 14th December 2020, 06:06 PM   #19
bwaslo is offline bwaslo  United States
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Accelerometers to measure panel vibrations?
This one (the old ACH-01) can be connected like an electret microphone (use a 9V battery or the like to power it). It claims an essentially flat response, but that depends on how it is mounted of course. And, as someone earlier said here, you'll get a different measurement with about every place you mount the sensor, and you still only get to know how that point vibrates, with out really much info about how much that will radiate sound. You also can identify the frequencies of resonant vibration, finding something that fixes or changes it can be surprisingly difficult.
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Old 14th December 2020, 06:17 PM   #20
cracked case is offline cracked case  England
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Remlab mentioned a Bluetooth accelerometer available from Amazon in his " midrange experiment", I found something similar " Bluetooth 2.0 6 axis IMU sensor on amazon uk. Despite trying to isolate drivers from the cabinet I still find the wall vibrate, I have no idea if it's caused by the transmission of vibration or by alternating air pressure inside.
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