Author Topic: Fun with materials  (Read 1650 times)

Offline dBe

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Re: Fun with materials
« Reply #30 on: November 20, 2019, 10:06:46 PM »
Iíve never seen (or heard) 11.5K be an issue in cabinets.  Granted, this resonance will probably shift downward with larger sizes. Even so it has been my experience that cabinet materials with their resonances are the most problematic below ~ 800Hz.  Cabinet hoot is really bad at about 400Hz.

Offline HAL

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Re: Fun with materials
« Reply #31 on: November 21, 2019, 08:46:47 PM »
Yep, lower in frequency is worse for cabinet vibrations.  Having the accelerometer makes them easy to find.  Just run a log sweep on the speaker and measure the response on a panel with it attached.  Then you know what to work on to damp.     

Now to try some constrained layer damping materials and see what happens with other samples.   The CAE VB-2 from Parts-Express is already posted on the MEDEX sample. 

Offline steve

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Re: Fun with materials
« Reply #32 on: November 22, 2019, 06:44:04 AM »
Yep, lower in frequency is worse for cabinet vibrations.  Having the accelerometer makes them easy to find.  Just run a log sweep on the speaker and measure the response on a panel with it attached.  Then you know what to work on to damp.     

Now to try some constrained layer damping materials and see what happens with other samples.   The CAE VB-2 from Parts-Express is already posted on the MEDEX sample.

Thanks for all your time and efforts Hal. Much appreciated. A couple of questions I would like to ask.

What was the thickness and L x W of the samples tested?

If these are small pieces, is it possible with your setup to perform a test on a larger piece, say 20 inches by
35 or 40 inches?

Thanks again Hal.

steve
« Last Edit: November 22, 2019, 06:47:12 AM by steve »
Steve Sammet (retired, owner, EE, SAS Audio Labs)
"V" Very Low Capacitance ICs
SAS Audio Labs Test Phono Stage
SAS Audio 11A Tube Reference Preamplifier
SAS Audio Labs 25 W Triode Reference Monoblocks
2 way test Spkrs, 28 - 20khz  -3db (28hz)

Offline HAL

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Re: Fun with materials
« Reply #33 on: November 22, 2019, 11:42:48 AM »
The samples are all 1" x 3" x stock material depth cut from the raw stock.

The Dremel vise is to small for larger panels to be tested. 

Offline steve

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Re: Fun with materials
« Reply #34 on: November 24, 2019, 05:53:23 AM »
The samples are all 1" x 3" x stock material depth cut from the raw stock.

The Dremel vise is to small for larger panels to be tested.

Thanks for providing the information Hal. I, personally, found the info. interesting and useful indeed.

cheers

steve
« Last Edit: November 24, 2019, 06:04:03 AM by steve »
Steve Sammet (retired, owner, EE, SAS Audio Labs)
"V" Very Low Capacitance ICs
SAS Audio Labs Test Phono Stage
SAS Audio 11A Tube Reference Preamplifier
SAS Audio Labs 25 W Triode Reference Monoblocks
2 way test Spkrs, 28 - 20khz  -3db (28hz)