Fun with materials

HAL · « **Reply #40 on:** 7 Nov 2019, 05:29 pm »

Mike,
Great video! CLD is a great way to do it. One thing I want to test.

Impulse response testing similar to my test setup. I am looking at both frequency domain version as well. Very cool!

brj · « **Reply #41 on:** 9 Nov 2019, 07:25 pm »

Great, thanks a lot, Mike... now I find myself watching videos on building fiberglass boats and wondering how fiberglass reinforced cabinets (with gel coat finish!) would turn out...

(Seriously, that's an excellent link - some really great content among his videos!)

HAL, looking forward to your results!

jtwrace · « **Reply #42 on:** 9 Nov 2019, 07:43 pm »

With all this effort, you might want to test the sound transmission loss of materials to SAE J1400 and sound absorption of materials to ASTM E1050 and ISO 354. Then you're at least doing it to standards...

HAL · « **Reply #43 on:** 9 Nov 2019, 08:07 pm »

Those probably require calibrated systems and all I need are relative values compared to a standard material MDF. I do input the accelerometer sensitivity to the CLIO measurement system.

This will be fine. Will try the vise method in the video, but mod it slightly to go with my setup.

HAL · « **Reply #44 on:** 14 Nov 2019, 02:40 am »

New test setup ready to check out and then start testing. Using the Smacker setup and the vise method without the pendulum fishing weight.

Also have a sample of damping material to throw in the mix after the initial sample tests.

HAL · « **Reply #45 on:** 17 Nov 2019, 12:34 am »

Have the impulse response test setup running and the CLIOwin 8.51 Standard system calibrated. The sensitivity of the accelerometer is being adjusted by the system software in the measurments.

Now to get the impulse generator working and do some trials with MDF to see what the system finds for response.

Some pictures of the new test setup and measurement system.

HAL · « **Reply #46 on:** 18 Nov 2019, 09:00 pm »

Modified the test setup for more stability for the solenoid. That made the measurements a lot more stable.

Measured all the samples Peter J sent and will be posting response graphs as I get them ready. There are a lot of them!

Endo2112 · « **Reply #47 on:** 19 Nov 2019, 01:55 am »

I would attempt to have the depth, or amount of material that enters the vise, exactly the same as well as the amount of pressure that gets applied for a consistent result, i'm sure you've already thought of this but it popped into my head after a beer or 3.

Good luck with this, i'm eagerly awaiting the outcome,

Don

HAL · « **Reply #48 on:** 19 Nov 2019, 02:02 am »

Don,
Exactly what I did to make the measurements. Marked the vise for depth and position. Best I can do.

Now to graph like 20+ samples!

charmerci · « **Reply #49 on:** 19 Nov 2019, 05:54 am »

My recent audio obsession is cabinets resonance - especially on cheaper speakers. What about No-Rez encased in Baltic birch (as SETman suggested earlier)? That should a fairly light, inexpensive cabinet.

HAL · « **Reply #50 on:** 19 Nov 2019, 12:16 pm »

To measure these samples they are clamped in a vise. If the sample has NoRez, then the foam layer would be compressed and not really operating as expected. Not really going to tell the full story. That would need and entire panel that is part of a box, and I do not have that at this point. Might happen if I take my Monoliths OB planar section and add NoRez at some point. Not something I plan on doing at this time.

I do have a constrained layer damping material from Parts-Express, CAE VB-2 to use on some samples and see the effect. It is a visoelastic material with a backing that adheres to the sample. That is in the measurements as well for one sample.

https://b2b.parts-express.com/cascade-vb-2-acoustic-damping-sheet-139-sq-ft--268-262

HAL · « **Reply #51 on:** 19 Nov 2019, 09:47 pm »

Did some comparison plots of the impulse response measurements with the test setup of material samples sent by Peter J.

First is the comparison of MEDEX and Ranger Board, The second is the comparison of MEDEX to MEDEX with CAE VB-2 constrained layer damping material applied. MEDEX is always the green plot.

Constrained layer damping needs more investigation. A lot of other comparison plots to post.

HAL · « **Reply #52 on:** 20 Nov 2019, 12:58 pm »

Here are more sample measurements. Each measurement has the material name as Peter J wrote it on the sample in the title. The green line is the MEDEX for comparison.

HAL · « **Reply #53 on:** 20 Nov 2019, 01:00 pm »

Next batch of measurements:

HAL · « **Reply #54 on:** 20 Nov 2019, 01:02 pm »

Next batch of measurements:

HAL · « **Reply #55 on:** 20 Nov 2019, 01:04 pm »

Next batch of measurements:

HAL · « **Reply #56 on:** 20 Nov 2019, 01:06 pm »

Next batch of samples:

HAL · « **Reply #57 on:** 20 Nov 2019, 01:07 pm »

Next batch of measurements:

HAL · « **Reply #58 on:** 20 Nov 2019, 01:09 pm »

Last batch of measurements:

HAL · « **Reply #59 on:** 20 Nov 2019, 01:13 pm »

The quartz sample was the one with the most pronounced resonance from the test.

Other woods that had damped resonances, I put cursors on them for highlights.

Constrained layer damping materials helped even MEDEX when a 1mm layer was added to the back. Nothing new, just a way to see the effect.

Lots of fun hitting stuff!