Data Analysis of the A/V Roomservice EVP vibration isolation pad

Puma Cat

Puma Cat

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So...I've been doing a lot of studies in reducing and attenuating vibration in my audio rack lately. I've been doing comparisons using wooden blocks under 1 3/4" hard rock maple boards, using cork & rubber and Diversitech closed-cell foam and rubber anti-vibration pads under the maple board, and Herbie's Audio Labs Tenderfeet under the DAC, either on the maple board or just on top of the top shelf. So, far, I've found the best vibration attenuation by having the DAC sitting on the Tenderfeet just sitting on the top shelf of the rack w/o the maple board.

Well, the footers I just got, the EVPs from A/V Roomservice work the best, by far.

Shown here is a plot of the vibration imparted on to my Schiit Gungnir DAC (Gumby). The vibration is imparted by a home-made slide hammer dropping onto the top shelf my Sanus Euro II audio rack (which has shelves of powder-coated particle board), with the iPhone running Vibsensor sitting on top of the DAC. The phone is hanging off the DAC as much as it can w/o falling off so it damps the DAC as little as possible. The iPhone is measuring the vibration imparted as Power, RMS, using the VibSensor app. The data is plotted in JMP 14.

The red trace is Herbie's Audio Lab Tenderfoot footer under Gumby, and the blue trace are the EVPs under Gumby.

Tenderfeet%20vs%20EVP.jpg


Wow. This greater than an order of magnitude lower amount of vibration imparted using the EVPs under the DAC vs. the Herbie's Audio Labs Tenderfoot footer.
 
Now, check this out...comparing the stock rubber feet on my Schiit Gumby (green trace) to the Herbies Tenderfeet (red trace) and the EVPs (blue trace).

Stock%20Feet.jpg


I will also be putting up a video of them on my little music box mechanism. They are incredibly quiet with the music box mech on top of them.

I listened to them under the DAC last night compared to the Tenderfeet. They made a notable improvement, the presentation and instrumental and vocal images were clearer and more focused, kind of like applying an Unsharp Mask to a photograph in Photoshop. This made the sonic picture "sharper" but in a very natural and accurate way, but not "over-sharpened" (this is why I used the Unsharp Mask analogy). Also, the presentation had a notable increase in perceived loudness, so I actually had to turn the volume down; I always find this a good attribute as it means I can hear more deeply into presentation at lower gain, which tells me that a layer of noise and grunge has been removed.

Oh, also, they are supposed to be even more effective under loudspeakers and turntables, devices that are maximally impacted by vibration and movement.

Will be ordering more of these, for sure. They are inexpensive and they appear to work very, very well.
 
Is there a pre load weight spec’d by the manufacturer of any of these items?


Sent from my iPhone using Tapatalk
 
Puma Cat said:
So...I've been doing a lot of studies in reducing and attenuating vibration in my audio rack lately. I've been doing comparisons using wooden blocks under 1 3/4" hard rock maple boards, using cork & rubber and Diversitech closed-cell foam and rubber anti-vibration pads under the maple board, and Herbie's Audio Labs Tenderfeet under the DAC, either on the maple board or just on top of the top shelf. So, far, I've found the best vibration attenuation by having the DAC sitting on the Tenderfeet just sitting on the top shelf of the rack w/o the maple board.

Well, the footers I just got, the EVPs from A/V Roomservice work the best, by far.

Shown here is a plot of the vibration imparted on to my Schiit Gungnir DAC (Gumby). The vibration is imparted by a home-made slide hammer dropping onto the top shelf my Sanus Euro II audio rack (which has shelves of powder-coated particle board), with the iPhone running Vibsensor sitting on top of the DAC. The phone is hanging off the DAC as much as it can w/o falling off so it damps the DAC as little as possible. The iPhone is measuring the vibration imparted as Power, RMS, using the VibSensor app. The data is plotted in JMP 14.

The red trace is Herbie's Audio Lab Tenderfoot footer under Gumby, and the blue trace are the EVPs under Gumby.

Tenderfeet%20vs%20EVP.jpg


Wow. This greater than an order of magnitude lower amount of vibration imparted using the EVPs under the DAC vs. the Herbie's Audio Labs Tenderfoot footer.
Click to expand...

How about a picture of your home made slide hammer and your methodology for using the slide hammer?
 
mep said:
How about a picture of your home made slide hammer and your methodology for using the slide hammer?
Click to expand...

The slide hammer is simply a 1/2" drive socket that drops down the unthreaded part of a bolt, onto the head of the bolt. The bolt is oriented vertically on the same place on the audio rack top shelf each time. A nut at the very bottom of the threaded section of the bolt serves as lock nut and a stop so that the socket drops repeatibly exactly 8 cm each time. The slide hammer is designed to impart the same amount of power repeatibly.
 
Puma Cat said:
The slide hammer is simply a 1/2" drive socket that drops down the unthreaded part of a bolt, onto the head of the bolt. The bolt is oriented vertically on the same place on the audio rack top shelf each time. A nut at the very bottom of the threaded section of the bolt serves as lock nut and a stop so that the socket drops repeatibly exactly 8 cm each time. The slide hammer is designed to impart the same amount of power repeatibly.
Click to expand...

I wonder if measuring the effect of the slide hammer is equivalent to the vibrations an audio system actually experiences. Seems like a good test for footfall issues with turntables.
 
MPW said:
I wonder if measuring the effect of the slide hammer is equivalent to the vibrations an audio system actually experiences. Seems like a good test for footfall issues with turntables.
Click to expand...

Hi Morgan
I am just doing the best I can with what the "tools" I have at hand. I don't have an engineering lab at my disposal. If I did, I'd be doing full-on DOEs.

I'm simply looking for "direction" and then verifying by actual listening.

For example, the Diversitech AVP's were a bust. The EVPs made a notable and audible improvement.
 
MPW said:
I wonder if measuring the effect of the slide hammer is equivalent to the vibrations an audio system actually experiences. Seems like a good test for footfall issues with turntables.
Click to expand...

I don’t see how they are related. We are talking about the difference between micro vibrations vice a mini shock test.
 
mep said:
I don’t see how they are related. We are talking about the difference between micro vibrations vice a mini shock test.
Click to expand...

I tend to agree which is why I asked the question. The test is being used to give direction before listening tests, but may give the wrong direction and rule out products that are very effective in dealing with the vibrations that actually occur when reproducing music in a domestic space. Just my guess without having ever performed any testing in this area other than with my ears, so take it for what it’s worth.
 
MPW said:
I tend to agree which is why I asked the question. The test is being used to give direction before listening tests, but may give the wrong direction and rule out products that are very effective in dealing with the vibrations that actually occur when reproducing music in a domestic space. Just my guess without having ever performed any testing in this area other than with my ears, so take it for what it’s worth.
Click to expand...

All I can say is the use of the various footers is audible and order of which sounds best is concordant with the vibration studies. The Herbie's Tenderfoot sounds better than the stock Gumby feet, and the EVPs sound (notably) better than the Tenderfeet.
 
mep said:
I don’t see how they are related. We are talking about the difference between micro vibrations vice a mini shock test.
Click to expand...

The force imparted by the mass striking the top of the audio rack shelf imparts measurable and reproducible level of vibration.

You can see here the vibration (resembling a ringing component) comparing the stock Gumby feet in red vs. the Tenderfeet in blue. The amplitiude and duration (time) of the ringing component for the Tenderfeet is notably less than the stock rubber foot.
DAC%20w_o%20and%20w%20Tenderfeet.jpg
 
Puma Cat said:
The force imparted by the mass striking the top of the audio rack shelf imparts measurable and reproducible level of vibration.

You can see here the vibration (resembling a ringing component) comparing the stock Gumby feet in red vs. the Tenderfeet in blue. The amplitiude and duration (time) of the ringing component for the Tenderfeet is notably less than the stock rubber foot.
DAC%20w_o%20and%20w%20Tenderfeet.jpg
Click to expand...

You are missing my point. Of course if you are doing a mini shock test you will be able to measure the impact and how it varies with different feet. The problem is nobody is doing mini shock tests on your rack while you are listening to music. The events aren’t comparable.
 
mep said:
You are missing my point. Of course if you are doing a mini shock test you will be able to measure the impact and how it varies with different feet. The problem is nobody is doing mini shock tests on your rack while you are listening to music. The events aren’t comparable.
Click to expand...

I don't agree. The experiments were to provide direction and led me to an effective solution that sounds better than anything I've used to date.

So with respect to MY requirements...its job done. And in that context, a success.
 
Puma Cat said:
I don't agree. The experiments were to provide direction and led me to an effective solution that sounds better than anything I've used to date.

So with respect to MY requirements...its job done. And in that context, a success.
Click to expand...

Great news! Victory!
 
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