Revisiting a low cost modification

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avahifi_lj

Revisiting a low cost modification
« on: 21 Sep 2016, 04:40 am »
Hello,

I recently had the foam surround replaced on my speaker woofers.  I mentioned to Frank what I was doing, and he asked if I had thought of doing his speaker damping mod before reinstalling the woofer.  For those not familiar with the mod, it involves applying a bit of modeling clay to the speakers.  Check out the following Audio Basic article for details:

http://www.avahifi.com/images/avahifi/root/audio_basics/ab_pdf/ab1982.pdf

In the Audio Basic article Frank suggests Plast-i-Clay, but he told me that any non-hardening modeling clay will work.  I could not find Plast-i-Clay, but did find Plastalina at my local Michaels (appears to be their house brand).  Plastalina comes in a variety of colors, and is fairly cheap.  The key thing to remember is that you need to use non-hardening modeling clay.

The basket/frame of my woofers are stamped steel, which frankly surprised me as I was expecting a cast aluminum basket/frame.  Adding the clay was pretty easy, and it added a lot of dampening to the basket/frame.  I didn’t add clay to the magnet assembly simply because it was already very substantial, and I felt that if any part of the speaker was going to have issues with vibration it was going to be the basket/frame.  Note that it’s important to not get any clay on the speaker cone or any of the moving parts (spider, wires, etc).

Once I got both speakers coated with clay (about ¾ of a pound per speaker) I installed them back into the cabinet, and fired up the system.  What I immediately noticed was a more controlled low end.  The bass didn’t necessarily go any deeper, but it sure was a lot more solid and defined.
The project is fairly easy, and well worth the time.

Larry

dB Cooper

Re: Revisiting a low cost modification
« Reply #1 on: 21 Sep 2016, 05:13 am »
I can attest to what Larry is saying, having done the suggested mods in times past with several sets of speakers, also turntables. The difference is significant on everything I've tried it on, including (scaled down) my Sennheiser HD650 headphones. As Neil DeGrasse Tyson says, "Science doesn't depend on you believing in it to work". The science behind why it works is explained in the linked file. The improvement you get if you do as Larry (and others, including myself) have done far exceeds what you would ever get from boutique cabling for a tiny fraction of the price.

Would love to hear from others who have tried this low-buck, high-yield mod. The laws of physics being what they are, it works just as well now as it did "back in the day".

WGH

Re: Revisiting a low cost modification
« Reply #2 on: 21 Sep 2016, 02:41 pm »
Modded my old VR-2's with clay. The sound became clearer, less colored, quicker, and smoother. For some obscure reason the woofer magnet was surrounded by a steel bowl shaped shield that rang like a bell when tapped so I wrapped it with VB-2 vibration damping material.



Wayne

dB Cooper

Re: Revisiting a low cost modification
« Reply #3 on: 22 Sep 2016, 02:10 am »
That shield is no doubt to manage the magnetic field so as not to interfere with the CRT monitors nobody uses anymore. I see the edges are wrapped but if its characteristics are as described, it could no doubt benefit from a coating of plastic clay as well.

I got mine from Michael's also when i did my HD650 headphones. They had it in a very dark grey color which is almost impossible to see without a flashlight. It's worth noting that AVA's modded Grado phono carts also make use of this material. Here are before-and-after shots of the Senns. I neatened up things before closing them back up. The foam areas are open so I left them alone.






mresseguie

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Re: Revisiting a low cost modification
« Reply #4 on: 22 Sep 2016, 02:52 am »
Cool stuff!

I have read of this before, but I have not yet tried it.

Thanks! :thumb:

Wayner

Re: Revisiting a low cost modification
« Reply #5 on: 22 Sep 2016, 02:54 pm »
There are also cabinet resonances and funny how I was fooling around with this on Tuesday evening. I had put some sorbothane dots on top of my Dynaco A25XL CBDs and thought I noticed a change in the sound field (wider, cleaner), but could not believe my ears, so I'm experimenting with my ARs.

'ner

2gumby2

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Re: Revisiting a low cost modification
« Reply #6 on: 23 Sep 2016, 05:23 am »
Would this mod also fork for subwoofers?

Wayner

Re: Revisiting a low cost modification
« Reply #7 on: 23 Sep 2016, 11:51 am »
Yes.

Minn Mark

Re: Revisiting a low cost modification
« Reply #8 on: 23 Sep 2016, 02:42 pm »
If I recall correctly, to quote Frank, "Meatballs don't bounce".  This mod was one of my earliest encounters with AVA (aka Frank and the Jensen (sic) Stereo Shop). Worked well for my ESS PS8 speakers.  I am now a planar man so don't use the plasticlay but Audio Basics is a wonderland archive of information.   :thumb:

Cheers,

Mark

dB Cooper

Re: Revisiting a low cost modification
« Reply #9 on: 24 Sep 2016, 01:10 am »
Would this mod also fork for subwoofers?

Absolutely. Just follow the guidelines in the document. I have used it on several pairs of speakers, several turntables, even my open back headphones (scaling down the amount applied).
« Last Edit: 24 Sep 2016, 02:37 am by dB Cooper »

JerryM

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Re: Revisiting a low cost modification
« Reply #10 on: 24 Sep 2016, 02:30 am »
Be mindful of the price of Plasti Clay if looking around online. This stuff is only $4.50 per pound from the manufacturer, (yet, oddly, $117.00 for 25 pounds). http://www.amaco.com/products/clay-modlg-6k-gray-1?taxon_id=448

It works!

murf

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Re: Revisiting a low cost modification
« Reply #11 on: 26 Sep 2016, 10:36 am »
Hello Audio Experts!
I used to use an epoxy product called "Supermend" on all my stamped steel driver frames.  I liked that it got 'semi-hard' & thought that might be better than clay...!?

https://www.amazon.com/Eclectic-Products-5330031-Supermend-Epoxy/dp/B000BPB15C?th=1

Murf


avahifi

Re: Revisiting a low cost modification
« Reply #12 on: 26 Sep 2016, 10:29 pm »
The reason for plasticlay is that it absorbs vibrations very well.  An epoxy based product will be too hard to work well.

The test is my old "meatballs don't bounce" observation.

Frank

jpm

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Re: Revisiting a low cost modification
« Reply #13 on: 27 Sep 2016, 02:41 am »
There seem to be a lot of mods that come and go in popular awareness while losing none of their underlying value. Maybe someone could start a "doomsday book" thread compiling tweaks of yore?

dB Cooper

Re: Revisiting a low cost modification
« Reply #14 on: 27 Sep 2016, 10:03 pm »
An epoxy based product will be too hard to work well.
Frank

Also not reversible if necessary, as plasticlay is, very easily.

dB Cooper

Re: Revisiting a low cost modification
« Reply #15 on: 27 Sep 2016, 10:06 pm »
There seem to be a lot of mods that come and go in popular awareness while losing none of their underlying value. Maybe someone could start a "doomsday book" thread compiling tweaks of yore?

If it works, it works, and this worked then and works now, the laws of physics having changed little since 1982. This isn't like painting the edges of your CDs with green sharpies.

murf

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Re: Revisiting a low cost modification
« Reply #16 on: 28 Sep 2016, 10:01 am »
The reason for plasticlay is that it absorbs vibrations very well.  An epoxy based product will be too hard to work well.

The test is my old "meatballs don't bounce" observation.

Frank

Yes, but I don't think that test is really definitive!  Supermend can be gouged with my soft fingernails when hard.  I also wanted to strengthen stamped frames.  So, strength plus dampng was my thinking.
I think I'm all 'cast frame' now, so stopped messing with the pretty things.  But I do have some clay somewhere....   :scratch:

These are my observations!

Murf

avahifi

Re: Revisiting a low cost modification
« Reply #17 on: 28 Sep 2016, 01:03 pm »
If you want to try this, do only one speaker of s pair first, then compare them with the system set to mono.

When you hear the improvements, you will be sure to do the other speaker of the psit.

Frank

murf

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Re: Revisiting a low cost modification
« Reply #18 on: 28 Sep 2016, 03:18 pm »
Hi Frank,
Have you done this mod to any of those fancy Seas drivers you were playing around with?

Murf

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rcag_ils

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Re: Revisiting a low cost modification
« Reply #19 on: 28 Sep 2016, 10:12 pm »
Frank,  did you mod the Biro speakers with this method while in production?