Dynamat-ing

drumiv

I am slowly starting to warm up to the idea of modding my new-to-me SDA SRS's. I've had them for a month or 2 now, so I know the sound. I got the new tweeters, and am thinking about the Dynamat/ JB Weld mod to the mids/base drivers. There're sure are quite a few choices as far as size and amount for the Dynamat. Which is the best choice for what I'm about to do? Thanks in advance.

zane77

I used the Dynamat Extreme and a believe that is what is recommended. Check ou this site, http://vr3mods.com/LCSDAUpgrade.php

heartystatue

^^^^ What he said^^^^^^^ I ordered mine at O Reilly auto parts and got it the same day.

codyc1ark

Here is a less expensive alternative that I have used in cars, and I'm planning to do some speakers once the weather takes a turn - http://www.fatmat.com

Good luck!

zingo

I like the 110mil GTmat.

drumminman

+1 on the Fatmat. A bit cheaper and for all intents and purposes it's the same thing. Comes with a roller, disposable knife and in different thicknesses too.

drumiv

Thanks for the info. How much is needed? Do you have to cover all surfaces completely?

westmassguy

The cheapest place I've found is eBay. The "wedge pack" is 4 sq ft, around $25.00 shipping included, and will do the smaller SDAs with a bit to spare, so your SRSs will need two kits, or the "trunk" kit, 20 sq ft, $90.00, which is most likely too much.
Some say you don't have to cover every sq inch, but I prefer to err on the side of caution, and cover every part of the basket, except the lip down by the flange. The first time I Dynamatted, I did the lip, and because it increases the diameter of the basket frame, the drivers wouldn't fit in the holes. Lesson learned. I use paper plates or jar lids as patterns. For the woofers, I cut a doughnut shaped piece, then cut the doughnut in half and slide it under the magnet. The "spokes" can be cut from the scraps left over from the round cutouts. I then use the back side of a 1" wood chisel to smooth out the Dynamat, making sure I have 100% contact, and also use it to round over any sharp edges. Be sure to cut out the center hole in the PRs, otherwise you'll change the T/S parameters.
For gluing the magnet assemblies, I switched to Loctite Power Grab, clear acrylic adhesive instead of JB Weld or epoxy. It's easier to work with, dries clear, and cleans up with soap and water.

zane77

^^Very nice and neat job^^

westmassguy

zane77 wrote: »

^^Very nice and neat job^^

Thanks zane

TennMan

zane77 wrote: »

^^Very nice and neat job^^

+1 to what he said.

westmassguy

TennMan wrote: »

+1 to what he said.

Thanks Ronnie

drumiv

Thanks, again, WMG. That looks like the way to go. Are you gluing the magnets directly to the Dynamat? I'm a little apprehensive about doing the magnets for fear of f..ing up the voice coils. Is there need to worry?

westmassguy

drumiv wrote: »

Thanks, again, WMG. That looks like the way to go. Are you gluing the magnets directly to the Dynamat? I'm a little apprehensive about doing the magnets for fear of f..ing up the voice coils. Is there need to worry?

You don't remove them, you just put a bead of glue around the front and back edge of the magnet. They're already glued in place, this is just a precautionary measure. The glue they used back then deteriorates or becomes brittle. This prevents the magnets from shifting.

drumiv

Gotcha, I was hoping that was the case. Thanks yet again.

Easy Runnin

Just to clarify. I don't think it's necessarry to dynamat the magnets. You dynamate the baskets and you glue the magnets.

nspindel

My understanding about magnet shift is that it is primarily an issue when moving the speakers, which is why the advice I've read here has been to lay the speaker on it's back whenever you're moving it so that the drivers are pointed straight up, in order to stop the magnet from wanting to shift downward during travel. Is this not the case? Is it possible for the magnet to shift on a driver during normal use of the speaker?

westmassguy

nspindel wrote: »

My understanding about magnet shift is that it is primarily an issue when moving the speakers, which is why the advice I've read here has been to lay the speaker on it's back whenever you're moving it so that the drivers are pointed straight up, in order to stop the magnet from wanting to shift downward during travel. Is this not the case? Is it possible for the magnet to shift on a driver during normal use of the speaker?

The magnets can shift if the speakers are handled roughly, dropped, fall over, or receive a sharp blow etc.
Since we all buy them used, god knows how they were handled before.

nspindel

The Wedge pack is also at Amazon, that's what I bought as well. Did a pair of 1C's and my 4.1's with that pack, with some left over.

http://www.amazon.com/gp/product/B00020CAVA/ref=oh_details_o05_s00_i00?ie=UTF8&psc=1

leftwinger57

I got my sheet and some scraps from an auto audio installation shop for free.They had just done a car trunk and had all pictured just laying around .I did pay for the squares but returned them because I had way more than I needed. Also shown was a later C/L purchase of Black Hole-5 of a square and scraps all for $18 and enough for the backs of my 2Bs

drumiv

What's "Black Hole-5", and what's it used for?

drumminman

drumiv wrote: »

What's "Black Hole-5", and what's it used for?

Black Hole 5 is an acoustic foam that enhances the properties of the polyfill stuffing in your speakers. It partially absorbs mid and low frequencies inside the cabinets so they don't reflect to the back side of the MW's interfering with movement of the cone.

When the stuff is applied properly (not to much, not too little) it cleans up congestion in the mid range, allowing the speakers to sound clearer no matter what volume you play them at.

Do a search - there are several posts about it including how to install it.

zane77

http://www.polkaudio.com/forums/showthread.php?148092-Improvements-To-The-SDA-SRS-1.2TL-Summary-Of-Modifications

This thread should explain all the mod's, good luck with some very fun projects

leftwinger57

Drumiv, I to was so new to the SDA line that I had 0 idea what these guys were talking about . D/L THE SDA Handbook .It gives all the liniage of the product, pictures of every speaker set and their nominclachure since they do not use names and all the techincal facts, parts lists and reasoning and the science of the design.Me,w/ my distorted logic never thought a pristine pair of originally $12/$1,300 speakers could get better but trust me it does and I still don't know what I'm talking about but the evidence is in hearing the things.

nspindel

You can also use Sonic Barrier. I used it with my 4.1TL's and like it a lot.

MAD

I know this is an old thread, but I'm about to dynamat my sda 2.3.

Should you dynamat the inside of the speaker spokes as well (obviously starting part way down to make sure the speaker won't hit it)?

I was thinking that sound would reflect off the spokes and back to the speaker cone.

Thanks for any input or advice.

F1nut

No, do the outer surface only.