Mortite, Rings and Gaskets

F1nut

First let say that I have the utmost respect for Raife, but I had a hard time buying into the Mortite tweak. I know Matt Polk suggested it, but he/Polk Audio used it in the early days because they could not afford real gaskets. Once they could afford the gaskets, they used them. That said to me that the gaskets were the preferred choice. Therefore, I made a decision to stay with the stock gaskets in all my SDA's and have to admit to shaking my head at all that decided to use the Mortite.

So, along comes Larry with his rings, which I had no problem buying into. I decided to install them in my 4.1TL's before doing the bigger SDA's and since all the drivers and PR's would have to be removed, I thought that I'd finally give the Mortite a try. I noticed that folks were running a single string around their drivers, then would carefully torque down on the screws day after day. Some reported that one or more screw holes became stripped from this process, which of course, is not a good thing. However, with the rings this was not going to be an issue. Regardless, I thought there had to be a better way to apply the Mortite and there is. Realizing that it is pretty sticky stuff I laid out a sheet of wax paper on one of my shop work tables. I then laid out a single strand and with a veneer roller, dipped in water to help prevent the Mortite from sticking to it, I attempted to press it out as flat as possible. This did not work at all as the Mortite stuck to the roller. Hmmmm....I then decided to try two strands together and for some reason this actually worked. After rolling it out I noticed that what I ended up with was the exact width of the lip on the speaker basket, great. I should mention that after I carefully removed the original gaskets I measured their thickness at 1/64". I measured the thickness of the rolled out Mortite at 1/32" or twice as thick as the original gaskets.

Ok, after running the rolled out Mortite around the lip, I used a punch to clean out the holes on the lip. I also remember thinking at this point that doing all those drivers and PR's in the big SDA's was going to be a real PITA. So now, all the rings are installed as well as the Mortite, so I buttoned everything up and sat down for a listen. I noticed an immediate improvement in detail, sound stage, bass, etc. I'm happy, but I still had this nagging concern in my mind about the Mortite and that I should have tried the rings and the Mortite tweak separately to see which was doing what. The next day I removed everything, scrapped off the Mortite (a PITA), cleaned up the lips and glued the original gaskets back into place. After reinstalling everything, I sat down for another listen using the same demo material. I immediately noticed that the bass response was better than the previous day with the Mortite. All other aspects of the sound remained the same, that is improved. This was especially interesting as I measured the thickness of the Mortite at 1/64", the same thickness as the original gaskets, after it had been fully compressed from installation.

I can only speculate as to the reasons why, but I believe that when using the original gaskets with the rings installed, better coupling is achieved than when using the Mortite. I think this is because the density of the Mortite is working against itself where as it seems to be a benefit when using the original screws. I can also understand how it would be a benefit if the original gaskets are damaged in some way by providing a tighter seal.

My conclusion is that the rings and original gaskets produce better results than the rings and Mortite. Therefore, I suggest saving the original gaskets as you may want to reinstall them as I did.

BTW, all the Mortite went out with the trash.

helipilotdoug

I did the mortite and rings at the same time too. I have tightened the screws on everything 4 times over the course of a couple of weeks. That mortite continues to flatten out as time goes on, and requires tightening the bolts again. I'm sure one day I will feel the amount of torque needed to twist the hex driver will be the same as it was the last time after I tightened them down. All I can say is Thank God for Larry's rings! If it was not for them, smashing the mortite down like I have would surely have stripped out the screw holes.

TNRabbit

Has anyone ever tried using blind nuts versus the rings?? They're what I used when I replaced the crossover panels on the back of my Carver AL-IIIs:





Also, aren't there only 4 screws in the mid drivers? Why not add 4 more between them if you're really concerned with tightening them down....

No sort of expert on any of the SDA line, I'm just thinking out loud from an engineering standpoint.

helipilotdoug

TNRabbit wrote: »

Has anyone ever tried using blind nuts versus the rings?? They're what I used when I replaced the crossover panels on the back of my Carver AL-IIIs:





Also, aren't there only 4 screws in the mid drivers? Why not add 4 more between them if you're really concerned with tightening them down....

No sort of expert on any of the SDA line, I'm just thinking out loud from an engineering standpoint.

Gary, I think the blind nuts would not work very well on these speakers because of how close to the edge the holes would be. The shoulder of the blind nut would be outside of the speaker cutout, and would more than likely contact the speaker. As you can see on the attached photo, the shoulder on the rings is very narrow. The MDF board might also crumble away with the spikes going into it, being so close to the edge. So I feel the rings would be a much better alternative. Just my .02 worth.

Vette C6.r

Excellent write up F1. Whenever I can afford the rings I will be joining you in not using the mortite.

Let us know what you think when you do the 2.3's please.

Toolfan66

Vette C6.r wrote: »

Excellent write up F1. Whenever I can afford the rings I will be joining you in not using the mortite.

Let us know what you think when you do the 2.3's please.

His 2.3tl's are done..:cool:

hearingimpared

Same respect for Raife here too! BUT . . .

I've always used the original gaskets (per your recommendation years ago) and used the PE sealer on the driver's gaskets that were shot. I've too found the original gaskets to be best. Using the PE sealer around the PRs performed nothing short of amazing.

I've said this many times before, I can't see using a material made for rain gutter and window to be good to use on MDF. Just from speaking to people here and the statement made by anonymouse mortite tends to dry and tears chunks of MDF out if the need arises to have to remove the driver again. The PE speaker sealer I use doesn't do that, it stays pliable.

Toolfan66

I have had no problems with mortite.. and it won't matter anyway as my gaskets are long gone..

Put a thin coat of Polyurathane over the MDF where the mortite is going to seal and call it a day..

zippty2001

man with all the mods for the SDA line i have a lot of reading to do before i start any lol my wife is getting a little upset with me i am getting a little obsessed lol

Face

helipilotdoug wrote: »

Gary, I think the blind nuts would not work very well on these speakers because of how close to the edge the holes would be. The shoulder of the blind nut would be outside of the speaker cutout, and would more than likely contact the speaker. As you can see on the attached photo, the shoulder on the rings is very narrow. The MDF board might also crumble away with the spikes going into it, being so close to the edge. So I feel the rings would be a much better alternative. Just my .02 worth.

I've used those with 4.5" drivers, it partially blocked the windows in the basket. On a 6.5" driver it's not as much of a problem, but as mentioned they would be right on the edge and wouldn't leave much material around them to be stable, especially on fiberboard.

DarqueKnight

F1nut wrote: »

...I had a hard time buying into the Mortite tweak. I know Matt Polk suggested it, but he/Polk Audio used it in the early days because they could not afford real gaskets. Once they could afford the gaskets, they used them. That said to me that the gaskets were the preferred choice. Therefore, I made a decision to stay with the stock gaskets in all my SDA's and have to admit to shaking my head at all that decided to use the Mortite.

Matt Polk actually said that Mortite was a higher performance alternative to foam gaskets. When I asked for a recommendation on gasket replacement material, this is what he said:

"Any of the foam tapes sold for weather stripping will work as well as the original. Use the light weight foam and the thinnest you can find. Do not use the heavier and usually thicker black foam rubber. For a better appearance, a little searching can probably turn up a dark colored tape that will match the baffle and basket color better than the standard grayish tape found in most hardware stores.

The idea here is to provide the best possible connection between the drivers, tweeters and PR's and the baffle. That means using the thinnest gasket that will actually provide a seal. However, there is a higher performance alternative. In the early days before we could afford to tool gaskets we used a product called Mortite which was a gray flexible clay-like material sold as weather stripping and for sealing up leaky windows in winter. We would roll it out, by hand, into round wire-like cords and apply to the driver baskets before bolting in place. I always felt that it did a better job of connecting the drivers to the baffle.

Caution; if you decide to try this it is much easier to strip out the screws for the drivers, tweeters, etc. Use as little material as needed to make a seal, apply evenly and carefully tighten the screws a little at a time going around the basket so that the load is always evenly distributed over all the screws.

-msp"

Based on MSP's comment that the Mortite was superior to foam gaskets, I inferred that Polk switched to foam gaskets because they were quicker and easier to install, with less chance of stripping screw threads in the baffle. Other speaker manufacturers, such as AR and Advent, previously used Mortite or a similar material for speaker seals, but switched to foam gaskets. Similar to Polk, I don't think they switched to foam gaskets because the foam was better, it was just much easier to work with and there was no risk of cabinet damage.

I also inferred that Mortite originally didn't come in strips of pre-formed tiny cords that easily peal apart as it does today. Since MSP said they had to roll the cords by hand, I assume Mortite first came in solid blocks, which certainly had to be a pain to work with.

F1nut wrote: »

...My conclusion is that the rings and original gaskets produce better results than the rings and Mortite. Therefore, I suggest saving the original gaskets as you may want to reinstall them as I did.

This is good advice and I kept all my original gaskets in case I didn't like the results.


Such Good Gaskets. They are enjoying their retirement. One day in the future, when I am more dedicated to audio than I am now, I am
going to put the original gaskets back on one of my SDA SRS 1.2TL's and compare it to the Mortited speaker.:)

hearingimpared wrote: »

I've said this many times before, I can't see using a material made for rain gutter and window to be good to use on MDF. Just from speaking to people here and the statement made by anonymouse mortite tends to dry and tears chunks of MDF out if the need arises to have to remove the driver again. The PE speaker sealer I use doesn't do that, it stays pliable.

I have been using Mortite since Nov. 2008 with good results. No drying out, no cabinet damage...and I like the improvement in clarity and bass performance. However as with any tweak, individual results will vary. That is why it is good to get feedback from many people with different speakers in different environments.

TOOLFORLIFEFAN wrote: »

I have had no problems with mortite.. and it won't matter anyway as my gaskets are long gone..

Put a thin coat of Polyurathane over the MDF where the mortite is going to seal and call it a day..

The polyurethane seal is a great idea.

anonymouse wrote: »

I wish I had known about the speaker gaskets being adequate before I applied the moretite. On the CRS+ speakers, the moretite takes small pieces of the particle board out when the driver is removed after moretite is applied, so the original gaskets will not work any more.

The holes can easily be repaired with wood epoxy, then you can go back to the original foam gaskets.

I can see where the Mortite might cause problems with particle board cabinets, as they are prone to crumbling and cracking. See the problems I had when drilling my CRS+ cabinets to install rings here.

I recently added rings to two pairs of CRS+'s that were in storage. These CRS+'s had modified crossovers. One pair still had the original foam driver gaskets and no Dynamat or foam tape applied to the baskets, so I was able to compare a ringed/Dynamatted/Mortited CRS+ pair to a ringed/Dynamatted/foam gasketed CRS+ pair. The ringed/Dynamatted/Mortited CRS+'s had more tactile bass, more clean rumble and growl, and sounded "larger".

I had previously compared my ringed/Dynamatted/Mortited CRS+ pair (black oak veneer) to an unringed/Dynamatted/Mortited CRS+ pair (teak veneer) and noted:

DarqueKnight wrote: »

I put the un-ringed teak veneer CRS+'s in place. The sonic effect was analogous to dimming the lights in a room: Some bass details were diminished. Some disappeared. There was an apparent overall veiling of the sound and the apparent sound level sharply decreased. There was no difference between the sound stage dimensions and image placement of the ringed and un-ringed CRS+'s. There was a night and day difference in clarity, apparent sound level and bass performance.

DarqueKnight

zippty2001 wrote: »

man with all the mods for the SDA line i have a lot of reading to do before i start any lol my wife is getting a little upset with me i am getting a little obsessed lol

At least you are at home and are not getting obsessed with a girlfriend.;)

F1nut

anonymouse wrote: »

I wish I had known about the speaker gaskets being adequate before I applied the moretite. On the CRS+ speakers, the moretite takes small pieces of the particle board out when the driver is removed after moretite is applied, so the original gaskets will not work any more.

You can repair the damage with wood epoxy sold at stores like Home Depot. It comes in a clear plastic tube. You cut a little bit off, kneed it until both parts are mixed and apply to the damaged area. Use a putty knife dipped in water or the like to smooth and shape the epoxy. After it cures, you can sand, drill, paint it, etc. Great stuff.

heiney9

Where can you get original gaskets, mine were mostly dust and in extremely poor condition? Can you say disintegration.

heiney9

helipilotdoug wrote: »

I did the mortite and rings at the same time too. I have tightened the screws on everything 4 times over the course of a couple of weeks. That mortite continues to flatten out as time goes on, and requires tightening the bolts again. I'm sure one day I will feel the amount of torque needed to twist the hex driver will be the same as it was the last time after I tightened them down. All I can say is Thank God for Larry's rings! If it was not for them, smashing the mortite down like I have would surely have stripped out the screw holes.

I put the Mortite on my 5B's, no issues whatsoever with stripping the holes, not sure why so many are having issues.

H9

Toolfan66

heiney9 wrote: »

I put the Mortite on my 5B's, no issues whatsoever with stripping the holes, not sure why so many are having issues.

H9

Can you say "No Patience" even when I did mine before the rings, I took my time and I still could see a little wood splitting. "Not bad" but enough to bug me, Thats how the Rings came to life..

heiney9

TOOLFORLIFEFAN wrote: »

Can you say "No Patience" even when I did mine before the rings, I took my time and I still could see a little wood splitting. "Not bad" but enough to bug me, Thats how the Rings came to life..

Perhaps I got lucky, but I did use a lot of even pressure on the drivers to "seat" the Mortite, so perhaps that exercise flattened the Mortite enough that I had no issues. I also was very careful to tighten in a crossways pattern.

DarqueKnight

heiney9 wrote: »

Where can you get original gaskets, mine were mostly dust and in extremely poor condition? Can you say disintegration.

There was noting wrong with my gaskets, but I wanted to have a replacement source in case I ever needed it. I asked Polk's customer service about this and Matt Polk responded as shown in post #12.

heiney9 wrote: »

Perhaps I got lucky, but I did use a lot of even pressure on the drivers to "seat" the Mortite, so perhaps that exercise flattened the Mortite enough that I had no issues. I also was very careful to tighten in a crossways pattern.

Same here. no problems. I was also careful not to over-tighten.

gdb

Also, aren't there only 4 screws in the mid drivers? Why not add 4 more between them if you're really concerned with tightening them down....

I stated that that was my plan, it was met with much grunting and cowering...... sort of like when man first saw fire I imagine!:rolleyes::D

BTW, I also plan to use fasteners similar to the TeeNuts you posted a pic of, except they're a lot finer/smaller pieces that don't have the spurs on them.;)

Face

Except for drivers with odd shapes, all the stamped 6.5" drivers here have only 4 holes, I'm sure there's a good reason for it: https://www.madisound.com/store/index.php?cPath=45_228_256&sort=2a&page=1

fbm211

Nice drivers.

Polkersince85

F1's preferrence for the gaskets may be related to what MSP said about coupling the driver to the baffle yet still sealing the air. The old gaskets may be flattened to the point of providing a near mechanical connection of the driver and baffle.

Any mortite than squeezes out or does more than fill the air gaps may be a waste and causes additional stress on the fasteners, baskets and baffles. I have a feeling that folks are using way more mortite than needed.

heiney9

Bottom line: no one will know unless they try it. You can speculate all you want about how much is in use, etc.

I think the improvements are worth it, but then the gaskets on my 5B's were in rough shape. I used a single strand of Mortite and I have no adverse issues and the 5B's have never sounded better.

I conclude it's a worthwhile tweak.

YMMV

H9

hearingimpared

I don't know man. I have both the orginal gaskets (excellent shape) and PE speaker sealer on the MWs and PRs, really don't want to take 16 MWs & two PRs out to Mortite them! I'm going to install Larry's rings with the gaskets and sealer and see how it goes.

heiney9

Whatever you think works for you Joe. I'm not saying anyone is wrong or right or whatever, but until someone tries it they won't know.

I prefer it, or rather they are no worse off and to me they sound a bit better. That's good enough for me.

YMMV

H9

gdb

Well Hell......I'm thinking that I'll experiment with both Teflon plumbers paste & tape! (after a really good sealing/smoothing of the mounting surface) The seal should be as airtight as a pipe connection, with a thickness in the .001"-.002" range....... and be easily removable at a later time.

hearingimpared

I hear ya Brock and you know I am a great believer of trying things especially tweaks (drool).

I gotta tell you though when I used that PE speaker sealer to seal that 2' split in the seam of my 1.2 TL and that was a couple a few maybe years ago and it still is air tight an not vibrating, I'm sold on the PE sealer.

Toolfan66

My vote is Mortite. I won't be going back, my 1.2tl's sound freaking fantastic. I will be taking them down one more time to do the tweeter brackets, then they can just sit there looking beautiful and sounding beautiful till the day I die then someone else can play with them how they want too.

Bobsama

I did/am still doing a L/R comparison on my SDA-1's. I Mortite'd them a month or two ago and I can definitely tell that the mortite'd speaker (the left channel) has more bass response. To my ears, the left channel's bass is also cleaner.

TrashyTrucker

Hey all,
I know this is a older post but I got an idea...What about plumbers putty? When I worked in the plumbing field before I became a professional driver (some 20 years back), we used plumbers putty to seal drains etc. It (putty) will not harden, crack or peel, What do you guys think? It seals out water. You would just have to roll it out manually like MSP said they did with the mortite back in the day and use sparinly.

just checking, sharing.
Matt

DarqueKnight

TrashyTrucker wrote: »

Hey all, I know this is a older post but I got an idea...What about plumbers putty? When I worked in the plumbing field before I became a professional driver (some 20 years back), we used plumbers putty to seal drains etc.

This was mentioned in another thread. I don't know if anyone has actually tried this.

schwarcw wrote: »

Since the Mortite sticks, why not use plumber's putty?? It comes on a rope (or in a tube) and is very similar to the Mortite. Plumbers putty will seal natural gas in fittings. It stays pliable and is easily removed. I suspect it would work as a speaker gasket. Anyone have experience to the contrary?

inspiredsports wrote: »

It would be great if somone could conduct the same type of testing that DK has performed on Mortite with some of the newer, more pliable plumber's putties.