[Wayne1]

While I had my passive radiator out of my Larger sub to treat with Elmers Wood Glue, I remembered an old tweak for stamped steel speaker frames. Years ago this was semi-common knowledge, but I don't see much mention of it any more.

The "tweak" is very simple and doesn't cost very much. It is fairly easy for anyone to do once they pull the passive or woofer from the cabinet.

All you need is a good sized roll of Mortite. You can also find a generic version in most hardware stores near the weather stripping area called rope caulk.

What the tweak consists of is covering most of the stamped steel frame of the woofer basket with the rope caulk. This will cut down on the ringing of the steel basket. The end result is better detail and definition, less smear, and a much tighter sound. This tweak can be used on ANY stamped steel frame speaker, not just VMPS.

Here is a picture of my Passive radiator and a semi sloppy job of adding the rope caulk:



Anyone coming to RMAF will be able to hear the results on my Larger Sub.

If you decide to try this on your own speakers, please share your results with us.

[Brian Cheney]

We do this with Dynamat Premium damping sheets, rather than rope putty, on the RM40 woofers and passives and the RMX woofers and passives.  It's tedious but worth the effort.

Your rosewood RM30's for the RMAF left yesterday and should arrive Friday.

[JoshK]

You actually stole my idea.  No but seriously I did think to do the same when I get to pulling out my passive.  

I have one minor cosmetic tweak that I did last night. It wasn't my idea, but I picked up a small jar of flat black enamel from the hardware store and with a small brush I painted the gold rivets on the neo panels.   I also painted all the heads of the screws.  

My wife came in when I was mid process and asked me what the heck I was doing.  I explained it to her and she said, "..but it didn't look bad".  I smiled and kept going.  When it was done she commented, "wow that really does look better, I wouldn't have guessed."   Well anyway, it is cheap easy and it is a nice cosmetic enhancement.  

Now I just need to find the right material to make terminal covers.  No black electrical tape is going to work for me.

[Wayne1]

We do this with Dynamat Premium damping sheets, rather than rope putty, on the RM40 woofers and passives and the RMX woofers and passives.  It's tedious but worth the effort.

Your rosewood RM30's for the RMAF left yesterday and should arrive Friday.

Dynamat most likely works better than rope caulk, but it isn't as cheap

Thanks for the update on the RM-30's. I will post photos when they arrive.

[JoshK]

Thanks for the tip Brian, I still have tons of dynamat left.

[TheChairGuy]

Wayne, et al,

Plast-i-Clay is cheaper than Mortite (like 1/3 the cost).....and is less sticky (your hands are less raw from kneading it around).  It also comes in colors (I don't think Gold tho, Josh   )

Works wonders.  Frank van Alstine wrote of it 20 years ago.

[KJ]

Would I be correct in assuming a cast frame emanates less ringing?  If so, does the cost of a cast frame outweigh the value of a stamped frame w/ damping sheets?  Just curious - not trying to pick on any designs.

-KJ

[KJ]

Following up on my last thought, is weight a concern with the frame?

-KJ

[doug s.]

Would I be correct in assuming a cast frame emanates less ringing?  If so, does the cost of a cast frame outweigh the value of a stamped frame w/ damping sheets?  Just curious - not trying to pick on any designs.

-KJ

imo, all other things being equal, a cast framed driver will outperform the same driver w/a stamped frame.  but, also (imo), the reason the vmps subwoofers far exceed the bass quality *and* quantity of pretty much any subwoofer out there at up to four times the cost, is that the whole is greater than the sum of the parts.  brian could possibly eek out a smidgeon better performance than what he has now by using drivers with cast frames, but the prices would likely be at least double.

re: your next question about weight, i may be off-bass here,    but i believe it's not so much the weight that's at issue, but you want the frame to be as rigid as possible, whilst also being small, so as not to interfere with the backwave of the driver.   which is why cast frames will generally outperform stamped frames.

doug s.

[BrunoB]

Wayne, et al,

Plast-i-Clay is cheaper than Mortite (like 1/3 the cost).....and is less sticky (your hands are less raw from kneading it around).  It also comes in colors (I don't think Gold tho, Josh   )

Works wonders.  Frank van Alstine wrote of it 20 years ago.

Even less expensive: the modeling clay from Dollar Tree store or Michael's :
400 gr for 1$, brand: roseart if I remember correctly.

I used  it to line the inside of my mid enclosure.

Bruno

[TheChairGuy]

Ah, good call BrunoB.  I don't have a Dollar Tree or Michael's near me...but for most in the US, these are readily available sources.

I found the Plast-i-Clay for $1.51 lb (450 grams or so) at http://www.allartsupplies.com/item.php?articleId=120

I bought Grey and Black.  The Grey was real Plast-i-Clay, the Black was a lookalike 1lb Mexican made clay from SMi, but it was not.  It smelled (literally, like crap), was very difficult to wash off and I felt ill for days afterward after it leached into my skin.  Stick with the grey if you buy from here..or better yet, confirm with customer service that grey is real Plast-i-Clay.

Incidentally, I used Mortite on many projects before reading about Plast-i-Clay and it works great (only a bit tackier on your hands - leaves them more raw afterwards on large projects).  It is usually found in the Paint Dept in Hardware Stores..tho sometimes elsewhere.

Edit/Additional: 10 years ago all you could find in Hdwe Stores was Mortite brand, but nowadays another competitor called Dennis, makes the same stuff.  It's called Dennis Rope Caulking Compound and sells for about the same as Mortite. It's about the same consistency as Mortite...not a big difference in that. Nationally, Ace Hardware stores carry the Dennis brand, I know.

[BrunoB]

Ah, good call BrunoB.  I don't have a Dollar Tree or Michael's near me...but for most in the US, these are readily available sources.

I found the Plast-i-Clay for $1.51 lb (450 grams or so) at http://www.allartsupplies.com/item.php?articleId=120

I bought Grey and Black.  The Grey was real Plast-i-Clay, the Black was a lookalike 1lb Mexican made clay from SMi, but it was not.  It smelled (literally, like crap), was very difficult to wash off and I felt ill for days afterward after it leached into my sk ...

ChairGuy,

Michael's has also an "artist" black clay but unfortunately it is much more expensive (< $4 a pound)

Modeling clay sticks well to the crossover parts (caps and coils). Be sure not to put clay on the soldering joints in case you would need to ugrade your XO.

Thanks for the tip Brian, I still have tons of dynamat left.

Here is a suggestion  if you have plenty of  Dynamat: it sticks well to the soundcoat of the main enclosure and to the wood of the mid enclosure.



Bruno

[zybar]

We do this with Dynamat Premium damping sheets, rather than rope putty, on the RM40 woofers and passives and the RMX woofers and passives.  It's tedious but worth the effort.

Your rosewood RM30's for the RMAF left yesterday and should arrive Friday.

Thanks B.

I have a lot of Dynamat Xtreme leftover from other projects that I could use on my dual Larger subs.  Looks like a project down the road...

George

[Jay S]

Great tip. I should try it on the woofers of my speakers and my sub driver.  

Here's another free tip: tighten the mounting screws of the woofers / tweeters of your main speakers.  Assuming the screws start off a bit loose, bass with tighten, highs will smooth out and the overall sound will get a bit faster and more coherent.  Just be careful since the magnet of your woofer will exert some pull on the tip of the screwdriver.

[mgalusha]

Another good use for the mortite and similar materials is to run a bead around the steel housing used on magnetically shielded drivers. Most of them ring like a bell if you tap them. Since they basically are a bell this makes sense. A bead of rope caulk or mortite does wonders to eliminate the ringing and costs only pennies given the amount needed.

[John Casler]

Great tweak!!

I remember using "modeling clay" on my Dalhquist DQ-10s back in 1979.

Most of the drivers were mounted freestanding on metal stands, which I could hear ringing (back when I could hear ) and taking a glob of clay and surrounding each of the stands stopped it.

Can't take credit for the idea though since I got it from a lot of guys who were using clay and mortite under their turntable platters to keep them from ringing.

Good call putting it on the woof baskets.  Crap, I've got 4 Largers, sounds like an all day sucker.