Dynamat inside ML woofer cabinets?

MartinLogan Audio Owners Forum

Help Support MartinLogan Audio Owners Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

asindc

Well-known member
Joined
Aug 4, 2005
Messages
396
Reaction score
0
Location
Washington, DC suburbs
Has anyone done this? I'm considering lining my Spires with Dynamat (or a more suitable alternative, if such exists).
 
In my opinion you're not going to get any (better) results. These types of materials help dampen vibrations of rattling panels and help with some sound insulation. I did some car audio before and I can't think of any meaningful use of dynamat (or equivalent) in hi end home audio, let alone inside properly built woofer box.

The way I see it is this: you use dynamite inside a car. For hi end home audio you would do acoustical room treatment. Same concept

My $0.02
 
I don't know if it helped but I used it on the inside top of the interfaces of my CLSs when I rebuilt them.

I have seen pictures of DIY speaker builders that use it to line inside of cabinets. Dynamat or a product I think is called Black Hole to line cabinets is worth a try.
 
Anthony,

I lined my SL3 cabinets and my Polk Audio sub with "Road Kill", which is a more robust version of Dynamat.

Totally audible and well worthwhile.

Any reduction in vibrations, be it cabinet or otherwise, is always a good thing unless something is "voiced" using cabinet vibrations. There are some speakers out there that are actually designed this way. :confused:

Highly recommended.

GG

PS: Also recommend putting a "strip" on each of the radial driver basket "ribs".
 
Last edited:
Anthony,

I lined my SL3 cabinets and my Polk Audio sub with "Road Kill", which is a more robust version of Dynamat.

Totally audible and well worthwhile.

Any reduction in vibrations, be it cabinet or otherwise, is always a good thing unless something is "voiced" using cabinet vibrations. There are some speakers out there that are actually designed this way. :confused:

Highly recommended.

GG

PS: Also recommend putting a "strip" on each of the radial driver basket "ribs".

Gordon,

Where did you find Road Kill?
 
Steve,

Agreed. That's the one Tony should buy.

Good price. Their "thickest" product / 0.08" vs 0.056". Right size quantity.

Tony, I see we have the same CDP.

Gordon
 
Pyramide or egg crate type foam treatment is meant to absorb the sound, it will NOT work inside woofer cabinets.

As far as dynamat and/or similar damping materials, well, unless your woofer box is made of something like 1/4inch think panel then it will NOT work either. Odysseys and Ascents are made out of 1inch think MDFs to give you an idea. Any vibrations of the (properly build) woofer cabinet would be caused by the mass/inertia of the woofer's moving parts, not the enclosure panels "flexing" (resonating). This is exactly why Descent uses evenly opposing woofers, instead of one woofer + tons of dynamat type material inside. That's how they cancel out those vibrations.

The damping materials you are talking about are all meant to decrease the resonance of the panels, but are not meant for woofer enclosures because these are built properly from the get go. The reason why dynamat and like materials are used mostly in car audio, is to take care of the panels that the woofer box design doesn't have control over, That's large area sheet metal that loves to resonate like a hell. Just push with your hand on the doors of your car to see how much these flex. Now, does your woofer cabinet panels flex like that? Not even close.

So again, it's not the enclosure panel's flex/resonance on your ML speakers, as much as (tiny) "movement" of the entire cabinet. In such case you'd be better off pouring lead to the bottom of the cabinet or adding any other type of extra weight to it like a piece of big and thick granite. Or screwing the cabinets to the floor...

One way or the other, those damping materials will NOT work, I don't know what kind of improvement some other members "heard". You'd be better off treating your room or simpler yet, start playing with the woofer cabinet placement. Oh, and put those spikes on if you haven't already, they help minimize enclosure movement.

The concept of using damping materials inside electronic equipment with moving (vibrating) parts (like CD player) is a totally different idea and does not compare to the above mentioned woofer cabinets.

But in the end, it's your time and money.
 
Last edited:
What I heard was quicker, tighter mid / low bass with less "overhang", improved pace and better sonic integration between mid - low bass notes as well as the panel and the woofer.

Kinda similar to installing spikes.

If that qualifies as "not working" so be it, but I suggest you give it a try (if you have not) before passing judgement.

And yes, I also treat my room, installed Mapleshade brass cones to replace the factory supplied spikes,and put a custom cut piece of 1" granite on top of the SL3 woofer cabinets to "weight" the cabinet.

Cumulative impact of all these "tweeks" had a substantive, positive effect on the speaker performance. Of course, YMMV depending on how articulate and transparent your "entire" system is.

GG

PS: I would also question your assertion that all woofer cabinets are properly constructed from the get go. IHMO, that is simply not true as witnessed by the wide variety of materials, thickness and bracing used by various speaker manufacturers.
 
Last edited:
The biggest offender with a woofer box -- after the passive inductor(!) -- is the garbled low and mid range rear wave energy bouncing back out through the cone, so adding more box stuffing does help....
 
That's changing the design "Q" factor, which is another performance issue and independent of cabinet vibration / resonance AKA ringing problems.

GG
 
Gordon,

Not "all" cabinets are built correctly, but the high end ones for sure and I think that Spire qualifies. The "tower" type speakers are more challenging in that matter since wall panel area is bigger and to prevent their flex, one needs to increase panels rigidity. And that can be only accomplished through stiffer and thicker panel materials (costly and not always practicable) and/or bracing.

Weight on top of cabinet worked for SL3s, won't work on some others (like Ascent/Odyssey) that have sloped boxes. That's why I mentioned about putting slab or pouring lead (joke) inside the box. That's a logical solution to a moving box not it's panels flexing. Same with damping material as it will keep "jumping" together with that box. As I mentioned earlier, Descent is a perfect example: no need for dynamat if the wall panels are rigid and forces are balanced. It's as simple as that.

In car audio, where dynamat type materials are used extensively, they help overcome two issues: exterior (road) noise and metal sheet panels' flex (rattle). But to fight that rattle nobody in their right mind would apply dynamat to the woofer's box, right? If we agree on the fact, that it's not the Spire's panels that are flexing, rather the entire box moving, then why wasting time on a solution that defies the logic?

Cheers
Greg
 
Hi Greg,

The Spire cabinet may well not need cabinet resonance improvements.

I personally don't know. I do know what I heard with the SL3 after installing Road Kill and a couple of other mods.

I hope Anthony tries and reports back on results.

Bottom line as I stated previously. I have taken steps in my system to try to eliminate any and all vibrations in everything to the extent practicable and it has yielded audible performance improvements. My philosophy with this and other mods is if one spends "x" dollars and the investment yields a doubling, tripling, etc. "jump" in performance, then it's money well spent.

One of the best examples is buying the appropriate hardware to adjust panel azimuth to perpendicular versus "laid back". The ROI is through the roof.

Best,

Gordon
 
well, if you applied these mods at the same time, I wouldn't give much (if any) credit to the damping mat itself. Seems like other mods played key role.

out of curiosity, what "tilting" hardware do you have in mind? it's been a really long time since I had SL3s (my first MLs ) so don't remember how much tilted towards the back they were, but my Odyssey and Ascents' panels are fairly vertical from the get go and there is some additional room to maneuver around that with the spikes. I've noticed that the newer breed of MLs have their panels more "laid back" indeed.
 
Greg,

I always install and listen to one change at a time to hear (or not hear) the impact. And I typically listen to each change for a week or two to determine efficacy. Such was the case with the SL3 mods I described. In fact, the process took several months if I recall correctly. I think I started with installing the dampening material, then installed the Mapleshade brass cones, and then played with "weighting" the top of the woofer cabinet.

Yes, I am talking about spikes that can bring the panel azimuth to 90 degrees without compromising speaker / floor interface coupling. Another way of saying is not to "shim" the back end of the speaker for the final install but this is a good way to get an idea what azimuth adjustment can do for the sound.

With the Summits, I ended up 2 degrees shy (back tilt) of being perpendicular.

Gordon
 

Latest posts

Back
Top