Shoud I put Sludge over deamplifer pro

[Robahr24 10+ year member]

Plan on laying down a layer of deamplifer pro in my cherokee with spectrum sludge, should I lay down the pro, than the sludge or the other way around?

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[DBDRAGGUY 10+ year member]

I would lay the mat down last. I dont see it working very well the other way.

 

[Rudy 10+ year member]

You definitely want to put the mat down FIRST and then put the Sludge over that - although it shouldn't really be necessary. Damplifier Pro is very thick, both adhesive and foil. I'd be really surprised if adding Sludge made any difference.

 

[FoxPro5 5,000+ posts]

After using every incarnation of the Sludge and Spectrum products on multiple surfaces as well as DP, I wouldn't hesitate for a second to tell you to put the DP down first. Liquid deadeners are really an automobile pheonomenon - they aren't used extensively across industries, at least not that I have seen.

*edit* wholly shiza, Don is fast! //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[Robahr24 10+ year member]

Think I should just put down a layer of deamplifier and just not deal with the sludge than? Just looking to make the jeep very quite but don't want to spend too much money, which is most likely gonna happen anways.

 

[FoxPro5 5,000+ posts]

Think I should just put down a layer of deamplifier and just not deal with the sludge than? Just looking to make the jeep very quite but don't want to spend too much money, which is most likely gonna happen anways.

Add more vibration damper if the first vibration damper layer is vibrating. Typically one layer with something like DP is enough, but that's not always the case. The roof being the exception, maybe.

Once you've reduced the "buzz" of the panel/substrate to the point you cannot hear it anymore, than any additional layers or coatings just add mass. This is probably why people confuse vibration damping and mass loading all the time. They are not the same.

 

[audioholic 5,000+ posts]

For roof flex, Ive been wanting to experiment with stiffening with via fiberglass. Who says you need to increase weight to lower the roof's resonant frequency? On my blazer Im threatening to fiberglass the entire roof to stiffen it up, thereby raising the rez freq to a more acceptable level, while not adding all that weight over my head that will possibly fall off some day.

 

[FoxPro5 5,000+ posts]

Who says you need to increase weight to lower the roof's resonant frequency?

You don't.

It's amazing how one's rear view mirror will stay still after you take care of the transmission line of vibration going through the roof.

 

[audioholic 5,000+ posts]

Yeah, especially in suv's. //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

Not to mention, its amazing how much you can do to improve the factory's design flaws. My blazer has cross ribs every so often to stiffen the roof's sheet metal. Well, these ribs only contact in a few places from the factory, leaving large flat areas prone to waving/distorting. All it took was 5 mins and a partial can of spray expanding foam to compress the ribs and sheet metal together all along the whole length of each rib, and noticeably decrease vibration noise just from driving (let alone from bass vibrations). This is why I like to tell people that many times your best tool for sound deadening and rattling isolation, is common sense and a little stick-to-it attitude.

 

[PaulD 10+ year member]

The sludge is good for getting to areas you just can't get to with the mat. Even better for outside on the wheel wells and under the floor pan.