greenfelt in basstraps

[SCDBM]

does anybody have experience with greenfelt/laminate underlayment for use in basstraps, i was thinking of sandwiching 20cms of rockwool 211 between 2 of these plates as they make nice stiff traps en have a contact noise reduction of 19db

or would this material be too hard/dense and just turn the trap into a reflector rather than an absorber?

[jhbrandt]

There is no information on this product for the use you intend.

The stated 19db noise reduction is for impact or IIC rating and has nothing to do with air born transmission. The 19db may only be an assumption by the manufacturer & marketing hype as well. Check for independent testing data.

I wouldn't bother putting it into the bass traps, IMO. Though, I don't see where it could hurt as long as it is inside the traps and not on the surface, facing the room.

Cheers,
John

[SCDBM]

Thanks John, so if i read u correctly it might reduce the effectiveness of the rockwool if placed on the front, because it's too dense? but it doesn't matter if it stops the waves from travelling through the traps at the rear end? sorry if my wording is a bit weird, but not sure how to describe it properly otherwise. and i wouldn't look at much for broadband absorbtion, but more focused on the <200hz range

[SAC]

Unfortunately it will not help with broadband or bass trapping.

[SCDBM]

That's clear, but will it hinder the performance of rockwool based basstraps if placed in the back end of the trap?

ofcourse the answer is try and measure, but it will bring quite a mess in my studio just adding them and then have to remove them again.

[avare]

Originally Posted by SCDBM

That's clear, but will it hinder the performance of rockwool based basstraps if placed in the back end of the trap?

ofcourse the answer is try and measure, but it will bring quite a mess in my studio just adding them and then have to remove them again.

You have received the correct answer from John.

In other words, we do not know exactly what the effect will be. The path to take you detailed the second paragraph quoted. Try it and find out. If you do, please post the results so that we may all learn from it.

Andre

[SCDBM]

ok will do that and let you know, however a as take ahead "theoretically" does too high density obstruct trapping low frequencies?

i.e. how do do these rubber/foam cubes work.

[SCDBM]

so i did some quick rew measurements last night with panels on the front AND back. compared to none it seems that it absorbs less at higher (>300hz frequencies) but it also narrowed a cancellation around 150hz with nearly 5db

I guess it's purpose could be tuning, emphasizing the low end on trapping.

going to try to see if there is a sweetspot (back and front maybe stacking a few of the panels, see if i can find some trendline or correlation

[avare]

Originally Posted by SCDBM

so i did some quick rew measurements last night with panels on the front AND back. compared to none it seems that it absorbs less at higher (>300hz frequencies) but it also narrowed a cancellation around 150hz with nearly 5db

I guess it's purpose could be tuning, emphasizing the low end on trapping.

going to try to see if there is a sweetspot (back and front maybe stacking a few of the panels, see if i can find some trendline or correlation

Thank you for the report. What are the locations, material used and the dimensions of your traps?

Andre

[SCDBM]

square block traps are in each corner (60 * 100 * 60 ) (= 6 rockwool 10cm 211 panels stacked)

and 2 additional traps of 60 * 20 * 100 (each 2 211 plates stacked)

I've applied the felt on each backend of the corner traps by default
and had none in the seperate 60 * 20 * 100 traps

for testing i added the felt to the fronts of all corner traps and front and backs of the 2 seperate traps

first goal was an easy way to insulate the rockwool
2nd goal was to stiffen up the seperate traps

so added bonus seems to be the behaviour mentioned above