[giankam]

Hello,

I tried to  build a limp mass absorber but I didn't have much luck.
This is what I did using tecsound t50 (very similar to mass loaded vinyl 5kg/m2, 2,6mm).



I put it in the corner where modes are stronger and after testing with rew I can't see any particular improvement.

I guess I did something wrong, even though the membrane is floppy and limp as supposed to be.
How could I improve it?
Thanks

[Big Red Machine]

Not an expert, but I do play one on tv.  To the best of my knowledge, the bass waves, being very long, need "mass" of significant depth to slow them down and change their "speed", so to speak.  I would imagine that a thin piece of dense material you have matches up with some natural frequency it can attenuate and that most certainly would not be 20 hz, for instance.

And now the experts will course correct....................

[Ethan Winer]

I guess I did something wrong, even though the membrane is floppy and limp as supposed to be. How could I improve it?

A piece of floppy plastic in the corner of the room won't absorb bass all by itself. The correct way to build a "limp mass" bass trap is to bond the membrane (spray glue etc) to a slab of thick rigid fiberglass.

--Ethan