best baffle damping material

[thadman]

I'm constructing a fullrange dipole (F/R HDS + 831882 + 2x RSS390HF) and want to make the baffle as acoustically inert as possible. What material sandwiched between mdf would provide the best damping?

Should I sandwich the material between every sheet of mdf or simply in the middle of the sheets?

Thanks, Thad

[BlueWizard]

Just to be clear, you want to sandwich some type of Solid Core material between layers of MDF. You are not talking about fiberglass or Poly-wool type dampening?

I'm no expert in this field, but the only thing I can think of to sandwich with MDF is more MDF. You could build out of 3/4 inch MDF, then glue 1/2 inch MDF to the inside. Plus laminate 3/4 with 1/2 for the front and possibly the back as well (or laminate two 1/2 sheets for the front and back). That would give on one big solid heavy cabinet.

It will be interesting to see if other have better ideas.

Steve/BlueWizard

[BHTX]

Green Glue?...
www.greengluecompany.com

Use it between two sheets of 3/4" MDF, then screw them together as needed.
Could use some other kind of damping material on the back of the baffle as well.
Other than that, I guess use as much MDF as possible to add mass?
Or, use expensive solid hard woods, which has its own disadvantages as well.
Anyone else? I'm interested in OB, so I'm currently learning and gathering ideas.

[Michail Bugaria]

Thick layer of sand between two thin sheets MDF

[el`Ol]

I built baffles out of polymer concrete feeding troughs (cuts had to be done with water beams). Nature`s equivalent would be sandstone.

[sreten]

Originally posted by Michail Bugaria
Thick layer of sand between two thin sheets MDF

Hi, beat me to stating the same answer, plywood is an option, /sreten.

[alain_online]

Hi all,
\

Originally posted by el`Ol
I built baffles out of polymer concrete feeding troughs (cuts had to be done with water beams). Nature`s equivalent would be sandstone.

El' Ol, is did you made and epoxy concrete ? And how does the sound is compared to a wooden panel ?
I've made some composite panels using molding technique (so no need to cut is) following the "opposite moduli" principle (epoxy+quartz+rubber --


Opposite moduli expoy composite ). The panels seem very inert, but I have not yet used it for making a flat open baffle, as I'm just finishing the wooden one.
All the best,
Alain

[el`Ol]

Hello Alain!

With wood you have more of the "paper cone magic", polymer concrete is more neutral. Here is my source:
http://www.durofarm.de/

[danny_66]

Here's a webpage from someone who did a research on different enclosure materials, you probably won't be able to read it because it's in Dutch, use a translator like http://babelfish.altavista.com/

http://www.hsi-luidsprekers.nl/Kastm...nonderzoek.htm

Don't forget the bracing !

[thadman]

The sand idea is intriguing, I may have to look into that.

Has anybody ever used 3M™ Conformable Sound Management Film Tape 9343?

Originally posted 3m's website
The unique non-woven micro fiber backing provides an unusual combination of performance attributes, such as conformability, elasticity, compressibility and durability. Excellent for noise reduction in automotive interior areas such as instrument panels and trim pieces by isolating offending substrates.

Keep the ideas coming! At the current moment, I'm planning on stacking 8 3/4" sheets of mdf together (thickness is necessary because each HDS is ~2" deep, so 2x2=4, >4") and sandwiching something in between.