Best compound to dampen enclosure?

[phase_accurate]

When you have your cabinets getting finished by a famous Swiss boat builder you may as well use a Swiss solution, which has some similarities to sand-filled walls but without the mess:


Hawaphone, the sound insulation from Korff AG

Regards

Charles

[Remlab]

Originally Posted by celef

I think the layer you apply to the inside must be dimensioned to the outer layer, i don not think it will only be effective with thin layers



i find bracing to work only around the area where it is attached, non braced areas are still hollow sounding



is this not a bit like cheating, like using a soft foam knuckle compared to a real knuckle, they will of course give different results but the panel has not changed its resonance character

Midrange experiment with Auto sound panel deadener and high density acoustic felt..
Look at my last several posts involving constrained layer damping.

[Remlab]

Originally Posted by celef

I think the layer you apply to the inside must be dimensioned to the outer layer, i don not think it will only be effective with thin layers



i find bracing to work only around the area where it is attached, non braced areas are still hollow sounding



is this not a bit like cheating, like using a soft foam knuckle compared to a real knuckle, they will of course give different results but the panel has not changed its resonance character

Celef..Hmm.. The name sounds familiar. ProAc? Or is that just a coincidence?

[Remlab]

If I were Stewart Tyler, I would choose a name like Celef to hide my identity

[markbakk]

The subject has been researched thoroughly, so I'll keetp it short. Mass, elasticity, boundary conditions and internal loss determine panel movement and amplitude of movement, panel size and shape determine acoustic radiation.
25mm HDF is not very well damped. The ratio mass/elasticity isn't really high either. It is quite heavy though, so any panel damping measurement has to be quite substantial. That is why I advised to decouple drivers. It can be really effective.

[celef]

Originally Posted by Remlab

Celef..Hmm.. The name sounds familiar. ProAc? Or is that just a coincidence?

oh no, its is pure coincidence

[markbakk]

Originally Posted by Remlab

Or is that just a coincidence?

Coincidence actually means something in acoustics.

[Remlab]

Yep. Sideways shot, oh well

[3wayaddict]

Well CLD with a box within the box is quite difficult and uses a lot of volume. An idea I have. Instead of the butyl damping, stick some very heavy plates to the walls with a very soft foam inbetween. Seems to me like this should dampen the walls very wel. Kind of the same as CLD. Except it's not a sealed box in side a box. PMC did the same with the outer panels on their flagship Fenestria speaker.

Decoupling the driver could also work very well though I'm afraid of doing it in practice on my speakers. I can imagine mounting the midrange on a soft damping material could compromise it's transient response. Also, such a system would have to be tuned very well to make it work in your favor and not against you. I can imagine that such a system could also make the midrange lose transient impact/attack and make it sloppy. So I'm kind of scared to put this in my own speakers where I only have one shot at it.

[krivium]

Hi,
It seems from this paper that some of your concerns shouldn't be if gasket is used on midrange box:

Linkwitz-Links

I share your thoughts about tuning but it should be possible to determine a working range if you know spec of material you use. For Sorbothane it is easy to find informations and help determining what is going to be needed for your case.
Then you use a dynamometer to specified torque when mounting drivers.

Maybe the way Linkwitz describe to mount the drivers ( by attaching them by the magnet, like you discovered by yourself when you prototyped your first box) is worth investigating too. It should help with damping of your box as a side effect too). It could be easier to implement than with a gasket for decoupling too.