Greetings, Denizens!

[RoyY51]

I have this little project going on and I am looking for some suggestions. I'm trying to find the most beneficial sound absorption/sound altering material that is available. This material will have to fit into 5"x5"x7" spaces. There will be 2, 3, or 4 spaces (depending on desired height), incorporated into stands under monitor-sized speakers. The spaces will be open front and back or side to side. I realize that 5"x5"x7" is not a big area to fill with something that will make a noticeable difference in sound quality, which is why I'm looking for the most effective material possible. Please don't bring up Shakti Stones or tuning forks...I'd like to keep this real.

Thanks in advance for your help!

[E-Stat]

Iincorporated into stands under monitor-sized speakers.

What are you trying to achieve by reducing reflections from the stands?

Please don't bring up Shakti Stones or tuning forks...I'd like to keep this real.

Shakti stones are EMF dampers to be placed directly above laminated transformers. They address a *real* problem. That's why we have R-core and toroidal trannies.

[RoyY51]

What are you trying to achieve by reducing reflections from the stands?


Shakti stones are EMF dampers to be placed directly above laminated transformers. They address a *real* problem. That's why we have R-core and toroidal trannies.

Actually, I was thinking more of bass absorption than reducing reflections...unless, of course, there is a more beneficial application that can be achieved in that small a space. At the moment, I'm thinking of stuffing Acousti-fil into beanbag-like pouches made of grill cloth and shoving those into the spaces.

Any further thoughts?

[E-Stat]

Actually, I was thinking more of bass absorption than reducing reflections...unless, of course, there is a more beneficial application that can be achieved in that small a space. At the moment, I'm thinking of stuffing Acousti-fil into beanbag-like pouches made of grill cloth and shoving those into the spaces.

Bass absorption is an acoustical challenge which takes very large traps to be effective. Stuffing small beanbags in the stand will likely have little effect.

If what you're looking for is mass loading to minimize resonance, you need sand or shot. While I haven't taken advantage of the capability, the hollow steel tube frames on the Sound Labs are designed specifically to be filled in that way.

[RoyY51]

Mass loading is not a problem...the stands themselves are cinderblocks. I'm coating them with a very thick pebbly, elastomeric substance and using thick steel plates top and bottom. The fill for the cavities is mostly for esthetics, but I'm trying to extract as much sonic benefit from them as I can. The unadorned blocks have given my speakers new life and now I'm trying to dress them up a bit, and at the same time wring every last ounce of audio magic from them that's possible.

I realize that this is just sonic chicanery on the cheap, but it keeps me off the streets at night. And who knows...sometimes the simplest, most obvious ideas have the most impact.

[E-Stat]

Mass loading is not a problem...And who knows...sometimes the simplest, most obvious ideas have the most impact.

Exactly. You need to treat your room next. Make some bass traps. I use a dozen in the dedicated listening room.

[RoyY51]

Sounds good...how did you make your traps and what materials did you use?

[E-Stat]

Sounds good...how did you make your traps and what materials did you use?

My solution has evolved over the years. The first answer is called the Jon Risch Quick & Dirty Bass Trap. It is simply stacks of tightly rolled insulation! While not as effective as other designs, it does work to an extent. Stack 'em high in the corners. I later had a sister-in-law sew some socks to cover them.

Quick and Dirty circa 2001

Several years later, I built improved versions using a different recipe: Tube Traps

Initial construction and placement

I ended up building eight 16" traps and four 9" traps. I followed the usual guidelines and distributed them around the room. When I moved into my current space, I did more experimentation and backed that with measurements. What I found was that I really needed to bunch the large traps behind my speakers for the most linear response. My situation may differ from yours since I use dipoles. Once again, I got my sister-in-law to make some Spandex socks for the traps.

Final placement behind stats

The other four are placed towards the rear of the listening room. My goal was to provide the smoothest bass response from the listening couch from 25-200 hz. The traps enabled me to get there.

[RoyY51]

Great info, E-Stat! I'd give you a greenie if I didn't have to "spread 'em around" first. You've definitely given me something to chew on.

[E-Stat]

Great info, E-Stat! I'd give you a greenie if I didn't have to "spread 'em around" first. You've definitely given me something to chew on.

You're welcome. Room treatments and proper speaker placement can make a huge difference in sound quality. While not exotic, I also treat the garage using DIY damping panels and nubby outdoor mats which minimize slap echo in an otherwise live environment.