Axiom Home Page Forums General Discussion The Water Cooler Raising Subwoofers

After messing with heights of some M5 bookshelves and noticing the tactile impression change in my 2ch room I was inspired to experiment with raising my subwoofers behind the screen in my theater room. I have dual subs at a front wall 1/4 width setup with the face of the subs 28 1/2” off the front wall. This leaves 12” of space behind them.

I raised the subs to 37 1/2” to center of driver to match the tweeter heights on my diy towers in a WMTMW vertical configuration. I used cinder blocks stacked, opposing the direction with each course to add stability. The blocks are literally “rock solid” and the net wight of each stand is about 320lbs. It took 16 blocks to build two stands.

They are 3$ per block. Best upgrade ever.

I did not get the low volume tactile presence as I get with my M5s, but the low end is so tight and nimble now. I thought it was great before (and phase plots agreed.) I ended up watching a demo movie all the way through by accident. Music is really improved as well. It was one of those upgrades I didnt know my system had. You think you are top notch.... then you find another notch. Lol.

You will need to bump up your sub level a few db to account for uncoupling from the floor.

Highly recommended tweak if your system has allowances for hiding subwoofers out of sight.

Trevor, would it be better to leave a space between the floor and the sub with, say, four solid posts under the feet?

Strictly speaking, yes.

Putting more solid boundaries and objects between and amongst the LCR channels adds to the pile of unknowns when you are trying to predict an outcome. The end result is a couple of towers similar to the footprint of an EP800. I shifted them back of the plane of the main speakers to reduce any interference as much as possible by 5 inches or so. They are concrete, so they don't really store or absorb much energy (inert.)

You can use some 2x4s or other framing as needed to make the stands sturdy. In this case, I was basically 50$ plus taxes for the experiment and some sweat. More of a quick solution than a pretty one I admit. But they are behind a screen wall in this case.

I do not perceive the cinder blocks had any negative effect on sound quality. I think the little bit of overhang they eliminated by removing the floor loading really opened up the rest of the frequency range. Pretty sweet.

They make a square tower 16" x 16" when stacked with the honeycombs vertical.