DIY Speaker Isolation Platforms

Posted by: ErikL on 28 November 2003

The weather is raining and there's beer. So, today I'm beginning a little DIY speaker isolation platform project.

I have bouncy, uneven, carpeted floors, with pseudo concrete below, so the sound should improve. My plan:

- Use 3 concrete anchors, 3/16" x 1-3/4" with flat philips head, in a triangle pattern per speaker
- Set a stainless ball bearing atop each anchor (these have not been purchase; I wonder what size to use?)
- Set 10" x 12-1/2" x 1/2" MDF atop each screw/bearing combo
- Set 3 nuts in a triangle pattern atop each panel of MDF
- Another round of ball bearings
- Another round of nuts
- Another panel of MDF
- Speaker stands atop all of this
- Level it all (by adjusting the anchors)

If it works, I plan to break the edges of the MDF, paint the panels flat black, and glue slightly oversized nuts to the MDF in the preferred position (my idea to prevent earthquake damage; my other idea is to eliminate the nuts and drill recesses into the MDF, domed if possible).

Based on similar DIY projects, what are some thoughts or advice out there? Pics would be cool too!

(PS- All of this is necessary as I didn't like the spikes atop screws setup)
Posted on: 28 November 2003 by ErikL
Another question (possibly for Tom Alves, whose design idea I borrowed):

With 2 layers of MDF, is all side-to-side rocking eliminated? I assume yes, if the floor screws are 2 front and 1 back and the bearing/nut combos are 1 front and 2 back?
Posted on: 28 November 2003 by Rasher
I used 6mm ball bearings.
What speakers are you using, and what improvements to the sound are you after? There seems to be a whole range of effects to be had in my experience, and they are not all good!
Posted on: 28 November 2003 by ErikL
I'm using cheap speakers that shouldn't be mentioned on any high end hifi forum. I suppose the good thing about a cheapie system is that effects will likely be much less profound than with a high end setup.

My project is more about providing a level, solid base for my speaker stands than it is about sound quality. I also want to rid of some of the floor rumblings that wave to and fro (the spikes atop screws and screw/coin combos didn't solve this). My spikes are too short for both the carpet and padding, so before any tinkering I had uneven, floating stands (thus mediocre timing).

My god this is a nerdy project.
Posted on: 29 November 2003 by ErikL
DIY Alpha v0.5

I think this shows just how poorly things were previously set up (I did not expect a huge difference):

I have screws in the floor, one MDF atop each set, speakers on top, and all leveled. Wow. I have to conclude that what I was listening to before was a muddy mess. Timing is worlds better, and there's a significantly higher level of clarity at all frequencies. For example, on track 1 of Grandaddy's "Sumday", I can now hear some neat cymbal work in the left channel during the chorus. I never heard this before. There's also better articulation of instruments, instead of a jumbled delivery. The overall sound is also more forward, which I like. The only downsides I can see are the bass seems thinner (but more precise), the floor rumbling still exists (but decreased), and there's a slight bit of sibilance. The pro's outweigh the con's so far.

I may or may not get out for balls and nuts today. But when I get everything, I'll report back.
Posted on: 12 December 2003 by ErikL
Update

I've been running my speakers on this inital MDF-screws setup for a few weeks now. At this point the sibilance is killing me. It's overbearing on the majority of my albums.

My speakers are currently toed in, and I suspect this is contributing to the sssssibilance. I will do some more drilling, and set them up without any toe-in soon (after I receive my new CDP, assuming that doesn't rid of it).
Posted on: 14 December 2003 by Stevea
Sounds like an interesting project, if not something to be contemplated in an earthquake zone.

After reading about concrete and stone slabs somewhere in this forum I decided to try some concrete paving slabs under my speakers, instead of the spikes into screwheads into a carpeted wooden trampoline. The slabs have not moved since. They are about 450mm x 450mm x 45mm. While I was hoping for, and got, an improvement in the base I noticed most benefit in the midrange. There was no downside in my case but if your midrange was already a bit shouty you might not like the result.

Steve
Posted on: 15 December 2003 by Rasher
Ludwig - Sibilance and lightweight bass was one effect I had when I found that I had set up my Mana Soundbases incorrectly. It seems worlds apart from the effect you really want, but you really are only a tweak away.
IMHO, you may have nailed the floor interface, but either the stand is slightly rocking on the new platform, or you need to try concrete or marble in place of MDF as Ghunter says. (Didn't I race you once through Vermont on a rat bike once in early 90's Ghunter? Wink). My personal bet is that there is a very miniscule rocking of the stands.
Posted on: 15 December 2003 by ErikL
Rasher, I think I'll do some testing with 4 screws beneath each stand base instead of 3.

Didn't Tom Alves have a lot of comments on his tinkering with 3 and 4 screws, balls, nuts, etc? As always, the search engine isn't turning up what I once found.
Posted on: 16 December 2003 by Rasher
I think 3 balls are better than 4, its the speaker stands themselves that I would focus on. Its those spikes that need sorting I think. Can you set up the stands with the speakers removed? and then do the edge lifting thingy to get it perfect?
It may be that you don't like the effects of the MDF and need to try another material.
Posted on: 16 December 2003 by ErikL
I can indeed set up the stands with the speakers removed. What do you mean by "edge lifting thingy to get it perfect"? And what do you mean by "its those spikes that need sorting"? Sorry.

Considering (as I should have originally) my setup last night, I should have place the two screws under the back of the stands, not the front. The speakers don't sit centered directly above the stand bottom plates, but the speakers' center of gravity is behind the center of the bottom stand plates.

With your input and some of my ideas, I think I'll tinker this weekend.
Posted on: 17 December 2003 by ErikL
No worries Tom- I eventually found the thread where you shared a lot of your experiences.
Posted on: 17 April 2004 by ErikL
Update

Yesterday I finally placed 4 nut-ball-nut combos about 0.75" in from the speaker stand spikes, threw down the second layer of MDF, placed the stands on top, and pressed play. Oh, before I go there- my new CDP rid of previous sibilance problems.

Okay... Either the fog lifted between the speakers and I or the fried egg sandwich cured my hangover (quitting ended). The mids were a bit clearer and the mid-bass (and below) was more tuneful. The greatest effect was on the top end, which had more clarity. I suspect Rasher was right about some wobbling going on before. This second level seemed to make the whole thing more rigid, so I'm pleased.

In a few months, I'll probably (finally) find balls small enough to place on the concrete anchors so I have anchors- balls- nuts- MDF- nuts- balls- nuts- MDF- stands.

In the meantime, I recommend this cheap DIY project to anyone with rocking/floating stands or speakers on thick carpet/carpet padding.