Coupling vs. Decoupling for Bass Response

Hi Marco,

You are correct that the pointed spikes are coupling your speakers to the floor and their vibration is causing negative effects such as directing unwanted vibration towards the equipment rack, your listening location, possibly to neighbors, etc. Much of the speaker's energy is being used to set your flexible floor in motion rather than is producing music. Not only is your bass response being compromised but much of the musical range is being affected as well. This is the case for all suspended wood floors and is a significant issue for many audiophiles. It is also an issue for concrete floors but not quite to the same degree.

The best method to deal with your issue would probably be more expensive than you have in mind but there are a few inexpensive solutions that will be helpful. If you mass load the floor under the speakers much of the floor's flexing will be minimized. Some other areas of the floor may also benefit from mass loading. You mentioned that you are on a loft so floor jacks under the joists is probably not an option. You should also decouple the speakers from the floor and from any massive supports (the exception would be a high mass support that is also highly absorptive). There are high quality and inexpensive compliant feet available that will accomplish this. You can contact any of the major audio suppliers for a specific recommendation.

Best Regards,

Barry Kohan

Disclaimer: I am a manufacturer of vibration control products.

It's not the speakers, it's Diesel the dog that's pounding the floor with his big paws.

Put tennis balls on each of his four feet and see if that helps.

By the way, I'm jealous that your studio is so much bigger than mine.

P.S. Barry and I are on the same wave length. When I suggested the heavy concrete pads, I didn't specify that they were to only go under the speakers, but I hope it was clear through implication. I would not suggest 1400 sq ft of heavy concrete as that would surely collapse your flooring altogether ;-)

Sorry for not responding earlier, but I seriously suggest paying a visit to the audio asylum boards. There you will find a recipe for DIY platforms in numerous shapes, forms and sizes, but the predominant ingredient is PEF, aka closed cell polyethylene foam. It is quite a hard foam, the only way I can describe it is somewhere between a mattress and rubber :) however it does wonders. The rest of the platform depends on budget, availability, aesthetics etc. Probably the best design is a sandwhich which consists of the following:
- 1/8" aluminium (mainly for looks)
- 1" MDF
- 2-4" PE Foam
- 1" MDF
- 1/8" aluminium

You can play around with the rest of the sandwhich but the main thing to keep there is the foam. Then on top of the sandwhich place your speakers on their spikes.

Cheers,
X

Hey X- You forgot the mayo and mustard! Where do you buy PE foam? That sounds like the same stuff Newbee was recommending that they use on hard floors - otherwise known as anti-fatigue mats...is that what you mean?

Albert, I seem to recall seeing some pictures of your studio renovations to accomodate your sound system....believe me, you have nothing to be jealous about!! I tried the tennis ball suggestion but he kept chasing his feet around and making even more noise!

Thanks all - Great suggestions!! I'll let you know what I come up with. As I said, the structural renovations would be most difficult and expensive so I think I'll start with the speakers and see where that leads me.

Marco