Spikes versus Rubber on wood floor?

Fiddler, I am an experienced builder as well as a licensed architect. I also have a minor in acoustics from MIT, and trust me, you don't begin to know whereof you speak, your limited personal experience notwithstanding. There are architects and architects; sorry you didn't find a better one.

As for your resonant floor, speakers coupled to the floor can't possibly move the floor for the simple reason that, except for down-firing subwoofers, transducers only move horizontally and floors only move vertically. So whether you say 'bounce' or 'resonate,' the floor would have to move; and if it doesn't, then perhaps the floor isn't the culprit; it could have simply been a standing wave between floor and ceiling created by an identical frequency peak in your previous system's response curve.

My guess, after all you've described, is that your new system's response is such that the natural room oscillation (standing wave) that got excited by the previous system, now doesn't occur.

Nsgarch, you could be right, but I doubt it since I fixed the problem with decoupling like many others have here.

I might not have a minor in acoustics from MIT and I also don't have an engineering degree either, but I can tell when my car is spark knocking and how to fix it from the experience of others. But I certainly don't need to tear the engine down!

The fact is, I did cure the problem in my room without having to tear my floor up or re-engineer the joists as you suggested. But I guess if you can't find a simple solution like decoupling there's always the big hammer approach, huh? And btw, being a licensed contractor doesn't mean you are an experienced builder. You know there are licensed contractors and licensed contractors!

And I anticipated your, "There are architects and architects; sorry you didn't find a better one.", after your, "apparently you have a very under-engineered floor."

From your attitude, it appears that you are the only competent architect around. Too bad everyone just doesn't hire you.

Fiddler, as in all professions, there are some incompetants, many bright ones, but few brilliant ones. The fact that your problem was solved with a speaker change and not with a construction project is what led me to my conclusion ;~))

Nsgarch, even though we "beat a dead horse" for a while, I do appreciate your willingness to offer your expertise. I have learned a lot from many like you here on the 'Gon who have always been eager to help.

And just as an aside, I don't believe "incompetants" is a word. But what do I know since I am not one of the...uh huh...brilliant ones :)

Whether to couple, decouple and dampen, etc., is determined by experiment. Theory does not help because whether any result is positive or negative depends on a wide range of factors. With a suspended wood floor, coupling will mean that the floor will be able to better act as a resonant sounding board itself. That is good, if you want some bass/midbass warmth, and bad if you want to tighten up the bass.

I personally use a Symposium Svelte shelf under my speakers. This thin, multilayer platform is coupled to the whole bottom surface of the speaker enclosure for effective transfer of vibrational energy to the platform. The inner layer then converts that energy to heat. This is an effective way or reducing the shaking of the speaker itself (generally not a good thing for sonics), and dissipates this energy instead of transferring it to the floor. This tightens up the sound noticeably, which is a good thing in my system.