Speaker spikes on concrete or wood floor best?

Jedinite:

I have a similar setup to yours. I have B&W 803ds that have 2" Eden sound footers, mounted on a 3.5" thick maple plinth. Under the maple plinth I have 3" diameter Eden Sound long spike carpet footers that pierce my carpet to a wood floor. This system sound fantastic, much better than footers alone or stock B&W spikes alone.

I would not eliminate the plinth, as this acts as a second stage of vibration sinking to your floor. If you go footers right into the wood/concrete floor, I think your speaker sound will degrade considerably, as concrete is the worst material to sink into (as it reflects sound back up). You can try discs under the plinth spikes to protect you floor, but I am not sure how good those will sound. Is the engineered wood thick or is it the 1/4" Pergo type?

You might also want to talk to the folks at Maple Shade. They can give you some tips about mounting plinths over various flooring materials.

I did extensive listening tests with my B&W 803ds with respect to spikes, footers, and plinths. I started with the stock 803ds flat on the carpet without stock spikes. I them went to stock spikes through the carpet (although they never really got a solid connection to the floor). I then went to speakers (no spikes) flat on a 3 1/2" thick x 18" diameter solid maple plinth, flat on the carpet. Then I tried 2" Eden sound footers directly on carpet. Then I tried 2" Eden sound footers on the plinth, plinth flat on carpet. Then finaly 2" Eden Sound footers on plinth, with 3" Eden sound deep carpet footers from the plinth to the carpet.

The last configuration sounded the best by a large margin. I expected an improvement in bass definition, but was delighted to find a improvement throughout the audio spectrum. Vocals were especially nice, and the edginess and brittleness I used to have in some recordings was gone. Imaging also improved. Bass impact improved to the point where I have now plugged the vent ports on the 803ds to improve detailing of bass transients.

As an added bonus, the standing stability of these 803ds was also improved. They are much more stable and a lot less "tippy". On their stock spikes, the slightest nudge could send them arcing toward the ground. Now they are rock solid.

Studiosoundman:

A lot of what you say makes sense, and I found that the simple steel spikes that come stock on the B&W 803d to be essentialy useless. But I might not have discovered this had I not had the problem of the stock spikes penetrating my rather thick, dense plush carpet. With that carpet, I need penetration well beyond 1 1/4" to 1 1/2", due not only to the carpet but the thick underlayment pad beneath. To be effective, the spikes must penetrate to the wood flooring surface. Add to this the stability problem. We have earthquakes here in CA, and a little shaking can send these topheavy B&Ws crashing to the floor. Even bumping them during vacuuming can produce unintended consequences. Ever wonder how may G's that $1000+ diamond tweeter will take before its damaged?

So I was looking for a stability solution as well as a sonic one, and extensive conversations with folks at Maple shade and EdenSound convinced me of a number of things.

(1) Its not just the shape of the spikes or the material they are made of, but the MASS as well. Brass spikes intrinsicly coupled to huge masses of brass are best. If I could afford 2" thick brass plates under the speakers I would use them, but at the current cost of brass (and cosmetics), that solution is out of the question.

(2) Spikes have a sonic "diode" effect, transfering unwanted cabinet vibrations to the surface they are imbedded in. This can be a bad thing if they are in concrete, as unwanted reflections back up in to the cabinet are possible.

(3) The use of thick, natural wood platforms of maple have a damping effect, and give you added sonic "sinking" if sandwiched between groups of massive brass footers.

So in my final implementation I got the stability I needed with a sonic improvement I was not particularly seeking, but am happy with nonetheless.