Bass Response and concrete floors

I had a pair of PSB Stratus Gold i's which I used both downstairs (concrete slab w/ carpeting) and upstairs (wood floor with carpeting). Bass downstairs seemed much tighter - punchier even. It was strange, too - downstairs (same room dimensions BTW) I could put them closer to back wall (3 feet or so). Upstairs I needed 6 - 7 feet or else they were your neighbor's kid's aftermarket woofer in the back of his Honda hatchback! Go figure.
As an organist I can tell you that the lowest pedal notes seem to have more punch in concrete floored buildings (yes, obviously different instruments in different buildings, but you get the feel for them after a while, and many are by the same builder).

I have used sub's on concrete floors with spikes. My experience is that the bass is tightened up and sounds very good. The floor gets rid of that flabby mid-bass and I know my sub went below 50hz.

Concrete is the BEST floor to have, period! I've lived in seven different houses and the best sounding room by FAR has been my concrete floored room (carpet covered). The inital transients are better, the decay is much more deliniated and the overall sound is way more real sounding. If you add a serious subwoofer to a concrete floored room, look out! You'll be floored (yes, pun intended!) by how well the bass couples to the room.

I think there are way to many audiophiles that are used to feeling the bass through their feet and their asses, and somehow think this represents "better" bass. IMHO they are dead wrong in their advice when they "dis" concrete.

I have to disagree that concrete is the "best floor". To me that's like saying solid state is the best amplifier (that might be true in some context--but not always). First consider that the speakers AND room work together to make up the listening experience. (of course all components matter--but these two are most significant in this context) How the speakers interact with the room is critical. Look at how much care goes into speaker placement--and it's not all about removing the room anomolies, it's also about working with them. For example, electrostatics must have a somewhat relfective wall behind them to create the imaging/soundfield.

The theory that concrete is best because it does not resonate or absorb base makes some sense, but not much. This theory needs to be taken into the context of the rest of the room. Bass losses are going to be much greater through sheetrock walls than from a wood covered (or pergo as I had mentioned) concrete floor. The concrete under the wood is great that it gives a rigid floor. Concrete as the supporting structure is probably always best. The best studios use concrete to support their floors under the speakers. But the whole floor is not concrete--it's wood. These are also rooms that use speakers with incredible bass response, which brings me to my second point. A non-resonating material (or one that resonates outside the useful audio spectrum) is also unforgiving. If you have near perfect responding speakers--then concrete might work. But again, the rest of the room has to be considered (more on that later). The speakers may need some resonance or warm reflection from a wood floor to sound their best. I think the guitar analogy mentioned above is a good one. The concrete in my opinion will be overly bright, but that is of course subjective and some people may actually like that. However, you don't see many symphonies playing on concrete floors do you? But you do have choral works in stone/concrete buildings like Westminster--hmmm??

The room and the speakers (or orchestra or choir) work in harmony. Westminster has highly reflective surfaces and very long delay times. It creates long delay times that decay relatively long (even with a large audience). But the first few decays are relatively high in terms of dB (only with a full audience). The result works very well for choral music--but you wouldn't want to hear a symphony there (neither would the orchestra players). Now examine some of the finest symphony halls. They also have long delay times, but try to attenuate ones beyond about 60ms as much (or realistically so) as possible. They don't want the echoic sound of Westminster--they want you to be able to hear every instrument. Why is this important when we are talking about concrete. It doesn't attenuate, and can create some real problems--but again, it must be taken into context of the rest of the room. It's possible that there is enough other attenuation, and that the relfection off the concrete does not create a "second sound image". Second sound images are reflections that are preceived as separate from the original sound that we hear.

So, in the end, I would not say that it is impossible to get good or even great sound out of a concrete floor, but it's highly unlikely to get the best sound with just a concrete floor that is not treated in any way (carpet, wood, or synthetic flooring--like pergo).

Abstract7: I would agree that bare concrete is suboptimal from an overall acoustics point of view. However, most concrete floors in homes or studios are going to be padded and carpeted, or covered directly with wood flooring without a subfloor (as mine are). Both these coverings work well. What is being disucssed here is the physical resonance of a suspended floor and the severe damage to frequency response and transient response that accompanies that resonance. There isn't a good-sounding studio in the world that has a flimsy, flexible floor. The huge advantage of concrete pads is that they drain the physical vibration of the loudspeaker cabinet into the ground, and prevent it from causing physical resonance of the floor/walls/ceiling. And that is all we're saying here. The reverberation characteristics of the room are a very important issue, but one that is totally separate from the issue of eliminating loudspeaker-driven, structure-borne vibration and resonance.

It is unfortunately little understood that the physical coupling between loudspeaker and floor can transmit MANY times greater sound energy into the structure than you could EVER achieve through airborne sound transmission. And if it isn't drained into the ground, it's going to reradiate from the structure back into the room. IMO, it is the job of the playback system and listening room to give you what is on the recording in as pure and noncolored a fashion as possible, and the only way to do this is to keep the room from literally being a sound source of its own.