[DanDan]

The Fallacy of ignoring the two Bass Octaves has been pointed out over and over again. The wood is not rigidly mounted. Even in those dubious figures, (Lino, Cork, jeez) the Absorption coefficients show the largest difference at LF, so the actual difference between actual installed wood and actual concrete will probably be big at LF. Fletcher Munson will not iron out
You chose to ignore the relevance of below 125 Hz in music, with this rigid slab justification.
Wood is never securely glued to concrete with say epoxy or whatever. There is a damp issue. This rigid slab sandwich is not of this world. Wood is normally resiliently mounted and will vibrate at LF unlike Concrete.
Can you describe to me the sound of a Jazz Trio omitting below 125Hz?

The term Building Acoustics as commonly understood over here is focussed on Noise issues. The term Architectural Acoustics is used when it comes to Theatres, Studios, Concert Halls etc. I have explained that those coefficient type measurements come from the world of Building Acoustics. Thus the restricted spectrum. In BA practice even those figures are simply averaged to derive an RT figure. This is used to calculate Noise issues. It is well recognised that these historical restricted spectra are inadequate, and progress is being made. I believe you would find much better private sets of coefficients gathered from actual Halls and Studios, measured with and without the installation of materials, seats, etc. in the world of Architectural Acoustics. As before, Sabine calculations are notoriously divergent with measured reality and do not apply in non diffuse environments. They may be used to get to the Ball Park, but they won't get you in.


I think many of us have explained already why we will not accept Reflectivity or any other singular measurement to describe tonality. That is a bit like saying that Frequency Response alone can describe the sound of speakers in a room, omitting all else. If you want to advance the discussion we need to leave that behind unless you can prove your case or refute ours.
Similarly changing the goal posts won't pass muster. The original statement was that Concrete and Wood, for practical purposes sound the same. Later restricting that to tightly defined issues of Reflectivity only, in a limited spectrum, on a rigid slab, not in a structure, is simply not fair play.

I am pleased to note that your 'proof' has shifted from absolute to qualified, i.e relevant over the 'majority' of the range. :-) However I don't think that you can call those six octaves a majority, certainly in terms of music. For instance, when mixing, using Eq in those missing octaves is very powerful. Smiley curve. Or back to the Jazz Trio with no bottom two strings and no cymbals :-)

If polished and varnished Hard Wood has a much higher Reflectiivity than acid stained Concrete in the 8kHz Octave, and I suspect it has, I think even you would concur that it sounds different?

Till Tomorrow, DD