[gregorio]

A proof, please.

Actually, the total dynamic range of 32bit float is 1528dB. The maximum value is +770dB (not as I stated ~+1500dB) and the minimum is -758dB. Still way beyond the +1 you stated and many orders of magnitude beyond any sound wave that can exist on Earth. Proof below, plus, castleofargh already provided proof with a practical example that exceeds your assertion.

"The largest number which can be represented is ~3.4 x 10³⁸, and the smallest number is ~1.2 x 10^-38. Doing the math:
dB_noise = 20 x log (1.2 x 10^-38) = -758 dB
dB_max = 20 x log (3.4 x 10³⁸) = 770 dB
The dynamic range that can be represented by a 32-bit (floating point) file is 1528 dB. Since the greatest difference in sound pressure on Earth can be about 210 dB, from anechoic chamber to massive shockwave, 1528 dB is far beyond what will ever be required to represent acoustical sound amplitude in a computer file.
There is one other aspect of 32-bit float files which is not immediately obvious. Files recorded with 32-bit float record sound where 0 dBFS of the 32-bit file lines up with 0 dBFS of the 24- or 16-bit file. Keep in mind that unlike the 24- or 16-bit files, the 32-bit file goes up to +770 dBFS. So compared to a 24-bit WAV file, the 32-bit float WAV file has 770 dB more headroom." - 32bit float files explained.

G