In searching for the acoustic attenuation in Al. I found a massive (52 chapters) MIT book "Physical Acoustics" available free (govt. sponsored research). In addition to finding the above, it includes such as how to make a barium titanate low freq. resonator of manageable size (a slab 2.5 m thick would resonate at 1kHz), and phonon-electron surface wave interaction, to mode coupling in a vibrating string.
DSpace@MIT : Browsing by Subject "Physical Acoustics"
p.s. small rod electrostatically driven -- free decay Q (in vacua) ~ 10^5 reduced to ~ 1/3 in air (includes plot of Q (pressure). Drilling a hole reduces Q to 1/10, etc. [IIRC] Done also at low temps. to find electron - phonon coupling loss, etc.