If the subwoofer cabinet is sufficiently dead, which I asssume would be the case for Velodyne's DD line, I suppose you could have a glass top made for the size table you'd like. Sorbothane feet inbetween might be of benefit. A couple of concerns that I'd have would be that the best location for smoothing out the in room response of lower frequencies might not be optimal for the coffee table location, and errant feet might damage the driver(s).

Cheers, Ian

Cheers, Ian

1: Roon on Mac Studio, G-Drive 10TB, 818v3, 7200.2, UHD722, LG 77G4
2. 808.6, 8kSE
3. 218, 3200's
4: Rivian R1T - 18 speaker 1200W Elevation by Meridian premium sound system
5. G68ADV (croaked), G98DH (also croaked), [HD621, Syles SL-S/PDIF, MD600 (2*4TB), QNAP 469L (4*3TB), MS200], Ayre MX-R Twenties, TBD