For a DSP speaker setup you can leave it on max.

For an analogue speaker system, it's only relevant for speakers designated as 'large' in your setup. Since the 'size' setting is a form of bass compression, personally I don't use it for music it and try to be sensible with the volume control. For movies, I use a cross-over on all my speaker and send the bass to my sub.

Edit: I think the only circunmtances in which I would use a size setting (which is for speaker protection from damaging bass) is using my system for movie listening without a sub.

Last edited by Cliff.; 2012-10-11 03:14.
Main system - Sources (Kodi-HTPC, Vero 4k, FireTV, Sat) into Trinnov Altitude 32 (8-16) (+Roon), Trinnov Amplitude 8 amp & Vivid Audio (Giya G3, V1.5) and REL Stentor III speakers. Others: F80 + Raspberry Pi and other Pi systems.