"Bookshelf" is an unfortunate label that compact speakers acquired back in the 1960's with the introduction of Acoustic Research speakers (of course, it helped popularize and drive hi-fi, because AR's acoustic suspension designs enabled deep bass from relatively compact enclosures). But the label stuck, and it implies that any compact speaker may be placed on a bookshelf and the owner will get top performance.
Bookshelf placement ALWAYS compromises sonic performance somewhat. The reason? Designers work hard to minimize "diffraction effects"--cancellations and reinforcements of frequencies caused by the edges of the speaker enclosure. When you place a speaker on a bookshelf, the surrounding shelf and the front of the bookcase in effect become an extension of the speaker's front pane and enclosurel, and this causes response irregularities. Even worse is to recess the speaker on the shelf. Then you introduce a sort of horn-loading effect (try cupping your hands around your mouth and listen to the change in your voice and you'll hear what I mean) on the speaker and it will not be favorable.
BBIBH is correct. For background music purposes, shelf mounting is fine. But for a neutral, well-designed musical speaker, bookshelf mounting significantly compromises all the designer's hard work. So do try and use them on stands.
Regards,
Alan Lofft
Axiom Resident Expert
