A sound diffuser for a ceiling speaker system having a downward-facing (when installed) flat disc cover plate and a flat barrel flange that assists in clamping a ceiling tile. The downward facing surfaces of the disc cover plate and a flat ring releasably attached to, and covering, the barrel flange are printable surfaces. The ring and the disc are magnetically attractable and are held in place with magnets. The ring and the disc cover plate can be rotated to align patterns printed on the ring and the disc cover plate to align to a pattern on the ceiling and to each other. Three-dimensional printing of the ring and/or the disc cover plate is included. The diffuser is preferably used in conjunction with the SMALL CEILING SPEAKER SYSTEM of U.S. patent application Ser. No. 15/710,654, the entire contents of which are incorporated herein by reference.