We produce message-on-hold programs featuring music and voice-overs. We used to always use external players that connected to phone systems using an RCA connector, and they sound great. Now, several of our new clients would like to use their phone system's built-in on-hold capabilities. This requires us to compress the production to a G.711 u-law (8kHz, 8bit, Mono) wav file, which of course does not sound good (in particular, we get a LOT of sibilance!).

Does anyone have any tips to offer on how we can tweak the file before compression so that it sounds good when compressed? Any EQ settings, plugins, or such that you would recommend we run?

Thanks!