So… I’ve since purchased an 802.11g wireless Ethernet bridge (just a WRT54G running Tomato) and have connected the SoundBridge to it. Now I can operate the DIR-655 in 802.11n mode and everything connects together fine.
In either configuration though (with the new bridge, or with the DIR-655 in b/g mode) I’m experiencing a new problem. My networked music server will work flawlessly for a few hours and then suddenly will not be visible from the SoundBridge anymore. I have a feeling that this might have something to do with the way that UPnP devices announce themselves on the network so that they can be found by other devices. Is it possible that the DIR-655 might be resetting this information periodically, and the music server neglects to republish it?
This did not happen with my old WRT54GP2, though that router had its own suite of issues.
Setup:
DIR-655 => Ethernet => QNAP TS-209
DIR-655 => 802.11g Wireless => Wireless Ethernet Bridge (WRT54G w/ Tomato) => SoundBridge