Actually, it probably is the speaker. Both of mine developed same
problem and other owners have reported same. There is a $1 replacement
speaker available I was able to find. About a 30 minute repair
job....most of which spent trying to get the case apart.
Makes a world of difference.

You can hear the results here.
http://www.acidplanet.com/artist.asp?PID=673036&t=5098
just hit play.




wrote:
Hello rec.radio.shortwave group - I'm selling a DX-398 with the mod
that increases antenna sensitivity and the AC adaptor, and a Sony
AN-LP1 antenna. Both pieces are about 5 to 6 year old and I've used
them at home and when traveling. I'm the orignial owner and I have the
original boxes and documentation. The DX-398 recently developed an
audio problem that sounds like the speaker is being overdriven;
however, being that the radio is not abused, I suspect the solution
lies in the circuitry and not the speaker. Someone with more
electronical skill than I can probably resolve the problem. This is a
nice combination and I'd prefer to sell them together. I'm in Atlanta.
Tom -