Can I suppress the beep from XFCE on logging out?

[Ralf Mardorf]

On Tue, 20 Oct 2015 15:34:00 +0000, Alan Mackenzie wrote:
>What is the beep trying to tell me?

I don't know, but I don't think it's useless. Perhaps it confirms that
all processes to exit a session exited with status 0 (ok) and perhaps no
beep or two or more beeps would inform you, if some processes exited
with another exit status (warning|error).

Regards,
Ralf