Hi, Anthony,
Thanks for your reply.
When I type the command below, I got the error,
Unknown target hd-sound-install
make[1]: *** [hd-sound-install] Error 1
make: *** [hd-sound-install] Error 2
I found out that under /usr/local/freeswitch/sounds/en/us/callie/voicemail, there are directories, 8000, 16000, 32000, 48000 for recorded voicemail greetings. It should explain why at first FS played in right sample rate. But after playing serveral time, FS complained about sample rate not matching. Any clue? Thanks,