Low Sound Quality for Voicemail

We got our voicemail setup for inbound calls. Our receptionist sounds like she’s inside of a box, the unedited sound file sounds great.

How do I get the sound quality in my voicemail to sound decent if the FreePBX wav requirements shrink the file down to a low quality?

Are you asking about voicemail greetings played to the caller? Messages left by the caller and played over the phone? Messages left by the caller and sent as email attachments.

For the first, convert the file to .wav, 8 kHz sample rate, 16 bit, mono, confirm that it sounds good in your editor, copy it to
(replace 1234 with the proper extension number)
and delete other formats of the file.

For message playback, set the desired format(s) at Settings -> Voicemail Admin -> General -> File Format.

Hi Steward, I’m referring to voicemail greetings played to the caller.

The file is in .wav, 8 kHz sample rate, 16 bit & mono format. I’m using Audacity, it sounds ok before uploading to FreePBX. When I call the voicemail our receptionist sounds like she’s in another room.

How do you get audio files in this format to sound decent?

Does it sound bad even when you call from an extension? If so, does the Asterisk log show it playing slin format? You should see something like
file.c ... Playing '/var/spool/asterisk/voicemail/default/1012/busy.slin' (language 'en')

If it’s ok from an extension but bad when calling in from your mobile, perhaps your expectations are too high; the narrowband mobile codecs are not great quality. VoLTE sounds great but both technical and business limitations result in it being rarely available.

If it’s ok from an extension but bad when calling in from an external landline or VoIP phone, please provide details (trunk type and codec, etc.)

What do I type into Asterisk to see if it’s playing in slin format?

In the GUI, go to Reports → Asterisk Logfiles. If nothing is there, you may have been affected by this bug:

Re-enable logging, make another test call and view Asterisk Logfiles again.

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