First of all i’d like to say “Hi” to all people out here. Nice to finly join your community
Now the issue:
I’ve crated list of many .wav files with specific messages for my Asterisk including welcome message.
I’ve used sox to convert them to .sln with:
For once I honestly didn’t know that this is “on the fly” conversion, but issue seems to be something different because .sln file with 8khz sampling is played slow and in low pitch as well. It’s even more stange as Asterisk should natively support it.
You have missed the “-c 1” option from sox to force the file to mono.
Incidentally, .sln is also normally converted on the fly, but because there is no need resample, converting it to A-Law or mu-law is a fast operation. Ideally you should have multiple copies, one for each codec actually used by the phone system.