Low fidelity through IVM

[sharp2037]

I recorded some WAV OGMs but when I play them though IVM, they quality suffers. Sounds hollow and distant. I am not really sure what to do. I have played a lot with the settings in IVM for sound but it doesn't seem to make much difference.

 

Any pointers? How do you guys record your prompts?

[pythonpoole]

Because telephone lines are limited to 8 khz, all sounds that you import will be down-converted to an 8 khz format.

 

If you have some wave/audio editing software, you may consider recording or down-converting the file to 8 khz mono pcm before loading it into IVM and this shouldn't require IVM to make any changes to the way it sounds.

 

But yes, 8khz is pretty universal for telephone lines and it will sound much worse in comparison to your original 22 or 44 khz recording, but at least it gives you an idea of how the audio will actually sound on the phone.

 

The best thing to do is to record the prompts in 8khz format from the beginning, you'll find it will retain more quality. It's the same reason that many text to speech engines come in both a 22 khz (for normal speech) and an 8khz format (for phone prompts).

[sharp2037]

Thanks for info! I think part of it is the modem was not of the highest quality either!

[pythonpoole]

Yes, voice modems can vary significantly in quality from 'poor & a bit hard to understand, but ok for personal voice mail' level to 'full business quality IVR level' the trick is to find a higher end one for a reasonable price. I had an Intel chipset based Voice Modem that cost me about $35, the quality was great (in comparison to others I tried) and I had no problems (apart from Caller ID).

 

The best quality can be achieved using a professional telephony voice card/board. They are much more costly however ($200+)