Connie Terwilliger – ISDN Voice Talent

January 22, 2010

Lots of mu-law / u-law questions

Filed under: Business, Recording, Technology — Tags: , , , , — connieterwilliger @ 9:55 am

There has been an uptick in posts to various groups recently about a very standard telephony format called mu-law or u-law.

This is one of the most common telephony formats and there are several tools that can be used to convert to this format – PC and Mac.

If you are on a PC, then most of the audio recording software that professionals are using will do the job – I personally use Adobe Audition.

For Mac, Switch from NCH works well and is pretty easy.

If you are new to telephony – here are a couple of caveats:

  1. The sound files use a low sample and bit rate in order to play them back over the phone – they will NOT sound good to your ears when compared to a regular file
  2. Always capture at a regular sample and bit rate of at least 44.1 and 16 bit.
  3. Downsample to 8K
  4. Do NOT change the bit rate to 8 bit or your end result will have a LOT of hiss
  5. Use the conversion program to do the final compression to 8 bit

If you are going to be doing a LOT of telephony work, then invest in Vox Studio. It is not cheap, but it will save you so much time, it will pay for itself very quickly.


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