Hi All, I dont know if this is the right forum to post this but here goes.

A client of mine is asking for a Voice Over project to be output as a u-Law 8bit 8khz.wav file for their companies telephone hold system.

A few questions: 1) Is there a certain level not to exceed when finally bouncing these type of files (e.g dont exceed -10dbfs or it will distort).

Also an average RMS level 2) Do you use dither from 24bit 48khz to 8bit 8khz or will it just add more noticeable noise to such a low bit rate 3) Quicktime can do this but not as a.wav file.

Any other programs Anything else I should know when dealing with this file format Thanks alot for your time.

You can use Barbabatch V4 for this, an excellent program for many things.

I wouldnt be surprised to find that Audacity can also handle this format as it was supported on quite a few of the older editing programs like Goldwave or Turtle Beachs Wave.

For those who dont know, A-law u-law are compacting schemes used in telephone network to get more dynamics to the 8 bit files that is available with linear coding.

Typically 1214 bit (linear scale) sampled at 8 kHz sample are compacted to 8 bit (logarithmic scale) for transmission over 64 kbits data channel.

In the receiving end the data is then converter back to linear scale (1214 bit) and played converted back.

SF9 here, i dont know about earlier versions, never done that before.

I felt the same about dithering for this.; when you ear the final result in fact, theres a few things you dont care about this is well lo-fi, i dont know this market very well, but i wonder if there is some better format handling within those vocal servers i guess if its still that spread maybe its due to investments inertia.

IN my day job I am a telecom engineer and work with this stuff all the time.

Roll off everything above 4k and below 300hz before down sampling.

I would also verify that they MoH system truly uses wav files - many use VOX files.

That said, it may not make any difference to some of the tiny telephone receiver speaker, I dont think, but those using headset would notice the quality.

App For 8Bit Ulaw Update Findings For

I found this post with google and thought I would update findings for the next person looking for answers.

Audacity 1.3 handles this very easily.

Here is a tutorial with instructions.

App For 8Bit Ulaw Windows 7 With Audacity

CUCME: Create an MOH audio file in Windows 7 with Audacity.

If you have Windows XP you can use sound recorder, a basic windows application to convert your file, but on Windows 7 it does not convert anymore.

In other wave editor (or video editor too) usually you have to choose to export audio as a wave and then change the codec in a extra sub men.

For batch converting Ulaw files (this is pretty much always the case), Soundgrinder is a cheap and reliable option.

U-law is compressed before requantization so 8-bit dither will just add noise.

Dont truncate to 8-bit either, just convert directly from your source to 8K 24-bit and save in the U-law format.

You may also want to record with a normal dynamic range and use a limiter to push the peaks down to -10dBfs.

Mac App For 8Bit Ulaw