CCITT U-Law & A-Law Conversion – Cisco IVR

I have been asked on a number of occasions by people viewing my website if I can help them with how to produce the correct file format for Cisco IVR systems, so I thought I would make a post about it.

Saving a good quality .wav or .mp3 to the required A-Law or U-Law file format for some IVR’s might seem like a waste of good audio to most people. You have recorded the good quality file, usually at 44.1 kHz 16 bit mono which is a standard CD quality recording, but after the conversion process the quality of the finished product is never as good when you play it back through your studio speakers. Don’t panic too much when you first hear the converted file, as once uploaded into the IVR your audio will sound fine. A standard telephone frequency is only 300hz – 3.4khz and therefore will eliminate a lot of the imperfections that you hear from your converted audio in the studio, your client will still be happy with the results.

So what software do you use to do this? Well …. I usually use Logic Pro software on a Mac to record my audio but it doesn’t convert files to this format, so for this task I use two (PC) software applications to convert the files. At first I used Sony Soundforge Audio Studio 9 which is available at a cost of around £30 from most retailers; however there is a free software application which I use now and it does the job perfectly well. This is called ‘Audacity’ it is this free software I am going to explain in detail below. Depending on when you reading this the software versions may have changed and moved on but as of today you can use the following versions:

Windows (98 / ME / 2000 / XP / Vista) – Audacity 1.2.6

Windows 7 – Audacity 1.3.12-beta (Unicode)

Mac – 1.3.8 (Unicode)

Open the Audacity application

Click File - Open – Select your master file (make sure your master file is a good quality audio)

You should now see the audio waveform open on your screen

In the bottom left hand corner you have a field ‘Project Rate’ change this to the desired frequency (eg. 8000 or 8 kHz)

You must do this before saving the file in the A-Law or U-Law format.

Click FileExport – Rename your file and chose where you would like to save this

Save as type ‘Other Uncompressed Files’

Click ‘Options’ button

Select the Header as WAV (Microsoft)

Select the Encoding as U-Law or A-Law

Click ‘OK’ then ‘Save’ - When you click save it will take you to the ‘Metadata’ details, here you can change fields specific to your project, I usually change Artist name to Kelly Carter etc …

Click ‘OK’ and you are done

The above process is based on a PC version of Audacity but for those of you using a MAC the process is still the same, however, the metadata fields will appear in a slightly different place after you click export rather than just before you save at the end.

Please comment if you have any further information on this that might help other Voiceover Artists to convert files in this way, or indeed if there is a different or easier way to do it. I do hope that somebody will find this post useful and I wish you all success in your Voiceover careers.

Kelly :)

2 Responses to CCITT U-Law & A-Law Conversion – Cisco IVR

  1. johnny says:

    It wasn’t obvious how to do this in Audacity! Thanks for the post.

  2. Dave says:

    Thanks a lot this really helped :)

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