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How to record speech

Here’s a pretty good way to record speech on the macintosh, and have it sound OK for listening to over the internet.

Here’s a pretty good way to record speech on the macintosh, and have it sound OK for listening to over the internet.

  1. Record the speech using audacity. (Don’t use an mp3 player unless it records in aiff or you will lose quality when you re-compress to a lower bitrate mp3)
  2. In Audacity, edit the bits out that you don’t want (like blank bits at the start or end of the recording)
  3. In Audacity, I like to add some compression (this makes the louder sections quieter and the quieter sections louder to make the listening level more constant within the track and also normalise (this amplifies the whole track to the loudest it can be without being so loud it distorts. You should compress first (as this reduces the highest levels, then normalise. The following settings are a good start:
    Compression
    threshold -12dB
    ratio 2:1
    attack 0.2 secsNormalisation
    Normalise using default. (centre on 0 and normalise to -3db)
  4. Next you need to edit the ID tags, which contain the information that is displayed in itunes. For our sermons at Church we do it like this:
    Song title = passage, (“1 Thess 1”)
    Artisit = preacher, (“Bryson Smith”)
    album = DPC (“DPC”)
    genre = speech
  5. Finally, export. Firstly I would save as an Audacity file to keep, or as an AIFF, so you have a full quality version on hand, then export to mp3 for the internet.
    It’s a toss up between file size and quality. Anything below 40kbps, you start to notice ‘ringing’ (called aliasing) around the high frequencies. We used to record our sermons at 32kbps, but this has enough compression noise to be annoying. 40kbps is tolerable, just noticeable. You don’t need stereo for speech, so mono is fine. If you set itunes to 80kbps, mono, it will output a 40kbs file. I like to export from audacity to aiff, then compress with the itunes encoder. I don’t remember why I do this, perhaps the audacity mp3 encoder is lower quality at lower bitrates than the itunes one.

That’s it! Check the quality, upload it to your webpage, or download to your mp3. If you are just taking a file from the web, and just want to make it smaller for you ipod, you can skip all the audacity bits and just encode it with itunes at the lower bitrate.

6 replies on “How to record speech”

I found the files quite fine to listen to at 32 kbps. At work we often even go as low as 11 (Yes the quality is poor, but it gets the message through quite fine). I am also aware that some people are still on dial-up and have poor connection on dial-up. For this reason, I would go for the smaller file size.

How do you go about changing the compression of Audacity? I open it up and I am not sure how to change the default settings…. thanks

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