Tuesday, January 23, 2007

MP3 for podcasts

Rupert asked me about hosting a podcast for a chum of his who is involved in the Pandora music project. In fact he made me a Vigilantes of Love station on there - very cool!
Anyhow with all this in mind I thought I'd summerise some of the steps I use for the perfect sounding speech podcast!

  • Record straight to hard disk - don't go via analogue tape or any compressed system. Pay attention to levels - you can't recover clipped levels after the event so it's better to record low rather than high - try and aim for peaks at -10dBfs.
  • Once in Audition or Audacity you need to remove any DC bias and normalise the signal.
  • Save it back to disk (keeping it uncompressed) but convert it to mono - stereo does chew up twice as much space/bandwidth - and you don't need it.
  • The Levelator is a superb post-process compressor for speech.
  • Re-import the Levelat'ed(!) file back into your DAW software and save the file out as an MP3 with the following specs; 48kBits, CBR, mono. Why CBR Phil? Well, this MP3 might be played on one of hundreds of ancient and new devices. My first MP3 player was a Diamond Rio500 which definately didn't support variable bit rate! For mono speech the difference in quality is not great.
  • ID3 tags - get them right - for both ID3 v.1 and v.2 flavours. I prefer Tag & Rename for getting that stuff done - it supports all the standard as well as custom frames. It's very cool to imbed an image with your podcast as well as notes, URLs etc. That MP3 file will have a life of it's own once it's running out via an RSS feed and you want to have the best chance of folks being able to find you. You'll be suprised how many aggregator sites scrap your file.
  • FeedBurner is the best way to make compliant XML for the RSS feed with a multi-media enclosure.
  • Finally, make sure you subscribe to your own feed (in Juice or iTunes etc.) - you should be the first to know if your feed gets broken.
That's it - go forth and podcast!

1 comment:

Kevin King said...

nice guide Phil, and if you need a mic recomendation I'd recomend the
Samson C01U - USB Studio Condenser Microphone

http://www.samsontech.com/products/productpage.cfm?prodID=1810&brandID=2

I've used it with good results