At SXSW iStockphoto has announced that it will include over 11,000 royalty-free, user-generated sound effects and music tracks starting as low as $2 each as well as a new Pump Audio collection of over 18,000 single-production music tracks as low as $29 for your creative projects, from Web video to TV shows, movies, commercials, public performances and even games.

iStock shares royalties with its contributing artists and is currently paying out close to $1.1 million a week and is now the first company to offer stock imagery, video footage, vector illustrations, Flash files and audio for purchase under a single payment model, on one convenient site.

Dr JM Pisano gives us a great article on audio compression which is used to add dynamic range to an audio signal. The four basis knobs on your everyday compressor are Attack, release and ratio which are explained in detail.

REAPER - a fully featured multitrack audio and MIDI recording, editing, processing, mixing, and mastering environment that can be virtually connected through ReWire.

With this app you get filter with cutoff and resonance control, stereo delay with cross-feed, 32 factory sounds and 96 user editable sounds just to name a few features. All to take with you on the iPhone or iPod touch.