To choose a shruti, you should know your own pitch (women generally sing between kaTTai 4 and 6, and men sing at 0-2). The beginners' audio lessons are at shruti G or kaTTai 5, and those given on Shivkumar Kalyanaraman's Krithi Archive are at shruti C# or kaTTai 1.5. For each file, the Western note and the kaTTai or shruti level are given. Click on a shruti to download (Please download to your computer and save rather than clicking on the file each time).

The first is the old set, followed by a 1 minute shruti set at 440Hz, followed by a long 8 minute file (about 40MB). Please save on your computer. Thanks to Samos Alixopoulos!

Update: Download Ganesh Balasubramanian's electronic tambura - version 3. See details below.