1KHZ SINE WAVE FOR MEASURING SYSTEM PERFORMANCE
Download this uncompressed low-distortion WAV file for measuring your system distortion level at 1KHz, beginning from the digital source:
1KHz / 0db tone @ 192KHz / 24bit samples - 60 seconds duration (zipped)
Below is a sample measurement on Macbook 12" with internal loopback in place with the above WAV file as a source (REW 5.19):