To provide the signal for the tests, a sine wave was generated on a PC with WinISD's signal generator.

The signal was monitored with TrueRTA's oscilloscope function. where the level was decreased in WinISD until TrueRTA showed no clipping of the signal was present.

This signal was then fed to an AV amplifier (Pioneer VSX-D711) which has a dB display and remote control, making adjusting the level whilst listening for turbulence easy.

The amplifier subwoofer out was fed to the 350w plate amp driving the test box.

Care was taken not to use high power for longer than several seconds, particularly for the 30hz tests, which is the tuning frequency of the box.

When driving with a sine wave at the tuning frequency, driver impedence and excursion are at a minimum, meaning more heat and less cooling of the driver. (This info comes from a Madisound discussion which has since dissappeared)