I've got the Stryke test disk which contains single frequency sine wave tones as well as single frequency "warble tones". I use it to mainly help calibrate my SVS sub and BFD equalizer. We've all heard that running pure sine waves for too long will fry your driver, so it's recommended that you use the warble tones. I think we all get a littl frustrated with the SPL meter's needle moving with the warbles...so, I anyway, risk the sine tones since it's easier to calibrate. My question is...how can warble tones be a single frequency? If they're "warbling", aren't they hitting (at least) two frequencies?