I'm going to pick this up for my iPod. You should allow us to attenuate the tones to different levels and also have it go higher than 75 Hz. That way we can use it for setting gains on amplifiers without having to burn a test tone CD. Maybe have it go from the 10 Hz that it starts at to about 10 kHz (for those of us with active setups) with attenuations at 0 dB, -3 dB, -6 dB, -9 dB, and -12 dB. That would be a perfect application then. Regardless, I'm going to buy it, I'm just throwing out some suggestions for future updates.