When tweaking an effect combi for unity gain, what's the best test signal?

[colcifer]

Music? White noise? Pink noise? Hmm...

[selig]

Music? White noise? Pink noise? Hmm...

Provided the effect isn't totally distorting the input, a sine wave is easiest because it's a steady tone. For that matter, it could be any static waveform since you're not trying to detect distortion.

The advantage of a tone over noise or music is the ease of measurement, since it's not wavering in any way.

Also, in some cases you don't want to match exact levels - a compressor or distortion effect is one example, where the average loudness is so high that if you match levels by the meter it may end up sounding much louder. Sometimes using your ear is going to be your best bet. But I suggest you start with a tone and see how far it gets you!

[colcifer]

Cheers. Sine waves sound good for a lot of effects but what about EQ based stuff? The effect I was working on was an amp cab - what would you use?

[Benedict]

I'm with Selig on the complex stuff like clean to distorted transition. Ears are best as freq changes are more subjective than purely level based.