I've been led to believe using anything other than a sine wave is asking for trouble. I tend to overthink things in an effort to understand why the world works the way it does, so here's how I figure this works. Throw tomatoes if I botch it up...Grant Bunter wrote:You may find a sine wave into the amp input will not fluctuate as much as pink noise...
When you measure AC, you're ideally measuring RMS. Whether your meter is capable of true RMS or merely simulated is a matter of cost, but for a sine wave source, it should be pretty close either way. The wave shape matters though... A sine wave average voltage is 0.7 times its peak. A square wave is ideally 1.0 times its peak.
Now, I haven't tested or researched this yet, but I've been pondering it lately. Here's how I put the pieces together in my head to where it makes sense, and is hopefully also accurate and correct. (Take with a grain of salt for now.)
The excursion of a driver is going to follow the wave shape, so it will move by an amount that is represented by the voltage, peak to peak. However, you can't measure peak voltage on most meters, only average. (On a scope, you could... but not everyone has a scope.) So, the voltage limits have to be expressed in RMS. Therefore, using a wave shape other than a sine will cause the average to shift, despite having the same peak. This would cause you to over-limit the amp if you calibrated with, e.g., a square wave.
OTOH, using a wave shape with less average power might cause you to under-limit the amp, such that peak voltage is much higher than you expected.
Tada! Now... did I get it right?