Measuring Resonant Frequency

[Steve_E]

I'm trying to figure out a good method of measuring resonant frequencies of open plates or closed boxes. I have both Sound Forge and VA and can capture the "taps" in each. What I don't know what to look at is on the different peaks, which I should be looking at?

For example on a new Sitka plate (using Trevor's methods), when I tap, there are a bunch of peaks/spikes. Some lower down in the frequency with spikes much higher. It's not clear exactly what I should be looking at.

What I've ended up doing is using iStrobosoft for the iPhone and getting a frequency (i.e. B2 +25) and then using a frequency table to give me the appropriate hz. I should be able to match that in the other tools. Can any of you share your methods and what I should be looking at?

Thoughts?
Steve

[jeffhigh]

It's generally (always?) the lowest peak
If you have your spredsheet for working out Moduli open and plug in the value straight away, the answer will tell you if you have done it correctly