Measuring Vibration in Equipment

I used a stethoscope to listen to the walls while I played a test disc of the different frequencies through my system to hear where the most vibration is at what frequencies. Works pretty well to identify trouble spots to treat.
Never used it on racks, etc. though.

I wonder if a large well marked (graduated) compass would work? It would be crude but maybe useful?

call up NOAA in the republic of boulder, give them your exact location via GPS, ask them to run a pinpoint seismologic test and get back your results on the richter scale. could cost a bunch but think how impressed your friends will be.

I use small shallow round dishes. I get mine from a lab glass supplier. Put water in them and shine a flash light on the water. Moving the dish around will show you the major resonance points. Make sure you don't overfill it so the water doesn't bounce out. You can also rent industrial strain gauges specifically designed for vibration measurements but unless you already have a degree in mechanical engineering this is overkill.

What we have used is small etched piezo devices taped to equipment platforms and feeding a sensitive gain stage (actually a modified phono stage). This gives good results but you have to trial and error a lot to get a reference point from which you can then further study vibration patterns and get meaningful, consistent results. Radio Shack used to sell a small flat piezo mic that can be used. Regards, Richard at www.vantageaudio.com