Wild Blue Pixel
TIP OF THE DAY
Friday, September 29, 2006
I'm playing the low B note on an Alto kalimba, and the Wah-wah sound is audible, but not as pronounced as with the middle A. We start with the sound hole covered, and go back and forth between open and closed:
Below we see the spectra for the five different regions in the wave form (closed-open-closed-open-closed):
There are lots of things going on here, most of which I don't yet understand! The low B works the opposite of the middle A, which we explored last week. Here, whenever we close the sound hole, the B is strong. When we open up, the B gets weaker, and some of that energy goes into making the F# and A louder. When we played the A last week, the A would be loud when we opened up the sound hole. This week we see that the A gets louder when the sound hole is open, even if we don't actually pluck it!
The oddest thing is in regions 3 and 5, which had the sound hole closed: there is a very broad feature around 800 Hz - this is near the high G of the kalimba, but it actually spans from approximately the high E to the B above the highest note. This feature disappears when we open up, and comes back when we close down. Note that it was not there in the very first spectrum.
Very strange, Dr. Science. Could you please explain what is going on? And what does this have to do with the way of the wah-wah anyway? Stay tuned for more!