Update on myDAQ accoustics - myBAT

This week we started on Subsonic signals, we have a simple labVIEW program but we still need to find a efficient way of analyzing subsonic signals. 

In this part of the project we are using the speaker as a microphone.  As you can see, the picture above shows the sub woofer with a mass in the centre, this is to improve its low frequency operation and also the heavier the mass the lower resonant frequency is.  The second picture shows the speaker bolted to 4 columns which are fixed to a square piece of wood, this is so there is a better connection on capturing infrasonic vibrations as there is a larger surface area. 

We have attempted various experiments and using the lift in the Sackville Street building we got a constant frequency of 9.94 Hz.  The other experiments had large variations in the captured frequency and showed no reliable results thus pushing us further to improve the labVIEW program.