Week 7 of the engineering project was the test week for the speakers that were built.  During this week completion of the vibrations test as well as the frequency response test were preformed.  The graphs below show the results from the frequency response tests at the two distances measured.

From these graphs, it can be seen that the MDF did the best job at giving a flat line frequency response.  This is noticeable in both the high and low frequency response graphs.  Another interesting observation from the graphs is that both gave a volume boost to the lower frequencies produced by the speakers, with oak having the highest volume, but a slightly more crooked frequency response line.  Another test that was completed this week was the vibration test to see how much the cabinets vibrated at various frequencies.  This was done using an application and the accelerometers in the iPhone.  The graphs below show the results.

MDF 100Hz

MDF 125Hz

MDF 160 Hz

Oak 100Hz

Oak 125 Hz

Oak 160Hz

These graphs show the acceleration in the x, y and z direction.  The most noticeable direction is along the y axis. For reference, if one was looking straight into the front of the speaker, the vibration would be moving towards and away from them.  This vibration is caused by the movement of the speaker, which is also along this axis.  The most noticeable difference is in the graphs of the 160Hz frequency where the oak has almost twice the amount of vibration that the MDF does.  This vibration is probably what causes the "boomy" bass that the cabinet tends to produce.  This is an unwanted attribute because what the speakers are sitting on will vibrate which can cause damage or unwanted rattling noise.  Another interesting observation is the graphs of the 100 Hz frequencies.  The sinusoidal wave that was shown on the phone suggests that this is the resonant frequency of the speaker cabinet.