frequencyresponse

From the impulse response we got from the measurements in the lecture hall, we calculated the frequency response of the room. Unlike what we would hope to get, the frequency response of the full impulse response can, in no way, be called flat. It varies around 60 dB but with variation peaks of nearly 60 dB!

As it seems, the loudspeaker performance is especially poor at low frequencies ( see full frequency response), which is according to our expectings as it is specified that the working range of the loudspeakers starts at125 Hz.

Concerning the early parts of the Frequency Response (5 ms), again it can't really be called flat. We recognize some very distinctive peaks which might be interpreted as room modes (but cannot be as the loudspeaker doesn't work at these low frequencies). We calculated the first room modes with Matlab, but as it was a very rough approximation of the lecture hall (it's not rectangular) and for the reason of working range, our results couldn't correspond to the figures.

The higher the frequency gets the more difficult it gets to distinguish clear room modes, which fits totally with our former knowledge about the modal density of a room.

N.B.

We have to assume that there have been some saving problems during the measurement with the source being at the left position, as the results for the second and the third position are exactly identical, which is absolutely impossible (It's even impossible to have twice exactly the same result for one and the same position).

Due to that we should workon the results of the measurement done with the left source with great caution.