In general there are very few recordings of a feedback signal. Obviously if it were a desired effect we would not be implementing a system that eliminates it. Thus, in order to analyze a feedback signal, we had to create and record one ourselves. The way in which we decided to produce the signal was the same as in the first diagram describing feedback. We simply took a mic, plugged it into an amp and speaker, and then faced the mic into the speaker. Then, we used a second microphone along with a MiniDisc Recorder to pickup and record the feedback signal produced by the system. The specific equipment used was as follows.
1 Sony MiniDisc Recorder
1 Sony ECM-MS907 Electret Condenser Microphone
1 Korg Bass Amplifier
1 AKG Condenser mic
1 Phantom Power Unit
Note that by recording this signal outside, there were very few walls for the signal to bounce back from. As well as the fact that any reflected signal that did occur would have been attenuated to a negligible power.
Here are some pictures of the setup and the equipment used.
Minidisc Recorder
Sony ECM-MS907 Electret Condenser Microphone
Amp Mics and Db Reader
Recording Setup
Results:
After a small amount of time and only a few complaints from the neighbors, we were able to record three main signals, Nick’s voice, just feedback and lastly Nick’s voice combined with a feedback signal.