MarkBarbieri
Semi-retired
- Joined
- Aug 20, 2006
- Messages
- 6,172
I recorded our son's 4th grade play last night. In my usual OCD way, I used a pair of high def video cameras and a digital audio recorder connected to the school's mixer board. I'm spending tonight pouring over the primary audio file tweaking the volume of various kids so that you don't have shouters and quiet mumblers. Its really quite tedious.
I just found a problem that was fun to solve. During one of the songs, we had a few seconds of feedback (a loud, annoying tone caused by a feedback loop between a mic and the speaker). I was able to eliminate the feedback without having much impact on the rest of the sound.
Here is the sound before the feedback was eliminated: http://barbierifamily.org/feedback before.mp3
Here is the sound after the feedback was eliminated:
http://barbierifamily.org/feedback after.mp3
I did fixed it using a program called Soundbooth. I looked at the sound using the spectral analyzer. The spectral analyzer is like a graph that shows time on the x-axis, frequency on the y-axis, and volume by color. Dark colors mean low volumes and bright yellow means high volumes.
In this screenshot, you can see a long, flat line a bit below 4khz. That's the feedback. Its a relatively loud tone at a fixed frequency a bit below 4khz and it shows up as a relatively bright, flat line in the analyzer.
I selected that tone using the marquee tool (a rectangular selector) and deleted that tone. The rest of the sound remains the same. None of the other frequencies are touched. It did leave a "hole" at the frequency where the feedback was, but it is hard to notice that a very narrow frequency band is missing. Here's what the analyzer looked like after the deletion.
OK, that had nothing to do with Disney or Photography, but it's sort of related to videography and I thought it was really neat. I'm also bored with tweaking the volume of an endless stream of kids. My son was narrator #55 and there were more after him, if that gives you some idea of how many speakers I need to adjust.
I just found a problem that was fun to solve. During one of the songs, we had a few seconds of feedback (a loud, annoying tone caused by a feedback loop between a mic and the speaker). I was able to eliminate the feedback without having much impact on the rest of the sound.
Here is the sound before the feedback was eliminated: http://barbierifamily.org/feedback before.mp3
Here is the sound after the feedback was eliminated:
http://barbierifamily.org/feedback after.mp3
I did fixed it using a program called Soundbooth. I looked at the sound using the spectral analyzer. The spectral analyzer is like a graph that shows time on the x-axis, frequency on the y-axis, and volume by color. Dark colors mean low volumes and bright yellow means high volumes.
In this screenshot, you can see a long, flat line a bit below 4khz. That's the feedback. Its a relatively loud tone at a fixed frequency a bit below 4khz and it shows up as a relatively bright, flat line in the analyzer.
I selected that tone using the marquee tool (a rectangular selector) and deleted that tone. The rest of the sound remains the same. None of the other frequencies are touched. It did leave a "hole" at the frequency where the feedback was, but it is hard to notice that a very narrow frequency band is missing. Here's what the analyzer looked like after the deletion.
OK, that had nothing to do with Disney or Photography, but it's sort of related to videography and I thought it was really neat. I'm also bored with tweaking the volume of an endless stream of kids. My son was narrator #55 and there were more after him, if that gives you some idea of how many speakers I need to adjust.
