Feedback whine when adding reverb to imported movie audio


I'm not sure if I have the right forum for this question but here goes anyway. As I was doing an audit on my saved files, I came across some videos I made in Quicktime using my iphone as a video camera. Naturally I didn't include any notes on how I accomplished this. These videos are from 3 years ago and were taken at my old family home which we sold last year. They are the only videos I've ever taken of me playing my nephew's guitar, which he apparently doesn't have anymore (lost or given away at school, IDK)

The track is in stereo and I imported it into Logic Pro through File>Movie>Open Movie. I thought I would add a touch of reverb. It was going well then a whine started and slowly but steadily grew in volume until it was decking the level meter (as well as blasting my ears in the headphones).

What the deuce? Feedback? Uh, how daphuq did that happen? There are no mics or pickups involved, it is all ones and zeroes being played back with more ones and zeroes to add reverb. I'm baffled.

Mac mini, OSX 14.6, Logic Pro X, Presonus 1810 audio interface Sennheiser headphones

If I could understand how this happened, I'd like to avoid it in the future. I was using Waves' Abbey Road Reverb plugin. I tried it both with and without the movie, and it kept starting to feedback. I tried some of Logic's reverb plugins and a few of them were on the cusp of feeding back, strange high pitched ringing that were definitely not in the original recording.
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rob aylestone

Well-known member
Reverb adds a delay and then feeds this back to the input, but slightly delayed and then does it over and over - very often reverb plugins use cleverer ways, but quite a lot have a control to determine how much feedback is applied, and if this is too high, then they take off. Perfectly normal - just look for the reverb plugin settings and see if you can find the knob - and turn it down.


It was the Plate Reverb plugin without any control for feedback.

I'm going to try doing a send to an aux channel with the reverb on that. Let you know how it works. If a large thermonuclear blast happens in southern NH, that'll be me


I ... I'm alive, it succeeded beyond my wildest expectations. No blinding flash before the oblivion. Well, I learned something new today and I was able to do something I've long thought about. Sadly (or fortunately), there are not many of these videos and who ever the hack was playing that guitar, sheesh, he oughta be ashamed of himself :D