Feedback can happen when the microphone is too close to the loudspeakers or when the volume is too high. The sound coming out of the speakers is fed back into the microphone, then out of the speakers again and so on. This feedback loop causes a howling noise or beep which can be very unpleasant.
Tips for avoiding feedback noise:
- Use headphones.
- Make sure that the computer loudspeakers are not being used.
- Turn down volume if possible. This reduces the risk of feedback.
- Make sure you are using the right audio input device. Sometimes, feedback happens when you think you are using the audio interface / lined guitar, but you are in fact using the computer's built-in microphone.
If you can't get rid of the feedback noise, you can disable monitoring. This way the microphone sound will not be monitored through the speakers. You won't be able to hear the microphone sound while recording, but you can still record and listen to the recording afterwards. Note that it is still a good idea to use headphones when recording with a microphone, to reduce audio leakage!