I always see monitor speakers hooked into recording systems in example diagrams. There are monitor outputs on my audio interface. Can you really monitor recordings on speakers in the same room as the mic? How is there no feedback? You can monitor with speakers in real-time during recording? Or is it meant for listening to it after you've finished recording?
Generally, monitor speakers are in a different room from the microphones. Monitor speakers can and do feed back into microphones.
They will feedback under certain circumstances. For example, if you have your monitors on and you're recording vocals right in front of the monitors, you will have crazy feedback, especially if you're using a condenser microphone. Think about it this way:
You have to imagine the audio signal path. If you have your monitors on and your mic on at the same time, what will happen? Let's say you sing into the microphone. The next thing that happens is the audio signal goes in the mic and then into your audio interface. Then, it goes into your DAW, back out of your DAW to the monitors, where it then feeds back into the microphone...repeat. As long as the input gain on your microphone isn't turned up too high, this won't happen. But if you have to have your mic in the same room as your monitors, just turn the monitors off (or mute them if your interface has an option for that) when you're using your microphone. Hope this helps :)
The monitors will only feed back if they are close enough to the microphone and the volume is turned up too loud.
You can use the monitors during recording. You can avoid feedback by turning down the volume or simply not routing the microphone through the monitors. With my current setup I have a few microphones pointing at a drum set. The microphones and my keyboard are routed through an audio interface. Only the keyboard goes through the main speakers, so there is no chance of feedback.
A bigger problem with using monitors while recording is that the sound from the monitors is picked up by the microphones. To get a cleaner recording, it is usually a good idea to use headphones where possible.
I usually use headphones while recording and switch back and forth between monitors and headphones when playing back, editing, and mixing.
Where you do need monitors in the same room as the microphones, and volumes are high enough that you get feedback, a good desk will give you the ability to isolate the exact frequency you get feedback on and cut it by 3dB, 10dB or more.
This will have an effect on the final recording, but sometimes that is the trade-off you make. If the Q is high enough (the frequency range being cut is narrow enough) it can be undetectable to the ear.