'The speakers are too loud' is the same as 'Gain is too high', just on the back end and not the front.
Obviously, turning down the levels in the room is going to reduce feedback, especially if the system is too loud for the room.
What you describe in this video is setting up a correct gain structure, which is a good idea by itself and might save you from SOME feedback (mostly because you have more linear control this way).


Feedback is purely an acoustic phenomena, so the ways to prevent it (in the field) are: changing distance (move mic away from speaker),. direction (point the mic away from the speaker) and frequency response (cut frequencies that are feedbacking back more than others - but use eq only after using the other options)
Looking in the room image, you can still do plenty there in order to reduce feedback by repositioning mics and speakers.
also, you did not mention which mic was feeding back, but lectern mics can be treated differently from the band and at the source, so you don't have to 'kill' the system  and the band can have the system 'flat' (or less processed) - just run that mic through a bus and eq it for feedback there (and use channel eq for tonality)

I would not use the sine wave method, it's too risky and you easily burn a voice coil this way and the sine wave is external to the system, and is not a part of the feedback loop.
You might find some freqs this way that do actually feed back, but you can also find others that are just simply too loud in the system or might sound harsh to you (which is very common with lower end speakers that tend to be less linear in their behavior).
What you are doing here is more VOICING the system than eliminating feedback.

The right way to do it is to excite-scan the system using an eq with an open mic (the main mic usually) - this is how some feedback eliminators work (the non real-time  kind), but only after setting the mics and speakers correctly.

I literally went into this video like 'what is this guy gonna teach me...'. But holy sh*t i've never even tought about using this whole pink noise/ sine wave stuff for setting stuff up like this! Thanks man, this is genius!

Its a little bit hard for non english speakers to understand, can you do a video of you showing how to do the whole process live?

Great video! However, I do want to clarify one thing you said about gain. The reason why you would want to reduce gain to prevent feedback, is not because of the “sensitivity” of the mic (because I agree, that doesn’t make sense), but adding gain means adding noise! I’m not talking about the noise floor that the mic picks up, but actually adding more noise to the signal, from the preamp itself.
Noise is what makes mics feedback sooner.
I do agree that the better solution is to turn down speakers, but sometimes you don’t have the luxury of doing so, because to much room reverb, or the people in the back can’t quite follow anymore.

Anyway. Long story, but you did explained it perfectly.

As a "journeyman" sound person with no formal training, I just recently discovered that I'd been running my speakers way too loud. Once I turned them down, it was easier to get all the levels I needed in the mix. But your explanation makes it easy to understand why. Thanks for all your content!

Sinewave sweeping to find the resonant frequency of the room...let's try this. I tried a 125Hz sinewave and it showed me the combing effect though.

'Sensitivity' is gain dependant. It is measured at a certain decibel level (ie 94db).. You need to increase your gain in order measure the sensitivity of a mic. Mic sensitivity varies at different gain levels. That's why 94 decibels was chosen to measure mics. But that's it also clue you in that you're understanding of a preamp at least at the time of making this video was incorrect.. doesn't make the rest of your video incorrect. It just means one of the main functions of the microphone is something you got wrong. But also indicates that the mic gain is just one of the factors that might be causing feedback. You can adjust all the other settings and EQ everything else and take care of all the feedback in a situation, yet still have the mics too hot. Because a hot mic doesn't necessarily cause feedback. It's how that might interact with a whole bunch of different factors. But yeah turning down your speakers is probably not what I would do as the first step. Because, thats often something that should not be adjusted regularly (unless in a mobile rig)...
Geez if I caught one of my assistant engineers fiddling with the levels of individual speakers in my venues, i'd flip the hell out on them. Adjusting levels like that would throw off any tuning and balancing that I had done on my system.. to mitigate microphone feedback? First thing I would have told him to do is high pass the channel and turn down the low end base frequencies from the EQ.. then I would tell him to check the batteries on the microphone because low batteries equals low performance.. I prefer not to slap a EQ on the master bus because it affects all other sources that way when it's just the microphone causing the feedback. EQ on the channel for the microphone or group, some compression, proper mic placement and technique (don't hold the mic like you're in a rap video) .. And of course ring out the room but never with eq on the master bus.
And if the artist is being difficult and not listening to me when I tell them not to hold the mic like a fool, then I'm putting a ducker on the mains. Every time they speak into the mic, it's going to drop the level of any other sound.. a lot of the times the feedback is happening because of a loud environment and not necessarily from the artist's own voice. That happens often when they're standing in front of a speaker stack and not paying attention.
Also you were mistaken when you say turning up the game increases the self noise of the equipment. That is a common myth. Julian Krause does a pretty good video dispelling this notion. You're mistaking self noise and signal to noise ratio

It's total loop gain that we need to control to avoid feedback. That includes microphone transducer gain, pre-amp gain, fader and EQ gains, power amplifier gain, speaker transducer gain and acoustic path gain (loss) from speaker cone to microphone diaphragm. Reducing any of these gains will mitigate feedback, but there is no reason to have excessive gain in the path from the mixer to the speaker voice coils, so I take your point and I like your method.

Again wow!

I never thought about putting the main out speakers on matrix

Thank you very much! As a sound engineer by training, this was one of the most concise and practical explanations anyone ever gave me!  I wish we had touched on this the same way at sound school.

Thank you!  This was a revelation!

This is absolute GOLD!!! AMAZING bro I love your content! so transparent and honest!!

As usual, Daniel has come up with magnificent tips with very high practical relevence, which could make your mix sound always excellent. Me too was in the same line of thought, as some of the performers in our church have too low volume and they move out of proximity to the microphone. Thanks a lot gentleman for your extremely helpful videos. It's very sad that you are heavily underrated...

very good vidéo! part on the  phase relation and monitor (wedges) placement would have been nice!

So simple, yet so correct. You earned a sub today, my friend.

thank you very much

All the tine i Find new information from your videos we appreciate what your doing

Another fantastic video Daniel!

Hello Daniel.. Thank you so much for your lesson about mixing we have learn many things from your youtube. We are from Nepal..!

God bless you Daniel