Preventing Microphone Feedback in a Live Sound PA

We will all stress about microphone feedback when we are mixing live. In this video, I will teach you my steps for preventing Microphone Feedback through the PA so you can feel confident handling any issues that arise.

This video is a part of my Behringer X32 Fundamentals Course where I teach five building blocks that I believe every audio engineer should know to be confident in mixing and handling issues.

[highheeledjack]

this is my fundamental of mixing
1. know your speaker ( using rta measurement )
2. know your gain on every mic (every mic has different setting of gain based on the system you're using, so careful)
3. use GEQ on every monitor ( mostly reduces 2k 4k 8k up to 5db or more and make another adjustment on another frequencies based on the room you're using )
4. prevent boosting frequencies on mic, don't be afraid and so pity on reducing frequencies, make adjustment later
5. ALWAYS USE LOW CUT ON VOCAL🤣

[Mesh_ach]

I am from Uganda. have learnt so much from you and this has made one of the best sound engineers here in my country. Thank you so much. God bless you Sir!

[vadimmartynyuk]

The issue I often have with ringing out feedback is that I ring out frequencies when there are no audience in the room, but when the room gets filled with people, room acoustics change a little which results in different frequencies prone to case feedback.

[DonaldMerrit]

My band used to run a feedback locator. During soundcheck we would pay attention to the feedback locator to see where we were having problems and we would adjust them before the show. I don't recall having to deal with increased feedback because more people came into the venue. Our audience sizes were between a few hundred to a couple thousand and the amount of people never seem to play into the feedback equation. From my experience the more people the less feedback

[PTZPROllc]

Great video. very informative. amatuer audio engineer here. So it's nice to see these tools in action and seeing results.

[luukmeijssen]

What also helps to prevent feedback, is to use less gain on the preamp of the channel, and to raise the fader more.
When you apply gain on your mic, not only does the mic get louder into the channel, but also you add more noise to it. (I’m not talking about the noise floor that gets amplified through the mic, but actually adding noise from the preamp itself).
The more noise you have in a channel, the quicker it’s going to feedback.

This trick helped me a lot when I had to amplify a few of those omnidirectional headset mics during conferences.

[franks]

Excellent simple explanation, thank you. I am a new audio engineer, the issue I am also having on my Walkman headset mic is that when my pastor speaks occasionally a word will be garbled. He is not changing tone and volume when this happens. We have an sq-5. Thx

[tobby]

I personally use the GEQ on my monitors and house speakers to kill feedback. I prefer to Eq my pastor mic and vocals so it sounds good tone wise especially if sending to stream etc. I know GEQ doesn't allow Q adjustments, but im ok with cutting just a lil bit more frequencies to get my tone.

[samyeomans]

In my couple of years experience in a church sound system that I had to fully change and is now finally getting a $50k upgrade done professionally, it’s mainly about a few key things. Speaker location, stage noise levels, microphone eq and gain.

[the-real-iandavid]

Drew Brashler - The Quick-change Artist!🤣 A very useful video. Thanks!

[Markygeegee]

A very good video Drew as you have address the cause of the issue well. I have a few suggestions...
- you should use differing terminologies for speakers. Either Speakers & presenters or monitors & speakers as it can be confusing.
- you talk about the EQ effecting what goes out to other sources. The better way to handle & think about this is to use the channel eq to correct the source & any issues unique to that channel. Then use the paramatric equaliser on the send (or even better is to insert & use a graphic equaliser, would be nice if behringer made the GEQ an option on the send like on the XR models). That way you are dealing with the issues unique to that listening position. Other locations (hopefully on diff sends) could have different issues due to types of monitors of physical differences in surfaces etc.
- the last one is a nit pick, with respect to the gate you mentioned it mutes the channel, but with this setup (as you explained by the 9db gain reduction) it is attenuating the channel.
Cheers

[petabb]

You're the best sound mixing teacher out there. I have XR-12/18 and can relate to some of X32 functions. I do wish if you can do some short videos on MR-12/XR-12 if you get a chance though. Thanks again.

[DuSpec]

Greate lesson ! I'm learning and this is the best guide so far.Thanks

[grevestudiotv]

Dear Brew, I think your videos are really essentiell for x32 users (especially non professional technicians)! People can learn a lot by watching them. One additional idea to the subject: The main vocal channel (lead singer) is important enough for me to insert a graphic eq (GEQ - A or B Channel of the DUAL GEQ) into that channel.
That helps me to reserve the parametric bands of the channel EQ for sound shaping and I can treat more feedback frequencies. Graphic EQs on monitors and Main PA is the next I do, as tobby917 already mentioned. But again, the way you explain the subject and the use of the x32´s onboard tools is great. Thanks a lot for the time you put into your video production!!

[royx]

Drew, great video! We have an X32 at our church and I was hoping for maybe some updated videos on X32 effects. Your previous ones have been great, and our Sweetwater rep actually recommended I watch your videos! But it seems like the newer firmware on the X32 has even more effects than before.

[commiekiller]

I ran sound for high school theatre productions for two years, and in that time, I learned to fight the uphill battle. The stage was abysmally treated, the face mice were omni directional, and there were speakers pointed directly at the actors. I was never instructed on how to fix the issues, so the school was lucky that I knew what I was doing or else it would’ve been a disaster. I did everything mentioned in the video and some extra stuff. I’d highpass everyone’s as close to their voices’ fundamental as I could get. I’d use the exponential (EXP3) gate to keep the mics off going below -45db. Lastly, I’d compress each voice about -25 db to make sure no shouts or belting caused the whole system to feedback. Needless to say, my EQ curves looked like Swiss cheese, but everything was working against me when those mics went on. Again, these configurations are for very, very aggressive feedback control, but when worst comes to worst, this is how I managed.

[greatnowwhat]

I just use a DBX feedback destroyer (in music mode so the filters are not too wide). Use 22 fixed filters that you let the device find every time you are at a new place or use different microphones and 2 live filters for in case of. Saves a lot of work and give a huge amount of extra DB's

[teguhdewaprasetyo.]

I'm from Indonesia, thank you teacher for the knowledge you have taught me, I really like it.

[shanerobertcooperramirez]

i haven't had a feed back issues in years and the mic's are pretty loud and we have a big echo and reverb sound in the room, my solution lower the gain, your speakers as far as you can, lower the monitor gain and test out different monitor placement untill you get an easy to control sound with the monitors and if and play with diferente volumes and eq settings as much as your hearts content and very important talk to anyone using a microphone and teach them how to properly use a microphone and learn the sound in the room and study the potential fixed for any distortion and feedback, honestly this might take a long time to perfect but once you understand whats going on you can pretty much apply this to scenario you might be mixing in

[techthisout]

this is the really tip of the iceberg I really suggest to use a 31 band GEQ on the wedges and the main PA + sidefill and so on. A microphone wouldn't resonate and create feedback always in the same exact frequency is a matter of physic and positioning of the mic compared to the tweeter, the woofer the inclination torwards the wedge... you can significally get better with GEQ of course, but it you start to get down every frequency that resonate you'll start to lose all the pressunre energy and the intelligibility. Better start with a great sets of speakers, choosing the right microphone for the right task and than start put hands on the EQ. Btw good overall intro lesson ;)