Unwanted FOH Feedback Live

M

McGurk

Member
I could use some help. First off, I’m primarily a hobbyist but last night I played an outdoor gig with my FM9, the first real gig at high volumes I’ve used it on.

I was running into issues, particularly with the 80’s hair metal set, where for me to have my guitar loud enough to be heard in the mix, my gain channels were giving me a lot of high pitch feedback at full volume.

I tried several guitars in case it was a microphonic pickup (I know that sound) and it happened with each guitar in all pickup locations.

In relation the the PA speakers, on my side of the stage there was one up on a stand to the right and slightly in front of me, and one down on the ground, straight in front of me. There was also a stage monitor, but that didn’t seem to impact it: on or off.

The only way I could get it to go away completely was to lower the amp gain to 3 or lower, but even that still had the problem of being too quiet. This was very disappointing, since that was way off of where I wanted to be tone wise for these songs.

The other guitarist was also using a modeler (NUX Amp Academy) and did not have this issue.

Any ideas of why it was so bad for me, or tips on reducing feedback without completely changing the tone? Thanks!
 
Do you have the ability to tweak your presets at a similar volume at home? That's a good way to avoid those kind of surprises at the gig.

It might not hurt to upload one of the presets with which this happens. FAS and others may have some insight based on that.
 
McGurk said:
I could use some help. First off, I’m primarily a hobbyist but last night I played an outdoor gig with my FM9, the first real gig at high volumes I’ve used it on.

I was running into issues, particularly with the 80’s hair metal set, where for me to have my guitar loud enough to be heard in the mix, my gain channels were giving me a lot of high pitch feedback at full volume.

I tried several guitars in case it was a microphonic pickup (I know that sound) and it happened with each guitar in all pickup locations.

In relation the the PA speakers, on my side of the stage there was one up on a stand to the right and slightly in front of me, and one down on the ground, straight in front of me. There was also a stage monitor, but that didn’t seem to impact it: on or off.

The only way I could get it to go away completely was to lower the amp gain to 3 or lower, but even that still had the problem of being too quiet. This was very disappointing, since that was way off of where I wanted to be tone wise for these songs.

The other guitarist was also using a modeler (NUX Amp Academy) and did not have this issue.

Any ideas of why it was so bad for me, or tips on reducing feedback without completely changing the tone? Thanks!
Click to expand...

This issue has been brought up on the forum many times. I had the same issue when I first switched from guitar cabs to FRFR cabs. To fix the issue, you'll need to lower the high frequencies that aren't needed for guitar. I haven't used a FM9 but if it has a global EQ, lower everything above 10K all the way down. That's what I did for my Axe-Fx II. I do the same thing with my Line 6 Helix Floor. If you don't have a global EQ, you can add an EQ or Filter block to each preset as the very last block in the chain and then lower everything above 10k.

Once you make those adjustments, you shouldn't have the problem anymore and you can even use controllable feedback like Slash, Zakk Wylde, etc.
 
FractalAudio said:
This is known as tweeter squeal. The magnetic field from the tweeter is coupling into your pickups. Move away from the speaker.
Click to expand...
Thanks! This sounds like the likely cause. I was relatively close to the speakers (within 3 feet of both of them). It was a rainy gig and we were squeezed under a canopy that made for a crowded stage. The other guitarist was center stage and further away from speakers.

GotMetalBoy said:
This issue has been brought up on the forum many times. I had the same issue when I first switched from guitar cabs to FRFR cabs. To fix the issue, you'll need to lower the high frequencies that aren't needed for guitar. I haven't used a FM9 but if it has a global EQ, lower everything above 10K all the way down. That's what I did for my Axe-Fx II. I do the same thing with my Line 6 Helix Floor. If you don't have a global EQ, you can add an EQ or Filter block to each preset as the very last block in the chain and then lower everything above 10k.

Once you make those adjustments, you shouldn't have the problem anymore and you can even use controllable feedback like Slash, Zakk Wylde, etc.
Click to expand...
I actually did lower 8k and above with the global EQ on a hunch. It may have helped, but maybe I just need to use some additional cuts with some blocks. Thanks!
 
McGurk said:
Thanks! This sounds like the likely cause. I was relatively close to the speakers (within 3 feet of both of them). It was a rainy gig and we were squeezed under a canopy that made for a crowded stage. The other guitarist was center stage and further away from speakers.


I actually did lower 8k and above with the global EQ on a hunch. It may have helped, but maybe I just need to use some additional cuts with some blocks. Thanks!
Click to expand...
Might be an unpopular opinion here but if you have the chance to play at gig volume during practice or by yourself, def make your presets that way. That way you can figure everything out without people looking over your shoulder or timing constraints. I dont have the ability to do that, so often when I make my own presets that sound good at home, they often have noise when played at a gig volume. So your problem is an easy fix but you can also just buy a few professionally made presets (or preset packs) because usually they vendors make them at gig volume and ive never had sound issues FOH with purchased presets. Just another solid option.
 
Jipps0525 said:
Might be an unpopular opinion here but if you have the chance to play at gig volume during practice or by yourself, def make your presets that way. That way you can figure everything out without people looking over your shoulder or timing constraints. I dont have the ability to do that, so often when I make my own presets that sound good at home, they often have noise when played at a gig volume. So your problem is an easy fix but you can also just buy a few professionally made presets (or preset packs) because usually they vendors make them at gig volume and ive never had sound issues FOH with purchased presets. Just another solid option.
Click to expand...
I did have opportunities to tweak my presets at the high volume, just not in the space and with all the same PA setup. That’s definitely good advice in my experience!
 
You mentioned lowering "gain" but what specific control did you change because there's not one called "Gain".

Did you adjust Input Drive or the Level in the Amp block, or did you adjust the physical Output knob on the front of the unit?

Because the other option is you might have had too much distortion... You can reduce distortion (Input Drive) and increase output level to keep the overall volume where you need it.
 
So it sounds like it’s tweeter squeal (thank you so much, it’s a relief to have an explanation. Two questions:

1. For JBL 15” pa speakers, what would you consider a safe distance to avoid the magnetic field.
2. Does cutting those 8k+ Frequencies help with tweeter squeal, or is that a solution to a different problem.

Thanks!
unix-guy said:
You mentioned lowering "gain" but what specific control did you change because there's not one called "Gain".

Did you adjust Input Drive or the Level in the Amp block, or did you adjust the physical Output knob on the front of the unit?

Because the other option is you might have had too much distortion... You can reduce distortion (Input Drive) and increase output level to keep the overall volume where you need it.
Click to expand...
I reduced the amp drive, and the input gain.
 
McGurk said:
So it sounds like it’s tweeter squeal (thank you so much, it’s a relief to have an explanation. Two questions:

1. For JBL 15” pa speakers, what would you consider a safe distance to avoid the magnetic field.
2. Does cutting those 8k+ Frequencies help with tweeter squeal, or is that a solution to a different problem.

Thanks!

I reduced the amp drive, and the input gain.
Click to expand...
I haven't read all the posts, so sorry if I missed the info but what are you connecting your FM9 to? Power amp, guitar Amp, real guitar cab, FRFR cab or direct to PA and only using the PA's monitors to hear yourself?

If you've already lowered the Global EQ high frequencies, you may want to try raising the global noise gate threshold or if there isn't a global threshold, you'll have to raise it in each preset.
 
McGurk said:
So it sounds like it’s tweeter squeal (thank you so much, it’s a relief to have an explanation. Two questions:

1. For JBL 15” pa speakers, what would you consider a safe distance to avoid the magnetic field.
2. Does cutting those 8k+ Frequencies help with tweeter squeal, or is that a solution to a different problem.

Thanks!

I reduced the amp drive, and the input gain.
Click to expand...
Can you post the preset? depending on the amp and cab you are using cutting highs in the cab block can help but proximity to the PA cab is going to play a huge part especially if it's running pretty loud.
 
GotMetalBoy said:
I haven't read all the posts, so sorry if I missed the info but what are you connecting your FM9 to? Power amp, guitar Amp, real guitar cab, FRFR cab or direct to PA and only using the PA's monitors to hear yourself?

If you've already lowered the Global EQ high frequencies, you may want to try raising the global noise gate threshold or if there isn't a global threshold, you'll have to raise it in each preset.
Click to expand...

Cliff said it was magnetic coupling (not acoustic).
 
McGurk said:
So it sounds like it’s tweeter squeal (thank you so much, it’s a relief to have an explanation. Two questions:

1. For JBL 15” pa speakers, what would you consider a safe distance to avoid the magnetic field.
2. Does cutting those 8k+ Frequencies help with tweeter squeal, or is that a solution to a different problem.

Thanks!

I reduced the amp drive, and the input gain.
Click to expand...
1. You need to determine this empirically as it will depend on many factors including gain, volume, IR(s) used, etc. Move away until the squealing stops.
2. Yes. It's a feedback loop. Reducing gain at the higher frequencies (by cutting) will reduce the loop gain and increase stability.
 
FractalAudio said:
1. You need to determine this empirically as it will depend on many factors including gain, volume, IR(s) used, etc. Move away until the squealing stops.
2. Yes. It's a feedback loop. Reducing gain at the higher frequencies (by cutting) will reduce the loop gain and increase stability.
Click to expand...
What is a tweeter squeal?
 
Can you turn of the tweeter of your cab/monitor? Just to check if it solves the problem.
Also try reducing the gain. Hope that helps....
 
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