Sh-4 Jb... help with monitor feedback.

[willsmythe37]

Hello all,

Thought I'd drop by the forums to see if I could find any information that can help. Alas... no, so here I am creating a thread. Please weigh in if you'all be so kind.

So I use a ltd MH1000-stb, stock Seymour Pickups:

I've been having issues with squeeling monitor feedback. I run a Helix modeller into the power section of a hot rod deville 212. Using the pre-amp emulations of an Engl Fireball.
No stomp distortion/overdrives. Just regular amp gain.
Mic was in front of combo amp (HRD)

Basically, when stage monitors (with tweeter) are at a comfortable listening volume... if I go within 3 feet of them, I get pretty horrid feedback. I've tried dialling back the gain to 3.5 on the amp sim... removing my compressor altogether. Still likes to come through.

This is worse when I jump to my lead channel that has a 3db volume boost (same gain level)... obviously a problem.

I really like the pickups, they have such great bite... but I really need to iron out this issue... it's distracting on stage. (And is surely worse for the crowd)
At this venue (full size stage) the engineer was helpful, I warned him this was happening and we scooped some of the problem frequencies outta the wedges using GEQ... still it prevailed.

I filmed my bands set, so had some audio to analyse at least.
Problem frequencies appear to be 2.2kHz, 3.4khz.... and there was another pitch higher it was just too tricky to isolate as the camera was a consumer level handycam.

Interesting things:
At rehearsals I used to have around 7.0 dialed in for gain... if I went over to the guitar amp, I'd struggle to get any 'nice deliberate' feedback
On the night of the show, I wound up rolling it back as far as 3.5... which I would normally consider unplayable. Sustain wise, it was fine?
(Almost as if the pickup was so sensitive that it was adding to the gain in the signal chain)

Looking up the frequency response of the Celestion speaker, I can see some similarities in problem frequencies. So will try and tastefully lower between 1.2khz to 5.5khz.

I tried to be smart as I'd played this stage before... so pre-emptively notch filetered some spots to see if it would help... no luck.

Does anyone know if you can get a frequency response diagram of the SH-4 JB?

There's a chart that shows 'resonant peak'... this is around 5.4kHz.
Should I cut around this frequency also?

I saw a post about confirming if your pickup is 'potted', can anyone elaborate if this has been done on these pickups?

Any solutions and possible causes?

 

[Derpottsie]

Re: Sh-4 Jb... help with monitor feedback.

Well all I can confirm for you is yes your pickups have been potted for sure. Unless youve ordered custom JB's and asked for them not to be potted. But my JB in my SG entices a lot of feedback but its manageable with volume control on the guitar. I'm not entirely sure on what to tell you about your problem here its a tricky one that I havent experienced. But yeah your pickups are potted for sure

Sent from my SAMSUNG-SM-J320A using Tapatalk

 

[beaubrummels]

Re: Sh-4 Jb... help with monitor feedback.

Welcome to the forum

So you have an amp with mic in front of it feeding a monitor and you're standing with the pickups in front of the monitor that is feeding the amp that is mic'd which is feeding the monitor with the pickups in front of it? Where is the amp and mic in relation to the monitor? I would try moving the amp and mic to a different location, or try aiming the monitor at a different angle or try aiming the amp/mic at a different angle, or try putting an isolation barrier between the amp and where you are standing/the monitor.

 

[2ndhandband]

Re: Sh-4 Jb... help with monitor feedback.

You're getting feedback through the monitor... from your guitar pickups???

I doubt it. Highly. I've been performing for over 25 years and mixing live sound for about a decade and I don't ever remember that being an issue. Not once. It's almost gotta be your amp mic.

My question is this: is your soundman off somewhere playing with himself while feedback is coming through the monitors??? This isn't your problem; the soundcrew should be punching that out with the graphic.Within seconds of hearing it. If this is not happening time to find new production.

 

[daenius]

Re: Sh-4 Jb... help with monitor feedback.

How is the monitor getting the sound? Is it signal routed out from your amp? Helix unit? Mic'd amp?

Could also be a problem of your monitors too, hard to say.

If you're standing super close to a speaker that gets its sound routed from your amp signal, and the speaker outputs certain frequencies that a guitar cab doesn't usually produce much of (but still gets sensed by the pickups), you can get feedback from the monitors and not the cab. Try using different monitors and try to find a good spot to stand? Oh yeah, is the monitor just outputting your sound or the whole band? Are you sure it's your guitar that's causing feedback or is it actually the band mix getting sensed through your pickups cuz your monitors are too loud? High stage volume can cause this issue.

 

[2ndhandband]

Re: Sh-4 Jb... help with monitor feedback.

How is the monitor getting the sound? Is it signal routed out from your amp? Helix unit? Mic'd amp?

Could also be a problem of your monitors too, hard to say.

If you're standing super close to a speaker that gets its sound routed from your amp signal, and the speaker outputs certain frequencies that a guitar cab doesn't usually produce much of (but still gets sensed by the pickups), you can get feedback from the monitors and not the cab. Try using different monitors and try to find a good spot to stand? Oh yeah, is the monitor just outputting your sound or the whole band? Are you sure it's your guitar that's causing feedback or is it actually the band mix getting sensed through your pickups cuz your monitors are too loud? High stage volume can cause this issue.

He said in his post that it's miced. And I repeat my previous statement: this is why your monitor rig has a graphic EQ.

 

[Mincer]

Re: Sh-4 Jb... help with monitor feedback.

Does the pickup squeal through a normal amp at rehearsal-volume levels (no mics, no monitors)? Check that first. If it doesn't, than this is a gain staging, or positioning problem. Loud guitar coming from behind you from an amp, and then blasting up in front of you will do that (face the amp backwards, build the tone internally with the Helix).
Check the output of the Helix going into the power amp of the Hot Rod. The signal might be way too hot.

 

[2ndhandband]

Re: Sh-4 Jb... help with monitor feedback.

Does the pickup squeal through a normal amp at rehearsal-volume levels (no mics, no monitors)? Check that first. If it doesn't, than this is a gain staging, or positioning problem. Loud guitar coming from behind you from an amp, and then blasting up in front of you will do that (face the amp backwards, build the tone internally with the Helix).
Check the output of the Helix going into the power amp of the Hot Rod. The signal might be way too hot.

From his description it sounds to me like it's the mic, not his pickups. Which again makes it the monitor guy's problem, or the soundman if monitors are being run from FOH. Either way it's something that a competent engineer should be able to resolve in a matter of seconds.

 

[willsmythe37]

Re: Sh-4 Jb... help with monitor feedback.

Thanks loads for the suggestions fellas.

Reply's in no particular order:

- I fully understand the doubt that the problem is in my signal chain... but I'm certain the feedback is caused by something within my rig. For example, other guitarists on the same stage can move around as they please, even putting their foot on the monitor whilst playing.

- Feedback problem was present when sound checking the guitar, before event began. It was at this point that I started dialling the gain on the amp model back, to try and get to a workable level. Keep in mind 3 other groups had already been up to sound check.

- Signal chain is (Guitar) (Helix and pre-amp model) ('Power Amp in' on HRD) (Amp Mic'd up... to front of house) Feedback occurs when guitar is coming back through the monitor.

- Regarding the "Power amp in" input volume being too hot, it's not like I was ragging the backline. It was lower than regular rehearsal volumes (A suitable stage volume). To elaborate, the volume I was sending to the amp from the pedal was around 60%.

- Amp is behind me, I'd say roughly 8-10 feet and I'm facing away from it, waist height. I'm stood in front of the monitor wedge, which is 3-5 feet away.
FoH stage right (is the closest) at 10-15 feets away. Nearby vocalist's monitor is 8-10 feet away.

- I'm a sound engineer myself. Flummoxed, hence which I'm seeking help of others.

- It doesn't happen when at rehearsals without a mic/monitors. I did try to 'Force it" by mic'ing it up through the provided PA system, which caused a similar problem but the offending frequencies were different, probably because of the angle, or lack of obvious tweeter in the speaker.

- Single engineer looking after both FoH and monitor mixes. He did adjust the Graphic EQ in the rig when I mentioned to him prior to the sound check, still had the same problem.

- Re: "not having experienced this before and thats in 20 years of engineering", same here. I've engineered for many bands and electric guitars are normally good as gold. Personally, I have never experienced this problem with previous modellers NOR regular high gain factory settings on older amps.


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Please keep those suggestions coming

Some more info:

The Helix has an 'input pad' setting and also allows you to select Line or Mic level on the output of sends/XLR outs.
Currently the Pad is off, and the output is set to line level.
Reason being, I can't hear any distortion at the input stage of the Helix and I contacted Fender customer service and they stated the 'Power-amp in' input requires line level.

As I wound up dialling the gain level of the 'pre-amp model' back as far as 3.5... I'll try using the pad (whether necessary or not). I suspect that I'll only wind up compensating with a higher gain value, which doesn't really fix the issue.

Thanks for your help everyone.

 

[beaubrummels]

Re: Sh-4 Jb... help with monitor feedback.

Does the mixing desk channel have a preamp? E.g. does your channel have gain or only attenuation? Was that set too high; not dialed right for unity on the fader? Or was the input impedence not set right for the microphone?

 

[Chickenwings]

Re: Sh-4 Jb... help with monitor feedback.

What happens when you plug straight into the amp, crank it up and stand in front of it?
What happens when you plug your axe into the other guitarist's rigs and stand in front of their monitors?
Work through a process of elimination of all the parts of your chain and you'll track down the source of the feedback.

 

[Kamanda~SD]

Re: Sh-4 Jb... help with monitor feedback.

What happens when you plug straight into the amp, crank it up and stand in front of it?
What happens when you plug your axe into the other guitarist's rigs and stand in front of their monitors?
Work through a process of elimination of all the parts of your chain and you'll track down the source of the feedback.

+ What happens when you plug in a different guitar ?