Feedback at a show. Only guitars effected?

[blindboybenton]

Point taken chuck

The show or as we call them here in the uk GIG. is done. it was a 50th birthday bash for the guitarist wife

Im off now for a shower and a cold beer.. Its a heatwave here in the uk

speak on the next post

bassman

[Bruce / Mission Amps]

Sounds like a simple case of HARDCORE EMI and high impedance tube circuits vs low impedance transistor crap.

[blindboybenton]

Sounds like a simple case of HARDCORE EMI and high impedance tube circuits vs low impedance transistor crap.

Hi Bruce. This post has got very long. But it did say that it happened with a roland cube and the pa and the valve amps
I did think at one point that it was valve amp related. Hence why i sent my guitarist off to get his Roland, Thinking it would work but it didnt

So in this case the valve and the transistor crap both had the problem.


Bassman1965

[J M Fahey]

Sounds like a simple case of HARDCORE EMI and high impedance tube circuits vs low impedance transistor crap.

That's a most unwarranted statement.

Any modern SS amp typically has 1 M input impedance as standard.

Some 70's and early 80's ones might have preferred 220K (notably Peavey), and that was by choice, they could have easily used 1M too.

Back to the guitar feedback problem, and lack of it in the Bass, let's remember that guitars can use up to 100X the gain Bass players do.

Even at "low volume" total loop gain (including acoustic waves from the speakers getting back to shake the guitar body or pickups) can be enough to feed back.

Also consider poor cables.

And last but not least: as was hinted by some, it might have been not actual feedback but some kind of interference.

[bob p]

if the EMI is that bad then I think you guys should wear Faraday suits to your next gig.

[blindboybenton]

Bassman,

Let me preface by saying I'm not accusing you of being un-knowledgeable about anything, but more details may help narrow this phenomena down.

Two statements by you:

"My guitarist turned up with a Fender Princeton, - feedback at Low volume . He drove home and got his Roland Cube 60 - feedback at Low volume"

"Myself and the other bassist using solid state amps. Not a problem"

That last statement rules out it being ONLY tube guitar amps, because a Roland Cube is SS.

You state that it's ONLY the guitar amps doing this, and NOTHING else is on...no PA, nothing. And, it's doing it at low volumes.

Are you sure you are describing "feedback" properly? Feedback is when a signal regenerates itself by being picked up by a microphone or instrument pickup and fed back through an amp/speaker at a level that allows the amplified signal to picked up again by a mic/pickup, fed back through, etc. It can be a squealing, piercing high-pitched sound, like mics tend to do...or it can be at certain frequencies that resonate, say, guitar bodies to vibrate pickups. Sometimes, you can control the feedback for effect. Think Ted Nugent "Stranglehold".

It takes a signal strong enough to overcome distance to make a guitar feed back.

Solid body guitars are less prone, but can be induced into controlled, or uncontrolled, feedback by being loud enough, and moving closer to a speaker with the pickup and front of the guitar facing the speaker.

Many semi-hollow electrics are more prone to feedback, just because their open bodies vibrate more easily, and pass those vibrations along to the pickup.

Acoustic-electrics are even more prone because they are even more easily induced into vibrating, given they generally don't even have a pickup mounted on a center block inside the body, like many semi-hollow electrics. They may have piezo or microphone pickups that are very easily driven into feedback.

So, what kind of guitars are being used? If they are solid-body electrics, and you don't have the guitars' pickups just a couple inches from a low-level amp...it's extremely unlikely that the guitars are "feeding back".

Also, feedback will occur at at any frequency, depending on the strength of the inducing signal and the resonant acoustic properties and frequency ranges of the object picking up the feedback.

Are you sure you are not referring to some kind of "interference"?

Is the noise always the same frequency? Is it high-pitched and squealing? Does the pitch and level change as you move to and from the amp? Is it a buzz? A 60Hz (or some equal multiplier, such as 120Hz) hum?

Has anyone checked out the voltage from the outlets to see if it is in a reasonable operating range for the equipment?

What else is ran on the same building circuit? The beer cooler? The entire kitchen?

Are there a dozen neon signs lit up and flashing around the playing area, and do they constantly have a bunch of fluorescent lighting on?

Are you, perhaps, picking up some outside radio frequencies from some nearby transmitter?

Are you using good quality "instrument" cables from guitar to effects/amp, and, possibly, good "speaker" cable from amp to speaker?

Are you using wireless guitar packs? If so, what are the operating ranges? If using something older that the FCC has prohibited, are you possibly picking up Eric Holder's bugging signals that he's trying to use to shut down the owner because he's conservative? (Sorry...couldn't help it! They just give us so MUCH to work with!)

Does all the equipment work normally elsewhere, louder and no...whatever you're hearing?

Are you entirely sure it's "feedback", and not "interference" or something else?

Describe the sound, as well as you can. It's hard to believe a low-level amp will cause feedback through a normal guitar of reasonable quality, from a few feet or more away. (Although, I did used to have a cheezy Kingston hollowbody electric that got dubbed "Feedback King" because of it's amazing ability to feedback at ANY usable level...if you weren't turned just right!)

More info may yield a better explanation.

Brad1

Hi

With the pa off and lights off. The Guitarist using the HK amp could hardly get any volume without feedback. He went back to basics and just had guitar and amp no pedals
Long guitar lead. still feeding back. Standing well away from the amp. still feedback. Tried the tone setting. still no change

The guitar was a ESP and he tried is jackson.
Moved to the other side of the stage. still the same

My own guitarist turned up with his Princeton and strat. same thing happened. He got the roland cube. same thing happened. It sounded like feedback and acted like it
Both guitarists did the show in the pa, where is was just slightly better

The Feedback was so bad. couldn't be used for any show. more like bedroom practice.
I do about 50-70 shows a year and have never had this. I think it has to be some sort of interference, But it was only happening with guitars.
I was using my solid state peavey bass head that night with 2 x cabs. Perfect as loud as you wanted. The other bassist had a Ashdown Mag300 + 1 cab with a lovely Gibson ripper
sounded great. He had no problem. The vocals were loud without any feedback issues


The show is done now, But it would be nice to know what it was

bassman1965

[bob p]

And you thought I was kidding, right? Here's an even better pic:

[blindboybenton]

That's a most unwarranted statement.

Any modern SS amp typically has 1 M input impedance as standard.

Some 70's and early 80's ones might have preferred 220K (notably Peavey), and that was by choice, they could have easily used 1M too.

Back to the guitar feedback problem, and lack of it in the Bass, let's remember that guitars can use up to 100X the gain Bass players do.

Even at "low volume" total loop gain (including acoustic waves from the speakers getting back to shake the guitar body or pickups) can be enough to feed back.

Also consider poor cables.

And last but not least: as was hinted by some, it might have been not actual feedback but some kind of interference.

Hi i do think it was interference, but from what? It acted and sounded like feedback. Poor cables no.. Changed them all and the same with 2 combos

I'm a lover of the valve for the bass, But that night i decided to use my Peavey solid state. Which i also like. If you get the tone you want from whatever you have... Great
A lot of bassist use " Transistor Crap " by choice

Basman1965

[blindboybenton]

All the suggestions are just confusing the situation Until someone looks at it that knows the basics of pa and stage gear, the conditions, settings, what was off, what was routed and what was not, is all speculation. The description does not add up, surely it is wrong on key points. Feedback or noise isolation is really simple, eliminating noise is not always so simple but in this case what terms were used and the description is far enough off to render any speculating a waste of time. The problem is simple, whatever it is, but none of us know what the problem is, let alone the cause. Have the sound guy check it and get out of his way. If he can't figure it out, he can't be expected to get a listenable mix to the audience either so the noise/feedback might be the best part of the show.

Hi

This post has got alittle long now.
Lets just say 1 x guitar solid body and 1 x guitar lead and 1 x guitar amp. that was it. No other pa or soundmen tweaking it
Tried all the gain/tone control setting. still the same

The noise it was making. sounded like feedback and acted like feedback. couldnt get any sort of volume before feedback. ( bedroom practice volume with parents a sleep in the next room )
This happened with 3 different guitars and 3 different amps valve and solid state

Both guitarist moved their amps off the stage and to the other side of the stage. Both used long leads, no change

While this was going on the PA was off

But not the bass amps !!. Ended up doing the show with guitarists into the PA. which had the same problem, Just slightly better
Both bands use their equipment weekly without this problem

I think it was interference, but from what ??

Maybe we will never know

[olddawg]

It's a rare gig that doesn't have some irritating problem. I played a very large bar/room last night with a huge PA and gigantic wedge monitors. When we set up, I told the sound guy that we like to keep out stage volume fairly low and I was using a very small amp compared to most lead guitarist he sees there and he would have to mic me up pretty good in the main mix. What happened..... He had my guitar blaring in the monitor mix to the point of feedback, our drummer had no vocal mic and no monitor at all. There was a huge restless crowd so we had to trudge on. I got him to turn my guitar down in the monitor mix at least. Nothing else got fixed. It was a good thing our drummer has a clue. He couldn't hear much of anything the whole night. And .... we we missing his vocal parts all night. I don't know if the drummers wedge had a problem or the guy was clueless at the board. I suspect the latter. Still...it was a great gig to a capacity crowd and we did two encores. No situation is ever perfect. Even on the road with the pros.

[km6xz]

That is a good point, a pro is not the one who can do it well under perfect conditions but one who can consistently perform by novel solutions to problems that occur in every real life event. That is the distinction between those who can be considered "pro" or amateur on stage or in the studio. In any field where craft and skill meet real life conditions with real time fixes to real time problems.

I always chuckled by hundreds of wannabee recordists who would come ask which settings on what compressors or which mics were used on a particular album they were trying to reproduce. My usual answer of "it is not important" was never believed but the reality is that it was the only truth they would ever hear on the subject. The choices made were directly related to the specific problems of the artist, the song, the acoustic environment, and emotional context that would never happen again as a whole.
Success goes to not the best but the ones with best anticipation and reaction skills. A successful stage manager in theater or concerts is never indecisive or slow to identify and creatively correct problems that would be a disaster for anyone else.
The thousands of schools charging good money for teaching music production are a waste of time and money. Those who can make it would be held back by the slow pace of a school, and had already devoured everything in print on the subject by the time they were 15. Their commercial value is not in the technique or procedure, anyone can follow the traditional pattern of events to mediocrity, but in the creative novel solutions to collection of non-optimum conditions present in every session or concert.

In the case this thread discusses, the sound guy was useless if he could not figure out a solution. But he would be typical of non-pros.
I would venture that most who work in the field are non-pros and just get by, most of the time, if the requirements are low enough. The good ones are rare and well compensated.

[blindboybenton]

In the case this thread discusses, the sound guy was useless if he could not figure out a solution. But he would be typical of non-pros.
I would venture that most who work in the field are non-pros and just get by, most of the time, if the requirements are low enough. The good ones are rare and well compensated.

Well in the most here in the uk we have a good music scene doing Bars and clubs and some bigger venues

The musicians use there own kit - Set up there own kit. Most of the time the band uses their own PA.The same for my band. Have done over 500 shows here on the south coast of the uk in the last 9 yrs. Not counting the shows in other places i have lived

Ive never had this problem..

Both bands did well and got a fairly good sound,

bassman1965

[blindboybenton]

Hello bassman

Reading some of the posts. its clear that the pa had no bearing on the sound as it was s/w off ( Not sure why ppl were telling you its the pa ).. if it was feedback, it sounds more like some interference

Nothing to do with Transistor equipment or valve

Gig is done and hopefully your reputation intact lol

Keep on plucking those fat strings

BBB

[km6xz]

The use of the term pa, was being used for audience directed sound, regardless of the specific equipment that it was originating from.
No one has describes the sound in a way that would help identify the sonic properties that would have been pretty easy to tell by ear.

[blearyeyes]

Bassman1965, what did the feedback sound like? High pitched screeching? A tone, a buzzing high pitched low pitched? Can you describe it a little more?

we might need a new section called the X files.