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Feedback Reduction Barely Working


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#21 treewiz

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Posted 03 September 2013 - 04:25 AM

I too am having problems with the FBS system in the Stagescape. It does'nt seem to be cutting any of the feedback especially in the monitors where I need it to work the most. What's up with this issue?


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#22 dboomer

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Posted 03 September 2013 - 07:28 AM

You wouldn't be able to actually "hear" it set any filters.  They are too narrow for human hearing to detect.

 

Feedback management is set on the input  page in deep tweak.  It is automatically assigned to those inputs that typically have problems but not set to all presets (e.g. electric guitar settings).  You want to use it in the universal setting if you are running any music through the mixer.

 

I would suggest as a start you make certain that your mixer is running the most current version of the firmware.  It is available on the downloads tab from the main Line 6 page.  Secondly create a new setup just in case somehow a switch was set in the wrong place.  Try a test with a single mic (vocal preset).  Switch to the input tab while in deep tweak and you should be able to see it set filters as you bring the system up into feedback.

 

That said, there is a limit to how much it can do and feedback will occur with all systems.  This will depend on your exact system, its layout and the acoustic space you are trying to work in.  Typically you can expect 3 to 12 dB improvement in gain before feedback.

 

If you are also using Line 6 speakers I would recommend shutting the Feedback switches to off and let the mixer do the work.



#23 litesnsirens

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Posted 03 September 2013 - 08:00 AM

I think another thing to consider with instruments is that there is a difference between the type of feedback you get with a microphone squelch and an actual note of an instrument feeding back, such as a guitar note. When you hear a mic feedback it truly sounds mono tonic like a sine wave. I've had more problems in he past with any system trying to tame a low G, G# or A on an acoustic guitar. But that to me actually sounds more like the guitar note itself building up including harmonics which is going to be far more difficult to tame because its far more complex and the M20d really does thin notches so that it has the least amount of effect on the overall EQ of your mix. When drums ring and then feed back I suspect it's the same sort of thing, more complex than a typical mic.
As Don points out you need to use less aggressive FBS settings for instruments (universal) or you'll get some weird side effects happening. For the acoustic guitar issue I would try using the PARA EQ to try to tame it... They tend to be too boomy anyway on he lower strings. Depending on what notes are actually feeding back either notch them (likely somewhere between 185 and 220hz) or even try a gentle shelf EQ from 220hz down and lower the whol range til you get a nice even sound, which should help deal with the feedback as well.
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#24 davec69

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Posted 15 April 2014 - 12:43 PM

A suggestion that I would offer when chasing down feedback.  Mute the other channels when ringing in a particular channel.  I can't tell you the time that I've spent trying to get rid of feedback on one channel, only to find that an open mic or instrument somewhere else on the stage was actually feeding back while I was trying to dial in the first channel.

 

Now I start by muting all the other input channels.  Getting control of the feedback on the channel that I'm working on, then as a last step, unmute each of the other channel one at a time.  If you get feedback when un-muting one of the other channels, then you can start on that channel for your next channel to test.  Mute all of the other channel and repeat.


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#25 bassman24

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Posted 16 April 2014 - 01:02 AM

I have no solution for the FBS not working, but just want to throw in some thoughts on feedback issues:

 

I found out that using Line Array type of Speakers are VERY prone to feedback (No matter if using an analogue Soundcraft desk, a behringer Xenyx something analogue desk or the M20d), just hold a mic or acoustic guitar somewhere near the speaker (even 30-40 centimeter will do the trick, no matter if on the side or behind the speaker) and off goes the typical "hummm" or "hiss".  At the Moment we are using H&K Soundcaddys. As said before until last year we gigged with an analogue Soundcraft EFX-8 from one of our guitarists and now with my M20d. We had feedback issues every time during our last gigs, no matter if using the new M20d or the old desk. Mainly the feedback is coming from one of the acoustic guitars which is using a combination of Piezo and microphone pickup. Unfortunately we cannot get the guitarist away from using one of the soundcaddys also as his monitor and he is always sitting just on the side of the soundcaddy. Bad augury, I know.

BUT: I used the preset for acoustic guitar direct for his Martin, which was not having ths FBS on the channel strip. Changed that to acoustic mic´d preset, which is featuring the FBS on the Strip by default. Looking forward to hear the difference at the next gig.

 

I´m also looking Forward to buy some L3T and use these on our gigs. Hope it will be a big improvement over the Soundcaddys, because our Soundcaddy Line Arrays are not designed to work as monitor AND FOH at the same time IMHO  :)

 

So, my conclusion is: OUR feedback issues are related to combination of ignorance, too less knowledge of the M20d and not the right use of our equipment, and isn´t really to blame on the M20d or the FBS built-in. Nevertheless our Sound has improved tremendiously since using the M20d :)

 

What we did and will do once again in the next few weeks is a technical rehearsal where we are going to test some new setups I have created and just Play around with all the Options the M20d offers until everyone in the band is satisfied with his and the Overall Sound of FOH and monitors. We can Play around without time pressure during the soundcheck before a gig. Maybe this is also an Option for you to just get together with the band and Play around with your Options until everyone in the band is satisfied and you can reduce or even eleminate feedback issues. At least this will give you a good Basic Setup for the next gig with only a little (or in some venues a little bit more)  tweaking necessary.


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#26 dboomer

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Posted 16 April 2014 - 09:18 AM

If switching the piezo channel to include FBS didn't help much then you have a very difficult problem. That would mean that the sound back to the guitar is so loud that is is resonating the body back into the saddle pickup.  Have you tried a Feedback Buster plug in the sound hole?



#27 SiWatts69

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Posted 16 April 2014 - 03:34 PM

Feedback is inevitably the root of all evil for us hobbyist sound techs with our M20's but ultimately, it is generated when our on-stage volume is typically higher than needs be. I hate to say it but guitarists and bassists are the worst... They set the stage levels with their backline then the singers grumble because they can't hear themselves, so the monitors get pushed up and up... hey presto whistles galore.

Get your backline players to reduce their on-stage volumes AND direct their cabs away from FOH so it is there purely for them. Now try doing an initial soundcheck with just vocal monitoring and backline (leave the FOH off at this stage), getting the monitors to a point where your singer(s) are happy. If you then "push" the monitors up an extra 5-10db with singers in place behind their mics, you'll likely induce the worst of the feedback frequencies for the M20 to notch out and can then drop the levels back down. Then record something.

The last time we ran the rig out, we did just that. Singers happy and on-stage levels sensible. We then did a basic mix in headphoneswith the recording before heading out front with everyone to tweak the mix and set FOH levels. Aside from a few inevitable whistles early doors ( as the room acoustics had changed with people) the M20 notched out the extra frequencies pretty quick. We were complimented on two fronts... how good we sounded AND on how sensible our overall volume was. Loud enough to be enjoyable but not so loud that people had to shout to each other to be heard.

My only gripe at present is a bass player who tweaks his bass guitar volume control during the set... we've a full gigs worth of recordings where his levels start out great but by the end of the first set his input has got too hot and is distorting.
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#28 Digital-sound

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Posted 16 April 2014 - 04:23 PM

I agree. I constantly battle with our guitar player. He claims he is not louder than the drums. I tell him to put his amp beside him and point at his head! But guitar players generally don't like to do that. They feel they need the tone of their amp. They have no faith in the front end sound apparently. At least, this is many of the guitarists I have played with. But not all. I have met a couple that use their amp as a monitor for themselves. We are a four piece. 3 of us use IEM. No need to mention who doesn't use an IEM! So he has an L2m as a monitor. I have stopped bringing a bass cabinet and run my bas direct. We mix it into our IEM's and I put my bass through the (non rattling) L2m. So we have made huge progress. Trying to get the drummer to move to E-drums. He is close....just not in the budget for him yet. But, at least he is willing. That is a start.

But I totally agree. Feedback is drive by people being too loud, and often the guitar player (waaaay more than us bass players!). Then the vocal wedge is never loud enough.
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#29 bassman24

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Posted 16 April 2014 - 10:53 PM

@dboomer: Yes, I have told our guitarist to use feedbackbusters, but he refuses also to use this Little helper. He think´s he is too quiet then.... *sigh*

 

@digital-Sound: Introduce your Drummer to this:

http://www.schlagwer...to/booster-set/

 

I promise, he will be A LOT quieter :D


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#30 SiWatts69

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Posted 17 April 2014 - 02:01 AM

I agree. I constantly battle with our guitar player. He claims he is not louder than the drums. I tell him to put his amp beside him and point at his head! But guitar players generally don't like to do that. They feel they need the tone of their amp. They have no faith in the front end sound apparently. At least, this is many of the guitarists I have played with. But not all. I have met a couple that use their amp as a monitor for themselves. We are a four piece. 3 of us use IEM. No need to mention who doesn't use an IEM! So he has an L2m as a monitor. I have stopped bringing a bass cabinet and run my bas direct. We mix it into our IEM's and I put my bass through the (non rattling) L2m. So we have made huge progress. Trying to get the drummer to move to E-drums. He is close....just not in the budget for him yet. But, at least he is willing. That is a start.

But I totally agree. Feedback is drive by people being too loud, and often the guitar player (waaaay more than us bass players!). Then the vocal wedge is never loud enough.


Our guitarist, if anything, is the opposite and often has to be told to turn up a tad on stage.
He uses an Egnater Tweaker and has the extension cab. The main cab is fired sideways off stage with an SM57 in front of it, fed to the M20d and he then has the tweaker extension cab on an angled stand firing back at him like a monitor from front of stage. As a result, his backline doesn't have much impact at all on the FOH levels as it isn't contributing to the sound projected from stage. Our bass player on the other hand...
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#31 Digital-sound

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Posted 17 April 2014 - 05:13 AM

@dboomer: Yes, I have told our guitarist to use feedbackbusters, but he refuses also to use this Little helper. He think´s he is too quiet then.... *sigh*
 
@digital-Sound: Introduce your Drummer to this:
http://www.schlagwer...to/booster-set/
 
I promise, he will be A LOT quieter :D


Actually, our drummer isn't too bad at all. Just our guitar player. But we have him in control....just have to have a leash on him all the time! Not allowed to run free!
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#32 dboomer

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Posted 17 April 2014 - 09:30 AM

@dboomer: Yes, I have told our guitarist to use feedbackbusters, but he refuses also to use this Little helper. He think´s he is too quiet then....  

 

He may think he's too quiet but his guitar/piezo system thinks otherwise.  It's true that he might not be loud enough to be heard but feedback doesn't care about that. :)

 

Here's what feedback actually is ... he plays a note and that note goes through the system.  The system sends it out in the air and some of it gets back to his soundboard and piezo where it gets picked up and sent back out.  If it gets there at a lower volume then it went in then it gets sent through at a lower volume and as you can see quickly dies out.  But if it gets back at equal volume or louder then when it was originally played the next time it gets picked up and set through it comes back even louder and it will keep building and building as the loop continues.

 

Usually the frequency response of these loops is not perfect and the FBS works by pulling out some of the peaks (which are very narrow).  Once the FBS has pulled out a number of narrow peaks and only wide peaks are left it stops being helpful because at this point it would simply be turning down the overall volume.  So FBS is helping some but not as much as you need it to.

 

So in his case the soundboard is concentrating the regeneration in one big group and there is nothing electronic that can fix it. He can either turn down, move father away from his monitor so the sound from it won't get back to it as loudly or make some mechanical compromises to de-tune the problem.  He has no other options ... well, or switch to electric  :D



#33 cruisinon2

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Posted 17 April 2014 - 09:53 AM

Actually, our drummer isn't too bad at all. Just our guitar player. But we have him in control....just have to have a leash on him all the time! Not allowed to run free!

 

You need a leash for the guitar player? But how do you keep the drummer from wandering off into traffic? They're easily confused... :P

 

 

 


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#34 Digital-sound

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Posted 17 April 2014 - 10:23 AM

Drummer is in a cage.
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