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Feedback when using Acoustic Guitar IRs (Impulse Response) Live

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Good people!

 

I have a handful of IRs for acoustic guitar, such as the 3 Sigma.  When I use them in Helix Native in a recording scenario or on my Helix floor model (through headphones) they sound great.  However when I play them live on a stage through a PA or even my Line6 PowerCab my acoustic guitar feeds back.    The only way I can get rid of it is to go into the Impulse Impulse Response and turn down the mix....like to 14%..... but then I have to turn up the level......   With all of this though the IR is barely noticeable....which kinda defeats the purpose.    Thoughts?    

 

Does anyone know how to keep the IR hot in mix without the feedback?

 

 

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You might want to record some bits and have a look at the sound in an analyzer. With acoustic IRs it's not unlikely that they will have tried to capture certain resonances and these might just be too much when used through monitors. Once you've found out about the offending frequency (or frequencies...), you may want to add a parametric EQ block, dial the frequency in and cut it out using a band with a narrow (high) Q value. Perhaps the 10 band graphic EQ will already be sufficient but for exact cuts a parametric EQ usually would be the better choice.

Also: What kinda acoustic guitar are you using? In case it's a full bodied one, I highly recommend using one of those rubber feedback blockers that you put into the soundhole. Makes a huge difference when it comes to feedback issues.

 

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Setup your tone at "stage volume" not isolated through headphones. That's the only way to induce the frequencies that are causing the problems so you can adjust them. 

As suggested above... an amplified acoustic guitar at stage volume will really benefit from a "feedback buster" (the rubber blocker in the sound hole). 

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You can try using a sound hole cover when playing live. That's a common solution. Acoustic IRs can accentuate the guitar's resonance frequency and encourage feedback. Try blending the IR with some of the direct piezo. That might help too.

 

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This is a very well known “issue” among acoustic players. You can read a bit about it in acousticguitarforum.com (Acoustic Amplification) for more information.

First of all, 3rd party IRs are not made with your guitar and this makes the problem worse since you don’t really compensate the distorted frequency response of your pickup signal of YOUR guitar.
Live sound isn’t the same as recorded sound with acoustic guitars. When you mic a guitar it can sound good in some situations. But you need a really quiet stage otherwise the guitar body will start to resonate and feedback. And that doesn’t sound like a guitar recorded in a studio anymore. IRs help the guitar to sound more like a guitar on a mic – but with all the problems a guitar on a mic provides.

That is why an IR mix below 20% (let’s say 12-20%) is normal for most users. But this is ok because this small portion of IR helps to reduce the piezo quack a lot. A higher IR mix can work when playing solo but in a denser mix the guitar will get lost quickly. Also, the higher the IR mix is the more it is important that the IRs were made with exactly your guitar.

I had some success with putting the IR block on a parallel path. The lower frequencies get more of the piezo signal, the higher frequencies more of the IR signal.
It also helps a bit that I create my IRs with a ToneDexter pedal for my guitars. After that I record an impulse through the ToneDexter and get an IR I can use with my HX Stomp.

With some work you can get nice results. My HX Stomp with ToneDexter IRs is the best acoustic setup I ever had. Works also great with mandolin and upright bass! Don’t give up too early!

All in all there is no way to make the IR loud in a hot live mix, nevertheless you can get a great sound with a bit of IR (to reduce the piezo quack) an the Helix parametric EQ to balance your sound.

Everything written here refers to live sound! Studio recording is quite different.

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I use a 3 sigma IR to make my electric sound like an acoustic for live applications.  Without any eq it tends to feed back around the 180hz mark. At that low of a frequency it just sounds like a boomy resonance but it's quite annoying.  It's very difficult to dial it out while at the same time maintaining a full balanced tone but I think I've managed to get it under control.  As suggested above you need to play it through the system to create a live patch.  I would suggest a spectrum analyzer app on your phone to help you see what frequencies are feeding back so you can try to control with EQ or maybe multiband compressor.

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4 hours ago, litesnsirens said:

Without any eq it tends to feed back around the 180hz mark. At that low of a frequency it just sounds like a boomy resonance but it's quite annoying. 

 

That has always been a problematic range for acoustic instruments... I'm not in the least bit surprised by your experience. 

 

4 hours ago, litesnsirens said:

It's very difficult to dial it out while at the same time maintaining a full balanced tone

 

The trick is to not use too wide of a Q, and only cut the amount that is needed. 

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I had the q as narrow as I can get it but the actual range of feedback seems you be between 170 to 200 (roughly) so if I go too narrow there's still a lot that's not being tamed so it's a real balancing act with amount of cut and Q settings.  What I have now is not completely solved but it's the best I can get it while maintaining a decent acoustic tone.  The other thing is it could be the room I'm crafting the sound in, maybe in a bigger / different room it may not be as bad.  I haven't really done much testing at the venues to determine if this is the case. I'm usually just wanting to get set up... go grab a bite to eat and then come back and play.

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