Using acoustic IRs

mark_jwedge · September 2020

I had an acoustic gig this afternoon. This is a bit of a rarity for me as all three of the bands I play in are pretty much 100% electric.

I have a Taylor 214ce and downloaded the 3 Sigma Audio Taylor IRs to use with my HX stomp and connected to the desk via a DI box. On the stomp I had the IR going into the tube mice preamp on the stomp then a reverb and delay with a compressor as a solo boost.

The sound had a very metallic edge to it and sounded nowhere near the other guitars players sound. He used the same model guitar into an LR Baggs preamp.

I was wondering if anyone has any tips of creating patches on helix/HX devices using acoustic IRs or any eq tips?

TimmyO · September 2020

Acoustic IRs are made for a particular source - were your IRS being fed with the input they were expecting eg intended for a piezo and being fed with a piezo intended for a magnetic and being fed with a magnetic

TheBigDipper · September 2020

TimmyO said:

Acoustic IRs are made for a particular source - were your IRS being fed with the input they were expecting eg intended for a piezo and being fed with a piezo intended for a magnetic and being fed with a magnetic

I didn't know that. Interesting!

Re Acoustic IRs in live use. My own experience is I'm better off with a preamp-type approach. I've played with IRs for recording purposes and you get time to adjust things without the pressure of performance. At the gig, I prefer my FlyRig Acoustic or K&K Preamp to using a Line 6 - with or without IRs. I've tried my HX FX and the FlyRig is smaller and easier to set up. I've only got K&K Pure Minis in my acoustic guitars, though - no onboard preamps, no magnetic pups or piezos.

mark_jwedge · September 2020

TimmyO said:

Acoustic IRs are made for a particular source - were your IRS being fed with the input they were expecting eg intended for a piezo and being fed with a piezo intended for a magnetic and being fed with a magnetic

Having done some reading around this morning, I think this might be the crux of it. The pickup system in my Taylor is piezo based and I don’t think I was using the right IR for that.

I loaded the whole pack of IRs onto my stomp so will have a play later and scroll through to the ones labelled piezo! Doh!

Roland · September 2020

With the right equipment you make your own IRs. I have an IR which matches my favourite acoustic to my Telecaster neck pickup. The acoustic has no internal pickup, and is too precious to gig with. However the IR make the Tele sound like it. No delicate guitar to worry about. No micing and feedback problem. No changeover time: I can play Crazy Little Thing Called Love on one guitar.

Grangousier · September 2020

Can you point to a good tutorial for doing that? I'd like to give it a try. Most tutorials I've seen are for doing amps and speakers, rather than acoustic instruments, but I've had a lot of good results using acoustic IRs.

Bidley · September 2020

I used this video. and downloaded a bunch of IRs and picked the one I liked. I'm really pleased with my acoustic tone through the Helix. I use my mandolin through it with similarly brilliant results.

Grangousier · September 2020

Thanks! - sorry to be clear, I was wondering of there was a resource on creating your own IRs from acoustic instruments. I found one thing that suggested using EQ Matching, but it wasn't clear exactly how to set up the source and target.

Roland · September 2020

It’s one of those logical problems which has different answers depending on what equipment you’re using. I used an AxeFX, which has an IR creation capability where you feed two signals in. It compares them, and produces an IR.

My acoustic was mic’d up. I don’t have a studio mic, so used my stage mic. The mic was plugged into the AxeFX, and routed to one side of the IR creation software.

My Telecaster, on neck pickup, was plugged into the AxeFX input1. The signal was passed straight through to my FRFR speaker, which was mic’d up with the same stage mic, and back into the AxeFX via input2. From here it went to the other side of the IR creation software. In theory this eliminates most of the characteristics of the mic and speaker.

The recording was done in a small room, with sound shielding, to eliminate minimise reflections. I strummed chords at various neck positions on both guitar, and created IRs. For the acoustic I tried several different mic positions and angles. I narrowed the choice of IRs down to three. We made a final choice at a rehearsal where we could all listen through the PA at volume.

mrkb · September 2020

You've just inspired me to "Tone Match" my acoustasonic to my strat humbucker using the AXE FX III - blimey its easy! Might tone match all the acoustasonic settings to make a very flexible "electric does acoustic" preset. Thanks!

Grangousier · September 2020

@Roland - thanks for that! Looks like I'll have to experiment with what I've got (not an AxeFX), but it might work...

Cirrus · September 2020

So, the deal with acoustic guitars;

They have a lot of resonances. It's how they project sound and are louder than an unamplified electric, so it just comes with the territory. Their typical frequency output is a ludicrous mountain range of peaks and troughs.

So if you make an IR of that and apply it to something that doesn't have many resonances (and electric guitars usually only have one major resonance, in the upper mids), then you're transforming a relatively smooth curve into a jagged one that mimics what the captured response of an acoustic would be like.

Now...

Do the same with an acoustic guitar; apply the resonant response of one acoustic guitar to the output of the guitar you're playing, which already has its own resonant response filled with peaks and troughs.

It is a far more unpredictable result. Some peaks will line up, and you'll get boomy, honky or ringy crazy peaks. Others will not line up, and will either result in strange dead spots or a peak and a trough just cancelling out and not doing much. It might work well, or it might be rubbish. It just depends on the particular shape of the signal and the IR response you're applying to it.

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Using acoustic IRs

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