Capturing acoustic guitars for piezo pickups

I’ve been thinking about it for a long time and I think I’ve come up with a method to do this and it could be a great way to improve the sound of piezo pickups, but I don’t know if it’s possible. The basic idea would be to capture “acoustic guitar profiles” so instead of sounding like a quacky piezo they would sound like the original instrument. The method would be setting up an acoustic guitar in a studio room, recorded both with the piezo and well placed quality microphones. Then install a vibration speaker, on the soundboard, those that make their sound by vibrating a surface. Then run the capture process, but instead of comparing the clean vs amp signals, it would compare the piezo version versus the one recorded with the microphones. This way, it could apply the harmonic distorsion, eq and compression to match the real sound fo the guitar. I don’t know if it’s possible, but if it was, then it could change the live sound possibilites for acoustic instruments. In fact it could be done with different brands of pickups and instruments (not just guitar, but also violin, cello…) creating a lot of flexibility. The user would just choose on the quad cortex menu the pickup he’s using and instantly it would sound like a studio recording. Is this possible? Is there a reason why it shouldn’t work?

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There is already a conventional way of doing this, no need for the Quad Cortex. Research creating a custom impulse response for your guitar. In short, you run your guitar pickup and mic’d guitar into your computer’s DAW. You play some licks recording both sources simultaneously. Then you need a VST type plugin that compares them and creates an IR file. I’ve done this and the results are stunning. You can buy off the shelve IR’s from people like 3Sigma, but I’ve found creating one custom for your guitar and pickup is more successful. The QC can load IR’s, so you can just load the IR into it and your done.

Thanks for the tip, but I’ve already done this with Izotope Eq matching and Voxengo Deconvolver and I think it doesn’t solve the problem. It only gets you so far, but the problem is that an IR is a static capture. It cannot understand all the differences which are much more complex than just an EQ curve. A piezo changes the eq in different ways depending on many factors. It also changes the dynamics of the sound and how it feels and reacts to playing nuances, so capturing this difference as if it was a compressor or an amp could work better than approaching with just eq. For example, it would know the differences between soft and loud playing, the same way an amp capture changes distortion amount depending on the input signal volume… I don’t know if it’s possible with current quad cortex software, but if it is, I think it could great

Yeah good point. I love your idea. Even if Neural made it easy for a custom acoustic IR capture, that would be a great QC feature.

On Kemper or Atomic I have very successfully used Sigma Martin 45 Impulse Response which gives a fantastic tone and feel for a few quid, stage and studio … I can 100% vouch for that after 20+ gigs last year.

Thanks Chalky but the problem is not which IR to choose, but the limits of that technology. I’ve used them before, but in the end, an impulse response is more like a static image of the whole sound and it applies it evenly to everything you feed into it. And that’s not the way a guitar changes frequencies and dynamics, it’s much more variable and nuanced. In some ways it’s the same as an amp, depending on the intensity of the notes it drives more the soundboard and changes the timbre. With IR’s there’s always one note that sounds horrible because that frequency has been hyped to match the eq curve. Also, as the piezo loses some frequencies, sometimes you have to apply some harmonic distortion to bring them back in a more natural way, if you did that with just eq it wouldn’t sound as good. Don’t get me wrong, IRs have drastically improved the sound of piezo pickups live, but for me it’s just not there yet.

I think it wouldn’t hurt them to try and it would be a massive bonus for those who play both electric and acoustic, it would even open the market for bowed string players which always have problems with pickups. It’s a very simple test if they already have a guitar with a piezo pickup (they would just have to buy a vibration speaker and lose a couple of days experimenting) If it works, then they could refine it, capture different pickups and make some tweaks on new upgrades.

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No disagreement at all … i’m just saying that compared with all the so-called acoustic simulation pedals I have bought / tried, that IR (when dialled in properly) is the nearest for acoustic guitar sound and (importantly) FEEL under the fingers for live stage use where you cannot hook up a decent mic configuration