Impulse response (IR) for an archtop with a piezo

[shpalman]

I think we all know that piezo pickups sound pretty terrible, but that if you want an amplified acoustic sound that it's a lot easier than trying to use a microphone.

Recently though I saw a video about the Audio Sprockets ToneDexter II (it was on the Andertons channel, from September 2025, "The Cure-All Solution for Bad Acoustic Pickup Tone?") which was impressive, but then the ToneDexter II costs more than what I paid for my Vox Giulietta.

But it turns out that a pedal which applies an impulse response, assuming you already have one, is of course a lot cheaper than a pedal which is able to make one itself. If you have the means to record your guitar into a computer using both a microphone and the piezo pickup at the same time in stereo then you put one on the left and the other on the right, and there's a python script (or jupyter notebook) which makes the IR from that. Yes it takes a few minutes and may require that you try a few times with different microphone placements. But it really does make the acoustic sound a whole lot more usable. With the Vox I think I still prefer the first one I made, especially in the context of the whole band.

I've also tried with my Sigma. At first I tried to make the signal from the P90 sound more acoustic, and then I tried with a relatively inexpensive piezo pickup next to the bridge, but it doesn't really work as well as with the Vox.

[Christian Miller]

I have the Tonedexter I and have had some decent results on a GJ style guitar. My Loar LH600, not so much. This may be down to the pickup. I think the unit works really well with under saddle piezos. The thing is I’m not up for doing that with my Loar in case I’m wrong and stuck with yet another terrible built in pickup lol.


Sent from my iPhone using Tapatalk

[Christian Miller]

I think you can do the same thing with a Valeton Gp5 now lol. Which is a tenth the price. And has an IR loader.

Oh well. Doesn’t have an XLR out lol


Sent from my iPhone using Tapatalk

[shpalman]

I've built myself a small pedalboard which features my tc electronic Impulse and a Sonicake acoustic preamp which has an XLR out. It's powered by a usb battery pack and a 5V-to-9V inverter. But for now I'm just using this into my Vox modelling amp set to one of the more FRFR models.

I'll have to make a decent video comparing the acoustic, piezo, and IR sounds. But it works well with the Vox because it has a saddle piezo (and a preamp for that matter).

I just found that there were threads a few years ago, which of course I didn't find before posting this topic:
Tonedexter - the answer to my Acoustic Jazz prayers?
Piezo for Archtop ? ( amplify an acoustic sound )

But the new thing here is the idea that it's possible to make your own IR and use a relatively cheap IR pedal, assuming you have the ability to record stereo into your computer. (Edit: I used the jupyter notebook from here: GitHub - kienphanhuy/Cuki-IR-generator-Python: Python version of Cuki IR generator . GitHub )

There doesn't seem to be an inexpensive way to try a saddle piezo on the Sigma, it would require buying a whole new bridge with a piezo in it, by the look of it. Even if I didn't drill the hole in the top for the wire to go through, it's still a significant investment just to try it out. I did also try a microphone on the Sigma and it wasn't really satisfying, in terms of being able to clearly hear myself with the band without getting resonance and feedback.

Then again, my Sigma has a P90 in it (it's more like the Loar LH-309) so I ought to just play it electric.

[GuyBoden]

Not IR, but I'm interested in trying transducers, stuck to the inside of my Classical Guitar, I try different locations, underneath the bridge feet etc.

Then, I'll experiment with IR, to try to get a more realistic acoustic sound:

[Christian Miller]

Not IR, but I'm interested in trying transducers, stuck to the inside of my Classical Guitar, I try different locations, underneath the bridge feet etc.

Then, I'll experiment with IR, to try to get a more realistic acoustic sound:

FWIW my Tonedexter works best on my classical guitar with the cheapest understand pickup you can get. It’s really good.


Sent from my iPhone using Tapatalk

[Christian Miller]

Here it is on silent guitars

It’s pretty good

I believe Yamaha has this type of tech built into some of their Electro acoustics now? It’s actually quite hard to tell from their promo bumf tbh.

Tbh live I find that I don’t want as much of this as when recording. The more direct cutting sound of the piezo is helpful with a bit of mix (the TD is set up to do this easily). Room acoustics affect things a lot.

Tbh a nylon string through an AER with the speaker pointed at the wall Tommy Emmanuel style does great.

Sent from my iPhone using Tapatalk

[mrwoland]

Hi!
I experimented a lot of systems, and so far I had the best results with a saddle equipped with a K&K fantastick, IR and some processing (mainly eq and reverb).

[shpalman]

There doesn't seem to be an inexpensive way to try a saddle piezo on the Sigma, it would require buying a whole new bridge with a piezo in it, by the look of it. Even if I didn't drill the hole in the top for the wire to go through, it's still a significant investment just to try it out. I did also try a microphone on the Sigma and it wasn't really satisfying, in terms of being able to clearly hear myself with the band without getting resonance and feedback.

It occurred to me that the reason a piezo mounted on the top of an archtop isn't really that useful compared to on a flattop, is that archtop tops are thicker so probably don't vibrate that much. But I did find an inexpensive bridge with a detachable bone saddle such that an under-saddle piezo element can be inserted. The result of that experiment was that there's a reason electroacoustics have onboard preamps. So now I'll try a (still inexpensive) piezo and preamp, the kind which you'd normally mount in the soundhole of a flattop. I'll find a way to velcro it to the back of the guitar down by the far end of it, or something. I doubt I'd be able to fit it into an f-hole and I don't want to do anything non-reversible to the guitar. So far I've only drilled a hole in the new bridge for the wire for the piezo, and filed the bottom of the saddle to compensate for the space the piezo takes.

[Spook410]

I have a Tonedexter I. Works well with full fidelity pickups like piezo's. It doesn't work well with magnetic pickups. Even very good ones like a Sunrise. The way it works is to use the sound of the guitar through a microphone (which you record) to apply a whole bunch of EQ adjustments to make it match as close as possible when the guitar is directly plugged in. There are other pedals out there that work on same principle. These devices are not Impulse Response (IR) loaders or players.

The only unit I have to claims some acoustic guitar IR's is a Mooer. I applaud their efforts and it's an interesting effect but they don't work all that well if you're looking for a convincing acoustic tone.