I’ve posted on the Fractal Audio forum about the 3 Sigma Audio acoustic guitar IR files in the past (ref). I wasn’t overly pleased with their J15 IRs (ref) when I paired them with the piezo output from my real Gibson J45. But I ponied up for the J45 IRs when they released them and used them on a guide track for a summer recording project that never really got off the ground.

I thought they did a good job of softening the “piezo sound” out of the very basic pickup and preamp system on the J45 I own. Is it a mic’ed guitar sound? Not really. But it’s not a piezo-straight-into-the-board sound either. It’s good enough for my work and I’d definitely prefer to run a preset on my FM3 with these IRs, live, if I was taking the J45 along to the gig.

Someone on the forum kicked off a new discussion of these 3 Sigma IRs (ref) and I thought it’d be useful to show the piezo signal contrasted against the IR-effected signal so people can draw their own conclusions about whether this IRs will work well for their acoustic applications or not.

Here’s the piezo signal that I captured on the re-amp track while I was playing:

/audio/2021-06-22-3sigma-irs-001.mp3

The only thing I did to that track was bring the level up +3.5 dB to better match the peak output on that track with the peak output on the track where the 3 Sigma IR was applied to the guitar using the CAB block in my Axe-Fx III.

And here’s the IR effected track that was captured at the same time:

/audio/2021-06-22-3sigma-irs-002.mp3

Someone on the forum mentioned a phasey sound with the 3 Sigma IRs. It wasn’t anything I’d noticed when I was recording and I don’t hear any phasing in either of those isolated tracks above. But when I did a mono blend of the piezo signal and the IR effected signal I definitely heard some phasing. So there’s a note for anyone using these: don’t blend your dry and effected signals (or at least expect some phasing or comb filter type thing to happen if you do blend them).

Finally, here’s the piezo panned hard left and the effected take panned hard right so you can blend and compare them using whatever monitoring system you use:

/audio/2021-06-22-3sigma-irs-003.mp3

I definitely like what the J45 IRs did to the piezo system on my J45. And it’s a heck of a lot easier to record my J45 direct and apply some IR magic to spruce it up than it is to get a great mic capture of my guitar happening in my home recording environment.

Call me a fan of the J45 captures at least. They were worth the $10 they cost from the 3 Sigma site (ref).