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Curve EQ Trick


This is kinda in response to a thread gone out of control over in the general discussion area (and I share in the guilt, most definitely).

This is a trick I used when trying to mimic guitars that I had with my Roland VG-88 and some amps on my Vox TLSE, etc.

I haven't tried this yet w/ my AFX because I simply haven't had the time. Hopefully I will soon.

What you need is this:

A sample of the tone that you wish to achieve. Something by itself, with no other instruments going on in the background. You need to be able to play what is in this sample. For creating a rhythm patch, the strumming of a chord (all you need is one for the most part) is great. For the lead tone, you might want a couple of samples. Maybe one note that is held & picked, while another that is a bent note. Maybe one up high on the neck and one down low. It all depends on what gets you there. It's easiest to get a note that is not bent.

You need a PC (Win/Mac/Whatever) with an audio interface to get audio in and out, and some sort of software that can load up VST effects (if you don't have a DAW there are standalone VST hosts that you can get free, or for a 30-day trial).

You need a "Curve correcting" EQ plugin. The one that I used is the Voxengo Curve EQ. Many daws come with an EQ that can do curve correcting. There is probably at least one free curve correcting EQ VST out there I would imagine.

A good idea of the equipment used to create the sound sample (guitar type, amp, pedals, etc.).

OK, so lets start with say an Eric Johnson lead tone. You can get a sound sample from his instructional videos. There are also some videos w/ decent sound up on harmony-central.com somewhere. Record a playing snippet from that source, and figure out what he is playing.

So we have a sample. Load it up in your software and use the EQ plugin (you're gonna have to figure out the steps for this on your own as it will be different for different software) to take a "snapshot" of that note. It will display a frequency analysis and an EQ curve (again depending on your software).

Now from research we know that EJ's lead playing consists of him running a strat into a Chandler/B.K. Butler overdrive pedal, into a plexi (he uses 50 watts now, used 100 watts in the past), and runs old cabs w/ celestion greenback reissues, IIRC. he used a 58 335 on the recording of Cliffs of Dover, and a few other songs too. So we pull up a plexi. Crank the Master Vol up to between 9 & 10 since that is where it is *supposed* to be for a non master volume amp. Feed it into a greenback cab in the cab block. In front load up the Tube Overdrive pedal (if you look in the manual, it's actually a model of a BK Bulter/Chandler tube OD pedal!).

OK, you've got your chain going. grab whatever guitar that you have that comes as close as you can to what he's using (again this is up to you). Now before you engage the OD pedal, bypass it and start dialing in the amp model with it's basic gain, treb/mid/bass and get as close as you can. Now turn on the TubeOD with everything set low and start to bring up the gain on it. Adjust the EQ on the pedal as necessary to get as close as you can by ears to his sound.

OK, you've gotten as close as you can w/o touching the adv params. Now record yourself into the computer playing that exact same note that Eric played, as close as him as possible. Try to mimic the attack. He's a gentle picker so don't go attacking that string with the pick.

OK, so you've got the real EJ sound, and your recorded sound. You've got the Curve correcting EQ with a snapshot of EJ's EQ curve. Now, take your sound sample and run it through the EQ. Again you're gonna have to play with whatever softeware and figure out how it works. What the EQ should do is take your sound sample and EQ so that the output is as close to the EJ sound sample as possible. Listen to that. That is where we are going. Now you should be able to see in the software exactly what frequency ranges were boosted or cut and how much.

What you need to do now is apply that same boost/cut to your patch. There are a few way of going about this...

if it's a broad range, try using the amps treble/mid/bass controls. This will give the least accurate results, depending. If the range is not quite so broad, perhaps try a parametric EQ or a graphic one for narrower cuts & boosts. Dial that EQ in (don't even listen to the patch at this point) according to the boosts & cuts shown in the curve correcting EQ software.

Now, you just have to experiment a little. Throw the EQ AFTER the amp and you should get just what the "corrected" sound sample sounds like. If you want a slightly more subtle change, throw it in front of the amp, some somewhere in the middle.

If you have the time to really sit and play, then don't use an EQ to ge the changes. Use the treble/mid/bass, the gain, the volume knob on the guitar (hint: EJ turns his volume knob down, and if you listen his tone in many spots is REALLY close to that "Clapton Woman tone"), and play with the frequency parameters in the advanced parameters, play with the Tube pedal's setting, etc.

In the case of EJ he generally has his amp set up for his rhythm tone, and then for his leads, he simply stomps on the OD pedal - no amp change from rhythm to lead. In cases like this, it's much easier to start with a rhythm tone and get the amp dialed in perfect. Then for the lead tone just ad the pedal up front and you know that all you have to do is tweak the pedal to get you the rest of the way to the lead tone.

Anyway, hope this helps some get where they want to go. It's helped me a lot in the past, and hopefully will again w/ the AFX!

Oh, if anyone has suggestions for preferred software for this approach, be it free or paid for, that would be great! Post 'em here.


Hmmm... I tried this several times with the ASSIMILATOR plugin for my TC Electronic Konnekt audio interface, but the result is not satisfying.

I don't think your way is wrong, but specially for me it won't help. In any case the best way to come close to your reference tone is experience. The more you have the closer you can get. Programming a lot with the Axe-FX is the best teacher I guess.

Even your way with reference and destination eqs needs a lot of experience.


Superwaldi said:
Hmmm... I tried this several times with the ASSIMILATOR plugin for my TC Electronic Konnekt audio interface, but the result is not satisfying.

I think a lot of it depends on your equipment and sources as well. For example, when I got my ToneLab SE I used that to cop an AC/DC rhythm tone that was absolutely spot on, and it was easy. I used to to cop an Eric Johnson clean tone. The EQ curves matched really well, but played through the amp, it just didn't sound quite right. I tweaked it from there on my own and got what I think actually sounded a little better.

I then tried with an EJ lead tone, and got close, but just never quite there. Even tweaking on my own I was never able to get it exactly where I wanted. Eventually I said screw it, my patch is good enough, I need to spend my time practicing (we were doing a cover of "When the Sun Meets the Sky" at a gig).

I think the source from where I got the EJ files was a good part of the reason why I couldn't get it quite right. It was a video, and it was highly compressed. That removes the highs and lows. When you see it on your computer or whatever it sure sounds right, but when you mimic it and play it in the room, you realize all of the bass and upper frequencies that are lost! My biggest issue with the tone was that when I got the EQ curves, it just sounded too muffled to me. When I birghtened it up it lost some of the smoothness, and I could never find the proper balance. I was also playing my Parker Nitefly which while it has a humbucking DiMarzio in the bridge, it's not the same one as EJ and my guitar is swamp ash where his old strat was likely alder. EQ should have been able to get me fairly close, but again, on PC speakers and in the room sound very different, and a compressed source didn't help.

So there is a bit of hit and miss, and you do generally have to fine tune with your ears.

It's kinda like the 80/20 rule. $20 will get you 80% of the results that you want, but to get that last 20% of the results, you have to spend an additional $80 to get there. :)
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