Real Mesa TC100 vs AF3 into guitar cab - looking for advice

Rekster

Rekster

Experienced
Is there any guides on usage of advanced parameters like negative feedback, presence frequency & depth frequency? Or should it be considered more trial and error?

I’m trying to do a real amp vs Axe FX III comparison. My goal was to post a video online. But I’m struggling to get the Axe to sound identical to the real tube amp.

I have a side by side setup in my room.

1) Mesa TC100 into Mesa 2x12 Vertical Rectifier Cab.
2) Axe FX III into Matrix GT1000FX into identical Mesa 2x12 Vertical Rectifier Cab

Proof provided with the attached photo. ;)

I’ve matched all amp settings.
I’ve tweaked Low Freq settings in the Speaker section.
Yes, cables are fine.
Yes, power amp modelling is on.
Yes, I’m aware cabs are not always identical but I’ve flipped cables and the difference follows the cable.

There’s a really low frequency thump in the real amp that I was struggling to reproduce with the AF3/Matrix amp. Mostly noticeable with palm mutes on low notes on the A string. With the AF3 there’s a dull thud. With the TC100 there’s a huge boom in the low frequencies. But the higher notes are crystal clear, there’s no mud from the low end.

I’ve fiddled around with input and output eq as well but haven’t had much success. The closest I’ve been able to get is to start deep diving and adjusting the negative feedback, presence frequency & depth frequency. That starts to bring in the low frequencies that were missing. But it’s still not perfect.

So my questions are, is there any guides on utilization of these parameters and going into a guitar cab (beyond what’s mentioned in the manual). Also, is what I’m trying to accomplish simply not possible? Will there always be a difference? Don’t get me wrong, the AF3 setup sounds absolutely amazing but I want to make the two setups indistinguishable. Just to say I can do it more than anything and also provide a demo for others. The more I learn here I’m happy to share with others and even work on a guide. @FractalAudio has said that he’s done an A/B before and can’t tell the difference. @FractalAudio did you have to deep dive into the negative feedback/depth settings to accomplish this? Perhaps it’s just this particular amp model?

Looking forward to any input as I’ve been tweaking for a few weeks now. This isn’t critical, more of an exploratory situation. I’m really enjoying what I’m learning along the way!
 

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OrganicZed said:
My suggestion is to direct your attention to the speaker impedance curve. Select a similar cabinet impedance curve and match the low frequency resonant frequency to the cab.

A tone match would be another step to help get them sounding as close as possible.
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Great response. I'd like to avoid tone match, I want to see the modelling work to replicate what I'm hearing in the tube amp. If that's possible.. As for speaker impedance curve, great point. I've set it to a 2x12 Recto. Of course that doesn't indicate if it was generated from a 2x12 Vertical or Horizontal cabinet - if there would be a big difference? I did set the low frequency resonant the best I could. Used Leon’s trick of adjusting until there was suitable vibration.
 
To add onto what OrganicZed has said and to what you have already tried, I would take a look at the Speaker Impedance parameter found in the Power Amp page. I'm sure others will chime in and be of more help. There are some helpful tips here on the forum as well as the Wiki.
 
Isn't it the case that the modeled Master wheel doesn't behave like the real Master wheel?
I would start here.
 
painkiller said:
Isn't it the case that the modeled Master wheel doesn't behave like the real Master wheel?
I would start here.
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I think that’s really the point of this thread. Can I make it behave the same? I could quote other threads where @FractalAudio has stated he’s had an af3 and neutral power amp side by side with a tube amp and guitar cab and couldn’t tell the difference. I’m just trying to learn how to do this. This thread is not a complaint, it’s just me trying to discover and learn along the way… I enjoy this stuff!
 
BBN said:
I've tried the same thing, but never gotten it to be the same without Tone Match.
This thread may help: https://forum.fractalaudio.com/threads/why-your-amp-doesnt-sound-like-our-amp.172907/
Click to expand...
Thank you, I’ll read through it. It’s a substantial difference in bass response which is why I thought I was onto something with negative feedback/depth settings. I’m not expecting a perfect match but the boom of the low frequencies is so substantially different that I’m trying to see how to adjust for that. Depth/negative feedback seem to be making a night and day difference, that’s for sure.
 
Sorry for the lighthearted humor.

I’ve ran into this with my Dual Rectifier. The only thing I can suggest is creating a custom impedance curve for your cab (mentioned before,) and make sure to turn your Matrix up. Don’t be afraid to turn up in general, and/or add some eq after the power amp.
 
Rekster said:
Thank you, I’ll read through it. It’s a substantial difference in bass response which is why I thought I was onto something with negative feedback/depth settings. I’m not expecting a perfect match but the boom of the low frequencies is so substantially different that I’m trying to see how to adjust for that. Depth/negative feedback seem to be making a night and day difference, that’s for sure.
Click to expand...
Start with the 'Speaker Impedance Curve' in the Amp block. Try a bunch of different cab options within that setting. See if something gets you closer.
In my 'attempts', I found that using the Output Eq was the fastest way to get them closer. I had to boost the lows significantly using the 8 band Eq, to replicate my amp.
That, along with the Speaker Impedance Curve (presets) were the only way to get that low end woof/punch that my amp creates.
 
Jambi said:
Sorry for the lighthearted humor.

I’ve ran into this with my Dual Rectifier. The only thing I can suggest is creating a custom impedance curve for your cab (mentioned before,) and make sure to turn your Matrix up. Don’t be afraid to turn up in general, and/or add some eq after the power amp.
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Sorry, didn’t mean to be so sensitive. I just wanted to make it clear I’m trying to learn here. Not complain. 😉

If a tube amp will always behave different I’ll accept that. I certainly have no complaints about the tones I’m coming up with on the af3!
 
Rekster said:
Mostly noticeable with palm mutes on low notes on the A string. With the AF3 there’s a dull thud.
Click to expand...
I am with you on that "thud" brother. I has the characteristics of a rubber band, and I've given up trying to make any Mesa amp model get that tight, choked-off, chunk-chunk that you hear Petrucci do at least once in every video he's ever done. Seems to me you shouldn't have to reach into the deep parameters to get it to do that. If, for example, you can get a real DR to sound that way, I don't know why I find it impossible to replicate it in the Axe III. (But I'm past trying, since it's close enough for me for now.)
 
TSJMajesty said:
I am with you on that "thud" brother. I has the characteristics of a rubber band, and I've given up trying to make any Mesa amp model get that tight, choked-off, chunk-chunk that you hear Petrucci do at least once in every video he's ever done. Seems to me you shouldn't have to reach into the deep parameters to get it to do that. If, for example, you can get a real DR to sound that way, I don't know why I find it impossible to replicate it in the Axe III. (But I'm past trying, since it's close enough for me for now.)
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I wish I could explain better, but there’s a low frequency that just envelops me with the tc100. Without fiddling with depth and negative feedback it’s just a dull thud in the af3. If I can use some of my mic’s to accurately record the difference for everyone to hear I’ll certainly try.

Again it’s mostly noticeable with palm mutes. If I play full chords the two setups are almost indistinguishable.
 
TSJMajesty said:
I am with you on that "thud" brother. I has the characteristics of a rubber band, and I've given up trying to make any Mesa amp model get that tight, choked-off, chunk-chunk that you hear Petrucci do at least once in every video he's ever done. Seems to me you shouldn't have to reach into the deep parameters to get it to do that. If, for example, you can get a real DR to sound that way, I don't know why I find it impossible to replicate it in the Axe III. (But I'm past trying, since it's close enough for me for now.)
Click to expand...
Unfortunately, this is the truth. The “real” Mesa power amp does something that cannot be replicated completely with a Matrix. Through the FX Return? Sure, all day. For better, or for worse.
 
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