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Another Axefx vs Amps thread

FractalAudio

Administrator
Fractal Audio Systems
Moderator
The Suhr RL also has a bit of a muted high end in comparison to a real speaker impedance. Here is a plot of its impedance curve:
http://masterplant.com/electronics/Z.pdf

Note how the real speaker has an impedance of around 80 ohms at 20 kHz where the RL has a little less than 60 ohms. That's about 3dB less high frequency load and, depending upon the amp, will make things sound "rounder" due to the reduced high frequency content.

Comparing an amp into a load box to a model of that amp without an accurate impedance curve of said load box is necessarily going to produce discrepancies.
 

Chris Hurley

Experienced
The Suhr RL also has a bit of a muted high end in comparison to a real speaker impedance. Here is a plot of its impedance curve:
http://masterplant.com/electronics/Z.pdf

Note how the real speaker has an impedance of around 80 ohms at 20 kHz where the RL has a little less than 60 ohms. That's about 3dB less high frequency load and, depending upon the amp, will make things sound "rounder" due to the reduced high frequency content.

Comparing an amp into a load box to a model of that amp without an accurate impedance curve of said load box is necessarily going to produce discrepancies.

Anybody that wants to see how much of a difference the impedance curve can make- just play with the impedance curve page in the amp model block. It makes a big difference.

Maybe just rolling back the HF resonance in the impedance curve will get him closer to what he is looking for
 

Heavyplayer

Experienced
Anybody that wants to see how much of a difference the impedance curve can make- just play with the impedance curve page in the amp model block. It makes a big difference.

Maybe just rolling back the HF resonance in the impedance curve will get him closer to what he is looking for
This is definitely something I'm going to mess around with a LOT more as I believe Cliff has updated it. Hopefully it's just what I need and maybe the "clank" is just nothing more than too much high end curve.
 
There are advantages and disadvantages to both. Both can sound great. If everyone just accepts that and picks the right tool for the job the better. In my worthless opinion, the fractal isn’t 100% there yet, though it may only be a small percent off. Tube amps with load boxes for silent stages is not even this close, also IMO. You also can’t carry 2 full stacks, a massive pedalboard, a stable of rack gear, and a trunk full of amazing microphones with one hand. It is unfortunate that every day it seems harder to be “allowed” to cart the real u gear around and play it at a decent volume fir it to sound proper. It is what it is. I don’t imagine there will ever really be a need for two camps (digital vs tube). Just use whatever meets the gig requirements. Fractal is a bit ahead in this respect by quite a bit. Now, everyone will get upset about this post. Haha
 

Chris Hurley

Experienced
There are advantages and disadvantages to both. Both can sound great. If everyone just accepts that and picks the right tool for the job the better. In my worthless opinion, the fractal isn’t 100% there yet, though it may only be a small percent off. Tube amps with load boxes for silent stages is not even this close, also IMO. You also can’t carry 2 full stacks, a massive pedalboard, a stable of rack gear, and a trunk full of amazing microphones with one hand. It is unfortunate that every day it seems harder to be “allowed” to cart the real u gear around and play it at a decent volume fir it to sound proper. It is what it is. I don’t imagine there will ever really be a need for two camps (digital vs tube). Just use whatever meets the gig requirements. Fractal is a bit ahead in this respect by quite a bit. Now, everyone will get upset about this post. Haha
now you've done it... haha
 
  • Haha
Reactions: J.C
Impedence curve is very important, to get your comparisons closer, try to replicate how the suhr’s curve looks, in the axe model.

I saved this picture that was posted here a while back, from someone who plotted various load boxes -

5A7DC217-E303-4456-AF00-C791A1A4D4AA.jpeg


I think the ‘reactive load’ impedence curve is the same as the fractal x load right? Comparing yellow (suhr) to the purple (fractal U.K. mode), you will probably need to turn up the slope parameter, increase high resonant frequency, narrower q for low peak, and slightly higher low resonance.

From messing around with the impedence curve to match what I measured off my cab, it goes a long way to making the models sound more like my real amps. The slope parameter is especially impactful.


Nothing wrong with using tone match also, it’s just eq. I don’t see people hesitant to use a parametric eq when it’s needed. It’s basically just having something with better ears than us make an eq curve to make one sound more like the other. I quite like using it as a diagnostic tool to compare two similar patches to see where the major differences are in eq profile.
 

FusionFanatic

Inspired
I'm open to read and listen to others experiences most are live or FRFR. I've done this as well and you can't hear as huge of a difference. What I been talking about all along is isolated. Where you can hear more of the differences. Again not OMG, but it's there. Live is a whole other situation and we all know WE the players care more about that than most listeners.
This is true. I have both. Real amp vs the Fractal .. In the room.. will be different. Yeah... the tube amp and guitar speaker will sound bigger (at a volume where the amp ‘opens up’ a bit).
BUT... when recording or going thru a PA on a live gig... your tube amp with a mic in front of the speaker will basically give you the same thing.
No?
 

FusionFanatic

Inspired
Do you think that your opinion will somehow magically unlock some technical detail I've overlooked in my nearly 20 years of doing this?
^^ This guy knows his stuff better than anybody. Cliff has nothing to prove... he’s restless in the pursuit to make FAS as good as it can possibly get. If there’s a problem.. FAS fixes it. If there’s a ‘wish’... that may get implemented. I think he and his company established that a while ago and continues to do so.

Not satisfied? Take the time to learn... or just play your glorious tube amp. You’ll still sound like you.

Oh... and let’s not forget the BIGGEST thing... practice. It goes without saying... much of your tone is in your hands.
 

TSJMajesty

Fractal Fanatic
Oh... and let’s not forget the BIGGEST thing... practice.
Absolutely! And it applies to the gear as well, especially with something as complex as a FAS unit, along with the various ways of hearing it.
Since getting my Axe III, I've more inspired to practice than ever before. And it's really paying off. If that was the only benefit of buying it, I'd still be happy. But this gear, and this company, man. Just over the top!
 

Stratman68

Axe-Master
And now I'm accusing you of not reading. For fuck sake man wear your glasses. :D
Are u serious? So, because I DO NOT AGREE \like\appreciate your response's to some of the members that means I didn't read your post? Go back to school will you. Jeeezzzz!
 

Bruce Sokolovic

Power User
I too have sat down with the actual amps of a few models and found them too close to call using IRs.

I’m sure I can find some differences if I dig deep enough but I have songs to learn, gigs to get to, a family, I need to eat and sleep and it’s so close to my ears it just doesn’t matter.

Bottom line: if the axe doesn’t sound good, the problem isn’t the box. So in the end, what’s the difference?

Back in the Stone Age, digital gear either sounded good or it didn’t and wasn’t trying to replicate anything. Does the fractal serve your needs and sound good to you? Great. Use and enjoy it.
 

PowerTube

Member
This is why I always say that modeling is about 90% there. The Axe-FX is among the best I've heard, but there's still that unexplainable "something" that's not quite nailed yet.

I run a Boss GT-100 across a Marshall JCM 2000 DSL 100 in 4-cable method, and totally love the sound. I'm sure the Fractal units are way superior to the GT-100, but I also feel that this gives me that missing element, the real amp in the room.

Having said that, I also believe that it'll be 100% nailed one day, and Fractal may very well be the company to accomplish this. Either way, I can't wait.
 

Jason Scott

Fractal Fanatic
The Axe-FX is among the best I've heard, but there's still that unexplainable "something" that's not quite nailed yet.
If the modeling were perfect, it wouldn't get updated. However, at this point (with respect to recording) the differences are often trivial to the point of irrelevance, and myriad listeners have been (and continue to be) fooled in blind tests.
 
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FractalAudio

Administrator
Fractal Audio Systems
Moderator
This is why I always say that modeling is about 90% there. The Axe-FX is among the best I've heard, but there's still that unexplainable "something" that's not quite nailed yet.

I run a Boss GT-100 across a Marshall JCM 2000 DSL 100 in 4-cable method, and totally love the sound. I'm sure the Fractal units are way superior to the GT-100, but I also feel that this gives me that missing element, the real amp in the room.

Having said that, I also believe that it'll be 100% nailed one day, and Fractal may very well be the company to accomplish this. Either way, I can't wait.
So you don't even have an Axe-Fx but you're convinced there's "something that's not quite nailed yet".
 

RifferMcDuck

Inspired
Relevant to this topic I suppose: last week I brought my AFX3 to my friend's studio, because he's a big tube amp guy and I wanted to A/B it with him to show that it's identical in tone, and thus I am the more supreme human being in all matters and his studio and land will be mine by right of ancient custom. He frequently uses one of those IR loaders in place of a cab (I've never used one), so the plan was to just disable the cab simulation and use that. Anyways, once we got started I realized I was woefully unprepared for the A/B, and it took us some time to get a good setup going as I hadn't even considered which outputs to use and how to make sure the test was equal. When we ran the test, we found the tones were almost identical, however, the real amp was a bit more raw sounding with a little more output to the cab, but most of that difference, to our ears, came from a significant low-mid boost the Axe's tone had in comparison which allowed the mids of the real amp to come through a little better. Everything else was indeed identical in tone, and his conclusion was that he liked both individually and would ideally use them for different purposes.

Anyways, I wish I had posted in the community beforehand to make sure I had the A/B test setup correctly, because I don't feel that I got my big "they're identical!" or "the Axe is clearly better" moment I was hoping for. The most obvious explanation for the differences is that there was a combination of the amp models not having the same exact components (the amp used was the 5150 Blue 100W, but there's only so much I know about amp models, and I neglected to investigate just how different the A/B models were) and the signal levels not being identical altogether - which I can guarantee was an issue because we struggled with it for a bit. But either way, it was the first time I'd heard the AFX side by side with a real amp, and even with the differences (likely setup error) you would never be able to tell one of them was a modeler, which was a really cool experience altogether.
 

VegasGuitar

Experienced
I love my real vintage Marshalls, but for the last year or so they only get run once a month, and many times not even played through. I'm quite happy with the tones I get from my Axe-FX III, and if I get the bug for chest thumping, I just crank it up. Many times that missing "something," is the loud amp through a 4x12 right in front of you. But having recorded mic'ed up real cabinets at stadium volumes, and then the Axe at much more comfortable levels, I cannot hear a difference.
 
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