Axe-FX III with Real cab vs. the Real thing

Is there a noticeable difference when your playing Axe-Fx III with power amp and cab vs. Amp + cab?

  • I hear or feel a difference in the room, but I like them both equally

    Votes: 37 28.0%

  • I hear a difference in the room, but I prefer Axe-Fx III with a power amp and cab

    Votes: 17 12.9%

  • I hear a difference in the room, I prefer real amp with cab

    Votes: 25 18.9%

  • I can't hear or feel a difference, and don't think I could tell in a blind test.

    Votes: 53 40.2%
  • Total voters
    132
aens said:
This is exactly what happened to me last week when I was comparing my Fractal to a real amp. I thought my Matrix was somewhat on par on volume with my 2203 JMP. Matrix got to 105.5 dB (LAeq, full volume) which I thought was pretty loud, until I tried the real amp and…

2203 was at 118 dB (LAeq, master volume on 4) with a whopping 135dB LCpeak. Paint was starting to melt off the walls, so I had to turn down the real amp. I’m almost scared to turn it on again.
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Last time I did this I compared a Deluxe Reverb. A Deluxe Reverb is "only" 22W and it was still ear-ringing loud.
 
Budda said:
Thats when 2203’s sound awesome at least. Sounds like you used to use the JMP without fear prior to knowing the volume?
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True, master at 4 the 2203/2204 really starts to open up. I’ve learned that using the Fractal models. After 4-5 your sound will just get more unfocused. I recently moved to a new rehearsal place and it’s somewhat smaller (too small for a 2203) compared to the last one. Amp is kind of new for me as well and I had not really used it without a loadbox prior to last week.

IAmThePepperoniKing said:
The Matrix only got to 105dB? That’s loud, but not really. A Mesa Boogie V:25 will easily do more than that at 8 feet, probably more.
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I’m using the GT800FX (stereo mode) w/ 4x12 16 ohm speakers (80’s JCM800 1960B w/ white label G12T75’s). If I want more output, I can always use the bridged mode with one cab. It should then be on par with the 2203, have not tried it yet.

By the way, if you want to emulate the 2203 JCM here’s what gets me close on Brit 800:
  • raise bright cap to 1100pF
  • raise master volume to 5.25 (to match master on 4 at 2203)
  • lower transformer match to 0.8
  • drive at 6 sounds best to me, YMMV
2203 JCM/JMP is somewhat more bright, raw and dynamics behave a little more different compared to the Brit 800 (2204) model. Would be really nice to have a stock 2203 JCM/JMP (mkII) in Fractal but I understand we have so many Marshalls already.
 
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Orvillain said:
You can get a decent SPL meter for around £140/$150.
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Can you point me at some meters you think are pretty good in that price range, and maybe describe how you differentiate between those and less good ones, other than price?

I'm not questioning your statement, just trying to learn.
 
Orvillain said:
Typically the threshold for most people to be able to tell the difference in terms of dB is 1-3dBFS, depending on factors like age, hearing sensitivity, etc.

Perception of loudness isn't linear, so this is a really tricky question to answer.

I'd say though if you're trying to make scientific claims, then you need as much accuracy as possible. If you're just titting about at home, then just use your ears.

You can get a decent SPL meter for around £140/$150.



As I said before in the thread, when I match levels with my ears, I can still hear and feel a difference between the Axe3 going into a Seymour Duncan Powerstage, versus my Diezel VH4 - both into the same cab. Although honestly, I'm pretty confident that the Powerstage isn't the amp for me. I wanna try a class AB poweramp or one of the QSC ones that Cliff mentioned before.
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Was it here or somewhere else that the iPhone app Decibel+ was actually pretty close to a real decibel meter? I was impressed. It’s what I use to match levels when comparing, but I never expected it to be highly accurate.
 
FractalAudio said:
Last time I did this I compared a Deluxe Reverb. A Deluxe Reverb is "only" 22W and it was still ear-ringing loud.
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Last time for me was a Princeton Reverb, so evidently 12 watts I think. They sounded incredibly similar. I had to crank the Axe FX rig a little more than usual for general playing/listening in my studio to keep up with the baby amp. Loud, but I know the Princeton won't keep up with the drummer next time he is in. The Axe FX rig has a little more headroom for those occasions. :D

My "go to" live rig for 25 years before getting into Fractal had a Marshall JMP 2203 in it. They sound great to me. They are very finicky for getting a good sound (and must have been hard work to model because of this, less than ideal design parameters), and even in big rooms or outdoors where you can wind them up, they need a little attenuation. They really are very loud.

Liam
 
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Question, which is somewhat related to this:
Are the various amp models “leveled” to a common level?

For example:
  • I go to the 5150iii model and set the level in the amp block to -3db and raise the master volume until I reach 0,00db in the output block meter.
  • I then go to the Deluxe reverb model and set the level in the amp block to -3db and raise the master volume until I reach 0,00db in the output block meter.
The master volume setting I end up with in the two models, is this also the setting which would make the two amps equally loud in the real world?

Or are the various amps leveled completely independent from one another?
 
E-Sound said:
Question, which is somewhat related to this:
Are the various amp models “leveled” to a common level?

For example:
  • I go to the 5150iii model and set the level in the amp block to -3db and raise the master volume until I reach 0,00db in the output block meter.
  • I then go to the Deluxe reverb model and set the level in the amp block to -3db and raise the master volume until I reach 0,00db in the output block meter.
The master volume setting I end up with in the two models, is this also the setting which would make the two amps equally loud in the real world?

Or are the various amps leveled completely independent from one another?
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In my experience, absolutely levelled independently, so you need to adjust. Use the level balancing tool in Axe Edit to adjust the amp block level, it's not really a model accuracy consideration that I have noticed, but it would be difficult to do anyway.

A dimed Fender Twin in a small room would be unusable, similarly a Fender Champ in an open air gig turns out to be a little unhelpful, even when turned up and close mic'd. The Champ might sound just as loud as the Twin in a small room, but the Twin master volume would be way low down, to the point where it didn't really sound like a Twin anymore

The models all sound incredibly close to original amps, depending on downstream reproduction equipment, but you need to set comparative levels for yourself for the setting you are using them in.

Liam
 
I have done some tests today plugging the axe in the return of my jp2c head, I have removed all the options as written in @yek table. Globally it works fine

Except the jp2c in the axe, where the presence shift and presence knob don’t act anymore when the power modeling, cab and all the rest is disable. So I cannot really compare the real preamp with the one in the axe

Some of you that use a power amp, can you try the JP2c and see if these knobs works for you? To me there is zero tonal difference when you turn the presence, or turn on and off the presence shift
 
My name is mud said:
I have done some tests today plugging the axe in the return of my jp2c head, I have removed all the options as written in @yek table. Globally it works fine

Except the jp2c in the axe, where the presence shift and presence knob don’t act anymore when the power modeling, cab and all the rest is disable. So I cannot really compare the real preamp with the one in the axe

Some of you that use a power amp, can you try the JP2c and see if these knobs works for you? To me there is zero tonal difference when you turn the presence, or turn on and off the presence shift
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Presence should be part of the power amp since it's on the negative feedback circuit, so it's normal it doesn't work when you disable the power amp sim. On the other hand it should work on your real amp even when you plug in the fx return
 
DLC86 said:
Presence should be part of the power amp since it's on the negative feedback circuit, so it's normal it doesn't work when you disable the power amp sim. On the other hand it should work on your real amp even when you plug in the fx return
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thanks !

For what I have tried, only the volume in the clean channel worked while doing this. I don’t have tried to be in another channel but? using the head as a power amp 🤔, make no sense to be in Channel 2 ?🤔

Ok so someone who play with the JP2c of the axe, power amp and cab don’t have the presence boost etc. Another raison to keep the real head .
I have tried just by curiosity, as I play with the axe in monitors only everytime.
Except this detail, it worked well with a real cab, I understand why people does that to.
 
I'm using a powerstage 170 also. I like it but this thread has me wanting to try some new settings. In this thread Cliff recommends to use the Solid state poweramp option in the amp block. My question is:
If i'm using out 1 to foh and out 3 to the powerstage and 2x12 cab; Will this setting mess up the sound to out 1 FOH? Or is it such a small 'feel thing' that i won't even hear it at gigging volumes? I know i could run another amp block if it does, i'm just curious.
 
FractalAudio said:
We recently did a blind A/B test:

The cabinet was a stereo 2x12.

Into one side was a Deluxe Reverb. Into the other side was the Axe-Fx into a Matrix amp. The side which each was plugged into was randomized between tests.

The Axe-Fx's speaker impedance curve was set to match the cabinet (it's one of the stock curves). The knobs on the model were set to match the knobs on the amp.

The volume levels were matched.

A footswitch was connected to switch back-and-forth between the amp and the Axe-Fx. The tester was unaware which side of the cabinet was the amp or the Axe-Fx.

In every case the tester picked the device plugged into the right side of the cabinet as sounding "better", regardless of whether it was the Axe-Fx or the amp.

Form you own conclusions.
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by "better" you meant "right" right?
 
FractalAudio said:
Possibly. Hypex has much better damping specs. Never researched Purifi.

A lot of it is about transient energy storage. A tube amp stores a LOT of energy. Take a typical 100W tube amp like a Diezel. It will typically have 220uF of reservoir capacitance and a B+ of 450V. The energy stored is 22.3 Joules!!!

Now take a typical consumer Class-D "500W" power amp (actual continuous power about 100W). They usually have voltage rails around 50V and 680uF or so of capacitance. The energy stored (assuming bipolar supplies) is 1.7 Joules.

The tube amp has over 13 times the energy storage. So those palm mute transients are reproduced accurately. The Class-D amp runs out of gas.

For example, if your transient duration is, say, 100ms, and you're pushing a full 100W then the energy required is 10 Joules. The Class-D amp simply can't do it.

It's one of my pet peeves. People use cheap, low-end, consumer grade Class-D power amps and then make bold proclamations that the models don't sound as good as the real amp without understanding even a lick of the physics involved.

I put an Axe-Fx through a Crown X2 once and it Marty McFly'd me.
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Interesting tech info! If FAS hasn't already done it would it not be a good idea to let those that are not in that mindset to somehow make this common knowledge that are getting involved with this aspect of the game?

I mean I kind of had an idea but not at this level of understanding. It sounds like it would not only put FAS / Amp modeling in a better light but save a lot of people time and money/effort that are looking to run this type of setup to point them in the direction of a recommendation of what to look for and here's why! Just say'n.
 
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