Axe-Fx III Firmware Release Version 13.00 Public Beta

Thanks so much for continuing to innovate the "dark" side of the product. Lots of wish requests are to do with UI, controllers etc., things we as users know about. Cliff ultimately has our best interests in mind when he makes incremental accuracy improvements like this. He seems to be a "do the hard stuff first" and "in for the long haul" kind of person. I hope he gains as much satisfaction from this as we do (well, he actually knows how to dial this box in, so yeah I'm pretty sure he's thrilled right now).

I wonder if this new calculation method will work it's way into other blocks too? I don't use drive blocks hardly ever, which is fine, but I am so happy with some of my amp tones right now that I am kind of scared of a future update with amp block improvements.
 
Been noticing here lately when i install a preset under the cabs section it says empty. Is this supposed to be normal? never noticed it to do it before.
 
This is some wild fun. Thanks a zillion, Cliff. It's certainly casting a little sunshine on the doom and gloom that's gripped Melbourne at the moment. Much appreciated.

I've spent the last hour or so comparing the Box O' Crunch with an MI Audio Crunch Box V2. I don't know if that's what Cliff has used as a reference but it's been fun anyway. I'll make a little vid if you like. The MI Audio hardware is a brighter beast (at same dial positions) with less sag than the FAS version. However I was able get very close by making three little adjustments: 1. Changing the Red LED Diode+ Quantity to 2; 2. Changing the Diode- Type to 1N4001 (Qty 1); 3. Turning the Tone up to about 6 (similar to noon on the MI hardware). That seems to have toughened up the attack and injected a little more brightness on the model bringing it much closer to the MI Audio CB V2. I used EJ Clean preset's Vibrato Verb and Cab blocks as a foundation.
 
I'm thrilled the overdrives are getting some love!

Shame the Timmy didn't use antilog pots from the get-go for "normal" bass and treble controls. Tiny additional cost to do it right IMHO.
 
We like, we like


This is some wild fun. Thanks a zillion, Cliff. It's certainly casting a little sunshine on the doom and gloom that's gripped Melbourne at the moment. Much appreciated.

I've spent the last hour or so comparing the Box O' Crunch with an MI Audio Crunch Box V2. I don't know if that's what Cliff has used as a reference but it's been fun anyway. I'll make a little vid if you like. The MI Audio hardware is a brighter beast (at same dial positions) with less sag than the FAS version. However I was able get very close by making three little adjustments: 1. Changing the Red LED Diode+ Quantity to 2; 2. Changing the Diode- Type to 1N4001 (Qty 1); 3. Turning the Tone up to about 6 (similar to noon on the MI hardware). That seems to have toughened up the attack and injected a little more brightness on the model bringing it much closer to the MI Audio CB V2. I used EJ Clean preset's Vibrato Verb and Cab blocks as a foundation.
 
An explicit solution is one where the output does not depend on itself, i.e.
V = f(Vin)

An iterative implicit solution is where you have to iterate an equation to get the result. For example consider a hypothetical component where the current is a function of the voltage. I.e.
I = f(V)

In a series circuit with a resistor the voltage across the device would be
V = Vin - I*R = Vin - f(V)*R

Let's say the function is I = V^2

So then
V = Vin - V^2 * R

V is on both sides of the equation. One way to solve this is using Newton's method (x = x - f(x)/f'(x)). But that takes a lot of time because you have to keep iterating until the error is below some desired value. You also have to use the derivative which adds computations. The other problem is stability/convergence. Sometimes the solution "blows up" and doesn't converge. This is unacceptable in a real-time system.

A resistor in series with a diode results in an equation with an exponential (or log) function that needs to be solved along with its derivative.

Now when you add a capacitor in parallel with the diode you complicate things even further because now you have a nonlinear ordinary differential equation (ODE). So the current is not only a function of the voltage, the voltage has "memory" due to the capacitor. Solving these types of networks is extremely time consuming. Things like SPICE use implicit solutions like Runge-Kutta 4 (RK4).

I've been working on this for a while and came up with a semi-explicit solution that doesn't require iteration, has the accuracy of implicit solutions and is nearly as fast as explicit solutions.

This is a graph of a 1K resistor in series with a diode. The blue trace is the reference and was derived by solving the network using Newton's method. The red trace is the semi-explicit solution. If you can't see the blue trace that's because the red trace is nearly exactly on top of it.

View attachment 71052

On the Axe-Fx III solving the network using Newton's method uses over 30% CPU. The semi-explicit method is around 6%.
 

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Here you go.


Cool. The model is based on a V1. That particular model was completely done from a schematic as I don't have the actual pedal yet. It's possible that the schematic has errors. I will know when I get the actual pedal and make measurements. Or maybe it's the difference between V1 and V2.

The other big thing is the pots. Due to availability manufacturers are always changing the tapers. One run will have Log tapers, the next will have linear. Or sometimes it's just the whim of the designer. People naturally gravitate to putting the knobs at noon so the designer will tweak the taper so that the "best" sound is achieved with the knobs at noon.
 
Cool. The model is based on a V1. That particular model was completely done from a schematic as I don't have the actual pedal yet. It's possible that the schematic has errors. I will know when I get the actual pedal and make measurements. Or maybe it's the difference between V1 and V2.

The other big thing is the pots. Due to availability manufacturers are always changing the tapers. One run will have Log tapers, the next will have linear. Or sometimes it's just the whim of the designer. People naturally gravitate to putting the knobs at noon so the designer will tweak the taper so that the "best" sound is achieved with the knobs at noon.

The beauty about this insanely great product that you have created for us is its ability to bend and be flexible. The foundations are laid but we can tweak and twist them all we like - which I have done here. Michael Ibrahim, Mr Crunch Box and the (MI) in MI Audio, is the eternal tweaker. Every time he visits or we catch up he's made another tweak to one of his pedals or amps. So yeah, the 'whim of the designer' is very real with this one, for sure. I will be happy to send you mine - and anything else in my collection - if you wish. Just give me a holler. Tons of stuff here. Thanks again, Cliff.
 
I actually still don't use any drive pedals in my Axe III... it started long ago I had this thing to where 99% of the time I would not use drive pedals with my Mesas, I wanted to get tone purely from my amps... "My' sound came from my MKIII blue stripe which is very hot, but when I got the Mark V it drove me nuts to see everyone consider it standard practice to stick a drive in front of it because the amp was "lacking" gain. The Mark V has more than enough gain if you approach it with an old school Mark mindset, and with a lot of trial and error I was able to get the two to match standing next each other.

But yeah I still don't use any drives in my unit, I definitely use the Mesa patches, but tweak em to where I don't need any. I will tell you, I get crazy sustain and dynamics with my AxeIII and my old Ibanez RG3120, it sings like an angel. I haven't tracked anything for about ten years, and now having this unit I'm getting old music and even new recorded. It feels darn good, and definitely has been a big help to me.

Anyone else stay away from drive pedals by and large?
 
Table of CPU usage per drive type in v13 Beta.

Box o'Crunch and the Riot family record the highest CPU usage.

If you're low on CPU, it pays off to check out alternatives for diode-based drive types. Like a fuzz, cranked SDD Preamp, Tube Drive or FET Boost.

EDIT: updated for 13.3


BB Pre8.7
Bender Fuzz2.6
Bit Crusher3.7
Blackglass B7K2.7
Blues OD8.8
Box o’Crunch9.4
Compulsion Distortion (all)8.7
Esoteric ACB8.7
Esoteric RCB8.7
Eternal Love8.6
FAS Boost8.7
FAS LED-Drive8.6
FET Boost2.5
FET Preamp2.5
Face Fuzz3.8
Fat Rat8.7
Full OD8.6
Hard Fuzz2.5
Heartpedal 118.6
Hoodoo Drive8.7
Horizon Precision Drive8.7
Jam Ray8.6
M-Zone Distortion8.8
Master Fuzz3.8
Micro Boost2.6
Mid Boost3.8
OD 250 / Gray8.6
Octave Distortion2.7
PI Fuzz3.8
Plus Distortion8.6
Rat Distortion8.7
SDD Preamp2.5
Shimmer Drive3.8
Shred Distortion8.8
 
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Great job Cliff and co, the updated drives are wonderful! The Precision Drive is absolutely magic for sculpting high gain tones.



Great stuff Leon - I never really liked any of the Timmys, and the new one is no exception, but the OD250 and Box o Crunch are just right up my alley.
 
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