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Axe-Fx III Firmware 2.00 Public Beta #2

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2112

Fractal Fanatic
Can we get this clarified? I thought the default was 0.0
So with the new, we need to increase 5.0? Is that correct?
Perhaps if everyone agrees that this is best, maybe we could ask for a global auto increase? Rather than manually changing 300 presets.
You can do a batch reset using Fractool IIRC
 

Rex

Legend!
(sitting on my PC now, I will review this for more understanding)

Since I am working full time with these kind of stuff (loudspeaker nonlinearities), maybe I can shed some light on this mysterious parameter:
See, a loudspeaker is a highly nonlinear device. Just like mentioned before, trying to push the speaker "inside", you will see that you need more and more force as you pushing it in. The same is true for the opposite direction, but obviously, it's easier to verify if you push it in :)
The term for this effect is "stiff", since, you need more force to get the same displacement, depending on the position of the speaker. "Stiffness" represents the inverse of compliance - the less compliance you have, the stiffer is the speaker. And, as seen from the stuff I've written before, this depends on displacement.

So what's the deal with this effect?

See, an impedance just simply states a relation between voltage and current. So, as current drives the mechanical parts of the speaker, a voltage is induced back (called "back EMF") because of the speaker movement. In other words, the compliant mechanical load also affects the electrical side. This will result in a dynamic impedance change, which will change the behavior of a current coming from a power amplifier. Mind this depends on displacement, a mechanical parameter. Thus, to model the interaction on the power amp side correctly, you have also to model the behavior of the (dominant) mechanics. Apart from that, a change in compliance will also dynamically shift the resonance frequency of the loudspeaker, since resonance frequency depends on the compliance.

Hence, even on a guitar speaker, you can leave this parameter on, since a guitar amplifier would have to work with the same changing load.

Note: since this nonlinearity depends on displacement, you will have this effect more pronounced on notes giving you more displacement. However, displacement will drop by 12dB/octave above the (linear) resonance frequency of the loudspeaker (see the mechanical lumped parameter model on this, it's a second order system).

I suspect you won't hear any effect on higher frequency notes, but it gets more pronounced on the lower notes. You shall hear it as a dynamic increase in perceived bass, from a spectral point of view (at least this is the effect on the speaker side).

Compliance isn't the only nonlinearity, but one of the most pronounced with a high impact.

(Edit: Just added a little bit more about the relation of the mechanics to the electrical side - I was just implying to much)
Excellent information @moerker ! But help me understand something. Your description of compliance as a nonlinear function runs counter to my understanding. Compliance is a linear relationship between force and cone displacement.
 

phil92

Inspired
Excellent information @moerker ! But help me understand something. Your description of compliance as a nonlinear function runs counter to my understanding. Compliance is a linear relationship between force and cone displacement.
proportional, not necessarily linear. But I think what's most definitely non-linear is the compliance or stiffness in relation to frequency
 

REDD

Power User
I made a couple of identical presets a couple nights ago and one was 0.0 spkr compliance and the other at default 50%
I didn't hear a big difference but I had been playing for a while. I just switched back and forth tonight with fresh ears and I can hear the difference and I like the compliance preset way better. Sounds clearer and maybe rounder and more amp like if that's possible. Maybe rounder isn't appropriate, just better and more focused. Whatever I'm trying to describe, I like it.
 

James Nash

Member
I'm new to this forum, so please don't anyone take this as an insult... but I'm surprised there are as many concerns and/or followup requests generated by this release.

IMHO, this beta represents *outstanding* continued support and development:

1) We're getting a free public beta version of an interesting new form of amp/speaker modeling. No charge, no waiting.

2) We're getting it in a way that causes no disruption to current use of the product.

In my experience, a huge-co software/hardware company would basically NEVER do this -- they'd hold back the feature, bundle it with other stuff, and charge for it, likely with no regard for backward compatibility with your existing patches. And, honestly, part of why a bigger company wouldn't do something like this is... a desire to avoid increased support volume :)

Just a friendly reminder not to look a gift horse in the mouth :)

(Now, that said... I'm eager to understand this new parameter better, too... so thanks for the great discussion on speaker compliance! Cool stuff!)
 

Rex

Legend!
I'm new to this forum, so please don't anyone take this as an insult... but I'm surprised there are as many concerns and/or followup requests generated by this release.

IMHO, this beta represents *outstanding* continued support and development:

1) We're getting a free public beta version of an interesting new form of amp/speaker modeling. No charge, no waiting.

2) We're getting it in a way that causes no disruption to current use of the product.

In my experience, a huge-co software/hardware company would basically NEVER do this -- they'd hold back the feature, bundle it with other stuff, and charge for it, likely with no regard for backward compatibility with your existing patches. And, honestly, part of why a bigger company wouldn't do something like this is... a desire to avoid increased support volume :)

Just a friendly reminder not to look a gift horse in the mouth :)
Follow-up requests and concerns come with any new firmware update. Particularly so with major, full-integer releases like 2.00. Requests are part of the feedback loop for further updates. People feel free to make requests, in part because they know that Fractal listens to them.

Beyond that, I agree with everything else you said. :)
 

James Nash

Member
My (brief) experience with the compliance control has been 1) it's cool, and 2) it's a significant enough change that I couldn't just throw it on top of existing amp tones. I found changing compliance to 50% made my tones noticeably darker and rounder, so I needed to boost highs a bit to compensate (treble, presence, high cut, etc... a boost of at least 10-20% somewhere in there). Now, this was starting with a patch I already thought sounded great, so for a model you always wished were a little warmer, it might be perfect. But my first impression was this parameter might well lead to better tones in the long run, but it's probably not something that can be dialed in blindly for all existing patches.

After a little tweaking, I *think* I made my main TwoStone stage patch better by dialing in compliance at 10%, and boosting presence (I had it at 0, moved it to 4--sounds like a big change, but seemed about right at the time). Interested to hear those two sounds A/B in a louder stage context.

I find it interesting the default compliance value is now 50%... it's a bigger change to the default/stock presentation of the Axe than I expected. Suggests Fractal is re-calibrating their tonal baseline a little ?
 

REDD

Power User
Sounds like compliance takes a little bass off of one amp but not another, is it a fluctuation, amp specific type of effect?
 

reclavea

Power User
Compliance feature sounds incredible!

Seems like this "Compliance" feature can easily be ported over to the Ax8?....wishful thinking ;-)
 

electronpirate

Moderator
Moderator
This is another 'use your ears' appliance compliance (boom!) Like most others, it will affect different amps/cabs in ways that you will have to experiment with. Getting caught up in the 'what does it do?' interfere's with the 'how does it sound' process.

IMO.
 

moerker

Inspired
Excellent information @moerker ! But help me understand something. Your description of compliance as a nonlinear function runs counter to my understanding. Compliance is a linear relationship between force and cone displacement.
You are right, and wrong, at the same time :)
I was a little bit imprecise here, but the problem is a little bit sophistic.

At low amplitudes there is a linear relation describing a spring with F=1 / Cms * x (Force equals displacement divided by compliance).
But for high amplitudes, compliance will become more depending on displacement, F(x) = x / Cms(x). The resulting force is basically nonlinear (since compliance depends on displacement), and from a quick glance, also the relation (division is there, we just added a parameter dependency). But, if you are imagine compliance as a power series Cms(x) = c0 + x*c1 + x^2*c2 + ..., then nonlinear operations like squaring are involved. Thus, since terms which are not reversible like squaring are involved, there is a nonlinear process going on (and may rectify signal components).

That's what I meant with nonlinear relation - force working on the compliance is highly depending on the stiffness, thus resulting in a "nonlinear" force. Though we are just using linear relations and operations, because of the way we do it the result is nonlinear, and Cms(-x) == Cms(x) for a special configurations, which is clearly not linear.

So what I wanted to say: because of the nonlinear nature of compliance, the relationship will become nonlinear.
Sorry if I was there imprecise in the first post.
There are even more nonlinearities, so, more interesting stuff may come ;)

This is another 'use your ears' appliance compliance (boom!) Like most others, it will affect different amps/cabs in ways that you will have to experiment with. Getting caught up in the 'what does it do?' interfere's with the 'how does it sound' process.

IMO.
That sums it up pretty well. All what I've written is from a scientific/engineering point of view, but as a musician, the information "more displacement --> lower notes --> more pronounced effect" should be the best giveaway if you want to hear what is going on when you play on the knob.
 
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FractalAudio

Administrator
Fractal Audio Systems
Moderator
The easy way to understand compliance is to think of a spring. In Physics 101 we're taught that F = kx but that's an ideal spring. A real spring is nonlinear. Eventually you get to a point where compressing or stretching the string you run out of travel and the force goes nonlinear. A speaker is the same way. The suspension is essentially a spring and the greater the displacement the greater the force trying to restore the cone to its rest position. The compliance parameter controls how stiff that suspension is.
 

DLC86

Power User
The easy way to understand compliance is to think of a spring. In Physics 101 we're taught that F = kx but that's an ideal spring. A real spring is nonlinear. Eventually you get to a point where compressing or stretching the string you run out of travel and the force goes nonlinear. A speaker is the same way. The suspension is essentially a spring and the greater the displacement the greater the force trying to restore the cone to its rest position. The compliance parameter controls how stiff that suspension is.
So basically we can see it as a frequency-dependent compression with a pretty high threshold and a certain knee?
 

lqdsnddist

Axe-Master
So, maybe this adds a little “age” to a cone? A new cone is stiff. An older one broken in and more flexible?
In some circumstances yes, but not every amp is going to respond the same, for the reasons listed in previous posts, so always thinking of it as an aged or worn speaker won’t always give the expected results .

I think it’s often best to understand the concepts of what is going on, but then forget about all of that and adjust til it sounds good lol. Otherwise we can get too wrapped up in thinking about where something “should” be set, and not simply where it sounds subjectively best.
 

NeoSound

Fractal Fanatic
All I know is it sounds good with clean, edge of breakup and overdriven tones :) and makes them feel nice like there's more interaction between sound and fingers. High gain may not benefit as much but not sure?
 

lqdsnddist

Axe-Master
I'm new to this forum, so please don't anyone take this as an insult... but I'm surprised there are as many concerns and/or followup requests generated by this release.

IMHO, this beta represents *outstanding* continued support and development:

1) We're getting a free public beta version of an interesting new form of amp/speaker modeling. No charge, no waiting.

2) We're getting it in a way that causes no disruption to current use of the product.

In my experience, a huge-co software/hardware company would basically NEVER do this -- they'd hold back the feature, bundle it with other stuff, and charge for it, likely with no regard for backward compatibility with your existing patches. And, honestly, part of why a bigger company wouldn't do something like this is... a desire to avoid increased support volume :)

Just a friendly reminder not to look a gift horse in the mouth :)

(Now, that said... I'm eager to understand this new parameter better, too... so thanks for the great discussion on speaker compliance! Cool stuff!)

Fair point overall, but FAS, being such a small company, has always relied upon the user community to a large part for helping debug, and otherwise refine and improve products.

Cliff is brilliant, but sometimes a random user throws out an idea, way of making soemthing work easier etc, that Cliff and Co didn’t consider, so it gets added, and the product becomes even better.

I think most regular users here have all had at least some small degree of input into “their” product which is pretty cool, as is having open and direct communication with Cliff regarding ideas, questions etc.

It’s not like any other brand or product, which is exactly why so many of us are such massive FAS fans
 

moerker

Inspired
So basically we can see it as a frequency-dependent compression with a pretty high threshold and a certain knee?
Both - "amplitude at certain frequencies"-dependent. It's not like happening suddenly, but any time, and changes dynamically.
 
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