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Wish Speaker Resonance PA equalization tied to Master Volume level

shatteredsquare

Fractal Fanatic
connect speaker resonance PA equalization to master volume level...

...in that if the master is very low to barely cracked, the speaker resonance settings will have very little audible effect on power amp equalization. As you turn up master volume and get more pushback from the speaker impedance curve, the equalization effect of the speaker resonance settings becomes more pronounced and audible.

like when you turn up the tube amp, barely cracked it's a little whisper coming out of the speaker, all preamp EQ, smooth/flat/crisp, and as you turn it louder it blooms into the lows/highs/scoop of the power amp flexing against the speaker impedance curve, up to the point it starts to break up at the power amp.

:lightbulb::openlock::crystalball:
 

FractalAudio

Administrator
Fractal Audio Systems
Moderator
You're fundamentally not understanding speaker impedance and it's influence on a tube power amp.
 
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shatteredsquare

Fractal Fanatic
yeah this is where I like to vocalize my fundamental misunderstandings to the betterment of the modelling community.

you're saying there's no relationship between the voltage output of a power amp into a speaker and the amount of influence the speaker impedance curve has on the power amps equalization? When you turn up a tube amp from whisper-level to sweet-spot, the EQ scoop from the speaker impedance curve blooms in proportion to the PA output. Right now the only thing that blooms in proportion to master volume is PA distortion...speaker resonance is fixed, albeit manually adjustable.
 

Rex

Legend!
yeah this is where I like to vocalize my fundamental misunderstandings to the betterment of the modelling community.

you're saying there's no relationship between the voltage output of a power amp into a speaker and the amount of influence the speaker impedance curve has on the power amps equalization? When you turn up a tube amp from whisper-level to sweet-spot, the EQ scoop from the speaker impedance curve blooms in proportion to the PA output. Right now the only thing that blooms in proportion to master volume is PA distortion...speaker resonance is fixed, albeit manually adjustable.
The speaker impedance curve is constant, just like in a real speaker. Changes in tonality when you hit the power amp harder are caused by saturation of the amp, which varies by frequency due to the speaker’s impedance curve. This behavior is already modeled.
 

shatteredsquare

Fractal Fanatic
The speaker impedance curve is constant, just like in a real speaker.
Tracking that, I'm referencing the fixed speaker impedance curve. More specifically, I'm referring to the proportional relationship between how hard the power amp is pushing against the speaker and its fixed impedance curve, and how much pushback the PA receives from the fixed speaker impedance curve. The harder the PA pushes, the more that fixed speaker impedance curve shows up audibly in what comes out of the PA. The wonderful amplifier "bloom" you get when you can, on occasion, turn up and lay into it.

Changes in tonality when you hit the power amp harder are caused by saturation of the amp, which varies by frequency due to the speaker’s impedance curve. This behavior is already modeled.
That's an explanation of what the speaker page does in relation to the power amp and is already described in the FAS literature, tracking all that.

The behaviour not currently modeled, and what the wish is for, is for the speaker resonance settings (the fixed speaker impedance curve) to be proportionally linked to master volume level as they are in real world. With the master barely cracked at 0.20, the amount of speaker resonance high/low is in its own dimension, you can get obscene amounts of high/low boost...with the amp, you wouldn't have that amount of resonance available until that PA were pushing the speaker hard enough to start getting the impedance curve imprinted in it...as you turn up the master, you start to get more of the impedance curve equalization effect, "bloom"... proportionally linked to how high the master volume level is set. All the adjustment is there, just currently not linked.

I could further clarify to say have the speaker resonance amount parameters be linked to master volume level, since the other parameters regarding the speaker impedance curve wouldn't change with a fixed speaker impedance curve. If it is actually fixed. I thought the speaker impedance curve changes under load, the harder it gets hit, since the electromagnet starts moving more and more. I'm not the one doing the math, I'm just the consumer peasant helping with open source R&D. :grimacing:
 
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FractalAudio

Administrator
Fractal Audio Systems
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Tracking that, I'm referencing the fixed speaker impedance curve. More specifically, I'm referring to the proportional relationship between how hard the power amp is pushing against the speaker and its fixed impedance curve, and how much pushback the PA receives from the fixed speaker impedance curve. The harder the PA pushes, the more that fixed speaker impedance curve shows up audibly in what comes out of the PA. The wonderful amplifier "bloom" you get when you can, on occasion, turn up and lay into it.



That's an explanation of what the speaker page does in relation to the power amp and is already described in the FAS literature, tracking all that.

The behaviour not currently modeled, and what the wish is for, is for the speaker resonance settings (the fixed speaker impedance curve) to be proportionally linked to master volume level as they are in real world. With the master barely cracked at 0.20, the amount of speaker resonance high/low is in its own dimension, you can get obscene amounts of high/low boost...with the amp, you wouldn't have that amount of resonance available until that PA were pushing the speaker hard enough to start getting the impedance curve imprinted in it...as you turn up the master, you start to get more of the impedance curve equalization effect, "bloom"... proportionally linked to how high the master volume level is set. All the adjustment is there, just currently not linked.

I could further clarify to say have the speaker resonance amount parameters be linked to master volume level, since the other parameters regarding the speaker impedance curve wouldn't change with a fixed speaker impedance curve. If it is actually fixed. I thought the speaker impedance curve changes under load, the harder it gets hit, since the electromagnet starts moving more and more. I'm not the one doing the math, I'm just the consumer peasant helping with open source R&D. :grimacing:
The speaker resonance is NOT proportional to the master volume level in the real world. The speaker impedance curve does change under drive level (at the speaker terminals) and that is modeled but the amount of change is very small. And, in fact, it changes exactly opposite to your description.

I can only think that you have something fundamentally wrong in your setup. The Axe-Fx III is extremely accurate in its modeling, especially the power amp modeling as that is where much of the magic happens. This has been proven time and time again in controlled studies. We compare the models to the amps at levels from barely audible to ear bleeding using measurement equipment as well as listening tests and blind A/B evaluations.
 

FractalAudio

Administrator
Fractal Audio Systems
Moderator
The resonance of a network doesn't change at different signal levels. A loudspeaker is a physical network. Its impedance curve is its impedance curve.

The impedance curve determines which frequencies go into saturation first when you hit the power amp harder. That's your "bloom." It's already modeled.
In a loudspeaker the resonances do change a bit vs. applied voltage but the effect is subtle. The Axe-Fx III models this (it's the Speaker Compliance parameter). For all intents and purposes though it's pretty much a static network as the parameter shift only occurs at large excursion values which only occur at very low frequencies (excursion is the integral of applied voltage).
 
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Rex

Legend!
In a loudspeaker the resonances do change a bit vs. applied voltage but the effect is subtle. The Axe-Fx III models this (it's the Speaker Compliance parameter). For all intents and purposes though it's pretty much a static network as the parameter shift only occurs at large excursion values which only occur at very low frequencies (excursion is the integral of applied voltage).
Yeah, right after I posted that, i realized that there is some impedance change at large excursions, so I deleted the post. I didn't realize that you were modeling that compliance change already. Thanks for the clarification.
 

shatteredsquare

Fractal Fanatic
And don't confuse speaker impedance effects for our good, old friends Fletcher and Munson.
that's probably most of it, nothing is missing at all, i can turn down the high/low resonance amount and get the same low MV smooth speaker effect I'm looking for from being accustomed to playing the roadster at bedroom levels. I'm realizing recently that the speaker page is where you tune the high end resonance frequency to get the amp the way you remember it sounding at home...bumping the high resonance frequency down from 1200 to 1000Hz-900Hz fixes like 90% of my high-end issues that i was trying to fix before in the preamp bias and cathode follower settings...flailing blindly...
 

shatteredsquare

Fractal Fanatic
looking for an amp simulator
that's what authentic page controls did for the whole wonder box...strictly by hiding options from the monkeys, monkey immediately gets better at using it because monkey isn't knobing stuff that shouldn't be knobed.

I was just thinking if I've got master on 0.20 and speaker resonance down to almost off, it sounds exactly like a 100 watt beast does at bedroom levels...if you could link the master volume to those high/low resonance amounts, have them cap out wherever they are set at their current position, and as master starts from 0.00, the resonance amounts come up from 0.00 as well...power amp bloom...
 

FractalAudio

Administrator
Fractal Audio Systems
Moderator
that's what authentic page controls did for the whole wonder box...strictly by hiding options from the monkeys, monkey immediately gets better at using it because monkey isn't knobing stuff that shouldn't be knobed.

I was just thinking if I've got master on 0.20 and speaker resonance down to almost off, it sounds exactly like a 100 watt beast does at bedroom levels...if you could link the master volume to those high/low resonance amounts, have them cap out wherever they are set at their current position, and as master starts from 0.00, the resonance amounts come up from 0.00 as well...power amp bloom...
None of my amps behave that way. And I have nearly 100.
 

DLC86

Fractal Fanatic
I bet what you are hearing is just fletcher munson effect which you don't exeperience with the axe fx cuz you play it at a different level and/or compensate the changes in master volume with the level knob.

Try to match the effective volume of both the amp and the axe at various master volume settings and see (hear) if you still find them to behave in a different way.

PS: I hear that bloom you're talking about even when I turn up the volume of my solid state power amp connected to the axe fx, and that is surely not influenced by speaker impedance
 
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Rex

Legend!
I was just thinking if I've got master on 0.20 and speaker resonance down to almost off, it sounds exactly like a 100 watt beast does at bedroom levels...if you could link the master volume to those high/low resonance amounts, have them cap out wherever they are set at their current position, and as master starts from 0.00, the resonance amounts come up from 0.00 as well...power amp bloom...
So you actually want to duplicate the thin, weak sound of a monster amplifier choked off to almost nothing? Easy peasy. Just turn Master Volume down to 0.2. Done. :)
 

shatteredsquare

Fractal Fanatic
In a loudspeaker the resonances do change a bit vs. applied voltage but the effect is subtle.
How about applied voltage dependant frequency response of the speaker measured coming out of the speaker at different master volume levels? I'm tracking the actual speaker resonance center points don't change much, but I'm still convinced that if you measured a sweep at low MV levels coming out of a speaker, then measured the same sweep coming out of the same speaker at a higher MV level, you'd see a different frequency response, more bass/highs/scoop. I don't think it's completely fletcher munson. There are some low frequencies that straight wouldn't get pushed below a certain MV level, they just wouldn't get pushed out, wouldn't hear/feel them, not enough energy yet. Those low freqs start getting pushed as the MV comes up, it starts forming the scoop, the bloom starts, on a gradient...up to the MV sweet spot where the PA starts distorting. School me!

 

Rex

Legend!
How about applied voltage dependant frequency response of the speaker measured coming out of the speaker at different master volume levels? I'm tracking the actual speaker resonance center points don't change much, but I'm still convinced that if you measured a sweep at low MV levels coming out of a speaker, then measured the same sweep coming out of the same speaker at a higher MV level, you'd see a different frequency response, more bass/highs/scoop.
Cliff addressed that in his post above:

In a loudspeaker the resonances do change a bit vs. applied voltage but the effect is subtle. The Axe-Fx III models this (it's the Speaker Compliance parameter). For all intents and purposes though it's pretty much a static network as the parameter shift only occurs at large excursion values which only occur at very low frequencies...


1572755847839.png
 

shatteredsquare

Fractal Fanatic
Rex you are the coolest geriatric hype man ever. FAS isn't talking about frequency response measurement, FAS is talking about measurements taken at the material. I'm talking about what I hear, a missing connection between MV level and frequency response coming out of the speaker, relating to the speaker resonance currently being the same audible amount at all MV levels. A frequency imprint from the speaker impedance curve resonance that should be connected to MV on a gradient in some capacity, in relation to how high the MV is set, which it currently is not.
 
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