Closed Speaker Resonance PA equalization tied to Master Volume level

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shatteredsquare said:
Rex you are the coolest geriatric hype man ever.
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Sorry, I don't know what that means.


shatteredsquare said:
FAS isn't talking about frequency response measurement, FAS is talking about measurements taken at the material.
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Nor that.


shatteredsquare said:
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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Can you post a clip that demonstrates the missing thing you're hearing? I'm genuinely not getting what you're describing. Unless...

When you turn up MV on a real amp, things get a whole lot louder. Feedback from the speaker to your guitar gets stronger, and the frequency response of that interaction comes into play more strongly. Some pitches get reinforced more than others. When there's a full-volume monitor in the room next to you, the frequency response of the entire guitar/amp/speaker system changes significantly.
 
shatteredsquare said:
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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The speaker frequency response remains the same regardless of the voltage applied, that's been already proved.

http://forum.fractalaudio.com/threa...egarding-speaker-cabinets.135191/post-1599277
 
DLC86 said:
speaker frequency response remains the same regardless of the voltage applied
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sure, makes perfect sense. I'm not talking about the speakers frequency response, I'm taking about the whole machine, speaker coupled with power amp, and how its frequency response changes at different volume levels. At low MV there are some frequencies it just can't push, they won't be heard, not enough energy. As the MV comes up, those frequencies start getting pushed, the speaker starts to move at those frequencies which shows up at the power amp, the power amp has to dedicate energy to those frequencies now being used, energy which cuts into the available bandwidth...causing the scoop to bloom, you start to hear the impedance curve get imprinted audibly on the sound the higher the MV goes, up to the sweet spot where the PA starts to break up.

scenario 1: super low MV, barely a whisper, all preamp... you hit a low E power chord, let it ring...brush the high E string...high E doesn't have trouble coming through.

scenario 2: MV just past the ideal sweet spot, PA starting to break up, loud af in real life. Hit a low E power chord, let it ring...brush the high E string...you won't even hear anything unless you dig in hard, and even at that, the high E comes through as a broken fizzle until the low E decays to stop sucking all the juice.
 
A dual rec gets that crazy bass boost from the speaker impedance curve since there's no PA negative feedback. That crazy bass boost isn't active at bedroom levels, low MV, the PA isn't pushing hard enough yet. Maybe mathematically, but you can't hear it, you can't feel it, its not coming out of the speaker yet. You turn up MV and that bass boost gets stronger and stronger the higher you push the master, until you have to turn down the bass knob because you're getting so much low end from a different source. How is that not applied voltage dependant frequency response differential?

It's on a gradient tied to the MV, amp bloom, the speaker impedance curve audibly showing up with increasing strength the higher the MV goes, boosting lows/highs/scoop on a gradient, tied to MV level. Also the reason why after you've spent an hour dialing an amp in, got it the way you like it, if you bump the MV it all goes out the window, everything changes frequency wise, drastically.
 
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shatteredsquare said:
A dual rec gets that crazy bass boost from the speaker impedance curve since there's no PA negative feedback. That crazy bass boost isn't active at bedroom levels, low MV, the PA isn't pushing hard enough yet. Maybe mathematically, but you can't hear it, you can't feel it, its not coming out of the speaker yet. You turn up MV and that bass boost gets stronger and stronger the higher you push the master, until you have to turn down the bass knob because you're getting so much low end from a different source. How is that not applied voltage dependant frequency response differential?

It's on a gradient tied to the MV, amp bloom, the speaker impedance curve audibly showing up with increasing strength the higher the MV goes, boosting lows/highs/scoop on a gradient, tied to MV level.
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How can you exclude that is not caused by fletcher munson curve?

If you're so sure about what you're saying maybe you should start taking scientific measurements and demonstrate it.
But mind you, there's a good chance someone who's been working on this for 10+ years (Cliff) already did that long ago.
 
shatteredsquare said:
sure, makes perfect sense. I'm not talking about the speakers frequency response, I'm taking about the whole machine, speaker coupled with power amp, and how its frequency response changes at different volume levels. At low MV there are some frequencies it just can't push, they won't be heard, not enough energy. As the MV comes up, those frequencies start getting pushed, the speaker starts to move at those frequencies which shows up at the power amp, the power amp has to dedicate energy to those frequencies now being used, energy which cuts into the available bandwidth...causing the scoop to bloom, you start to hear the impedance curve get imprinted audibly on the sound the higher the MV goes, up to the sweet spot where the PA starts to break up.
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What you're are describing here seems almost like the speaker has a gating effect, if the voltage is too low it doesn't move at all.. but afaik it doesn't work that way, I don't know.
But my bet is that those frequencies you aren't hearing at low volumes are not speaker's fault but your ears fault (again: fletcher munson curve)


shatteredsquare said:
scenario 1: super low MV, barely a whisper, all preamp... you hit a low E power chord, let it ring...brush the high E string...high E doesn't have trouble coming through.

scenario 2: MV just past the ideal sweet spot, PA starting to break up, loud af in real life. Hit a low E power chord, let it ring...brush the high E string...you won't even hear anything unless you dig in hard, and even at that, the high E comes through as a broken fizzle until the low E decays to stop sucking all the juice
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That's easily explainable with the effect of power amp distortion/compression
 
DLC86 said:
How can you exclude that is not caused by fletcher munson curve?
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1. Fletcher Munson doesn't physically vibrate your eyeballs when you turn up. The frequency that vibrates your eyeballs was not physically present at MV levels lower than that point. It's bass boost from the speaker impedance curve that doesn't show up unless the MV is pushing hard enough. The MV comes up, the low boost gets stronger, the scoop gets deeper. Fletcher Munson is active as always, sure, but it's not entirely Fletcher Munson.

2. Fletcher Munson would not cause the PA to fall apart, requiring you to turn down the preamp bass knob to compensate for the increased low end frequency production tied directly to MV level. Yes that has to do with distortion, which yes is already modeled perfectly. I'm not talking about the distortion aspect of it, I'm talking about the equalization aspect of it, the audible effect of that speaker impedance curve getting audibly more prominent, tied to MV on a gradient. An effect I can replicate currently by lowering the high/low speaker resonance to taste at lower MV settings, where in real life the speaker resonance amounts themselves don't change, but the frequency effect of the speaker impedance curve on the PA is lessened at lower MV levels.
 
shatteredsquare said:
1. Fletcher Munson doesn't physically vibrate your eyeballs when you turn up. The frequency that vibrates your eyeballs was not physically present at MV levels lower than that point. It's bass boost from the speaker impedance curve that doesn't show up unless the MV is pushing hard enough. The MV comes up, the low boost gets stronger, the scoop gets deeper. Fletcher Munson is active as always, sure, but it's not entirely Fletcher Munson.
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That's a scientific explanation! I'll start capturing IRs with a seismograph attached to my eyeballs now, LOL! :tearsofjoy:

Joking apart, I don't think you really got what Fletcher Munson is about.
 
shatteredsquare said:
A dual rec gets that crazy bass boost from the speaker impedance curve since there's no PA negative feedback. That crazy bass boost isn't active at bedroom levels, low MV, the PA isn't pushing hard enough yet. Maybe mathematically, but you can't hear it, you can't feel it, its not coming out of the speaker yet. You turn up MV and that bass boost gets stronger and stronger the higher you push the master, until you have to turn down the bass knob because you're getting so much low end from a different source. How is that not applied voltage dependant frequency response differential?

It's on a gradient tied to the MV, amp bloom, the speaker impedance curve audibly showing up with increasing strength the higher the MV goes, boosting lows/highs/scoop on a gradient, tied to MV level. Also the reason why after you've spent an hour dialing an amp in, got it the way you like it, if you bump the MV it all goes out the window, everything changes frequency wise, drastically.
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All this is patently false. Furthermore everything you describe is Fletcher-Munson. You can read about it here:
https://ehomerecordingstudio.com/fletcher-munson-curve/
 
FractalAudio said:
All this is patently false.
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Right, so the rectifier bass boost comes from the speaker impedance curve and no negative feedback. I know that from FAS's own tech notes and forum posts from in here. Anything I'm talking about in here I learned from lurking in here, just consolidating and connecting dots.

1. The bass boost comes from no negative feedback and the follows the speaker impedance curve.
2. Fletcher munson is occurring simultaneously, as it does anywhere else you turn something up louder. Incidentally, the fletcher munson curve is similar to the same scoop curve as the speaker impedance curve. You're getting both at the same time. It isn't just fletcher munson.

The bass boost and concurrent scoop/bloom that comes from no negative feedback and the speaker impedance curve should get progressively more prominent as the MV increases. With MV on 0.05, the amount of bass boost from the speaker impedance curve is way exaggerated right now. I don't know what 0.05 equates to on the amp compared to what the modeled MV pot curve is, but what I'm getting at is there is a missing connection between speaker resonance and MV right now, with MV that low, the audible effect of the speaker resonance scoop should be nil, as it is it's really prominent, the EQ scoop doesn't change much from 0.01 to the point the PA falls apart, just the distortion characteristics.
 
shatteredsquare said:
Right, so the rectifier bass boost comes from the speaker impedance curve and no negative feedback. I know that from FAS's own tech notes and forum posts from in here. Anything I'm talking about in here I learned from lurking in here, just consolidating and connecting dots.

1. The bass boost comes from no negative feedback and the follows the speaker impedance curve.
2. Fletcher munson is occurring simultaneously, as it does anywhere else you turn something up louder. Incidentally, the fletcher munson curve is similar to the same scoop curve as the speaker impedance curve. You're getting both at the same time. It isn't just fletcher munson.

The bass boost and concurrent scoop/bloom that comes from no negative feedback and the speaker impedance curve should get progressively more prominent as the MV increases. With MV on 0.05, the amount of bass boost from the speaker impedance curve is way exaggerated right now. I don't know what 0.05 equates to on the amp compared to what the modeled MV pot curve is, but what I'm getting at is there is a missing connection between speaker resonance and MV right now, with MV that low, the audible effect of the speaker resonance scoop should be nil, as it is it's really prominent, the EQ scoop doesn't change much from 0.01 to the point the PA falls apart, just the distortion characteristics.
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The speaker impedance curve is completely unrelated to the MV. I don't know how or why you keep coming up with this. I have a Dual Rectifier sitting right next to me. If I set the knobs on the model the same as the amp they sound the same and at all MV settings.

Furthermore who ever plays an amp with MV barely cracked open? An amp sounds best at its sweet-spot which occurs when the power amp is working hard.
 
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FractalAudio said:
Furthermore who every plays an amp with MV barely cracked open? An amp sounds best at its sweet-spot which occurs when the power amp is working hard.
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guess if the OP is using the amps in the sleeper cab of his truck he might want to keep the MV low ? Probably gets pretty loud in such an enclosed place....

😱
 
shatteredsquare said:
scenario 1: super low MV, barely a whisper, all preamp... you hit a low E power chord, let it ring...brush the high E string...high E doesn't have trouble coming through.

scenario 2: MV just past the ideal sweet spot, PA starting to break up, loud af in real life. Hit a low E power chord, let it ring...brush the high E string...you won't even hear anything unless you dig in hard, and even at that, the high E comes through as a broken fizzle until the low E decays to stop sucking all the juice.
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When you hit that power chord in scenario 2, the power chord produces harmonics that can mask the sound from the high E string. As the power chord decays, the distortion fades, and the high E string is unmasked.
 
FractalAudio said:
To put this to bed once and for all here is a Tone Match of our reference Dual Rectifier in Modern mode (no neg. feedback) with the MV just barely cracked open:

View attachment 59751


If what you are saying is true there would be a big dip at the low resonance.
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Looks flat, what's a tone match look like when you get the amp just below PA breakup? I'd think you would start to see the boost freqs at the speaker resonant freqs start to show up. Why would there be a dip in the lows when it's barely cracked open? The speaker doesn't leech low end, It would be flat if it's barely cracked open, just preamp + speaker filtering. The speaker resonance would start adding lows at the resonant frequencies as the MV comes up.
 
shatteredsquare said:
Looks flat, what's a tone match look like when you get the amp just below PA breakup? I'd think you would start to see the boost freqs at the speaker resonant freqs start to show up. Why would there be a dip in the lows when it's barely cracked open? The speaker doesn't leech low end, It would be flat if it's barely cracked open, just preamp + speaker filtering. The speaker resonance would start adding lows at the resonant frequencies as the MV comes up.
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What part of "MV just barely cracked open" was not clear?
 
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Am I confused. or are you really chasing a memory of a tone from the past?1572819311828.png
 
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