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Axe-Fx III Firmware Version 10.02

DLC86

Fractal Fanatic
This is what I've been working on:

Firmware 11.0 introduces our new high-order speaker impedance modeling. We've curated the impedance data from nearly 50 cabinets. You'll now be able to select the impedance curve to use with an amp model (selecting an amp model loads the most appropriate curve for that model).

Why is this important? When you look at speaker impedance curves they look pretty simple. However that data is obtained when the speaker is mounted on an infinite baffle. As soon as you mount the speaker in a cabinet that impedance data changes, sometimes quite radically. The modes of the cabinet introduce significant peaks and dips in the impedance due to the back EMF created. Some of the cabs we measured have deviations from the published curves by 4-5 dB or more.

To understand why this happens the impedance of a speaker is dependent upon the acoustic load. In an infinite baffle the load is constant. Put the speaker in a box and the load is greater at some frequencies and lower at others because the sound waves bounce off the walls and constructively or destructively interfere with the motion of the speaker. For example, consider the sound emanating from the speaker and bouncing off the back wall of the cabinet. When the sound wave reaches the speaker it will either aid or oppose the motion of the speaker. If it aids the motion then the impedance will be lower and vice-versa.

I hope to have a beta this weekend.
Joking aside, could this address the reason why some still find more pleasing to use tube power amps vs SS?

If that's the case this update has perfect timing for the new icepower PA I'm assembling :cool:
 
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DLC86

Fractal Fanatic
Joking aside, could this address the reason why some still find more pleasing to use tube power amps vs SS?

If that's the case this update has perfect timing for the new icepower PA I'm assembling :cool:
PS: I also wonder if the amplitude of those peaks and dips in the impedance curve change at different volume levels since they're induced by sound interfering with the motion of the speaker..
 

Randalljax

Fractal Fanatic
is this something that is a leftover from the Axe fx 2 days .

I remember a post where Cliff said the missing piece of the tube amp puzzle lay in the impedance interactions of the cabs and being able to measure that accurately , this would have been early in the AX2 , but I think was way to cpu intensive 5 years ago
 

FractalAudio

Administrator
Fractal Audio Systems
Moderator
PS: I also wonder if the amplitude of those peaks and dips in the impedance curve change at different volume levels since they're induced by sound interfering with the motion of the speaker..
The impedance has a nonlinear component but it is very small relative to the linear component. IOW the amplitude of the wave is proportional to speaker displacement so the impedance curve is relatively constant vs. applied voltage. The nonlinear effects occur as the voice coil moves out of the magnetic gap and this is already modeled.
 

DLC86

Fractal Fanatic
The impedance has a nonlinear component but it is very small relative to the linear component. IOW the amplitude of the wave is proportional to speaker displacement so the impedance curve is relatively constant vs. applied voltage. The nonlinear effects occur as the voice coil moves out of the magnetic gap and this is already modeled.
Got it, thanks! Love these technical explanations
 

Joe Bfstplk

Power User
This is what I've been working on:

Firmware 11.0 introduces our new high-order speaker impedance modeling. We've curated the impedance data from nearly 50 cabinets. You'll now be able to select the impedance curve to use with an amp model (selecting an amp model loads the most appropriate curve for that model).

Why is this important? When you look at speaker impedance curves they look pretty simple. However that data is obtained when the speaker is mounted on an infinite baffle. As soon as you mount the speaker in a cabinet that impedance data changes, sometimes quite radically. The modes of the cabinet introduce significant peaks and dips in the impedance due to the back EMF created. Some of the cabs we measured have deviations from the published curves by 4-5 dB or more.

To understand why this happens the impedance of a speaker is dependent upon the acoustic load. In an infinite baffle the load is constant. Put the speaker in a box and the load is greater at some frequencies and lower at others because the sound waves bounce off the walls and constructively or destructively interfere with the motion of the speaker. For example, consider the sound emanating from the speaker and bouncing off the back wall of the cabinet. When the sound wave reaches the speaker it will either aid or oppose the motion of the speaker. If it aids the motion then the impedance will be lower and vice-versa.

I hope to have a beta this weekend.
Sweet! Can't wait to try it when my replacement AxeFX3 arrives....
 

shatteredsquare

Power User
ooooooh man i can't wait to hear how this sounds, FAS for the MFin win yet again! :trophy:

please tell me you guys have one of those old oversize mesa recto straight/slant cabs handy...

 

yek

Moderator
Moderator
This is what I've been working on:

Firmware 11.0 introduces our new high-order speaker impedance modeling. We've curated the impedance data from nearly 50 cabinets. You'll now be able to select the impedance curve to use with an amp model (selecting an amp model loads the most appropriate curve for that model).

Why is this important? When you look at speaker impedance curves they look pretty simple. However that data is obtained when the speaker is mounted on an infinite baffle. As soon as you mount the speaker in a cabinet that impedance data changes, sometimes quite radically. The modes of the cabinet introduce significant peaks and dips in the impedance due to the back EMF created. Some of the cabs we measured have deviations from the published curves by 4-5 dB or more.

To understand why this happens the impedance of a speaker is dependent upon the acoustic load. In an infinite baffle the load is constant. Put the speaker in a box and the load is greater at some frequencies and lower at others because the sound waves bounce off the walls and constructively or destructively interfere with the motion of the speaker. For example, consider the sound emanating from the speaker and bouncing off the back wall of the cabinet. When the sound wave reaches the speaker it will either aid or oppose the motion of the speaker. If it aids the motion then the impedance will be lower and vice-versa.

I hope to have a beta this weekend.
Great stuff. This fulfills an old wish of mine: the ability to select from a number of impedance presets.
 

shatteredsquare

Power User
When the sound wave reaches the speaker it will either aid or oppose the motion of the speaker. If it aids the motion then the impedance will be lower and vice-versa.
i bet this will sound insane, getting flexing and blooming speaker+PA interaction the way you only get at MV levels making the wine glasses fall out of the cabinets, but without the domestic disturbance complaints
 

smcrosby

Power User
This is what I've been working on:

Firmware 11.0 introduces our new high-order speaker impedance modeling. We've curated the impedance data from nearly 50 cabinets. You'll now be able to select the impedance curve to use with an amp model (selecting an amp model loads the most appropriate curve for that model).

Why is this important? When you look at speaker impedance curves they look pretty simple. However that data is obtained when the speaker is mounted on an infinite baffle. As soon as you mount the speaker in a cabinet that impedance data changes, sometimes quite radically. The modes of the cabinet introduce significant peaks and dips in the impedance due to the back EMF created. Some of the cabs we measured have deviations from the published curves by 4-5 dB or more.

To understand why this happens the impedance of a speaker is dependent upon the acoustic load. In an infinite baffle the load is constant. Put the speaker in a box and the load is greater at some frequencies and lower at others because the sound waves bounce off the walls and constructively or destructively interfere with the motion of the speaker. For example, consider the sound emanating from the speaker and bouncing off the back wall of the cabinet. When the sound wave reaches the speaker it will either aid or oppose the motion of the speaker. If it aids the motion then the impedance will be lower and vice-versa.

I hope to have a beta this weekend.
Exciting times! :D
 

1234

Inspired
For those who understand what Cliff wrote and have a more technical brain than me...

Does this mean if you paired the Supertweed with, say a 1960A or Bogner, you'd select the impedance data for that cabinet?
 

shatteredsquare

Power User
I also have 2 of these cabs loaded with various speakers. They are the bomb! Don't feel likeI need anything else in the 4x12 variety. Very useful in split 2x12 mode as well...
100lbs of whoopass! oversize recto 4x12 with Celestion G12T-75 speakers is 50% of Korns sound, the other half being 2 channel dual recs and 7 string ibanez's tuned down 1 whole step...

 
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