The Speaker Page

Information about what amps (models) use negative feedback and how that affects things like the speaker page parameters would be useful.

How all the settings work together and interact is something I struggle with. I tend to shy away from most advanced parameters because of lack of knowledge of the implications of one parameter in regards to the others.

Me too, and I even have something of a technical understanding of the parameters. Do you think a visualization flow chart/schematic would be helpful? If so any suggestions?
 
@guitarmike it might be possible to create a pdf where all the amp block controls are on one page.

Then connect the interacting controls together with some directed lines?

Sounds difficult though.
 
Information about what amps (models) use negative feedback and how that affects things like the speaker page parameters would be useful.

How all the settings work together and interact is something I struggle with. I tend to shy away from most advanced parameters because of lack of knowledge of the implications of one parameter in regards to the others.

Negative feedback does not affect the speaker impedance. Speaker impedance is an independent variable. The default values are based on the speaker cabinet most commonly used with the amp. In the case of a combo it's the internal speaker. For heads it's the mating cabinet, if one.

A typical speaker has a low-frequency resonance with some frequency, Q and magnitude. The Q is typically around 2, frequency around 100 and magnitude around 12 dB. These values are dependent upon the speaker construction and, to a lesser extent, the cabinet.

The voice coil inductance causes the impedance to increase at high frequencies. Unlike a pure inductance which would increase at 6 dB/octave, voice coil inductance is semi-inductive and typically increases at 3-4 dB/octave. The "break" frequency is dependent upon the actual inductance and is adjustable.

The Axe-Fx is unique in that it lets you adjust these values. Most products just use a fixed curve.
 
Last edited:
True. Negative feedback has no effect on speaker impedance. It does, however, affect how the amp reacts to speaker impedance. Less negative feedback equals a stronger reaction to speaker impedance.
 
If I ever find myself contemplating any of these whacky parameters, I know it's time to just pick another IR and move along. LOL
 
People over-think this. The speaker's impedance is largely decoupled from it's IR. IOW, the frequency response of the speaker + cabinet is not very related to the driver's impedance curve. What does this mean? Pick an IR that you like. Adjust the amp block speaker impedance curve as desired. You're never going to see IR producers publish speaker impedance data because most don't know how to measure it and there is no standard format for the data.
Extremely helpful; thanks for the insight for how you recommend using this.
 
Back
Top Bottom