• We would like to remind our members that this is a privately owned, run and supported forum. You are here at the invitation and discretion of the owners. As such, rules and standards of conduct will be applied that help keep this forum functioning as the owners desire. These include, but are not limited to, removing content and even access to the forum.

    Please give yourself a refresher on the forum rules you agreed to follow when you signed up.

FW 11b - Overview of New Speaker Impedance Modelling


Power User
IR/CAB are synonymous as far as I'm concerned, with one small distinction: CAB is a block. IR (any of them) is what you load into a CAB block. An IR is a file that defines a speaker to the AXE II/III in terms of frequency response. There appears to be an option to load and mix/match up to 4 IR's in a given CAB block.

Joe Bfstplk

Great video as usual Leon

One question: when you say the greenback Brit IR at 4:54, what is the difference between IR and a CAB?
The Cab IR imparts the frequency response of the speaker, mic, and mic technique.

The impedance curve affects the way the power amp breaks up, as well as imparting at least some EQ as well, making the output greater to some degree at the points where mechanical resonances and the rising-slope impedance added at higher frequencies due to the voice coil's reactance. The amps with no negative feedback, such as Vox AC30, Morgan AC20, and others, will interact more with the speaker's impedance curve, and amps with more negative feedback will interact proportionately less with the speaker's impedance curve.
Top Bottom