• 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.

Impedance curve in amp section?

How many of you guys are tweaking the impedance curve in the amp block with the amp and IR you're using? For example, if you use say a Friedman with a Mesa cabinet, will you change the impedance curve to a Mesa cab, or just leave it where it defaults? Fender amps with a 412 cabinet, will you change the impedance cruve to reflect that style cabinet etc, or do you guys not think about it too much? Just curious if you guys mess with that stuff a lot or not :)
 
I don’t touch it and everything sounds great.
Got ya! I kind of assumed. Oddly enough, when you mess with the impedance curve with say a Vox and pull the amp up right away with a Friedman IR, it sounds like a Vox right off the bat, and when I change the impedance curve to the Friedman, it sounds less like a Vox. Go figure :tearsofjoy: haha
It definitely has it's place though, but I've definitely gotten distracted from tweaking too much and not playing haha
 
I almost always change it, I usually prefer the "correct" impedance curve.
Got ya! I can see the plus and minus of both ways with an example from my previous post. I appreciate you sharing! It's cool to hear how other people are using their Axe Fx because the options can be so deep!
 

unix-guy

Legend!
I've found the Texas Star 2x12 works well with my preferred IRs... But sometimes others work better with different amp models.

Any time I try new IRs I'll try out some of the different curves to see what sounds best.

Sometimes a different curve can do wonders especially in the bass response.

Also, some of the amps default to reactive load, which isn't likely "authentic".
 

unix-guy

Legend!
Which amps? There shouldn't be any that do this except for the Tube Pre model which isn't an amp.
I don't remember off the top of my head... If I see that again I will report back.

I haven't tried the Tube Pre in quite a while, so I'm pretty sure that's not the one where I saw it.
 

FractalAudio

Administrator
Fractal Audio Systems
Moderator
I don't remember off the top of my head... If I see that again I will report back.

I haven't tried the Tube Pre in quite a while, so I'm pretty sure that's not the one where I saw it.
I think you're wrong about this. I checked every amp model and NONE default to anything other than a speaker impedance other than the Tube Pre.
 

Joe Bfstplk

Fractal Fanatic
I try to do best guess on matching the curve to the cab. I have quite a few 3rd party IRs, and the list of curves doesn't evem cover every cab in the rather extensive factory IR list.

Is that impedance measuring tool still in the works, @FractalAudio ? Also, will we eventually get more curves, and/or be able to add our own or 3rd party ones?
 

Mark Al

Inspired
How many of you guys are tweaking the impedance curve in the amp block with the amp and IR you're using? For example, if you use say a Friedman with a Mesa cabinet, will you change the impedance curve to a Mesa cab, or just leave it where it defaults? Fender amps with a 412 cabinet, will you change the impedance cruve to reflect that style cabinet etc, or do you guys not think about it too much? Just curious if you guys mess with that stuff a lot or not :)
I almost always tweak this, the low end could sometimes be boomy, and I need to shrink the low end peak a bit. And for warm jazz tones, I often tilt down the high end. This is one of the most effective tools to deal with boomy IRs...
 

Mark Al

Inspired
This curve is specific to a cab and speaker, this calls for philosophical/methodological question regarding amp modeling block:
1. Could the impedance curve considered part of the cab and speaker modeling as well?
2. I wonder if the IR already captures some of the impedance curve information, does that overlaps with this part of modeling...?
3. If one can capture speaker and cab characteristics well enough, would it make sense to model the cab and speaker out-right and make it an alternative to IR player instead?

The current Cab blocks does IR, smoothing, proximity, mic pre-amp modeling, which seems have a lot of overlapping with what's captured inside the IR already. Maybe it makes sense to separate cab from IR player...
 
I almost always tweak this, the low end could sometimes be boomy, and I need to shrink the low end peak a bit. And for warm jazz tones, I often tilt down the high end. This is one of the most effective tools to deal with boomy IRs...
Cool! Thank you for the response! Are you saying you'll choose an impedance curve that works best, and then even further tweak the curve?
 

Mark Al

Inspired
Cool! Thank you for the response! Are you saying you'll choose an impedance curve that works best, and then even further tweak the curve?
Yep, I do both and it’s often depending on the IR, output system and amp BMT settings. For example, generally I shrink the low end peak/bump with IR and headphone listening, but when using my PowerCab212 (speaker modeling mode) on a stand, I’d prefer a larger low end peak/bump depending the speaker I use. Another example is I sometimes shrink the low end resonance on the curve here but turn up the amp bass control a bit... It all depends on what my ear craves :)

This curve is super effective when carving tones. Only after all the EQ segments sounds pleasant to my ear, I begin to fine tune the response and feels.
 

Kamspro

New Member
I always play through a matrix and a 4x12, and its a huge difference whitout the right curve if i change amp. Wish it was possible to change this globaly
 

Smittefar

Fractal Fanatic
Which sort of impedance curve best fits a ported 1x12 cab. The ported cabs were/are quite popular, because they sound more like a 4x12 than a regular 1x12. Which impedance curve would you choose for such a cab (assume I'm deaf and cannot use my ears :D )
 
Top Bottom