SIC Speaker Impedance Curve for tone?

scottp

scottp

Fractal Fanatic
So I was looking at the SIC's for the various IR's we have.
I was very surprised to find factory preset #8 Plexi 50W, its SIC is heavily modified from its default curve!

So that led me to ask the questions, are people doing tone shaping with the SIC?
If so, fine tuning or major changes?
Like what is your methodology doing this?

I have struggled in the past with Marshalls that are too ice picky.
It seems like when I start getting the treble in check, the core tone is lost. Kerang?

And I do like using the Input EQ (amp block) to low cut there, eliminating too much low end carrying on through the amp.
Yes when I create tones I'm playing above 85db.
 
I used to mess with SICs a lot. I found the best thing was to mess with the low end, to get the low peak to sound right with the key of the song I was working on. If it was a metal tone, I'd pedal the open lowest string, palm muted, and it was easy to get the low frequency resonance to be enough but not too much. With the high end, it's very tricky, so I preferred, after much experimentation, to leave that alone!
 
And to clarify, with the low end, I would mess with all the parameters, by sweeping the frequency until I found one that seemed to gel well with the root note I wanted to focus on, then I'd balance the amplitude and Q of it to get it to make the tone powerful, but not to overpower it, so again, balance!
 
I don't use any factory presets so I don't have the reference you're referring to. But, I used to play with the SICs some as well. In some cases it's useful for tweaking the sound. Lately though, I find I'm getting better results by leaving the SICs alone and adjusting the Hi and Lo cuts in the cab and the BMTP on the amps. I Lo cut up to 120 and Hi cut down to 5000 if needed. At volume, this sounds very natural to me on the Marshalls and the variants.
 
In the past I've tried to set SIC for best accuracy / authenticity (not tone shaping) to the amp/cab pair I'm using by:
  • Prior to Dynacabs, setting the SiC to the closest matching standard SIC for the cab IR I was using based on whatever information I could get for that standard SiC selection (mainly from the name), and from the cab IR info available (and sometimes (rarely), from specific SIC values provided by IR makers which could be input directly on the speaker page).
  • For my real guitar cabs, trying to figure out the actual SiCs and input those manually for presets I use with my real cabs.
  • Letting the amp block selection dictate the amp's influence on the overall speaker curve (those auto-assigned Xformer values change by amp selection and are constant across varying standard SiCs for a given amp).
  • From time to time I would tweak the LF/HF Reso levels to taste but only when I thought the standard SiC I'd settled on as most authentic, sounded extreme for some reason.
  • Once Dynacabs arrived (all my presets use DC now) I let AutoDCImp choose the authentic curve for the DC cab I've chosen in the first DC cab slot (I tend not to mix DC cabs - just mics on the same DC cab).
Though I've read many posts made by users who audition standard SiCs like one would audition IRs and pick the one they like best, it's not something I've personally done very much. Not that there's anything wrong with it ("there are no rules" as we say), but I've stayed away from it for the following reasons:
  • We have so many authentic (commonly practiced with real rigs) tools / techniques for EQ available in Axfx: Amp Tone Stack, Amp Pre EQ, Amp Post EQ (moveable to other amp circuit locations), EQ Blocks (Filter, GEQ, PEQ), EQ tabs within FX blocks, Cab Block EQ, Global EQ ... with a lot of best practice information available on each type to learn from.
  • My appetite for auditioning standard SiCs after working thru the process of finding / dialing in an IR mix is usually limited. Though I can see / hear that changing standard SICs can have a dramatic impact, I usually feel like changing the standard SIC upends the IR auditioning I'd just completed - one depends on the other - so to audition both together systematically to find magical combinations I'd be auditioning multiple standard SiCs for each of multiple IRs auditioned - too much of an exponential rabbit hole for my taste (I guess one could argue that standard amp tweaks also complicate IR auditioning - and I guess that's true, but somehow I've already accepted that I'll go back and forth between amp adjustments and IR mix selection - adding SiC auditions to that goes over the top for me).
  • A major reason I enjoy Axefx tones so much, and a big reason why tone shaping on Axefx takes less effort for me than on other units I've owned, is the built in baseline authenticity and accuracy, which is continuously improving with updates. In addition to all the other built in amazing component authenticity, with Dynacabs, authentic to real SiC curves can be auto-set for any given amp/DC pair. I feel that changing the authentically set SIC for something else (even if it sounds better to my ears) just short circuits me in terms of my most authentic starting point, from which I will continue into refinement using the more traditional real-life-like tools noted above.
  • I try to stick with the tone shaping tools which are most authentic irl and widely known in terms of how they work and which have information widely available on how to use them. As a tone shaping tool, SiCs are one of the farthest from this definition imo, since irl the curve is set when a given cab is plugged into a given amp - typically, there is no SiC curve tweaking or swapping possible irl - it is what it is - so, though it's great we can use it to taste in the modelling realm, it's not something we can find much specific guidance on (ie I can take courses on how to use EQ). With all the other tone shaping options available I tend to just dig myself into deeper holes with the less well known (or not at all known irl) tool choices like SiC tweaking.
Not meaning to dissuade anyone from using SiC for tone shaping - I'm often tempted since it's one of the more obscure / advanced methods that I can actually hear well in action - in most presets if I swap around SiCs, the differences I hear are dramatic - where as other advanced tone shaping options (ie tube swaps etc..) elude me as far as my ability to hear any differences at all. Just my related thoughts in response to the interesting question posed
 
Last edited:
You must log in or register to reply here.
Back
Top Bottom