Exhilarating/unsettling Amp Modeling Experience

Discussion in 'Gear Chat' started by toomanycats, Dec 6, 2019.

  1. Chocol8

    Chocol8 Well-Known Member

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    You are not overthinking this at all, you are hitting on the difference between a profiler and a modeler.

    A Kemper profiler captures the amp as it was set. You have a tone stack and can edit, but it won’t behave exactly like the real amp so anything beyond small deviations may warrant another profile. You won’t need hundreds per amp, but you might need a handful.

    The modeler, models the behavior of the controls. If you turn the mid knob it should behave just like turning the mid knob on the real amp. The downside is if it didn’t come with a Valco model, you can’t make one or profile the amp you have. You need to choose a different model that is hopefully close, or beg the vender to include your amp in a future update.

    Speaker emulation is currently the part where modeling lags the most. IR’s capture the frequency response/coloration of speakers very well, but they do not capture cone cry and non-linear speaker distortion.
     
  2. Rusty Rat

    Rusty Rat New Member

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    So I think I may be able to give you an answer. It may not be the perfect answer, but it is an answer.

    For the Axe FX, there are two different approaches to getting 'the sound'. There is 'the sound' of the amp, and then 'the sound' of the cabinet. The amp models are precisely that...models. Each component of the amp circuit has been measured and converted into a mathematical model. Everything from the input impedance, tube sag, resistor values, capacitors, power loading, interaction with cabinet impedance etc. So the model interprets how it should behave and interact with other parts of the model (amp, or effect, or whatever) based off your chosen settings. This is how it doesn't treat everything like a linear set of variables and how you might get breakup beginning at say, a setting of 5, and a relatively clean tone at a setting of 2. I believe the guy at Fractal has had each of these amps in the shop to actually measure these values so they can be converted into the model. There are also different settings that take into account the 'actual' knobs on the real amps vs ideal situations. For instance, a particular amp may not have EQ settings on the amp itself, but you switch to the 'ideal' model, and you will have EQ to affect the tone.

    The sound of the cabinets are achieved (I believe) via convolution sampling. There are Impulse Responses for each cabinet type, along with a specific mic model and placement. When you are creating a preset, you have the ability to choose from over 2000 combinations of cabinet settings. This is to account for the myriad permutations of cabinet + mic possibilities. Plus you can load in 3rd party IR's as mentioned in an earlier post. The sound of a cabinet mic'd with a 414 dead center vs off-axis can yield a dramatically different sound. Switch to a sm-57 and the sound changes yet again. So that is why there are so many cabinet permutations. Now I do not know how they account for differences in recording the IR's. Mic selection and placement during the sampling of these cabinets will vary the sound....this I think is why some of the cabinet models are better than others.

    This is my understanding of the thing. If I have posted info in error please forgive me and feel free to correct.
     
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  3. LongBlackTie

    LongBlackTie Well-Known Member

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    I have the original Axe Fx ultra and still use it all the time. Perfect box for me. Headphone availability is so useful with young kids
     

  4. bleys21

    bleys21 Well-Known Member

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    I'm certainly no expert on the Kemper, as I've only owned it for about 3 months, but in my experience, I can take a Rig that I download (I don't have any amps, so nothing for me to profile right now) and I can still adjust the knobs (gain, bass, mids, treble, all the usual suspects) and to me, it reacts just like I was turning those knobs on the actual amp. Now, from reading the Kemper forums for a while, the overall opinion there is to get a "perfect" copy of an amp, you must profile it exactly how you want it, but again, for me, it sounds great and allows me to raise/lower the gain, or the bass, or whatever.


     
  5. redman

    redman Well-Known Member Supporting Member+

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    I've never been big on amp modelers, stomp boxes or any of those things like most others here I prefer the raw sound of a tube amp and the one pedal I did use faithfully was a Wah some songs just had to have it like Gavin Degraw's I Don't Want To Be but that was the extent of my use of effects of any kind. That said I recently went on the search for a digital device I could plug my headphones in and rock out without disturbing my neighbors I live in an apartment for seniors 55 and above. I started off with the plugs, then bought a Quilter 45 watt pedal sized head then I bought a used Line 6 Pod I think was one of the first versions as it is labeled "The Ultimate Guitar Direct Box" instead of 2.0 or XD anyway this thing is okay for noodling or scratch tracks but not where I would use it on stage or a serious recording session. I did however try several different options available in the local music stores that included a GC. I came across a used Fractal AX8 now the thing was around a grand so I'll never own one but it absolutely blew me away. I have no idea how many different cabs and amps you had to play with but well more than I'll ever use. It helped that the girl waiting on me knew this thing well and just blazed through so many tones it was crazy.
    Anyway I will never say anything bad about digital offerings to the guitar players world again.
     
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  6. uglyvw

    uglyvw Well-Known Member

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    For me it is a combination of usefulness and simplicity. I run a digitech rp500 into a Peavey Valveking most of the time. I find it easier to start with the basic tube tone that I enjoy and use the pedal for all the effects.
     
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  7. Beyer160

    Beyer160 Well-Known Member

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    This is pretty much why I'm not interested in a Kemper. It's an impressive piece of kit that works for a lot of people, but the "profiles" only emulate one particular setting of an amp- the Kemper EQ controls are like studio EQ controls that adjust the tone, but they don't emulate the tonestack of the amp. You can't bias it, pull the V1 or put a 12ax7 in the PI. A lot of people don't know or care what difference that makes, and that's cool. I do, though.

    Again, that's not to dump on the Kemper- it's pretty amazing at what it does. It's just that it doesn't quite work for my personal paradigm.

    I just downloaded Positive Grid Bias and Bias Amp because they were on sale, and I get a heck of a lot of use out of the original versions when recording ITB. Does it sound exactly like the amps it's emulating? No, but it does sound good and it's $100 worth of plugins that I find useful on their own terms.
     

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