[ckemper's help needed] Profiling two mixed amps

    Hello,


    The KPA is good at reproducing tube sounds and it works very well with a single amp. But what happens when I want to profil 2 (or more) different amps with 2 cabs and 2 mics mixed together ? Is the KPA as accurate as it is with a single amp ?

    Edited 2 times, last by VanHalen ().

    It is very accurate in getting the sonic print of the recorded mix of the two amps. It is somehow different from having two physical amps recorded at the same time.
    I also doubt profiling a very clean amp and a very distorted amp together can be successfully achieved in terms of realistic representation. AFAIK, no-one has tried yet. Would be curious about this, but I miss the means to try myself.


    You might want to refer to the wiKPA for what has already been said on this forum about the matter :)

    Thanks viabcroce.


    I already posted several messages about "profiling mixed amps" (2 or more) in other threads. If I make a JCM 800 profile and then I make a Dual Rectifier profile three months later, I'll have two different profiles and it will not be possible to have a mixed profil of the two.


    However, I've got an idea but I want you to tell me what you think about it. My goal is always to blend/mix amps to make a profile working on a KPA even if I don't have the two amps at the same time. To simplify, I'll just consider two amps but I can use more ones.


    When I make a profile, I split the signal just before the return of the KPA and send it to my daw in order to record it. I'll record the two or three squences of the profiling process coming from the mic. The total duration af the record will be about 45 seconds.


    Three months later, I make another profile with a different amp and I use the same recording technic.


    I assume that the duration of the profiling process and the duration of the two or three sequences are always the same.


    I take these two recordings, I mix them in my daw then I make a new profile with the KPA sending to the return of the KPA my mix. The difficulty is to know when beginning sending the mix the KPA.


    What do you think ?


    I think you're slightly confused as to how the profiling process works. Its not like an IR where you send a wave file to the KPA. The KPA is analyzing the response to the signals it is sending out, and using a refining process to fine tune an EQ match. To do what you want, you'd need a complex signal chain to profile both amps at once. But ideally, loading up 2 profiles simultaneously would do the job. However, that functionality likely won't come until were in a second (or more) generation unit.


    EDIT: Wait, I think I understand what your saying. During the profiling process of each amp, you record miced amps to your DAW. Then at a later date, you start the profile process bu feed it to nothing and send the return signal back to the KPA from your DAW with the mixed signals. Could work actually, but you loose the refining process.

    I'm not enough into the concepts behind profiling, but I guess that, if the KPA doesn't change the sequences it sends to the amp according to the amp's response, what VanHalen (LOL) is suggesting (if I got it right) might work.


    Basically, you don't send the KPA's real test signals anywhere, and feed it with a response a real amp gave time before. A kind of differed profiling, if you... Will ;)


    Mixing two profiles this way has still to be proven doable, but meanwhile it might be worth trying a simple, single differed profiling just to see what happens.
    This might open to new creative ways of using the unit.

    I opened a thread here about the duration of the profiling process : http://kemper-amps.com/forum/i…ad&postID=68027#post68027

    Quote

    EDIT: Wait, I think I understand what your saying. During the profiling
    process of each amp, you record miced amps to your DAW. Then at a later
    date, you start the profile process bu feed it to nothing and send the
    return signal back to the KPA from your DAW with the mixed signals.

    Quote

    Basically, you don't send the KPA's real test signals anywhere, and feed
    it with a response a real amp gave time before. A kind of differed profiling, if you... Will

    Exactly.


    There are several difficulties with this technique :
    -the mix of the two recordings must be very accurate : we must be careful if the two profiled chains have different latencies
    -the recording quality should be high of course
    -know when beginning sending the mix to the KPA


    If someone has a good result with this technique, I think it should be a feature request because maybe the Kemper could record the signals on the USB key and compute the new mixed profile : no computer, no sound interface, no daw needed.

    BTW,


    Will, I don't think the refining process has to immediately follow the profiling. I've never been able to try of course, but AFAIK, you can refine a profile at any time.
    Can someone confirm this?

    Quote from viabcroce

    BTW,


    Will, I don't think the refining process has to immediately follow the profiling. I've never been able to try of course, but AFAIK, you can refine a profile at any time.
    Can someone confirm this?


    You have to do the refining before storing the profile AFAIK.
    By the way i don't do refining anymore. Refining is not mandatory IMO.

    It's an interesting idea, but I can't see how you would sync the output sound so that it was exact. Certainly could be tried though.

    Go for it now. The future is promised to no one. - Wayne Dyer

    I'm referring to sync with the KPA input signal for profiling. I guess you could try it as many times as necessary until you hit the jackpot.

    Go for it now. The future is promised to no one. - Wayne Dyer

    Quote from mba

    You have to do the refining before storing the profile AFAIK.

    Thanks :)



    Quote from Zappledan

    I'm referring to sync with the KPA input signal for profiling. I guess you could try it as many times as necessary until you hit the jackpot.

    OK, now I get it :)
    I guess there's a large tolerance for sync'ing the input and the output... but, again, it's just a guess...

    Quote

    I guess there's a large tolerance for sync'ing the input and the output... but, again, it's just a guess...

    Remember this : the KPA is able to adapt itself to the profiled chain : if this chain has a 30 ms latency (for example when you profile a virtual amp on your computer), the KPA will reduce it so when profiling the mix, even if you send to the return of the KPA with a little lateness, it could work. Look here : http://kemper-amps.com/forum/i…page=Thread&threadID=7260

    You know, I was thinking about this today and mulling over some workarounds - for instance, recently I had a mix where I needed to layer together a medium-gain and a high-gain version of the Same Amp. (No, this is not the same as picking an in-between amount of gain.) Anyway, seeing as how we have a new standalone Cab Impulse Import utility, imagine if we had a:


    Standalone Rig Merge Mix Utility.


    Imagine being able to take a number of .kipr's as input files (but at least two), adjusting some mix sliders, and then synthesizing a new .KIPR model in software that we could run. The effects might have to be forced to off for this - it's the distortion and cab models we really care about here.


    Now Wouldn't That Be Neat.


    -djh

    Why not record the dry signal and reamp it into 1 or more amps? (and mix the tracks)
    You could tell us if it's really useful because i'm not sure about it.
    I never used 2 amps with the Axe-Fx.

    This is a good idea but I wonder if it gives the same thing because these two technics relies on two different file types. With my method I keep a recording of the response of the test signal and the KPA can extract information later whereas with the KIPR files the information has already been extracted.

    Profiling multiple amps at once is definitely doable provided you have All Amps Physically Available and ready to respond in Real Time to the profiling process. But if you Don't have the amps physically available or you Don't have the gear/space necessary to get them both Running, Mic'd and Premixed prior to profiling, you're out of luck. The best you can do there is to profile the two amps separately, and then reamp your tracks.


    Hence, the idea of creating an offline KIPR generator. It gets you the result you're looking for, and doesn't require anything new KPA firmware-wise nor would it require double the DSP on the Kemper end. It would also allow you to create layered KIPR blends involving amps that you only have the KIPR's of (which is pretty much how most of are using the Kemper in practice.)


    And no, it doesn't rely on two different file types. Just two or more KIPR's, each of which have independent and complete knowledge of their respective profiled amps. Some clever offline DSP would be involved, but CK already knows how to accomplish this I suspect.


    -djh

    To be honest, I think the simplest solution is to allow loading of dual profiles which I'm betting the Kemper isn't powerful enough to do. You dual amp guys may be out of luck until the KPA 2 hits the market...

    Quote

    the Kemper isn't powerful enough to do

    If think you're right but it's because of that we're trying to find solutions to blend/mix amps the best way possible. Maybe in ten years we'll never talk about that anymore.
    dhodgson and I gave two solutions. Maybe Chris Kemper has another one. I hope he'll give us his opinion.