Dissertation help

    Hello guys. I'm approaching the end of my undergraduate degree on an Audio & Music Production course and have decided to make the Kemper the focus of my dissertation, seeing as I have one and I reckon I'd be pretty content going on for 10,000 words about it. Creating this thread as I just want to check a couple of things experiment wise and then later on I may also whack a questionnaire or an A/B test thing if anyone would be kind enough to help with feedback on that

    Anyway, experiment wise, obviously I'll be profiling an amplifier using the Kemper and then comparing the original amp and the profile and see how accurate it is...I'm just wondering, is there a 'proper' way to record audio from both the original amp and from the KPA, either at the same time or separately using a DI signal back from a DAW? The main thing is I want the same audio signal being fed into both amps

    Also I'm not sure but is the KPA equally good for clean, distorted and bass profiles? I imagine it is and even then I can test it myself and ramble on about it in my dissertation, but worth asking

    Cheers

    If you end up with a well done scientific analysis, this could be really interesting. Yes, the profiler does clean, distorted and bass really really well. There really doesn't seem to be any discernible difference between it and a tube amp. I'll be interested to see what you come up with.

    Hi DominicDot,
    What a great excuse for developing your Kemper knowledge and skills!
    Although, I have never done any profiling, I am interested in what you are doing. I've had a Kemper for just over a year now. I can honestly say it is the best piece of gear I have ever bought.
    Keep me posted on what you're doing.
    Kind regards
    Pre-Amp

    Haha, cheers for the enthusiasm guys. Hopefully I just haven't left it too late to get a decent one done. If anyone also knows and in depth articles about the profile or modelling/profiling in general whether it be amps or say DAW plugins can you point me in the direction

    Anyways, I'd imagine reamping would be a way to start, both with your profiler & the exact setup you profiled to begin with. With a prerecorded take of course :) AD/DA and reamp box will need to be of (great) quality I'd say to hold up to any kind of scrutiny, to include the most transparent preamp gain you can find. I noticed once that the profiler manages to reamp things in the exact same way everytime for me (sample points matched exactly). I figure a real setup will choose to behave differently for every time it is used to reamp the same take. High sample rate & bit depth would help in close comparisons. If you get enough data and if it's your thing, consider some statistical analysis.

    ... and since you're in that dept surely they'll allow you to use their facilities/gear for the purpose of your research, by your adviser's request :D and you can brush up on some Tinn-R if you choose to do any analysis beyond superficial/descriptive drivel.

    Quote from Redoubt9000

    Anyways, I'd imagine reamping would be a way to start, both with your profiler & the exact setup you profiled to begin with. With a prerecorded take of course :) AD/DA and reamp box will need to be of (great) quality I'd say to hold up to any kind of scrutiny, to include the most transparent preamp gain you can find. I noticed once that the profiler manages to reamp things in the exact same way everytime for me (sample points matched exactly). I figure a real setup will choose to behave differently for every time it is used to reamp the same take. High sample rate & bit depth would help in close comparisons. If you get enough data and if it's your thing, consider some statistical analysis.

    ... and since you're in that dept surely they'll allow you to use their facilities/gear for the purpose of your research, by your adviser's request :D and you can brush up on some Tinn-R if you choose to do any analysis beyond superficial/descriptive drivel.

    Is there a recommended Reamp box? Going back to my first post, is there a recommended setup for this kind of thing? If anyone could explain it or link me to an article with it, cheers guys

    I've no recommendations, as I've never reamped anything until I got my KPA in. I believe the box just changes the impedance of your line-level signal from your interface, out to your amps instrument input (which is expecting a high impedance load), no? Afterwards, you just have a mic setup to capture w/e you're feeding into the amp.

    A decent reamp box runs several hundred USD if I remember correctly? Radials & countryman seem to be the goto gear as far as cheap/reliable go (I've seen even cheaper alternatives and DIY options). Price is a bit of a drop in the bucket against AD/DA converters, unless you've a good interface to begin with, or again as said, if you've access to equipment not of your own. Google should yield quite a bit in terms of how to reamp.

    What would have me a bit concerned is the generations of conversion you'll encounter (again if you're going to be anal about it).
    From your DAW into the kemper's own converters, I'd assume
    Digital (D), Analog (A)
    D --> A (interface out)
    A --> D (kemper's conversion running signal through your profile)
    D --> A, if you're running a line-out from the kemper
    A --> D another generation into your interface.. til you finally see the waveform in your DAW.

    That or skip the the additional stages of conversion by using spdif, but with spdif you're locked into 44.1k... I'm unsure if 88.2k is available or if it just gets downsampled regardless through the kemper.

    In typical reamping I'm guessing it's only two gen of conversion? Out then in, no?

    I'm bored -_- wait, there are only weeks left, are you on semester or quarter hours lol or prep for next term?
    Lots to think about I guess.

    Yes, really, you'd better always start with Wikipedia and Google, I've just searched your question and found possible answers to it, try to search. Or if it doesn't work, try to ask for help at papersgear.com, I'm sure they are competent with your question :)

    Quote

    It's just a matter of keeping things equal in both chains. Quality of converters etc are of lesser concern - any detrimental effects here should be equal for both.

    All this comes after profiling *(except for a thing marked in bold below; you'll get to that) - and make sure you don't change a single thing, or bump the mic on the cabinet, move furniture around the room, change position much etc between profiling and recording passes. Set the kempers "constant latency" option to ON.

    You can use the kemper as a DI box, so you can record a good quality signal. see the reference manual (or is it the basic manual?) for output settings to achieve that. I think what you want is "git studio" setting, as this is line level.
    Record the "wet" signal of the kemper alongside the Di track for reference (see why in a bit)

    Reamp box suggestion: http://www.diyrecordingequipment.com/collections/frontpage/products/l2a - easy to build if you have a soldering iron, great quality.
    Use that for both the amp and for the kemper when you get to that point.
    First:
    Use one of the analogue line outputs of the kemper into you DAW (you want to keep the post-amp and post-kemper AD/DA conversion equal). Make sure you don't have "space" enabled on the kemper, and no effects etc enabled.
    Run the recorded di signal out of your audio interface's line output, into the reamp box, then into the kemper (with the newly made profile). Record that, and compare with the "wet" reference track. Adjust the volume on the reamp box to match this fairly closely. This might take a few tries (record, compare to reference track from step one, adjust, repeat).
    Now you should have a decent representation of a guitar signal going into the kemper.

    Now take the plug from the input jack of the kemper and move it to the "real" amp, so the reamp box goes into there.
    Play the DI track.
    Adjust the preamp gain knob on your interface so that it sits at maybe 70%, no higher, and probably not below 50% - this is to keep the signal pretty clean as it goes through the preamp of your interface. hopefully, you have a fairly clean preamp there.
    ACTUALLY: This step should be done before even taking the profile, so you can adjust your amp settings (master volume) to give good level but not too hot into your interface. It's probably fine to do this with just your guitar rather than a DI track, just make sure you play more or less the same stuff with the same weight. You'll want to stay below -10 on the peaks on the meters.

    Then plug the reamp box back into the kemper and match the volume level there in the output section to be at more or less the same volume going in. But you can adjust to greater detail inside the daw afterwards, this is just to get it fairly close. (you NEED to level match very closely in the DAW once you've recorded both "final" tracks).

    Now you should get more or less "exact" copies from the kemper and from the amp.

    Then record the kemper playing the di track, and then the amp.

    Level match and phase adjust (since one will be delayed by xx samples) the two tracks, and compare.


    Did I miss anything here?


    Also: during profiling, the kemper can switch between the real amp and the profile for comparison. Maybe this can be recorded? Would that yield an even more comparable result, I wonder?