My findings using the KPA as a DI solution

  • Initial testing for using the KPA as a direct profiling solution with my Bogner Shiva 6L6. The goal was to accurately capture the Shiva's preamp section. If successful, this configuration would allow me to use the Shiva as a power amp/cabinet for the KPA.


    Configuration: Guitar>KPA Input>KPA Direct Output>Shiva Input>Shiva FX Send>KPA Return>KPA Master Outputs>Logic. Recorded directly into Logic. No post processing used.


    Clip posted on soundcloud...
    http://soundcloud.com/johnny-n…/kemper-profiling-session


    Clips are as follows:
    (1st clip) Pre-profile, reference amp
    (2nd clip) Post profile, reference amp
    (3rd clip) Post profile, pre-refine KPA
    (4th clip) Post profile, post-refine KPA


    Findings/Notes:
    1. Volume drop on passes 2-4.
    2. Pre-refined result closer to original than post-refined, but still not acceptable.


    Conclusion:
    While an EXCELLENT solution for capturing exact mic'd cab tones, I don't believe it to be quite as capable when direct profiling. I hope future updates improve this ability.

  • You have some level differences between the first clip and the subsequent ones.


    More importantly though, how long did you refine your profile for with the Kemper? Because your refined stage takes it way away from where it shoudl sound quite a bit (and how did you refine?). It's important to refine for a really long time, not what's shown in the videos, but literally turn on refining, and then play lots and lots for at least 5 minutes solid, I refine for about 20 minutes now and get much closer to the tone I'm sending.

  • You have some level differences between the first clip and the subsequent ones.


    More importantly though, how long did you refine your profile for with the Kemper? Because your refined stage takes it way away from where it shoudl sound quite a bit (and how did you refine?). It's important to refine for a really long time, not what's shown in the videos, but literally turn on refining, and then play lots and lots for at least 5 minutes solid, I refine for about 20 minutes now and get much closer to the tone I'm sending.


    Re: Level differences. I know. I mentioned it in my notes. That shouldn't be happening IMO. I didn't alter any knobs or settings.


    Re: How long did I refine. I refined for over 5 minutes using various chords at different velocities all up and down neck in addition to single note runs.


    The point of my posting this wasn't to field critiques about my processes...just to share my findings so that some might benefit. Feel free to spend the time to post your own results using your own techniques. I would like to see if other users experience similar results or not. :thumbup:

  • Obviously I'm not in your room and hearing what you're hearing, but clips 3 & 4 sound like a successful DI Profile.
    How does this all sound through your Bogners poweramp?


    I'm listening on studio monitors...a pair of Event Studio Precision 8's. Through these monitors I hear a very noticeable difference IMO.


    Playing back into the amp's return feels/sounds VERY different from the real thing as well. The lack of punch that I've mentioned in another thread is definitely there in addition to a more unpleasant eq curve. Not good.


    I took some screen captures using Logic's "Match EQ" plugin...maybe this will help you visually see what I was hearing.


    1st clip - pre profile reference amp
    [Blocked Image: http://i239.photobucket.com/albums/ff194/chameleon101663/01Screenshot2012-04-22at102045PM.png]


    2nd clip - post profile reference amp
    [Blocked Image: http://i239.photobucket.com/albums/ff194/chameleon101663/02Screenshot2012-04-22at102111PM.png]


    3rd clip - post profile pre refine KPA
    [Blocked Image: http://i239.photobucket.com/albums/ff194/chameleon101663/03Screenshot2012-04-22at102140PM.png]


    4th clip - post profile post refine KPA
    [Blocked Image: http://i239.photobucket.com/albums/ff194/chameleon101663/04Screenshot2012-04-22at102208PM.png]


    Can any audio engineers out there decipher these readings and explain if my ears are terrible or not? 8|:wacko:?(

  • Thanks for your Post and some comments from me.


    - The volume change after profiling is crucial.
    The Profiler will automatically finetune the volume of the profile to unity gain, so it will fit well to all other profiles in terms of volume.
    To have the best A/B comparison, the volume of the reference amp is adjusted by the same amount. This should not cause a problem.
    The volume change has to happen at some point, so it's a good idea for the Profiler to perform it as early as possible, that's the profiling procedure.


    - This is why recording 1 and 3 are obsolete, 2 and 4 is the real A/B comparison.


    - Direct profiles are not as challenging as full profiles, thus many users achieve perfect results.


    - The match eq pictures do not show what we heard in the clip, but the miked speaker, right?



    Can you describe how you cabled the KPA and the Bogner?


    CK

  • Just my 2cents worth as a regular DI profile user.
    I think your lack of punch is simply a matter of getting the gain staging right. The shiva doesn't have an fx return level. It may simply be a matter of getting the level hitting the shiva fx return from your kemper up to the same level as the level provided by the preamp when you play the amp alone.
    Ive owned shivas in the past and fx levels have always been a problem with them on all versions albeit no quite so bad with more recent ones.(the fx sends are very hot requiring attenuation on your fx units input and therefore having to really ramp up the volume on its output. Ive had to go as far as introducing an mxr micro amp after fx in a shiva fx loop in the past)

  • Just my 2cents worth as a regular DI profile user.
    I think your lack of punch is simply a matter of getting the gain staging right. The shiva doesn't have an fx return level. It may simply be a matter of getting the level hitting the shiva fx return from your kemper up to the same level as the level provided by the preamp when you play the amp alone.
    Ive owned shivas in the past and fx levels have always been a problem with them on all versions albeit no quite so bad with more recent ones.(the fx sends are very hot requiring attenuation on your fx units input and therefore having to really ramp up the volume on its output. Ive had to go as far as introducing an mxr micro amp after fx in a shiva fx loop in the past)

    + 1000.
    I have similar issues as chameleon101663, that partially solved, increasing the volume from KPA. It's doesn't sound exactly as the original, but close enough.
    Increasing the volume sound "opens up" with more punch, but still comparing the profile with the original, the original is more "alive".

  • Just my 2cents worth as a regular DI profile user.
    I think your lack of punch is simply a matter of getting the gain staging right. The shiva doesn't have an fx return level. It may simply be a matter of getting the level hitting the shiva fx return from your kemper up to the same level as the level provided by the preamp when you play the amp alone.
    Ive owned shivas in the past and fx levels have always been a problem with them on all versions albeit no quite so bad with more recent ones.(the fx sends are very hot requiring attenuation on your fx units input and therefore having to really ramp up the volume on its output. Ive had to go as far as introducing an mxr micro amp after fx in a shiva fx loop in the past)


    +1 I had a Shiva for a number of years and loved it. But my Shiva was the older one and the FX send/return was not at your "normal" level. I even had to use a special cable from Bogner with it. Without that cable the send/return was very tempermental. Do you have any other amplification that you can try with the KPA? You might want to check out FRFR just because of the weight of that amp. I remember using it to hold up my car once while I changed a tire :).


  • Re: Volume change - Makes perfect sense!
    Re: 1 and 3 obsolete - I agree on comment about #1. #3 is included to show the before-and-after profiling for comparison. #3 SHOULD sound better but does not (by a long shot) IMO. It seems to sound worse.
    Re: Match EQ pictures - These charts show what was heard in the clip (the direct un-miked sound). Speakers were not used in this profile at all; the profiled sound was coming from amp's FX send.
    Re: Describe cabling - Configuration: Guitar>KPA Input>KPA Direct Output>Shiva Input>Shiva FX Send>KPA Return>KPA Master Outputs>Logic. Recorded directly into Logic. No post processing used.


    And in response to all the Shiva comments...I agree but that's not the point (which is why I'm testing a different amp today). The problems I've mentioned have happened with every amp I've tried to direct-profile so far.


    BTW I found a better analyzer & will re-conduct the test with my Reason Bambino Grande.

  • Still think it might be a matter of gain staging even with a different amp.


    It might be that the amount of attenuation required to profile that amp (as I said it is very hot, which is one of the things that make it such a ballsy sounding amp) cannot be matched in make up gain on the output of the KPA. In that case you will need something after it (like for example an MXR micro amp) to bring it back up to that level.


    Im not dissing on the Shiva, its a fantastic amp. I do know that whenever I used anything in the loop I had a helluva job getting a sound from it as good as when nothing was in the loop.


    I tried a TC electronic G major and a Boss GT pro. On both those units I had to turn the input level almost completely off to avoid clipping their input from the shiva fx send.


    Neither unit was able to 'make up' the gain lost at the input stage without going into clipping. An mxr micro amp sorted out the level difference quite nicely.


    I find with all the modellers Ive used in the past this problem manifests when using them into the fx loops of many amps. They don't sound bad, just lack 'balls'. Again the micro amp has always been of help in this regard.


    If you have any sort of clean boost or eq pedal you can try them as an experiment. It might not be the sound you want as many of them add their own sound to the brew, but it should give you an idea if that is the problem

  • Test #2 using the KPA as a DI solution, this time using a Reason Bambino Grande.


    Configuration: Guitar-KPA Input-KPA Direct Output-Bambino Input-Bambino FX Send-KPA Return-KPA Master Outputs-Logic. Recorded directly into Logic. No post processing used.
    http://soundcloud.com/johnny-navarro-lv/kemper-profiling-session-1


    Clips are as follows:
    (1st clip) Post profile, reference amp
    [Blocked Image: http://i239.photobucket.com/albums/ff194/chameleon101663/01Screenshot2012-04-23at104043AM.png]


    (2nd clip) Post profile, pre-refine KPA
    [Blocked Image: http://i239.photobucket.com/albums/ff194/chameleon101663/02Screenshot2012-04-23at104307AM.png]


    (3rd clip) Post profile, post-refine KPA
    [Blocked Image: http://i239.photobucket.com/albums/ff194/chameleon101663/03Screenshot2012-04-23at104346AM.png]


    Notes: The pre-refined proflie feels/sounds much better than the post-refined profile...that should be opposite, no? ?(

  • BTW...played the "unrefined" DI profile back through the amp fx return. Feels/sounds MUCH better. Something about the refining process changes the original DI tone/feel too much IMO.


    Adding Till's cabinets after-the-fact seems to work nicely as well (for recording).


    I think I could live with this...but I'd definitely like to see the KPA refining process do as good a job matching the DI signal as it does on matching the mic'd signal.

  • Notes: The pre-refined proflie feels/sounds much better than the post-refined profile...that should be opposite, no? ?(


    Yup it should. What's interesting is there's a distinct rolloff displaying in your graphs, and in fact for the refined one some of that is coming back but as you say that sounds worse.


    What I recommend is increasing your refining time, and I dont' mean do small refines of a few chords here and there, i mean start refining then noodle away on it for as long as you want, just jam out and when you remember that you're still refining then go and stop. Ignore the advice about just loud chords, the more you give the KPA to work on the better. Sometimes I just play for half an hour or more before stopping refining, the result is always much better than short refining stages of "here's some chords" then stop to hear the difference, then "here's some more" etc.

  • Yup it should. What's interesting is there's a distinct rolloff displaying in your graphs, and in fact for the refined one some of that is coming back but as you say that sounds worse.


    What I recommend is increasing your refining time, and I dont' mean do small refines of a few chords here and there, i mean start refining then noodle away on it for as long as you want, just jam out and when you remember that you're still refining then go and stop. Ignore the advice about just loud chords, the more you give the KPA to work on the better. Sometimes I just play for half an hour or more before stopping refining, the result is always much better than short refining stages of "here's some chords" then stop to hear the difference, then "here's some more" etc.


    I disagree. :D


    I don't think that's how CK meant for the refining process to work or the manual would say "noodle around for 30 minutes". You shouldn't have to refine for a half hour to get great results. Such extensive refining isn't necessary when I use mic'd cab tones...and I'm totally happy with the results. :S

  • We should not forget that here we are stretching quite a bit the original purpose of the Profiling process, I've tried it with power amp and cab and was sounding like an amp...to me...but loosing all the flexibility and ease of being FRFR. I think that by now my ears are used to that paradigm and I would not go back hauling a 4x12 around even if somebody would do it for me (and it is not the case). But that is just me....

    "Music is enough for a lifetime, but a lifetime is not enough for music" Serghei Rachmaninoff