Treble detail in profiles woes

    I'm just wondering, is there any sort of lo-pass on the return input? Just because I've been trying to profile my Mesa again and I keep running up against a problem of missing detail at the top end. I'm assuming there's no way to take SPDIF as the Return source?


    https://www.gearslutz.com/boar…?p=14082324&postcount=125


    The problem is manifesting here. The other people in the thread are in fact right upon re-listen a few hours later and with less ear fatigue, I'm definitely missing that detail in the upper end. But just jamming up definition or using a studio EQ doesn't do it. If I try and do a merged profile the result seems to completely lack the distortion character too. It's like I'm missing that tiny bit of transparent upper mids area that makes it sound glassy, like you can hear every nuance of the guitar from the amp, but with the Kemper it sounds like distortion is being overlayed evenly.

    The trouble is it's driving me up the wall. I've tried profiling a dozen different ways, re-routing the mic through a UAD preamp and back out to the Kemper, adding verb to the Kemper source in cause it's a room thing (it really doesn't seem to be, although I couldn't quite nail the room sound with the inbuilt verbs). Changing definition and clarity settings, adding EQ's, these gave a very glossy high end but didn't bring back the detail there (if you know what I mean).


    Of course the most frustrating thing is that I have no technical language to explain exactly what I'm hearing there, only diffuse emotive terms such as clarity, glassiness, transparency, grit, complexity of distortion, hearing the "woodiness" of the guitar push through... gah.

    If anyone has any suggestions, or have I hit the limit of the algorithm/cab resolution here with the Kemper when it comes to distortion and detail?

    The Kemper recording definitely lacks some top end. Also seems like some of the noise of the Mesa recording is gone in the Kemper. How is the input noise gate set?

    Quote from Per

    It's like I'm missing that tiny bit of transparent upper mids area that makes it sound glassy, like you can hear every nuance of the guitar from the amp, but with the Kemper it sounds like distortion is being overlayed evenly.

    Quote from Per

    Changing definition and clarity settings, adding EQ's, these gave a very glossy high end but didn't bring back the detail there (if you know what I mean).

    Have you tried mixing a bit of the direct signal in via the Direct Mix parameter, Per?

    Maybe Reamp Sense is set too low? There isn’t as much energy in high frequencies, so the top would be the first thing to suffer if the signal wasn’t high enough. Applies to Clean sense, too.

    Hey guys, thanks for the thoughts.


    Monkey_Man - Yes, it adds some clarity but makes it sound quite different.


    sambrox - I thought about this too, but it didn’t improve things.


    The profile is in the rig exchange if anyone has a decoder to check out what’s going on with the cab frequency graph.


    I tried making a merged profile too, but interestingly the Kemper decided the signal was way cleaner than it in fact was when I did that and the merged result was dramatically different when it came to distortion, I’d have thought this would preserve more treble however the top end was still missing. I was getting much closer with a classic profile.


    I thought about what if it’s because of power amp distortion too, so I pulled the master all the way down to below 1, and still the same problem.


    I’m wondering if it’s the conversion on the Kemper? Is there some way to tell the Kemper to use SPDIF for the return during profiling? Then I could ensure that it uses my interfaces converters for the job.

    No you're right that couldn't be the case and I just realized why. Originally when I made those tracks I was using the A/B switching during profiling to record both re-amps, so the mic'd up amp version is going through that return circuit and yet clearly it has all of the treble content, it's just the profile that lacks it.


    I was wondering whether it's down to background noise, or perhaps overzealous noise gating in the profiling process? On the other hand you can hear how much BG noise there is in the mic'ed up reamp and it's not really getting in the way at all. The Kemper seems to have a more extended bass than the original when looking at the analysis tool in Logic (but it's not great because it only has 64 frequency plots and it's linear rather than log so it's very hard to see in the critical areas what's going on).

    I wonder if it's down to the cab resolution?

    does this happen only with your mesa or with other amps as well? what mesa model? seem to recall there was some kind of mesa that the kemper couldn't profile correctly?

    Haven't tried it with another amp, however the profile is accurate in others ways including the amount of compression. It's the loss of treble that doesn't make sense.

    I wonder if the valvulator could help here though to match the impedance.

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    Interesting, maybe. But I just tried with my other little amp I have in America, which is just a horrible little practice amp and while the Kemper did an admirable job and in many ways improved it's tone what's noticeably missing is really just the treble/definition. The Kemper adds in quite a bit of mids too, it's a surprisingly wide deviation in frequency from the actual source :


    http://peranders.com/music/demostuff/Kemper_per_reamp2.wav



    vs the actual amp


    http://peranders.com/music/demostuff/SM58Amp_per_reamp2.wav



    Based on the fact that we know my inputs are good, and the output is also good, and from what I can tell my Kemper sounds much like everyone else's Kemper out there, then I think either I have the worst two cases for it to try and profile that just flummox the algorithm or perhaps this is an problem in the current OS (I'm using the latest 6.0.0.14574), because I don't think I have a buggy unit (though you never know).


    I'm wondering if professional profilers ever encounter this, if they do maybe that's what the EQ they all seem to slap into the X slot is for? When I tried the EQ it couldn't bring back the complex treble sound though, just boost what's there. Maybe it's only something that crops up under a really specific set of circumstances. I can't imagine no-one else has encountered this at all.

    Sitting thinking about this later, the frequency difference is so great I’m left wondering... it can’t be possible that it’s a foldover artifact can it? Just the way other frequencies go up as the treble goes down.


    I think my money is still on some sort of lo-pass, or noise gate, or the resolution of the cab section though.

    It's looking more and more to me like your particular Mesa has a built-in gate, man.


    If you re-read the thread with this possibility in mind, clues immediately pop out at you, like when sambrox said:

    Quote from sambrox

    Also seems like some of the noise of the Mesa recording is gone in the Kemper.

    ... and these possible pointers:

    Quote from Per

    I was wondering whether it's down to background noise, or perhaps overzealous noise gating in the profiling process?

    Quote from luntho

    what mesa model? seem to recall there was some kind of mesa that the kemper couldn't profile correctly?

    Quote from Monkey_Man

    Correct IIRC, Thomas.


    I think it had something to do with a built-in noise gate that couldn't be disabled except via physical, internal intervention.

    Hope this helps in some way, Brother Per. ;)

    It’s possible however, if there were a gate it would be audible in the re-amp through the amp itself (it isn’t), and also that doesn’t apply to the other amp which isn’t a Mesa and shows an even more stark loss of treble.

    Hi, the Mesa (first profile) is a 5:25 Express using an e609 silver mic, the second profile is some crappy Marshall practice amp using an SM58.


    No to any switcher or splitter.


    The signal path is as in the manual, Kemper send to amp input via jack, mic to return via XLR, guitar to Kemper front plate during profiling and for original take with Kemper delivering over SPDIF left dry, right monitor mono. Then reamp signal to Kemper via SPDIF, return all monitor (default setting). Space off, pure cab off, everything else in default state on the Kemper (had to factory reset it recently in order to be able to install the last OS update).