Harsh freq at around 2200 hz in all profiles - or is it just in all amps?

    I've noticed all Kemper profiles have a harsh "whistling" freq around 2200hz - more noticeable in high gain profiles, and some more than others, but it's always there. If you're monitoring thru a DAW, set up a notch filter at 2200hz, toggle it on/off, and you'll notice a piercing "whistling" tone leap out when you toggle the notch filter off. Or with the Kemper's studio EQ (post amp/cab), a mid-band cut at 2200hz, maximum gain reduction, highest Q, will also work. What I'm wondering is if it's something specific to the Kemper, or if it's just that all guitar amps have this going on? i.e. is it inevitably just part of a guitar amp's distortion overtones?


    If anyone feels inclined, could they try the notch filter on/off trick (at around 2200hz) and let me know if they're hearing the same thing? And if anyone's got some distorted guitars they've recorded from a real amp, if the same thing is noticeable here too?


    I suspect it probably is, and also that what I'm noticing is just an acoustic phenomenon whereby if you cut out a harsh freq, then put it back in, it REALLY leaps out. BUT it is only at this specific freq that, when you cut and then remove the EQ, it suddenly sounds so harsh - hence just curious whether this is specific to, or maybe just more pronounced, with the Kemper.


    EDIT: to be more accurate (or less...) this harsh whistling freq isn't always at exactly 2200hz - say somewhere between 2000-3000, usually between 2000-2500 tho. But try a notch filter on/off anywhere around there, you should hear what I'm talking about - unless of course it is just my Kemper!!


    Also, have tried thru headphones (direct from Kemper) and hear exactly the same thing toggling the Kemper's studio EQ on/off at that freq - just to rule out monitoring equipment or environment being the cause.


    And again, I suspect it's probably just a nasty freq range for any distorted gtr amp - but just curious to get some 2nd opinions!



    Remember... you are not hearing the amp or cab but the microphones interpretation of the amp and cab. Also, be careful what frequencies you cut until you got a full mix. Some of those 'undesirables' sound good against bass, drums, and vocals.

    Larry Mar @ Lonegun Studios. Neither one famous yet.

    Since no asked yet, what are you monitoring your sound with? It is possible your speakers have a resonance there. I have played my Kemper thru a few sets of speakers and the high end is different on all of them. Very crispy sounding on some, etc.

    Quote from RosboneMako

    Since no asked yet, what are you monitoring your sound with? It is possible your speakers have a resonance there. I have played my Kemper thru a few sets of speakers and the high end is different on all of them. Very crispy sounding on some, etc.

    That is why I asked about the waveform - if it isn’t in the signal before the speaker, it could be related to the crossover for the tweeter. https://www.soundonsound.com/s…akers-crossover-frequency

    Quote from RosboneMako

    Since no asked yet, what are you monitoring your sound with? It is possible your speakers have a resonance there. I have played my Kemper thru a few sets of speakers and the high end is different on all of them. Very crispy sounding on some, etc.


    Quote from paults

    That is why I asked about the waveform - if it isn’t in the signal before the speaker, it could be related to the crossover for the tweeter. https://www.soundonsound.com/s…akers-crossover-frequency


    I did consider this, should have mentioned - to rule it out, I also tried through headphones (direct from the Kemper) and toggling the studio EQ on/off - same thing, always around that freq (let's say between 2000 and 2500 hz) always a harsh whistling tone that sounded better cut out, and that really leaps out horribly if you put it back in.


    Quote from BayouTexan

    Remember... you are not hearing the amp or cab but the microphones interpretation of the amp and cab. Also, be careful what frequencies you cut until you got a full mix. Some of those 'undesirables' sound good against bass, drums, and vocals.


    Oh, definitely, I am careful of this - I use the Kemper for recording, so am always trying to set up the sound to work well in a mix context. And btw, I'd never use a notch filter on gtrs (or much else for that matter, unless for an effect) - I just mention it here as it helps quickly demonstrate the difference with that frequency in/out. Been experimenting with a few profiles that 'd consider to be very well balanced already, and am finding that the best treatment is just a normal bell curve, quite a steep Q, couple of db reduction. Definitely, as with any "bad" freq, too much out and it starts to negatively affect the sounds character.

    To verify, try having a technician / friend, connect an oscilliscope or spectrum analyzer to the Kemper Main Output then Monitor to verify if the 2kHz - 3kHz is present. This eliminates the crossovers, speakers and anything else beyond the Kemper as any issue.

    Quote from BobWalters

    To verify, try having a technician / friend, connect an oscilliscope or spectrum analyzer to the Kemper Main Output then Monitor to verify if the 2kHz - 3kHz is present. This eliminates the crossovers, speakers and anything else beyond the Kemper as any issue.

    I don't know anyone with this equipment... But if monitoring thru headphones (which I've tried) what else is there besides the Kemper and the headphones?


    Just out of interest, have you tried what I suggested - notching out the frequencies (on a distorted profile) somewhere between 2000 and 2500 (wherever it sounds harshest) and then removing the EQ to see if the harsh whistling tone then leaps out? Now this is definitely creating an "aural illusion", whereby the harsh freq sounds worse/louder than it really is when you suddenly remove the EQ - but it does help to identify these frequencies.


    btw, in practice, I would not use a notch filter to remove them - just a bell curve with steep-ish Q and few db gain reduction, just enough to tame the harshness without killing the overall character of the sound. And I do think it most likely that this harshness is simply there in distorted amps, and typically does need cutting, similar to how there's always some "mud" around 250-300 hz. But if no-one else is hearing what I'm hearing at this freq range, then maybe it is my Kemper...


    Admittedly someone else trying this notch on/off trick may not be conclusive - the harsh whistling tone is there to varying degrees from profile to profile (another reason why I think it's probably just a natural artifact of the amps), and it may bother some people more or less - but it would help at least somewhat in determining whether it's normal or not.

    Quote from paults

    You most likely have a real time analyzer in your GAW. Or you can probably download a free plug-in. Seeing the waveform is the way to confirm or rule out the issue is being something in the Profiler.

    I've got various EQ analysers in my DAW - do you mean the sort of frequency spectrum analysis that Pro Q shows - or the actual waveform of the audio? (there's a stock Cubase plugin that will show the latter). I'm not sure what I'm looking for in either of these tho that would determine whether this harsh whistling tone around 2000-2500hz is just a natural feature of guitar amps, or if it's a problem with the Kemper?

    Quote from dave5150

    Is the whistle still present if you turn off the amp block in the Kemper?

    Ah, good point! That would help rule out anything to do with my pickups. Will try this next. Although as this harsh freq is only really there on dist tones (and I suspect just a natural artifact of a distorted amps overtones) I'm not sure if it's going to answer the question of whether this is a Kemper thing or an amp thing.

    Quote from dave5150

    Is the whistle still present if you turn off the amp block in the Kemper?

    Can't hear much difference at all with amp block off - not sure what this tells me though, other than at least it's not some ghost signal ever-present in my Kemper or pickups. The question remains whether this frequency range is more harsh with the Kemper than if you were to record a real amp. If it's normal tho (i.e. not a particular fault in my Kemper) then it's sort of a moot point anyway I suppose - is what it is. Usually doesn't take much EQ to tame it - after all this only came to my attention because of a profile where it was particularly bad. Most profiles it's still there. but bearable/tameable. At this point I guess it's just a matter of technical curiosity as to whether the Kemper accentuates this harshness due to it's profiling tech or digital nature.

    Quote from urpilus

    Hi, I've noticed it too: I lower, with post-eq, the 2.500hz frequency in almost all the distortion rigs.

    I leave Q at 707.

    Cool, thanks, sounds like it's normal (at least for the Kemper) - and to be clear, it's only with some distorted profiles I find this frequency range unbearable. With most, it's there, but bearable/tameable. Solution - stick to my previous policy of only working with profiles that sound good to begin with!

    Quote from alligatorlizard

    Can't hear much difference at all with amp block off - not sure what this tells me though, other than at least it's not some ghost signal ever-present in my Kemper or pickups. The question remains whether this frequency range is more harsh with the Kemper than if you were to record a real amp. If it's normal tho (i.e. not a particular fault in my Kemper) then it's sort of a moot point anyway I suppose - is what it is. Usually doesn't take much EQ to tame it - after all this only came to my attention because of a profile where it was particularly bad. Most profiles it's still there. but bearable/tameable. At this point I guess it's just a matter of technical curiosity as to whether the Kemper accentuates this harshness due to it's profiling tech or digital nature.

    Try turning the amp block off and then stacking some dist blocks together like a Kemper drive and a mouse or muffin and add a 3rd if you need to.

    Quote from alligatorlizard

    Can't hear much difference at all with amp block off - not sure what this tells me though, other than at least it's not some ghost signal ever-present in my Kemper or pickups. The question remains whether this frequency range is more harsh with the Kemper than if you were to record a real amp. If it's normal tho (i.e. not a particular fault in my Kemper) then it's sort of a moot point anyway I suppose - is what it is. Usually doesn't take much EQ to tame it - after all this only came to my attention because of a profile where it was particularly bad. Most profiles it's still there. but bearable/tameable. At this point I guess it's just a matter of technical curiosity as to whether the Kemper accentuates this harshness due to it's profiling tech or digital nature.

    If the Profiler would emphasize certain frequencies of a profile, this would have been reported by numerous makers of profiles, simply because it would easily be spotted in the A/B comparison.


    Post an audio clip, so we can check if it sounds wrong.


    CK

    Quote from ckemper

    If the Profiler would emphasize certain frequencies of a profile, this would have been reported by numerous makers of profiles, simply because it would easily be spotted in the A/B comparison.


    Post an audio clip, so we can check if it sounds wrong.


    CK

    Yes, fair enough, I think you're right. As I hope I made clear, I was more leaning towards the hypothesis that all dist amps contain some potentially nasty freq's, and that it wasn't a fault with the Kemper - but just wanted to get some other opinions just in case. Also, it definitely isn't a problem in all profiles - I just noticed in some particularly harsh sounding profiles that this particular freq range seemed to be the (main) source of harshness, and then out of curiosity examined a variety of other profiles, and found this same sort of "whistling" tone WAS there in all of them, if you really isolated it that is. But mostly, it's either fine as it is and clearly just a natural part of the full freq spectrum of a dist gtr amp (e.g. sounds bad if you cut it!), or in some cases does benefit from a bit of gentle EQ-ing - but then I don't think it would come as a surprise to any audio engineer to hear that dist grs benefit from a bit of smoothing in the low-highs! So I'm happy to wrap up this thread with the conclusion that nothing is untoward here, and I shall go back to my previous policy of only working with profiles that already sound pretty sweet to begin with.


    btw, with regards to the possibility of any fault in my Kemper itself, I sent some audio/DI to Kemper customer support over the weekend (for this, and another reason) and they were very helpful, compared the files, and assured me it all sounded as it should. So I shall stop overthinking this and get back to making music with it

    Mr Kemper himself posted the main EQ controls use these frequencies. If you are using the EQ post amp and turning up the TREBLE you will get a lot of the 2-2.5 kHz you are talking about.


    For high gain you should always use the EQ as PRE AMP and then add a studio EQ as your first stomp after the amplifier to really dial in the EQ.


    Since amplifier clipping adds a ton of high frequency signals, you can roll of some highs before the amplifier to get a smoother distortion. And then the STUDIO EQ is used to get you back where you want to be. Clipping a 100 Hz sine wave brings in 300Hz, 500Hz, 700Hz, etc out to infinity with gradual lowering volumes.


    Every decent high gain sound I have ever looked at has this type of a frequency response. A flat line starting at 100 Hz and and ending around 5 kHz. Usually 10-15 dB drop between 100-5k.



    So you should adjust the studio EQ to get something like this curve. The actual low end cuts pretty hard below 100 Hz. The slope above 5k gives you the airy and lively sound. Your IR will dictate that slope usually.


    If you are EQ'ed to this slope and it stills sound really bad, I would start looking into a different IR. It is very important to keep your signal in phase. If your IR was not recorded in-phase you can get this curve but it will sound dark/weird/thin because the phase is not correct. So you get a signal at the right volume but it is out of phase with signals near it and they cancel each other out.


    I always use a program called Goldwave. A stand alone app that does FFT while recording audio to see the frequency response. GW is a stand alone app. If you are using a DAW there are other options out there. It would be a good idea to have one of these type of apps running so you can see the EQ changes you are making. Personally, my ears are terrible so I need help from an app like this.


    Another option is EQ'ing IRs to fit. If you purchase IRs they come as a WAVE file. These files can be loaded and edited in EQ software. Again, phase is important. Applying digital filters can cause phase errors just like real filter. Making small changes to the IR should not drastically change its overall shape.


    You can also download ROOM EQ WIZARD and run sweeps on your Kemper with No amp blocks/effect/eq. This will give you a freq sweep of the IR that can be converted to an IR right in REW.


    IRs are stored in WAVE file formats at 1024 or 2048 sample counts. So you will want to clip the new IRs to 2048 or something slightly larger.

    To clip in time use 2048/Sample Rate to get an approx time.

    2048 samples / 48000 samples per second = .04267 seconds. I would clip at say .043 or .044.