SOLVED Loud buzz through studio monitors on some lower notes

    Hello all,


    I just got my Kemper unpowered head and am shocked at how good this thing is and how easy it's been to use. My only issue so far is with the combination of the KPA and studio monitors I'm using (KRK Rokit 6 - 1st gen). When I approach what I'd consider a moderate volume range, I start getting a nasty buzzing sound on some of the lower notes on guitar: worst is low E string @ 12th fret, second worst is open low E, happens more infrequently elsewhere on the low E string. Occasionally happens with dyads on the A+D strings also. Seems equally likely to happen with clean or overdriven profiles and with single coil (low output) or HB guitars.


    The quality of this sound is somewhere between buzzing and a really fast rattle and sounds like it's not good at all for the woofer, so I've resorted to turning the KPA down to avoid it, which does work but is way less fun. For reference I've never been a "cranked amp" player, mostly bedroom and smaller jams, so my definition of moderate volume is pretty quiet by most players' standards. It's weird because I can play recorded music at a higher volume than this through these monitors without problems, but I'm sure there are differences between that signal and what the Kemper puts out.


    I'm plugging the KPA's main output straight into one monitor (to avoid an unrelated issue with my Scarlett 2i2 inputs clipping, new interface is inbound to resolve that) so there's nothing else in the chain at this point. I'd appreciate any thoughts on whether this can be resolved or if it's just a limitation of woofers this size. Thanks!

    I could be way-off here, but this is all I've got, mate:


    Is there an input-trim knob on the monitor? If so, dial it back and increase the monitor's output level if it has a switch / knob for that.


    If there's no input trim, use the KPA dialled back the way you've been but increase the monitor's level.


    If there's an input trim but no monitor-level adjuster, you're just going to have to find the loudest combination of higher-trim / lower KPA output level vs lower-trim / higher KPA output level.


    Welcome, mate.


    Could it be a natural resonance issue happening between your KRK monitors and whatever they are sitting / resting upon?


    @obeymydog, just for a sanity check, try temporarily moving your KRK Rokit monitors from wherever you currently have them, and put them on a rug on your floor, or on some cushions. Then play the same problem notes, and see if you are still getting the weird behavior.


    Let me know if that changes anything.


    Cheers,
    John

    Monkey_Man - Thanks for the welcome and suggestions. There's no input trim on these monitors but I tried increasing the monitor level while keeping the KPA turned down - the problem still occurs at the same volumes either way.


    John - Thanks for this idea, it does make sense that I might be hitting some resonant frequencies outside of just the monitor's woofer. I took the monitor I've been using down from its cinderblock stand and placed it on the carpeted floor - I could go slightly higher in volume (KPA master vol from 4.6 to 5.6) before the issue reappeared. It was closer to what I'd consider a reasonable practice volume but still felt kind of limited. I tried again with a pillow underneath and it seemed a bit worse. In all cases, the buzz seemed to be very directly localized to the speaker cone itself but I know the ears can play tricks with noises like this. Just in case, I did repeat this with the other monitor and had the same results.

    Quote from obeymydog

    Monkey_Man - Thanks for the welcome and suggestions. There's no input trim on these monitors but I tried increasing the monitor level while keeping the KPA turned down - the problem still occurs at the same volumes either way.


    John - Thanks for this idea, it does make sense that I might be hitting some resonant frequencies outside of just the monitor's woofer. I took the monitor I've been using down from its cinderblock stand and placed it on the carpeted floor - I could go slightly higher in volume (KPA master vol from 4.6 to 5.6) before the issue reappeared. It was closer to what I'd consider a reasonable practice volume but still felt kind of limited. I tried again with a pillow underneath and it seemed a bit worse. In all cases, the buzz seemed to be very directly localized to the speaker cone itself but I know the ears can play tricks with noises like this. Just in case, I did repeat this with the other monitor and had the same results.

    Something doesn't seem right with those KRKs.


    The 6" woofers might just not be up to the task of reproducing the low frequency range of the KPA amp profile you are using. Could also be the cross-over circuit.


    I guess, at this point, I could only suggest you look into getting a dedicated active FRFR monitor for your KPA, such as the Yamaha DXR10. Then you can go from quiet to riot, clean to scream, with no limitations.


    For a more budget oriented active FRFR solution, you might want to check out the newer model Alto (TrueSonic series 2), like the Alto TS210 or TS212.


    The Yammy DXR10 would be definitely be the higher end solution, however, and it get's a lot of love here on the KPA forum.


    If you are unable to invest in a new monitor at the moment, then a possible temporarily stop-gap solution would be to add a studio EQ stomp in the KPA, and do the trick of adding a high pass filter (shelf) to cut the offending low frequency issue. But you will have to play around to find exactly where the problem low frequency (frequencies) live, with your particular KRK Rockits + KPA setup.


    Cheers,
    John

    I agree that it seems like the monitors are the limiting factor and an active FRFR cab might be the best way to go.


    The DXR10 sounded like a good option to me too; my only concern is seeing some threads here where users have found its sound at lower volumes to be imbalanced/unpleasant. Something about a stiffer speaker needing more juice to really get working? It seems the CLR gets high marks for low volume performance but I'd rather get away with something less pricey if it's not a huge sacrifice in tone.


    So I've got some more digging to do to figure out which FRFR to try; my local retailers don't have many of these in stock but with luck I'll find something to demo before making the decision. If you've gotten to play through a DXR10 at home/bedroom levels, I'd love to hear any of your impressions.

    Quote from obeymydog

    I agree that it seems like the monitors are the limiting factor and an active FRFR cab might be the best way to go.


    The DXR10 sounded like a good option to me too; my only concern is seeing some threads here where users have found its sound at lower volumes to be imbalanced/unpleasant. Something about a stiffer speaker needing more juice to really get working? It seems the CLR gets high marks for low volume performance but I'd rather get away with something less pricey if it's not a huge sacrifice in tone.


    So I've got some more digging to do to figure out which FRFR to try; my local retailers don't have many of these in stock but with luck I'll find something to demo before making the decision. If you've gotten to play through a DXR10 at home/bedroom levels, I'd love to hear any of your impressions.


    I own a KPA PowerRack, so I don't use an active FRFR. I own a XiTone passive 1x12 FRFR Wedge (which is amazing).


    I am going to tag @Ingolf, as I know he has used both the Yammy DXR10 as well as the CLR. I am sure when he sees this, he will chime in with his thoughts and recommendations.


    Also, don't forget to try and demo one of those new Alto's (TS210 or TS212). I have seen some good reviews on those, and they certainly appear to represent some great "bang for the buck".


    Cheers,
    John

    As for CLR vs DXR10:
    As I have repeatedly said, the CLR is the flatter sounding one which means (because it lacks the mid pronunciation of the DXR 10) it always wins for clarity vs the DXR.
    That doesn't mean that the DXR10 sound boxy or muffled, just a little bit 'biased' towards mid pronounciation.
    If this is important for you or in a special use case you have to decide for yourself.
    I will say that the DXR10 sounds excellent at low volumes as well, not only cranked.

    Really appreciate the thoughts and suggestions here. I thought some more about what I'll be doing with this gear (i.e. not leaving home with it) and decided to try some bigger/better monitors before jumping into a FRFR cab solution. I checked with a couple local retailers today and lucked out - one had a sale on HS8s (buy one get one 50% off 8o ).


    So far these seem perfect: more than enough volume with no weird noises/vibration and significantly better detail and balance than the KRKs. I can see why these monitors get so much love here and elsewhere - I've been listening to music nonstop when not playing. I think I'm set now, time to get picking/tweaking profiles and just playing the damn thing!

    Quote from obeymydog

    Really appreciate the thoughts and suggestions here. I thought some more about what I'll be doing with this gear (i.e. not leaving home with it) and decided to try some bigger/better monitors before jumping into a FRFR cab solution. I checked with a couple local retailers today and lucked out - one had a sale on HS8s (buy one get one 50% off 8o ).


    So far these seem perfect: more than enough volume with no weird noises/vibration and significantly better detail and balance than the KRKs. I can see why these monitors get so much love here and elsewhere - I've been listening to music nonstop when not playing. I think I'm set now, time to get picking/tweaking profiles and just playing the damn thing!


    Yammy HS8's are awesome. Glad you found your solution.


    Cheers,
    John