On stage phasing or comb filter sound.

  • While playing live with my Kemper, I was hearing a weird, sort of phasing, comb filter effect. Kemper XLR outs sent to FOH stereo. On stage I have one monitor in front and one monitor behind me with only my guitar Kemper sound and my vocals. Has anyone experienced this? Is there a way to eliminate it? Thank you!

    Rik


    Kemper toaster >Kemper remote> 2 x Alto TS310 powered speakers Furman M-8XAR

  • rik777

    Changed the title of the thread from “Phasing or comb filter on stage.” to “On stage phasing or comb filter sound.”.
  • Try inverting the phase of the monitor or FOH signal. It happened often to me.

    It would be great if we could do that on the Kemper directly.

    Really? Yes it's been happening at some point during my performances. It doesn't happen right away. Weird. So invert the phase on the monitor or at the soundboard, huh? I will ask the sound guys if that's possible. I don't think it's inherent of the Kemper. Wonder if anyone else has had the same issue.

    Rik


    Kemper toaster >Kemper remote> 2 x Alto TS310 powered speakers Furman M-8XAR

  • could the guitar monitor behind you 'bleed' into your mic and create this?

    feedback doesn't always have to be loud screeching, something like this (layering of identical signals a few milliseconds apart) could also happen.

    also, could one of the monitor signals be delayed just a tiny bit by some extra processing from the FOH or monitor mixer and the other signal not?


    do you send an extra signal for (mono) monitoring or is your Main Out stereo signal summed to mono by the FOH/monitor mixer? Using super short delay setings to create a 80s thickening effect in stereo could potentially be responsible for comb filtering when summed to mono.


    that's all I can think of right now, and no, I never experienced something like this, but my monitor is always receiving a mono signal from the PROFILER, with the Monitor Out set to 'Master Mono'.

  • Agree on the reverse phase setup. I use a small powered wedge in front.

    Main XLR R (Master Stereo) to front via polarity adapter ( Short XLR F to M link with reversed leads) Then on to FOH (still out of phase which he fixes at that end)

    Main XLR R to FOH direct

    Monitor out (master L) direct to rear wedge or power amp out to speaker.


    Sounds complicated but in practise works really well. I considered hard wiring the reversed lead but on occasions where there is a different distance between front and back causing an odd sound, it's easy to pop out the adapter and play 'in phase'

  • Thank you DonPetersen . No extra signal for mono monitoring. The FOH sends me a summed mix into both onstage monitors. Yeah. I will check with the sound man next time. Thanks for the help.

    Rik


    Kemper toaster >Kemper remote> 2 x Alto TS310 powered speakers Furman M-8XAR

  • Hey man I've had this same thing happen to me at really high volumes through a 4x12 with the kemper sitting on top. I think mine was a heating problem but I've also heard of the bass from the speaker rattles the kemper enough some of the components inside vibrate causing that weird noise. Idk the validity of it but it might be too much bass. I switched to a 2x12 and haven't experienced it since

  • does it only happen when you are moving onstage or turning your head, or do you hear it when you are perfectly still? sounds exactly like kriswylde described above, just phasing issues from the combined stage speakers. If the soundman isn't having an issue at FOH, it is likely not being experienced by your audience.

    ...on that note, I've played gigs where the soundman WAS my audience...

  • does it only happen when you are moving onstage or turning your head, or do you hear it when you are perfectly still? sounds exactly like kriswylde described above, just phasing issues from the combined stage speakers. If the soundman isn't having an issue at FOH, it is likely not being experienced by your audience.

    ...on that note, I've played gigs where the soundman WAS my audience...

    Lol I too have played gigs where the sound guy is the audience lol. It's happened when I'm still or slightly moving. Seems to be only happening on stage. And it doesn't happen right away. Seems to happen after an hour or so on stage. I'm going to try moving the back monitor and see if it occurs. Thanks!

    Rik


    Kemper toaster >Kemper remote> 2 x Alto TS310 powered speakers Furman M-8XAR

  • Lol I too have played gigs where the sound guy is the audience lol. It's happened when I'm still or slightly moving. Seems to be only happening on stage. And it doesn't happen right away. Seems to happen after an hour or so on stage. I'm going to try moving the back monitor and see if it occurs. Thanks!

    are you using the powered output into the monitor? Also when doing this do you feel any heat coming off the kemper? Mine would heat up pretty bad when using a passive cab after about an hour into practice at high volumes. If I remember cutting the low frequencies helped stop the weird phaser effect for me. Also I remember it only being certain notes that would cause it. If it is the vibration of components inside then maybe putting a layer of foam underneath it may help


    I forgot to ask is the kemper sitting on top of the monitor?

  • are you using the powered output into the monitor? Also when doing this do you feel any heat coming off the kemper? Mine would heat up pretty bad when using a passive cab after about an hour into practice at high volumes. If I remember cutting the low frequencies helped stop the weird phaser effect for me. Also I remember it only being certain notes that would cause it. If it is the vibration of components inside then maybe putting a layer of foam underneath it may help


    I forgot to ask is the kemper sitting on top of the monitor?

    Mine is non powered going xlr left and right to FOH. I place it on top of a chair. It doesn't heat up.

    Rik


    Kemper toaster >Kemper remote> 2 x Alto TS310 powered speakers Furman M-8XAR