Powerhead "feedback" when in live performance

    The Kemper has proven to be a jewel no doubt.


    One problem I am having though concerns "feedback" in live performance situations. I prefer my sound to only come directly from my guitar speaker cabinet, NOT the house PA, etc..
    So, I do not mic my cab or utilize a separate output feed to a board. The rooms we play are not that big and my Orange 212 handles the job when using a Marshall JVM410H or Mesa Roadking II with no feedback problems. However, the same rooms and setup using my Kemper as the main and only amp - - - ?(


    Scenario:
    Kemper powerhead directly into a 212 Orange cabinet with Celestion Redbacks for a rating of 300 watts at 16 ohms. With no other Kemper outputs being utilized, the cab is placed (as designed by Orange) to sit on the floor horizontally. I tried several horizontal positions with none of them being within 10'minimum of the Powerhead. Also, the cab placements were never directly in back of me but rather off axis at least 45 degrees to either side. Results are great until I need to crank the powerhead to keep up with the other instruments during live performance with Drums/Bass/Keys/Vox.
    In a practice situation though, with my volume not needed as loud, no feedback problems..


    Any thoughts or suggestions?

    Sounds like the profiles you are running have more gain than the traditional amps you used previously. Also possible that some effects such as delay and reverb are contributing to it.


    I know this is a stupid question but....... I presume you are using the same guitar(s) and it isn’t just a new guitar with microphonic pickups or something.

    guitars that I always use exclusively are a strat and a paul, nothing else. I am in a classic rock cover band.
    interesting about the gain comment though. I use as much gain as needed with the Kemper profiles to get as close to those particular 2 amps.
    however, now that it is right in my immediate thoughts, I do not get feedback when performing the cleaner parts of a song, hmm...
    Right off the top of my head I can think of numerous songs and no problems until the bridge, etc..
    Over the Hills and Far Away (Zep)
    Run to You (Adams)
    Ramblin On (Zep)
    Lady (Styx)


    I believe this is the culprit - now. how to address it when not actually performing.
    I guess we can try playing gig levels at rehearsal.That should prove interesting and annoying. Get those ear plugs out beforehand!!

    Are you kidding? The feedback is the interaction between the guitar and the cabinets and the loud volume... Forget the show ... go in a room alone plug the guitar the kemper very loud and the cabinet very loud as you make it louder and louder at one point you'll hear feedback


    Just plug your Kemper on the house PA and use a cabinets for monitoring only. You dont want to plug it to the house PA? (strange) You prefer your sound that comes out from your guitar speaker cabinets only? Buy an amp head coz Kemper is not an amp head. It must be plugged into the house PA. You dont like it? You create the problem...


    And I must repeat that coz often problems is based on non-respect of this principle:


    DONT USE THE KEMPER AS AN AMP HEAD, A KEMPER IS NOT AN AMP HEAD!!!

    Quote from Gforce guitar

    And I must repeat that coz often problems is based on non-respect of this principle:


    DONT USE THE KEMPER AS AN AMP HEAD, A KEMPER IS NOT AN AMP HEAD!!!

    sorry but you are TOTALLY wrong on that one Gforce. It doesn’t matter how often you repeat it or how big you make your shouting font it doesn’t change the fact that a powered Kemper is a perfectly good substitute for a traditional amp head. Yes, it is also a fantastic solution straight into PA or sudio desk but whether someone wants to use FOH plus IEM, FRFR or traditional guitar cab to monitor is entirely a matter of preference (or requirements/limitations) but the KPA is designed to work either way.

    Quote from Wheresthedug

    sorry but you are TOTALLY wrong on that on Gforce. It doesn’t matter how often you repeat it or how big you make your shouting font it doesn’t change the fact that a powered Kemper is a perfectly good substitute for a traditional amp head. Yes, it is also a fantastic solution straight into PA or sudio desk but whether someone wants to use FOH plus IEM, FRFR or traditional guitar cab to monitor is entirely a matter of preference (or rewuirement/limitations) but the KPa is designed to work either way.

    So we disagree again... ;) LOL But I wont start to debate 10 times with you. And I maintain what I said a lot of the problems we read here (feedback etc) are from members using the Kemper as an amp head. A Kemper is not an amp head. using small or capital letters won't change my opinion. And BTW I dont have feedback on stage or any other trouble I sound terrific and super. Why ? because I plug my Kemper in the PA and dont use it as an amp head BYE I'll let other debate with you or say that you are right. Hope they wont say ''He is right!!! I got feedback on stage and I am happy with it. I use it as an amp head and I wont plug it in the PA'' LOL BYE (I wont comment anymore on this... tired to debate with you... got to practice music Sorry

    I m sorry but it isn’t a debate just a statement of fact.


    You are, of course, correct that the feedback is caused by the volume from the cab on stage. Nobody would dispute that. Basic physics proves your point to be correct. However, it is completely irrelevant whether that volume is provided by the Kemper or a traditional amp - completely irrelevant. The powered Kemper is an amp head and you are simply giving misinformation to people which is misleading and unhelpful. I have no desire to argue with you or anyone else I simply don’t believe that spreading misinformation based on opinions which are contradicted by the laws of physics is helpful to other users.

    Update :
    As of this writing after band practice today, I do not get either of my 2 amps to "feedback" with their volumes more than loud enough (perceived volume) to fill the rooms we play as agreed upon between the 4 of us.
    When we tried it with the Kemper, the "feedback" occurs even before we 4 felt the guitar volume (perceived volume) was sufficient for our
    actual room performance.


    Can you say frustrated/confused!?!?


    A test I am now considering just being a novice audio person: I have a decent SPL meter somewhere, just have to locate it.


    noting the reading using my SPL placed 1 meter from the Orange cabinet while using the Kemper till feedback occurs.


    noting the SPL reading when using either the Marshall or Mesa amps at our (perceived volume) that is sufficient for when playing actual rooms.


    Like I said, I am just a novice at audio if even that...

    Edited 3 times, last by PhilsKF: clarification of terms. ().

    Quote from Gforce guitar

    So we disagree again... ;) LOL But I wont start to debate 10 times with you. And I maintain what I said a lot of the problems we read here (feedback etc) are from members using the Kemper as an amp head. A Kemper is not an amp head. using small or capital letters won't change my opinion. And BTW I dont have feedback on stage or any other trouble I sound terrific and super. Why ? because I plug my Kemper in the PA and dont use it as an amp head BYE I'll let other debate with you or say that you are right. Hope they wont say ''He is right!!! I got feedback on stage and I am happy with it. I use it as an amp head and I wont plug it in the PA'' LOL BYE (I wont comment anymore on this... tired to debate with you... got to practice music Sorry

    Wow... how old are you?

    OK, that’s interesting and disappointing but not the end of the world.


    Whilst it would/will be interesting to know the difference between actual and perceived volume measured on a db meter I don’t think there is much to be gained frm it. In your case perceived volume is what matters - if you can’t turn up loud enough to be heard in the band it really doesn’t matter what the db meter says you are putting out.


    As has been said earlier, volume is one of the man contributing factors to feedback but not the only one. Gain and EQ are also major factors.


    Starting trouble shhooting by reducing gain first. Increased gain adds a serious amount of compression which increases the risk of feedback. I often find that profiles thatsound amazing at home or recorded tend to have WAY too much gain to be useable live. Guys that like really hi gain sounds almost always have at least one noisegate in the chain (even with a real amp) to get this under control.


    The next stage is eq. Are you expierencing general chaotic noise like microphonic pickup type feedback or a specific note/frequency that just catches and takes off on its own? The latter would suggest the room is part of the issue and is being excited at one or more specific frequencies.if those frequencies are more prevalent in the profile than the real amps they will excite the room more and start feeding back earlier. A good example of this is when a monitor engineer eq’s the stagesound. They will boost individual frequencies on the GEQ to see where the mics star feeding back. Some frequencies will cause an open mic to feed at ridiculously low volume. By reducing those frequencies only the overall level can be run much louder.


    Have you tried making a Direct profile of you Marshall and Boogie at rehearsal and comparing like with like?

    One solution I have used to control bad feedback in a live setting with high gain profiles is to add a feedback suppressor in the line from the kemper to the speaker. Set it up during the sound check to detect the open string feeback frequencies and then lock that setting so it does not add any extra EQ dips whilst you are playing. This does affect the tone a little, so it is good to be able to turn the suppression off when using cleaner profiles that do not have a feedback problem. Other solitions I've used are to put the speaker on the other side of the stage away from where I'm standing, or to avoid using a speaker at high volume by putting the sound through the FOH and use in-ears or a monitor ( with feedback suppression in the pa aux out to the monitor . E.g. soundcraft ui16 has this)

    Thanks...
    I actually thought about a feedback exterminator a few days ago but then decided:
    1. it would probably "mess" with the total overall frequencies and not sound good to me or the patrons.
    2. another piece of gear to contend with


    I do not own one or have access to borrow one for testing purposes. However, the Kemper covers so much tonal ground for me that it may well be worth buying and trying. I am really tired of lugging around the big, heavy, tubes needing upkeep amps and their quirks.

    There should be no need for a suppressor, the KPA is not doing anything different to a regualr amp in your scenario. I use my back line like a regular amp every weekend, no issue.


    Few suggestions from me:
    Try reducing the gain
    Try a few different profiles
    Try judicious use of the noise gate, it often catches the start of feedback.



    Bearing in ind I play a semi (Gretsch) in a high gain profile at high volume ( albiet I've sealed the soundholes, but its still more susceptible) and feedback is not an issue with the KPA.


    BTW - You should always mike up an amp - backline is too directional and no control in the overall sound. You will blast people at the front and people at the back will not hear you. KPA gives you the option to go direct and i strongly suggest it.


    I mike up my amp in the smallest of venues for control, not volume.

    Thanks for the tip on upping the noise gate threshold. :thumbup: I've have found it very distracting at gigs to get howling feedback when I kick in a lead boost (stops when i start playing) and this solution works perfectly and is ofcourse rig specific. A 2:1 gate with a threshold of 4 fixes the problem completely. Don't know why I didn't think of that option before! I guess that's the value of this forum :D

    There is of course the trade off with the noise gate but glad you found it useful. I found this to be the case with my ENGL previously which had a built in noise gate and it helped with feedback.


    Pickups also have an impact although in your case you were comparing to another amp so not an issue.