Amp in room?

  • If you hook the Kemper up to the "usual" speakers (monitor, PA, FRFR) then the air moving feeling is diminished a lot.

    I've noticed that myself, along with the fact that feedback doesn't see to work the same as with a regular amp / guitar cab.


    As a purely intellectual point of curiosity, that's something I don't really understand. I routinely push 105db. That should be moving some air, and thus I should feel it more, but with the FRFR I don't. And yet, the actual guitar tone sound like a cranked amp.


    My ears tell me all the frequencies are there, or it would sound funny. But clearly something's different as I don't feel the same, "chest thump" and the feedback / responsiveness characteristics are also different.


    Could someone with a bit more knowledge in this area offer some insight on why this is the case?


    I love the FRFR, I just like to understand these things.

  • If you have your DXRs in wedge position, they don’t have the same kind of floor reflections as a guitar cabinet, and a hand held 105db measurement from a speaker pointed at your head is a different acoustic volume level than a guitar speaker that is pointed at the backs of your knees. You can get more thump by sitting them upright, even if you angle them up a little, to be able to hear the horn better.


    And, since FRFR are more linear, they don’t have peak frequencies that allow you to easily get feedback at the same notes as conventional speakers.

  • If you have your DXRs in wedge position, they don’t have the same kind of floor reflections as a guitar cabinet, and a hand held 105db measurement from a speaker pointed at your head is a different acoustic volume level than a guitar speaker that is pointed at the backs of your knees. You can get more thump by sitting them upright, even if you angle them up a little, to be able to hear the horn better.


    And, since FRFR are more linear, they don’t have peak frequencies that allow you to easily get feedback at the same notes as conventional speakers.

    I usually put the meter on the floor in front of my feet though that's probably not optimal, either.


    I didn't realize how much of the resonance thump comes from interaction with the floor, but it makes sense given that the floor is something with which to resonate. The DXR also has a few EQ curves on the back, which I haven't experimented with.


    That said, I used to run a one 12 sealed V30 cab on a small X stand to point it at a 45, which also raises it off the floor by 8 or 8 inches, but I still got a pretty decent thump from that. I wonder if the same lack of peak frequencies (albeit different ones) that affect feedback are also a factor in thump.


    I'll try sticking it upright to see how that feels, thanks for all the info!

  • I think part of the thump might be to do with the general shape of guitar speaker cones compared to PA cones. If I have interpreted what I've been reading properly it seems that guitar speakers tend to have steeper sides than PA cones. This affects the the dispersion and causes the beaming effect. Whereas PA and Monitor speakers seem to have a shallower cone which causes a wider dispersion. Maybe I've got that totally wong though. It's the kind of thing that Monkey_Man would know the answer to :(

  • I think part of the thump might be to do with the general shape of guitar speaker cones compared to PA cones. If I have interpreted what I've been reading properly it seems that guitar speakers tend to have steeper sides than PA cones. This affects the the dispersion and causes the beaming effect. Whereas PA and Monitor speakers seem to have a shallower cone which causes a wider dispersion.

    I was thinking about the beaming thing when Paul was talking about frequencies, so maybe there's something to that.

  • I was going to guess some weird resonance with the floor but the different cone shape seems reasonable as well.


    Whoa, super cool if that tinnitus thing works even for half the people even if it is for a short while.

  • How do you realize which rig is Studio or Merged?