Differences in volume levels between profiles if you change the output power of your power amp

    I have the Kemper Rack (non-powered) that I run through a Crown XTi-2000 power amp which has step attenuators on the front panel. The power Crown is connected to a stereo pair of 15" plus horn EV PA cabs and also to a pair of 12" plus horn EV PA cabs, sometimes for shows I just take the smaller PA cabs for the Kemper if the venue is smaller. I use the stereo XLR outputs of the KPA to go into the 2 XLR channel inputs of the Crown. The Crown also has a pair of XLR ouputs at each channel as a "thru" output that I then send to the PA board for the FOH and monitor mix.


    Before the gig I will set up my volumes on the profiles within the "performance" I plan to use at my expected stage volume settings using a specific setting on the Crown step attenuators. I then set up a dB meter, and select each profile/performance I plan to use for the gig and I make sure that the volume levels are correctly set right for the rhythm guitar and lead guitar parts for each song by adjusting each rig volume on the KPA using the rig volume setting then saving that profile by hitting the save button and selecting the "replace" option on the KPA front panel.


    Once the gig starts I might find that my overall volume is either too soft or too loud, so I change the step attenuators on the Crown power amp to compensate for this. So let's say once the gig starts, all my amp settings are too loud, so I lower the step attenuators on the power amp. However when I make any change to the power amp output settings, it changes the relationships of the profile and or performance volumes of the different profiles. So for example, I play a song where the rhythm volume setting that I previously used before changing the power amp volume and this rhythm setting is just right with the new power amp setting. When I step on the remote to change to the lead setting or to kick in the boost stomp effect, the lead setting will be way louder in comparison to what it was prior to the power amp attenuator being changed. Or sometimes it will be the opposite, the other profile will be way softer than it was in comparison to the previous profile volume.


    So say I am playing a blues song like Key To The Highway, and I create a performance where I have a rhythm amp profile of a Fender Twin in crunch mode for the rhythm part of the song, and I have a MESA Mark IV profile that I am using for my solo that is set up at 3dB louder than the Fender, and let's say that I have the attenuators on the Crown set to 6. If I then find that I am too loud overall, I move the step attenuators on the Crown from 6 to 4. And at this setting lets say that the Fender Twin volume is perfect for the rhythm. But when I change over to the MESA for my solo, instead of there being a 3dB difference in volume it might be 6dB or more louder than the Fender, whereas before I changed the power amp volume settings the difference was only 3 dB. And with some profiles when I step on the profile for my solos, instead of the solo profile being louder than the rhythm setting it actually comes out being way softer than the rhythm volume. Of course these volume changes are also daisy chained to the PA FOH and monitors as well.


    In the case of the lead volume being much louder than expected I can always chop the volume on my guitar, but if it's way softer, I'm stuck now. I have to run over to the KPA and crank the rig volume for that profile so I can cut through for the solo and in the mean time my solo doesn't start when it's supposed to and it throws the whole song out of whack with the rest of the band.


    The issue occurs whether I have to lower the Crown power amp overall output, or increase it beyond the original setting.


    Have any of you run into this kind of situation? If so is there a simple solution or is this just the way the KPA behaves? Is there a better way to deploy the KPA with a separate power amp that avoids this kind of problem?

    It sounds like something to do with the Crown’s DSP oe EQ/Compression. The Kemper should’s change the relative volume as the overall volume changes.


    Why are you using the step attenuator? Why not just set the Crown up at high volume and use the Master Volume on the front of the Kemper to control stage level?


    Another thought is that using a db meter to balance rig volumes isn’t a great way to work. There can be a substantial difference between the db reading and perceived loudness depending on EQ, Gain, Compression etc. All of this is also affected by the other instruments in the mix. The best way to set levels is just by ear during a a song or two at sound check. Failing that use a Loudness meter rather than A or C weighted dB meter to measure perceived loudness over time rather than peak levels.

    the only dependable way to set volumes across Rigs is to play these Rigs at the 'real world' volume and in context (with the band).
    This is not a shortcoming of the Profiler, it's just the way human hearing works, especially when non-linear factors like distortion and compression are a part of it.


    I use rehearsals for this.


    Even changing the overall volume (MASTER) could affect the (perceived) balance of the Rigs theoretically.