Kemper KPA Core Tone Tweaking
Amp Settings
The Amp block features the following parameters:
- Definition - Changes the nature of the distortion from vintage to modern
- Power Sagging - Increases simulated power sagging of the profiled amp
- Pick - Boosts or cuts the transient in the pick attack
- Compressor - Reduces the dynamic range of the profile
- Clarity - Increases the "clean" character of the amp while it remains distorted
- Tube Shape - Make the distortion "softer" or "harder"
- Tube Bias - Allows the signal to push into clipping more easily, increasing dynamic headroom inside distortion
- Direct Mix - Adds the direct (dry) guitar signal into the processed tone
The profiling process defaults all of these to 0, with the exception of Definition which varies depending on the profiled amp and Tube Shape which defaults to 3.3. If something seems "off" about a profile, you may want to see if any of these parameters are radically changed. For some profiles, extreme values here can make an "organic" profile start to seem processed and fake. Try resetting them to default values and see if the tone improves.
Definition gets quite tricky. It's set by the profiling process but can be altered after the fact. Many times a tightening boost in front of a modern high-gain amp will cause this to be set to max (10). It's very similar to a pre-distortion EQ, darkening or brightening the signal to adjust the relative balance of how the fundamentals vs. the overtones are distorted. While it works well for a quick tweak, I find it's no replacement for some finely-tuned parametric EQ in front the amp. If the tone sounds a bit too harsh or thin, try turning this down, then using a Screamer or pre-EQ to add back any needed tightness or high-end saturation.
Power Sagging affects the dynamics and feel of the amp, and can help get mutes to sound right. If the amp feels a bit too stiff and fast, try turning this up.
The Pick setting I find I usually like to leave alone; however, every now and then I'll bump it up or down a bit. The same goes for Clarity. While many love this setting, I find it takes away from the real tone of the amp and makes everything sound like a similar crunchy tone.
Turning up Tube Shape can add a bit more bite or edge to the distortion, like you are pushing the power amp harder. I often like to add a bit here, but it's important not to overdo it. Tube Bias is similar, although I find this one a bit trickier - it seems to add volume as you turn it up, which can lead to an instant impression that higher settings are better. However, too high can make dynamics become artificial-sounding and the tone a bit harsh.
The Compressor in the amp is great, mostly affecting crunch tones. It is neither pre or post distortion, but part of the profiling process itself, making it very transparent yet powerful.
Cab Settings
- High Shift - Moves the high-frequency resonance
- Low Shift - Moves the low-frequency resonance
- Character - Emphasizes or removes the formant peaks that characterize the cab/speaker(s)
- Volume - Used to level different cabinets
I like to use the High and Low Shift settings for mild adjustments if the cab sounds too boomy or fizzy. A little goes a long way, and I'm rarely tweaking past +/- 0.4 - beyond that and things can start to sound a bit weird or artificial. High shift can also help to try to match another cab profile's tone, almost like you are moving the mic or changing its angle.
Character I generally leave alone. A little boost can help accentuate the cab, but too much can make it sound fake. Going negative often sounds quite stiff or flat, and I avoid tweaking in this direction.
Pre-EQ or Boosting
I often like to use pre-EQ or some kind of boost/overdrive to tighten up or otherwise enhance the distorted tone. I almost always favor this approach over making big tweaks to the Definition parameter of the Amp block, although I do like to mess with Power Sagging, Tube Shape, and Tube Bias - they alter the tone in ways that are difficult or impossible to achieve using EQ/boosts.
The simplest and quickest way to do this is to use the Green Scream effect, which is a model of a Maxon OD808 pedal, which mirrors the circuit of the original Ibanez Tube Screamer. The typical settings when using such as an overdrive is to set Drive down to 0% and Tone between 60 and 100%. The Green Scream effect's Tone parameter at the <0.0> setting matches 100% on a real Screamer. Turning up higher than <0.0> has no impact on the tone. I find I am almost always between -1.3 and <0.0>. Volume doesn't matter - I like to leave it at <0.0>. Some like to turn Volume up heavily, but this is only necessary on older real amps that couldn't be pushed into distortion without the input volume boost. It doesn't matter on a high-gain amp - you can use the Gain knob to get the right amount of distortion. The only time it may be worthwhile using a non-0.0 value is when you want to be able to toggle the Green Scream on/off to switch from a cleaner tone to a more distorted tone.
A more powerful approach is to use the Studio EQ effect. It gets you both a more transparent sound (the Screamer tends to add a little compression/color) as well as greater control over exactly how frequencies are manipulated. This features 2 fully parametric bands, plus low and high shelves. Sometimes it's as easy as boosting a parametric band by about + 4-6db, lowering the Q down to like -2 or -3, and then sweeping the frequency to find the sweet spot. Usually it's between 800 and 3000 HZ. You can use the low shelf to trim some woofy low end - I find a -3db cut around 150 HZ to do the trick. If this isn't refined enough I like to use the other parametric band for this purpose. I'll set the frequency to about 40 HZ, gain to about -4 db, and then lower Q until I can hear the lows start tightening up. Then you can start trying different settings to refine. Sometimes, you may need to also trim some extreme high end with the high shelf if you get a harsh, crackly distortion in the high frequencies.
The Treble Booster effect also works well as a boost, but I find it doesn't offer enough control - it's basically a high shelf. It can be a bit more transparent than the Screamer and doesn't cut The Lead Booster can