Posts by Deny

I'm sorry but I still don't get it. Yes I've read the manual, and after reading CK's explanation about the distortion sense, that one is ok and out of the way. But the clean sense still puzzles me. I guess my question is, why does it affect only clean tones? Now keep in mind that I always store the input settings with each rig, I never keep the input section locked because I build specific rigs for specific guitars. So if I'm working on a high gain rig, you're basically saying that it doesn't matter where clean sense is at, is that it? I can leave it at 0 or 10 (with the input led glowing constantly red) and it doesn't make any difference, is that correct?

Boy, this is really weird and confusing. Is that offer of a technical explanation still on? I'm a bit on the geeky side and am a little frustrated that I can't get the concept behind the clean sense control through my thick skull. Please? I have a reasonable understanding of audio and DSP so no need to go easy on the technical jargon.

Here's my update: according to Kemper Support, the MIDI switching lag is "under 100 ms", which I suppose really means "around 100 ms". I'm now curious to measure it myself with all the midi controllers I own, (2 or 3) and also using a computer. I'm not making any promises, it's a reasonable amount of work to set things up and I'm not sure when or if I'll be able to get around doing it.

I own a regular tube screamer and use it a lot with settings:
Tone: 6
Volume: 5
Drive: 0

The Green Screamer in the KPA indeed seems to remove more low end than my TS9, and seems to have more distortion at position 0 as well. Also as per CK's explanations the equivalent tone setting in the Green Screamer should be around -2.0, which to my ears remove way too much top end, I ended up using -1.0 which should be equivalent to 8 in my TS9, so I think the controls are a bit off indeed. I would love to see variations on the Tube Screamer, even if it would be a single stomp with a "mode" selector (TS9, TS808, Keeley, Boss OD1, etc). It would also be nice if the controls responded more like the originals in these new models.

Quote from ba_hill

I did a quick test to measure the time it takes for the Kemper to change the sound after a MIDI program change message is sent. I measured about 150 ms. That's not 0 but it's quite a bit less than half a second. What I did was send a program change from Logic to the Kemper and recorded the audio from the Kemper. I played a long note to and switched between a quiet clean patch and a loud distorted one so I could clearly see the difference. Here are a couple of screen shots that show what I saw. the first picture the bottom track has 2 squares in it that represent the program change messages. The top track is the output of the Kemper.

Waveform

Timing

The timing is in SMPTE units - hh:mm:ss ff:bb, where ff is frames (in this case 25 frames per second) and bb is SMPTE bits (80 bits per frame). You can see that the time between the PC message being sent and the change in sound is at most 3 frames and 60 bits. That is less than 4/25ths of a second, about 150 ms.

This seems like it may be in the range where it just isn't an issue for some people but is a problem for others. I haven't found it to be a problem in my music. Would someone who does notice a lag take some measurements to see if what they are experiencing is different or if it's just that 150ms is too much for their use?

Brian

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I haven't measured the exact time it takes for a patch change via MIDI so I'll take your word for it, that means it's less than I thought it was but still too high for live use IMO. Consider that the main competitor of the KPA does a patch change in 20-25 ms with delay spillover off and 25-30 ms with delay spillover on. I'm not asking that these figures be matched, but taking 5 times as much is a lot to take, patch switching times should be improved ASAP IMO, I'm sincerely hoping that Performance Mode will take care of that.

Quote from paults

Every processor has some kind of "patch A to patch B" transition logic. Some mute briefly, some make a near instantaneous change. But, the only way to experience an issue with any of these methods is to be actually playing (or sustaining notes) across the change.

Is that what you are doing when you hear this?

My guess is most people don't ever need do that, especially when the sounds differ in gain amounts. So, most people would never experience an issue with a fraction of a second mute/morph.

From a musical arrangement perspective, most patch changes would happen right before the beginning of a measure/right before playing a different sounding part. If a transition is 500ms long, that would equate to one quarter note at 120bpm (uptempo dance beat). If it is closer to 250ms, it is closer to an eighth note at 120bpm.

It can't be done with a conventional multiple amp rig, either, unless the signal is split to constantly feed multiple amplifiers, and each one has a completely separate effects chain. If you do it with two "real" amps and a simple A/B switch, you'll hear a "click" in the middle of your sustaining note, the gain staging difference between clean and dirty will cause a notable volume and tone change, and, any shared reverb and delay would sustain the "click" and make other strange artifacts from "spill over" noises.

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My Eleven Rack, which costs 1/4 of the price of the KPA, does instant patch changes. No lag whatsoever. Instant means switching to a new patch without missing the attack on the first note of a solo, for instance. IMHO BTW, the first note is also the most important more often than not, especially if you're not playing a million notes per second.

On to real amps, I own a JMP1 MIDI preamp and a Boogie Triaxis, both are selected through a switching system that I've built myself and then into a TC G-Major2. I have no lag problems with that rig either.

And not that it's in the same league, but it's probably worth noting that my poor Line6 HD500 also has no lag when switching patches at 1/6th the price of the KPA.

What I am beginning to realize is that most users don't mind having to wait a 1/2 second before being able to hear the entire attack of a note. Until proven to the contrary, my conclusion for now is that the lag exists for *everyone*, but for some obscure reason many users choose to look the other way. I will not. For what I've paid for the KPA, I think it's more than reasonable to expect that it changes patches quickly and flawlessly, so Kemper team, please fix it.

At first I was going to suggest that the waveform could be selectable in the tremolo effect, but had a better idea, so here it goes: the chopper effect would produce a harder effect than the tremolo because instead of a sinus or triangle waveform it would abruptly cut the sound (depending on the depth parameter setting) using a square waveform. It would have the usual pulse width parameter which determines the percentage of the waveform on the positive half of it, but why stop there? I thought it would be interesting to spice things up a bit by adding 4 "switches" that would allow for producing some very interesting rhythmic patterns (think Fruity Loops).

So the parameters would be:
Time/speed: in seconds or hertz, and would be syncable with tap tempo/MIDI clock
Multiplier: 1/2x, 1x, 1.5x or 2x (relates to the above and would be really only useful when using tap tempo/MIDI clock)
Depth: depth of the effect, how much it "cuts" the sound
Pulse width: the percentage of the square waveform it stays open or closed (sound is heard/not heard)
Switch1, Switch2, Switch3, Switch4: each one of these, when ON will cause the effect to be applied on that slot, when OFF there will be no effect in that slot.

Note that a traditional, simple chopper effect would be achieved by using pulse width 100%, switches 1 and 2 ON and switches 3 and 4 OFF.

Quote from Gibson

I have a boss fc-50 and a Line6 HD 500 both with tons of lag when switching rigs.

Yep, just gave my HD500 a go as a MIDI controller for the KPA and sure enough the lag is there. I've contacted support about this issue today but I don't expect them to get back to me in less than a few days because of the holidays, let's see how that develops - I'll post my findings in this thread.

If I may ask, which firmware version are you using? I'm on 1.54 (latest), maybe that's why I'm having problems? And I apologize if I sound a little harsh, it's just that I've got my KPA a little over a week ago and this is my first attempt at connecting it to my MIDI footswitch, I have a gig coming and I'm getting worried that it lacks the capacity for fast patch changes. Even though you've just told me it does, not having seen it even once gets me a bit edgy.

Also waiting for a fix on this issue, Lexicon MPX-R1 MIDI footswitch owner here. I don't think the problem is related to specific MIDI controllers, a program change message is a program change message, there's not a lot that can be done differently about it. I'm on firmware 1.54 if that makes any difference, and the switching lag is of almost half a second, worst than anything I've ever owned. The lag happens on all my patches regardless of which effects I have engaged, most of them don't even have a wah loaded. I've done a system reset and flash memory format/init, no luck yet.

I could, but shouldn't have to. MIDI is a *standard*, not some form of occult electronic art. And it wasn't invented yesterday either. If my device works with every other piece of gear I own and not with the KPA, it's pretty obvious where the flaw lies and IMHO it should be fixed ASAP. Sending and receiving program changes is as basic as music technology gets, if the KPA can't handle that effortlessly I will probably start to doubt the technical expertise of the manufacturer / developer. And just for the record, I am not a MIDIot - I have been connecting and configuring MIDI devices for decades now, so I kinda know what I'm doing.

Or is everybody else also dealing with a half second lag between patch changes and pretending it doesn't exist?

I'm having the exact same problem with a Lexicon MPX-R1 MIDI footswitch, the lag between changing patches is like a half second or more, which renders the KPA basically useless for gigging with. My footswitch works flawlessly with every other piece of gear I own, so it's unlikely that it's the culprit. I have channel set to 1 on both devices, and no MIDI clock (turned it off because I thought it was causing the problem but it wasn't). Tried changing rigs using the front buttons, did a lot of patch changes via MIDI to see if the problem went away after a while but it didn't.

Help please?

Quote from Froschn

You can have more than just one usb-stick where you store different timepoints or different setups of your system and that you can restore to the kpa if needed. One with your own rigs, one with the rigs that you still need to try, one with the bought rigs....whatever you want.

The purpose of this feature request is to make managing rigs from the KPA itself simpler. I don't see how having multiple USB sticks with different sets of rigs would help accomplish that

Quote from Guitartone

There's kind of a way of doing that now.

When you save a rig to favourites, at the same time save a Snapshot...or just save a Snapshot.
Make a backup of your KPA, change the .kpabackup to .RAR.
Unzip it, you'll see a Snapshots folder.

Then, If you really want you can do this, do a 'clean up', delete all rigs and save only your Favourites/Snapshots.
https://dl.dropbox.com/u/55669…20amounts%20of%20rigs.pdf

Actually I have an even easier way of doing this, I use a shell script that copies all the rigs which contain my name (that's what happens when you favorite a rig) to a specific folder and then I can move them back to my rigs folder. Really easy for *me*, because I'm proficient in OSX/Linux shell scripts, but not really the easiest for someone who isn't computer savvy. The way you describe for doing it isn't the easiest either, most people already have their favorites and would have to go back and take snapshots of them. Not sure how many other people have, but I ended up with 240 of them which isn't a number you want to go back and take snapshots one by one. Anyway the reason I asked for this feature was to make our lives easier regarding rig management.

+1 Agreed, as long as it's implemented as a switchable option. Having as low latency as possible when playing live is my #1 priority, although I will be reamping occasionally so the option of locking latency for that application does make a lot of sense.

The reason I ask is so I can program a few Vai/Satch rigs. I'm giving them a try using the wah/LP and it's looking good, thanks for pointing me in the right direction

Quote from ckemper

We've got it all:

Cutoff = Manual
Resonance = Peak
Bandpass = Wah Wah.

The only thing that's missing is the switchable slope. We have set it to 12 dB/Oct for the Wah Wah and 24 dB/Oct for the Lowpass and Highpass. Optimal results!

What really gave it a unique and very interesting character was actually the blend control (from LP to BP to HP), but I understand there may be trademark implications if you put something like that in the KPA, that's too bad.

I make it a habit of disclosing a little of my personal experience and preferences as a musician before I do reviews, because they're only as good as a user's opinion, so by knowing a bit more about myself readers can make a better decision whether or not the review is valid for them or not.

I've been playing guitar for over 30 years, and my favorite guitar players are Shawn Lane, Eric Johnson, Jeff Beck, Richie Kotzen and more recently Guthrie Govan. Love their guitar tones as well and to that list I'd have to add Allan Holdsworth, whose playing I find a bit hard to digest at times but his gorgeous tone makes listening to him a pleasure. I've played solid state amps and Boss pedals, hybrid amps, all-tube amps, a combination of preamps (Triaxis and JMP1) and MFX (Lexicon MPX1 and Rocktron Intellifex) into a tube power amp, some Digitech MFX (GNX4 and RP1000), Boss GT-10, Line6 HD500 and Eleven Rack, which is the closest I've had to the real thing until I got the Kemper, which I'm sure you all know, nails it spot on.

I auditioned the profiles using my Ibanez Prestige RG1570 loaded with a DiMarzio Fred in the bridge and DiMarzio Humbucker from Hell in the neck position. The KPA was connected to my QSC K-10 FRFR speaker through the monitor output. Where applicable, I chose the Les Paul sets of profiles as they're the closest to the output signal of my own test guitar - in fact they're set with the exact same clean senitivity I use for that guitar (5.0). Before auditioning I reset the EQ and turned all FX off, also adjusted the noise gate (turned off for cleans, and just enough to eliminate hum on distorted profiles, usually between 1.3 - 2.2).

Now on to the profiles.

I've got a bunch of them but will comment of the ones which stand out so far, others might too as I play more with them.

My favorite of the bunch right now is the Stiletto. It sounds simply amazing, creamy, rich and incredibly responsive throughout all the included profiles. I'll probably built my lead tones around this set of profiles.

The Plexi is also *really* good, probably one of my workhorse amps from now on.

The Supro, Lindy Fralin VVT2 and /13 LDW are great for cleans and bluesy stuff, although I'm still digging and only auditioned the raw profiles, haven't built many rigs of my own yet.

The Peavey 6505 and classic 50 are just gorgeous (although very different), worth mentioning because they stood out from the rest.

Also worth an honorable mention was the Hiwatt DR103, not that it's my cup of tea - just wanted to add it to my collection as I'm aware it has quite an unique tone and it delivers. BTW one of the best cleans of the bunch, lots of uncompressed headroom that's clearly noticeable.

A few general observations: I didn't care much for the tweaked rigs, liked the raw profiles much better. In fact like I've said, even on those I've turned all FX off and reset the EQ before auditioning. So I believe congrats to Andy are in order for a job well done

I'll add more comments to this thread as I play with the rest of the profiles.

Cheers,
Deny

Quote from ckemper

Is there a difference between the Pro Filter and our Lowpass / Highpass?

There are a few.... Here's an excerpt from the user manual:

"The Pro-Filter is based on a filter included in Native Instruments’ popular software
synthesizer Pro-53. It has a fat, rich sound that works very well as a tone control, but
tying the Cutoff to a controller pedal also allows for great wah-wah sounds.
For advanced effects, you should try modulating the cutoff using the various Modifier
components. For example, you can produce filtered effects that sync to the beat using
the Step Sequencer.

Controls
Cutoff sets the operation frequency of the filter. Filtering occurs above and/or below it as
defined by the LFP/BPF/HPF knob.

Reso sets the filter bandwidth – turning it up narrows the frequency range and thus
increases accentuation of the center frequency.

Slope controls the rate at which frequencies are attenuated past the cutoff frequency. When
turned down, frequencies are attenuated softly, at a rate of 12dB per octave. When turned up,
frequencies are attenuated at a rate of 24dB per octave, producing an intense filter sound.

LFP/BPF/HPF blends continuously between three different filter modes:
- Lowpass (LFP) – the filter passes low frequencies and attenuates high frequencies
- Bandpass (BPF) – the filter passes a band of frequencies and attenuates frequencies
above or below that band
- Highpass (HPF) – the filter passes high frequencies and attenuates low frequencies"

Oh and while you're at it, why not add also a "delete all rigs except favorites" function? Or delete currently filtered? Or delete all except currently filtered? Wow, that would be seriously awesome and a great time saver.

Guitar Rig has a module called "Pro Filter" that's just delightful for adding from subtle to intense pre-gain filtering in several interesting ways, I'd love to see something similar in the KPA.