Posts by Klappy

Quote from SonicExporer

Some of you guys you are apparently misunderstanding what I wrote, read it again. Nobody is discrediting anyone.
There was some commentary a bit earlier on in this thread (and I run across it too often) where some forum members like to toss in names such as Sneap or MW or others as if it that has any bearing on whether there is a problem or not with tones from the KPA. Instead the implication is that we are hearing things, or doing something wrong and that name PE's would not be using the KPA otherwise. This is utter nonesense is all I'm pointing out.

Agreed, but you did propose ulterior motives to Sneap and Wagener's statements which isn't fair either. We don't know their intents or motivations.

Yeah, I'm academically curious and I'm learning a lot too. Seems like differences can be heard and measured. How important these differences are up to an individual user. I've said before that they aren't important to me, but I'm still curious about their nature and I plan to do some of my own testing when I get a chance. In the mean time, the Kemper is still the ampiest sounding digital box on the market, so I'll keep enjoying it despite what some measurements tell me.

There seems to be a few themes running in parallel in this thread: What are the limitations of the Kemper, how do you solve the root cause of the issue, and how do you work around it. I'm more interested in the first two questions (in an academic sense) since my goal is to have digital amps that sound like real amps, and not so much reproducing exactly the tone of amplifier X. Also, the sounds that I like (70's Marshall and earlier) seem to be reproduced better than some fuzzy and modern high gain sounds. The lack of fullness has also been noted on this forum for distorted bass, which is possibly an even bigger issue than it being missing in distorted guitar.

To address the first theme these are my questions:
1. Why does the Kemper only sometimes reproduce even harmonics? Some tests show missing even harmonics, some don't.
2. Why does it do a worse job profiling power amp distortion when it's the even order harmonics that are missing?
3. If and when ALL the even order harmonics are missing, why does the timbre still sound pretty damned close, minus some fullness and girth?

In the analog world, I would trace a schematic of the amp to get to the root of any issues I have with it, but this Kemper is a black box, making it much harder to discuss with any real inside knowledge.

Well if it's the even harmonics missing, you can try adding a low level of an octave up after the amp section to at least get back some even harmonics. It might help a bit.

I have to admit that I'm a little surprised that it's the even harmonics missing, but these tests seem valid. But I still think there is something else going on here as well. I remember reading an AES paper on distortion perception a while back that noted the importance on the presence of intermodulation distortion on the way we perceive total distortion. THD levels alone didn't account for listeners subjective perceptions of how distorted and pleasant/unpleasant source material was. IMD was a big factor as well. I suspect that the purpose of the refining process is to match the IMD profile of the original amp. These missing harmonic distortions might not be as critical as the plots initially suggest, but I don't want to downplay their absence too much.

That Supro is a real beauty! I like the that it has a little flame, but not too much, and I love the tobacco-burst. I'm also a big of the reissue Supro amps too. My guitarist plays a Coronado exclusively now.

I'm curious about what's under those gold foil covers, if they use rubber magnets like the original 60's Teisco gold foils. Those are some of my favorite single-coil pickups.

Here's the link to the tests I was thinking of:

Harmonics missing in profiles

Turns out it was the even harmonics that were missing, so add that to the confusion. To further the confusion even more, @deadpan did some profiles that captured these missing harmonics (see page 6). Contrary to some suggestions in the older thread, IMHO, these sine wave tests of profiles are both relevant and meaningful. They accurately depict the harmonic spectrum at a steady-state for a given note at a given signal level. It's not the whole picture, but it is an important part of it.

Quote from cybermgk

Unlike others in the thread, I haven't ever gotten along with a PRS, after 4 tries.

I find the PRS's more ergonomic, but I just can't get along with their sounds. I've always found them to be very generic sounding, like a universal compromise. I like guitars that really have their own strong personality, and a good Les Paul has this. I'd prefer a Teisco or a Jolana that had a strong personality over the PRS's I've played.

I see a bunch of people here swapping their PRS pickups, so perhaps that might be a way for me to find one that works for me. I'm still a sucker for classic designs though, so it might have to be one of their newer models with pickguards. I also hate flame-tops too. Hello Starla!

I don't like the ergonomics of a Les Paul, but I love the look and sound. The body is too small and the balance point is off with the waist shifted too far towards the neck. Most are also too heavy. I much prefer the ES-33X line. They also sound better to me. Full on Gibson humbucker, but with more character.

Quote from ColdFrixion

As far as the gain structure, the profiling manual makes mention of the following:
"You might also run into trouble when profiling a sound in which both the pre- and power amps of the reference
amplifier are driven into distortion. If the resulting Profile sounds unsatisfying, try to reduce the volume of the
power amp. This will make the sound somewhat more transparent, without significantly reducing the amount of
distortion. The same is true for those modeling amps which offer a separate gain control for pre- and power amp."

Well, that seems to support the idea of odd order harmonics not being reproduced well by the Kemper. Power pentodes generally produce more 3rd harmonic distortion than 2nd due to the load lines being chosen to optimize output power. This is a generalization, but is usually true in guitar amps. Small signal preamp tubes (even pentodes like the EF86) use different operating points and have more even than odd harmonics. This might explain all the deficiencies that are being discussed here, especially the fuzz issues. I don't see them as necessarily separate issues.

I'd suggest running some tests on amps with master volumes that are hard to profile. Change the balance between preamp and poweramp distortion and see if it nails the distorted preamp sounds better.

Regarding the inability to capture fuzz: I think someone here previously demonstrated that the Kemper doesn't capture odd-ordered harmonics well. That would explain why it can't do fuzz. You need the odd harmonics to get square or semi-square waves. I'm more a fan of even order harmonics from a tube preamp, which might be another reason this issue never bothered me much.

I agree with Shreck. No one is trying to divert from the topic, they are just disagreeing with an aside that you brought up. If there is a miscommunication here, it might be best to let the multitracking issue rest until Sonic can post his example. But that onus is on Sonic now to make some files, since ColdFrixion demonstrated his point.

Shreck, I can't point to any specific examples online, but in my experience, lower gain classic rock sounds with less bass (and chugga chugga) show the effect much less, to the point that I didn't notice it in my own profiles. But I'll admit that I'm not as scrutinizing as I used to be with sounds (kind of liberating actually). That being said, I still can't deal with whatever deficiencies are in the Helix and Axe, so everyone has their sensitive spots.

I agree with Sonic and Shreck about a slight difference in the fullness/low-mid, but I agree with ColdFrixion about the differences not increasing in magnitude across multiple tracks. I actually like the Kemperized versions better, they sound tighter to me and would probably work better in my mixes. But the differences are still small to me and not worth caring about in the big picture. They still sound like real amps to me, which is where modelers (even the good ones) lack.

Here's a thought on what might be causing the issue: The KPA algorithm isn't designed to capture reverberation. Even a close miked amp isn't immune to reverberations, modes, and early reflections completely. Maybe these subtle cues are responsible for the loss of 3D and body, effectively making the Kemperized sound more like jt was miked in an anechoic chamber.

Quote from OneEng1

The cell phone analogy is adept.... however:

If the smart phone had connection problems, and you couldn't hear the person you were talking to, and they had trouble hearing you, etc, etc, then all the bells and whistles wouldn't make most of us want the device since it fails to do its primary task ..... be a good phone.

Didn't hurt the iPhone any.

Good golly that thing sounds awesome!

I'm strictly in bar bands these days, and big gig for me is 300 people. I'm always surprised by this forum by people's stage setups. In the NYC area where I play, every club has a PA, no matter how small, and every musician still uses backline. Also, since I play mostly in original bands, there is usually no soundcheck (unless you are first) and there are very quick change-overs between bands (usually 3-4 bands per night). And when I play in NYC proper, they often "encourage" you to use the club's backline for quicker changeovers and less clutter backstage (AKA the hallway or storage closet).

I also come from an indie rock background where simplicity is the norm, guitar, pedal board (maybe), and a tube amp. These elaborate setups that my fellow Kemperites use with mixers, computers, IEM's, wireless, and floor monitors scare an old caveman like me . In the 90's I was touring with real roadies and I thought I was still being a little ridiculous by having them setup my bi-amped bass rig with a Marshall plexi and V4-B running through a split 8x10.

If only we could get an eq that morphed as a function of the output volume.

Marshall Lead 12. That was my studio secret weapon back in the 80's/90's.

I've done a couple of Earvanas. They only work when the slots are cut too high, like on many factory setups. When cut planar to the frets, they actually make your open string sharp. The forward shift of the nut makes the open string sharp to match the sharpness of the lower frets from too much tension when fretting the lower frets due to a high nut. Then the intonation is adjusted to compensate for this unnecessary sharpness. It's the absolute wrong way to correct for 1st to 5th fret sharpness IMHO. Think about guitars with zero-frets. They intonate perfectly to even temperament. You need to install an Earvana incorrectly for it to work correctly. And when done so, your action on the lower frets will be worse than nescessary.

The Gibson headstock design is more problematic compared to straight string pull designs (Fender, PRS), but like drog said, it's easily fixed. Martin uses the same principle and just made their 2 millionth guitar. There must be literally millions of guitars out there with angled string pulls without any tuning issues. Gibson just sucks as a company these days and doesn't bother to take the time to do a proper nut slotting. This is inexcusabable, especially since they own Plek machines that can do the proper angled/tapered cuts.

This takes a half a minute to setup, but sounds pretty good. I've seen similar tricks with business cards woven through the strings too.

I see the value of having mobile apps when used with tablets, but no so much with phones.

However, I disagree with your speculation that knobs aren't disappearing. I just received my TC Spectracomp in the mail today. With the PC editor, I can access at least 30 parameters, but there is only one physical knob. ONE KNOB! If there were three knobs instead, I could probably just use the editor once to do the basic setup and fine tune global thresholds, ratios, and attacks as needed. Instead, I'll be bringing my tablet to at least a few rehearsals before I feel confident that I dialed it in well enough for using it live. And as far as changing presets with my phone through the pickups, that seems unbelievably backwards when they could have been stored on the device itself.

Still, I decided to put up with this backwards approach to an interface (one knob, no local presets) because it's a fully parameterized 3-band compressor for $80. But I see the gimmicky control/interface decisions as a fail.

Long live knobs!