Something I've been seeing recently are "Profile clipping" errors that happen upon fresh boot. If I try to profile again, it works - as if the KPA silently reduced its gain to prevent future clips. Granted, I've been doing some kooky reamping experiments recently, but it's always odd when this happens.
-djh
Just like it says - I'd like to be able to get some of my favorite cab impulses into the Kemper without having to... oh, I dunno, profile a software cab sim on my PC? Awkward. Going the other direction would be nice too, although I suppose I could always run an impulse through a loopback amp profile running a desired cab model.
Probably not the first person to have mentioned this, I'm sure. Where is the Kemper staff commentary, BTW? Aside from the hardworking user base, Kemper's forum presence feels likes a ghost town with tumbleweeds and doors creaking in the wind.
-djh
dhodgson Some day, my son, you will too own such great gear. If you only practice that guitar 6h a day for ten years.
I hear substantial differences in sound as well on my Atc scm50asl speakers thru a cranesong avocet.
Anyway, your measurements are in accordance with my findings. The line out is a lot lower than the spdif out, meaning that with my converters ( who want a VERY loud signal and send a very loud one as well..) I have to amplify it with a line signal booster, a preamp... I also need to back the outputs by -10 plus trim about -18 to do profiling without clipping. There must be something to be done about this...
Wait a sec, I've been practicing 2 hrs a day for 30 years! 
No, really. It's kinda sad. D'oh! 
But these numbers got me thinking; the difference between consumer-level line out -10dBV (.316V RMS) and pro-level line out +4dBU (1.23V RMS) is 11.8 dB. I wonder if there's some "consumer vs. pro" level bit on the output preamp that Kemper is using that's being reversed. Imagine the mic levels being dropped by 11.8dB and the TRS line outs being raised by 11.8dB - that would be pretty ideal.
Can you describe the difference in sound on your Avocet?
-djh
BTW, I still see this bug in the v1.05 firmware. It's pretty easy to reproduce.
-djh
WorldStudios - Apogee & Big Bens? We all should have such gear! So, I took to measurin'.
First, there's nothing wrong with the S/PDIF levels. Turn all stomps & FX off, set Master Volume to 0, and:
S/PDIF In vs. S/PDIF Out: Sent -10dBFS out, got -10.1dBFS back. Presto.
Instrument In vs. S/PDIF Out: Sent a calibrated -10dbinst signal, got -10.3dBFS back. Presto again.
But there is a huge difference in levels between the KPA's mic and line outs with respect to the Saffire's mic and line in sensitivity.
Mic Outs: Send a calibrated -10dbinst signal, get +2.3dB mic level back on the Saffire at full trim (clipping!). I have to set Master Volume on the KPA to -12.3dB on the KPA in order to see a correct -10dB mic level.
Line Outs: Using TRS cables, using the same calibrated -10dBinst level signal I get a line level of -25.8dB at full trim with Master Volume at 0. Meaning, I have to add 15.8dB of line trim gain in order to see a -10dB level at the line in on the Saffire.
As far as practical recording goes, the Line Out and S/PDIF levels are decent; it's easy to calibrate my REAMP loop such that I can send out -10dB of instrument level signal and get -10dB back. Not so with the mic outs. Unless the Saffire's mic pres are unusually sensitive, I'd posit that the KPA's mic outputs are running ~12dB hot.
-djh
Yes, the S/PDIF outputs are low with respect to the analog outs, but that's because the analog outs are relatively loud. Even with the mic trims on my Saffire Pro 40 at min, I can't bring their levels down to match the S/PDIF levels. And if you bring down the Master Volume, the levels of both the analog and S/PDIF get reduced. Arggh!
-djh
Sounds good to me too - kinda on the edge of Rory Gallagher territory, always nice to hear.
-djh
1) Create a USB backup of your rig - and if you want to be fault-tolerant about it, Export your rigs to USB as well.
2) Download IZArc (Windows) and open up your .kpbackup file as a UNIX tarball. Delete all the rigs and/or cabs in it and save.
3) Restore your KPA from the .kpbackup you just created. After rebooting, all your rigs will be gone.
4) Import from USB only the rigs/cabs you care about. If you later decide you wish to blow these away and start fresh, you can just restore from the .kpbackup again.
-djh
That's nice - and, nice to hear. I remember reading one interview with C.K. somewhere - where he said he wasn't comfortable with the KPA doing bass profiles, just like doing modeler profiles or certain types of FX (Tube Screamer) profiles. I never really got why this might be the case for bass, unless it had something to do with low-end issues in the cabinet models perhaps. So many mysteries - all we can do is push the amp and see what happens.
-djh
hmm...found this "
S/PDIF can also transport 24-bit samples by way of four extra bits; however, not all equipment supports this, and these extra bits may be ignored."..do we know if the KPA can handle this?
I'd been thinking the same thing, Luntho after zooming into some of my S/PDIF recordings and comparing them against the analog versions. What's that, are those jaggies in the S/PDIF output?
Just now I synthesized a minutes' worth of 1kHz in 24-bit with Sound Forge and slowly faded out to digital black. I then sent this signal to the KPA in both analog and digital form, and recorded the results in both analog and digital form. To keep things simple, this was with all Stomps, Stack and Effects off. The digital result was as you guessed - the S/PDIF output from the Kemper, at least as far as my Focusrite Saffire Pro 40 is concerned, was 16 bit. I can't say the analog output was any better, though; around -87dB down the signal was basically getting lost in noise.
I'd like to hear from Chris on this one; if the Focusrite was throwing away bits 16-24 coming from the Kemper I have no way of knowing without doing further experiments. But it's possible that you're right.
-djh
I have a little bit to add to this subject, having done a weeklong workshop with Michael Wagener a few years back. Flemming Rasmussen did the tracking on "Puppets", so Michael had only limited info there but he did mix the album and here's what I can recall him saying about the guitars.
First, Bob Rock's "Thickener" (mentioned in "A Year In The Life Of Metallica", as well as the "Classic Albums: Making Of , Pt. 1") was also used by Michael Wagener on "Puppets" who credited Flemming Rasmussen with the technique. This involved tracking just the notes played on the 6th (and possibly 5th) strings and layering them in at about 11 & 1 o’clock pan-wise along with 4 doubles of everything else (i.e, the full riffs ‘n chords) panned at 7, 9, 3 & 5 o’clock or thereabouts. MW commented that simple hard L/R panning was a bit too extreme and this helped fill in the mono image (and the chugs, I would imagine.)
Second, he also mentioned that when recording rhythm parts that had thirds in them, James would record root 'n octaves while Kirk would record the third separately, also in octaves. Less intermodulation distortion that way, which explains the almost harmonized-guitar tone of Metallica's early rhythm tracks. Ronnie Montrose took this idea to the extreme on his instrumental album "The Speed Of Sound", which was around 1982 or thereabouts.
So, there you go - six rhythm guitar tracks on "Puppets", and God knows how many cabs, mics and amps were involved. But definitely no Tube Screamers for Jaymes on that album, unlike RTL.
-djh
Have you ever wondered why your KPA Mesa Amp model doesn't sound like the tone on your guitar hero's latest CD? You are profiling the same amp he uses, so why the difference? It is simply this: He not only used that amp, but he use both pre EQ (for tonal tightness) and post EQ (for both fatness and de-fizzing), multi-band compression (for even-ness), and an ideal miking setup. So in the end, the fact that your profile sounds like a naked miked Marshall really doesn't get you very far...
This is stirring the pot? I say nay. It's the truth, if what you're aiming for are contemporary wall-of-sound modern metal tones. Metal guitar production has been taking to ridiculous levels inconceivable from even ten years ago, and there are days when I feel like 75% of all the electric guitar-related forum bandwidth on the Net is nothing but this. Producers are the new gods, and everyone's been chasing some form of "Sad But True" since Bob Rock showed us the way in 1991. Before then it was 1978's Van Halen, was it not?
Unfortunately, the "Black Album's" recording story has never been documented in full; we're left with bits and pieces like this article (http://mixonline.com/recording…enter_sandman//index.html) but it gives you some idea.
It's easy to forget what unvarnished, simply recorded crunchy guitars really sound like, innit? Try - oh, the Ramones or maybe early Joan Jett. Or the aforementioned Van Halen 1 - dry cab on the left, reverb on the right - but even there was a complex (and subtle) signal chain that had been tweaked to death by Eddie which still required tons of outboard EQ according to those who were present. There's no shame in bringing this stuff up, it's all part of the Art of Recording and I'm kinda glad that the bar to getting great rock tones is a high as it ever was because it's such a moving target. Remember Syndrome from "The Incredibles" ? - "Once everyone has super powers, nobody will be." We're not at that point yet because it still takes great experience and a great ear to nail the sound that works with all of Our variables, and no two of us are alike - not our hands, our gear, or our amps.
Me? Couldn't be happier having the Kemper to play with. It's practical experience on the cheap! Most of us will never get to experience the full Bob Rock (or Beau Hill, Michael Wagner, Andy Sneap, Chris Tsangarides, etc.) treatment. But that's not to say we can't get a lot closer now. It's a great time to be recording.
-djh
A delicate little Xmas instrumental recorded in preparation for a new Kemper under the tree. Alas, it didn't come in time but when it did, I was ready to REAMP.
5150MK1 Green on the rhythm guitars
TillA Recto Raw 3 on the lead
Tell Nigel Tufnel I said hi. All Knobs On Eleven, eh.
http://soundcloud.com/dhodgson/wreckthehallskpa
Cheers,
-djh
Thank you! Did edit everything by hand, or were you able to semi-automate this process somehow?
-djh
I beg for someone to share an ENGL Savage metal profile, and a flat EQ DI version...It would be soooo great
Yes, it would. Verily. +1
-djh
Love it! Don't hold back, tell us what patches worked for you <g>
-djh
I was up late last night going through Every Single Factory Rig along with All 58 Pages Of User Uploads trying to whittle the list down to, simply, the profiles that seemed most promising for Crunch Purposes (in the Dream Theatre/djendt sense.)
That's 207 Factory Rigs and another 307 User Uploads for a total of 514 rigs. After a couple more passes of auditioning the ones that made the cut, I ended up with 68 rigs which are undoubtedly going to get whittled down further but I thought I'd pass them along. All I can say is, God Bless IZArc (http://www.izarc.org/) for making such a convenient (and free) tool for editing .kpbackup files. It's really worthwhile, one you've saved out all of your factory backup rigs and cabinets, to edit a .kpabackup file that contains No Rigs and No Cabs in order to keep the Browser in an uncluttered state. Then, you can just import only the rigs & cabs you prefer on the fly... if you don't like 'em you can always just wipe them all out and start over by reloading your empty .kpabackup.
Anyway, here's one person's list of the Better Than Most Hi Gain Rigs So Far:
2012-02-14_15-33-23_-_LW_DUMBLE-HRM-ST.kipr
5150MK1 Green - 2012-01-27 10-11-37.kipr
ACE 03 - 2011-11-09 19-23-59.kipr
B&P_3_FX - 2012-02-18 23-33-46.kipr
BEAVER PLEXI+TS - 2012-01-24 17-54-29.kipr
Black Cemetry - 2011-11-07 13-29-01.kipr
Brute&Phatt80sODBOOS - 2012-02-24 16-49-00.kipr
Bugera 333xl - 2012-02-21 12-28-45.kipr
Bugera 333Xl Rythm - 2012-02-21 12-51-33.kipr
Dancing Devil - 2011-11-07 13-24-13.kipr
DIEZEL CH2 - 2012-01-02 18-04-50.kipr
Dry Metal - 2011-11-06 19-35-36.kipr
Dry Queen - 2011-11-09 19-40-53.kipr
Dual Boogie Hi Gain - 2011-10-18 17-17-10.kipr
Dual Boogie Modern - 2011-10-18 17-17-14.kipr
EVH Lead2 - 2012-01-04 13-14-59.kipr
Fat Ed - 2011-11-10 13-34-07.kipr
Fireball Metal 2 - 2012-02-15 23-09-55.kipr
Fireball Metal 3 - 2012-02-15 23-16-08.kipr
Fireball Metal 4 - 2012-02-15 23-22-02.kipr
Fireball Rock 1 - 2012-02-15 20-42-43.kipr
Fireball Rock 2 - 2012-02-15 20-33-09.kipr
Flix HiGain - 2012-02-22 14-26-49.kipr
Flix HiGain Chorus - 2012-02-22 14-27-56.kipr
Gondwana MB Crunch2 - 2011-10-07 17-38-04.kipr
Hell's Kitchen - 2011-11-06 19-25-04.kipr
Hey Jim - 2011-11-10 12-54-29.kipr
JCM 800 Hi Gain - 2012-02-15 10-23-50.kipr
JMP77-001 - 2011-10-22 16-39-02.kipr
JSX ULTRA - 2012-01-20 20-50-35.kipr
JTM 45 ELEVEN RACK - 2012-01-25 13-58-42.kipr
King Vintage - 2011-09-16 21-08-55.kipr
LEGACY2 - 2012-02-13 22-25-32.kipr
LEGACY3 - 2012-02-13 23-31-53.kipr
Marshall Golub Crunc - 2012-02-21 20-03-45.kipr
MARSHALL YJM100 LEAD - 2012-02-03 20-20-55.kipr
Melodic Wha - 2011-11-10 13-36-26.kipr
MERROW 5150 SIG (RED - 2012-02-24 04-09-00.kipr
MESA F30HG1 - 2012-02-19 17-19-05.kipr
MESA F30HG2 - 2012-02-19 17-17-00.kipr
MESA F30HG3 - 2012-02-19 17-17-20.kipr
Metalcave - 2011-11-06 17-41-20.kipr
Mystic Crunch - 2011-11-09 18-33-51.kipr
OlaMrHectorSM57.kipr
PLEXI 50 ELEVEN RACK - 2012-01-26 16-54-36.kipr
Poulin Legion Solo - 2012-02-22 01-33-36.kipr
Sabbath - 2011-11-09 19-21-51.kipr
Some Brian May - 2012-02-22 14-06-28.kipr
Soul Dano Overdrive - 2011-10-18 17-21-48.kipr
Speed Licker - 2011-11-06 17-28-20.kipr
The Rover - 2011-11-06 17-10-16.kipr
TillS 2210 2 MICS - 2012-01-28 10-52-50.kipr
TillS 860 2 MICS 2 - 2012-01-28 10-52-54.kipr
TillS 860 2 MICS 3 - 2012-01-28 10-52-59.kipr
TillS BIAMP 1 - 2012-01-28 10-53-12.kipr
TillS BIAMP 2 - 2012-01-28 10-53-17.kipr
TillS JVM 2 MICS 2 - 2012-01-28 10-53-26.kipr
TillS JVM 2 MICS 3 - 2012-01-28 10-53-30.kipr
TillS JVM 2 MICS 4 - 2012-01-28 10-53-34.kipr
TillS JVM 2 MICS 5 - 2012-01-28 10-53-38.kipr
TillS RECTO MODERN 1 - 2012-02-05 16-35-12.kipr
TillS RECTO MODERN 2 - 2012-02-17 13-43-45.kipr
TillS RECTO RAW - 2012-02-05 16-37-43.kipr
TillS RECTO RAW 2 - 2012-02-17 13-45-01.kipr
TillS RECTO RAW 3 - 2012-02-04 11-17-18.kipr
TillS RECTO VINTAGE - 2012-02-05 16-41-44.kipr
TillS VK100 2 MICS - 2012-02-17 13-46-45.kipr
Triple Recto + Mesa - 2012-01-19 16-40-56.kipr
Wet Queen - 2011-11-08 20-20-56.kipr
-djh
1.05 borked my Kemper. I also had to reinitialize, go back to 1.04 and then re-load my profiles. I understand we are using a public beta and we update at our own risk, but I'd prefer these updates be tested a little more prior to release, especially since they are mostly minor bug repairs. Public betas should not brick your unit.
How is this reinitialization done? Glad to hear there's a method to allow firmware downgrades - not all gear will allow you to go "backwards".
-djh
1+1 = 2
-djh
Sweet! I agree, that rig was one of the factory ones that stood out to my ear when I was auditioning them all. You are on definitely on the right track. <g>
-djh
