Posts by ckemper

    LQP as documented says to profile the amp with all the eq flat and the amp gain at max.

    To be complete, the manual does not say to profile at eq flat and gain max.

    This is merely a recommendation for a more authentic over-all LQP.

    You can still make a LQP at your desired sweet spot, and it will sound authentic in that very setting, just like a regular Profile.

    Only deviating far away from that sweet spot might induce more inaccuracies due to the reasons mentioned in the manual.

    If you set the bass knob at "2" for profiling and mirror it to "2" in the Profiler, deviations of the potentiometers taper or even the printed scale on your amp can cause a small error. While the unaltered Profile is spot on, you might experience a larger deviation, when you turn the bass knob on your amp and the Profiler to "10" for an A/B comparison. The small error might get large when deviating by most of the scale.

    Once your target amp is well mic'ed and warmed up, it might be a good advice to make that "most accurate setting" LQP, as well as two or three sweet spot LQP's (including the mandatory mirroring of the sweet spot settings in the Profiler), and keeping all of them.

    Then they can be compared against each other the next day, and they might all work perfectly and equally, at any settings.

    btw, ckemper can I ask a specific question about Liquid Profiling:

    In cases where an amps tonestack is located between pre and power amp stages, how does a liquid tonestack simulate this?

    e.g. say the treble control on such an amp is set very low - this doesn't just lower the volume of the high freq's (as a post-amp EQ would), but it also alters the way the high freq's are subsequently driven by the power amp - so less distortion on them, or at least a different character. So, with a liquid tonestack modelled on such an amp, when you e.g. lower treble, does it also alter the distortion character of these high freq's?

    The answer is yes!

    To answer the theories of the adjaced posts:

    There is sometimes a common believe that all tube stages of an amp contribute to the overall distortion. But this is not exactly true.

    Some rules of thump:

    When nothing distorts, it doesn't matter where you put an EQ/tonestack. Always the same result.

    For example it doesn't matter, if you place an EQ before or after a delay or reverb, as long as the latter don't distort.

    On a vintage tube amp up to the Marshall Plexi, only the power amp section distorts. No master volume control, only gain.

    On later tube amps starting with the JCM800, the pre-amp section was given the ability to distort as well. A master volume knob was added to the power amp, to play distorted sounds at moderate levels.

    If a preamp distortion is prominent, the volume peaks of your guitar are compressed by the distortion, hindering the power amp from distorting on top. You have to crank the master volume to extreme values to have that second distortion. That additional power amp distortion tends to mudden the sound, so expecially in metal music one relies on preamp distortion only.

    You can of course lower the gain so that the preamp is clean and crank the master volume to have power amp distortion instead. This works well on "vintage master volume amps" such as the JCM800. But on dedicated modern high-gain amps the power amp section is highly linearized to provide less additional coloration (mud) at higher volumes.

    The Profiler is made for capturing (profiling) the most prominent distortion stage, that is either the preamp or power amp.

    For a Liquid Profile, you should be aware which stage you made distort, and set the EQ Position to Pre, if the power amp does the prominent distortion, or Post, if the preamp does the prominent distortion.

    ckemper What prompted the Liquid Profile development? It was a long-requested feature, and I recall years ago that you seemingly decided not to pursue individualized EQ stacks after exploring it at the time. Was there a paradigm shift? Or is it just the "no hope" as described above and giving into what guitarists want? ;)

    We have actually never decided against having individualized EQ. At the time I have announced the possibility that we might come up with such a solution, we have not explored the technique yet. It was always on our list, and all about priorities. The developement was done at a slower pace, while we were updating our effects and distortions. We felt that the latter was considered more important for our users.

    The most direct solution to all of these requests is to implement a tonestack creator so users can DIY. We are now in 'give a man a fish or teach him how to fish' territory.

    ckemper - have you considered this?

    I have considered it for a second or two.

    But as long as I don't see the community of (digital) guitar amps using parametric equalizers - or even for a better start, graphic equalizers - placed before the amp (!) to sculpture the guitar sound going into the distortion in a very easy way, I have no hope.

    Using graphical EQs for that purpose is known since the 80ies, I guess.

    Now with digital amps, it is a no-brainer in terms of cabling and noise issues.

    But it hasn't made its way in 15 years. Has anyone ever tried it?

    I have been waiting for long, that this existing 80ies technology, still present and evolved 'till today, will find a place in the guitar community.

    For sure it is possible to further parameterize the tonestack technique from the 1940ies, by using advanced computer technique from the 2000's and todays.

    As a player of a digital amp, do you need the technical echoes from the past, but combined with todays technique to improve it, to find your tone? I don't want to sell snake oil to you guys.

    What was the rationale for excluding the Sat and C45 switches from the Friedman tone stacks?

    I feel they defintely have an impact on gain and tone.

    We have chosen to avoid modeling controls and switches, that do not truly (!) interact with other controls and switches.

    The same is true for controls that in addition do not contribute to the task of adapting your guitar to the amp.

    All these controls are captured in the Profile, as usual.

    It is advantageous to mention these settings in the text tags of the Profile.

    The idea of Liquid Profile is to leave the majority of the tone sculpting to the Profiling process of an individual amp.

    Therefore we want the amp parts that are being modeled to be kept at a necessary minimum, to reduce the margin of error of the modeling process.

    The gain control with its optional brightcap is a cruical part for adapting your guitar to the amp, and at the same time the impact of the bright cap is dependent of the gain control position. This is absolutely worth being modeled.

    The same can be said for the tonestack, that serves a similar purpose, and has its own interdependencies as well.


    Thanks for this answer.
    It would be nice to have a list, which tonestack structure fits which amp.
    F.e. a specific Marshall tonestack (amp 1) fits also to Marshall amp 2.
    As a user I could see directly which tonestack I could use.

    So far there is no similarities to other models, that we know, but not listed. (Except those Fenders that I have mentioned.

    Except: All EVH amps seem to feature the same gain and tonestack structure.

    That is Peavey 5150, 6505 and all EVH amps.

    If you give us a later Marshall amp type as an example, we could have a look what similarities there are to the vintage Marshall amps.

    Yes, there will be more.

    We are currently working on a number of amp types, that we consider to be relevant as well.

    There will be e.g. Bogner and Diezel, and an additional number of Fender Types.

    Ampeg too.

    Some of the new Fenders share the same gain and tonestack structure as the Vibrolux.

    That is the Pro, Bandmaster, Tremolux and Vibroverb.

    We have decided to still feature them as separate Amp Types, so while still making the same sonical impact, they will display the exact type of the profiled amp.

    Sample Rate Converter? This is all beginning to sound like "Liquid Sampling" is coming to your favorite DAW. :/

    I know you can resample from 96k to 48k or 44.1k but can you up-scale from 44.1k to 48k with no problem, or does the DAW handle that? Like if I set my project to 48k, then any lower sample with be upscaled to that 48k?

    Yes. Liquid Sampling is quite an appropriate term.

    Upscaling is a standard technique similar to downscaling.

    It is even a bit easier, as it does not require an anti-aliasing filter. It's just interpolation.

    On most DAWs you can import 44.1 k files to a 48 k and they are automatically resampled. And vice versa.

    Logic does that same resampling in realtime during recording.

    the vast majority is 48k minimal.

    CD’s Were the only thing 44.1 and there are people today that weren’t even alive when those were the thing. Furthermore - I think a Kemper user can easily set up sample rate - I mean look at all the other Kemper features that aren’t “plug and play”. This thing is deep. Default it to 44.1 but have a 48 option. Protools is the industry standard - so should have that in mind - and why put excessive strain on the host computer recording. ALSO - sample rate conversion is re-sampling - might as well go analog… so this feature is great, but if it can’t do 48 - it’s worthless to many.

    Sorry so harsh - but “plug and play” translates to an excuse to me.

    But thanks for the “kind of usb” option.

    The Profiler has been designed for running on a sample rate of 44.1 kHz. This gives us a determined amount of calculation power and thus a stable system for the user.

    Internally we utilize sampling rates up to the MHz region, where needed. (Maybe in contrast to some PlugIns, that sound better when driven with higher sample rates from the outside.

    Therefore the Profiler would not gain better sound quality at higher rates. For guitar stacks with its speaker high end roll-off even 32 kHz or 24 kHz sampling rate would be totally sufficient. Many users use the HighCut to eliminate very high frequencies.

    If we provided selectable sample rates for USB, we would utilize sample rate converters as well, as we already do with S/PDIF, we had to use an SRC for each USB input and output.

    That truly would put a some strain on the USB interface, but mainly on our system , which was originally meant to be a digital guitar amp.

    I am sure that SRCs running in a DAW in a pure software environment will not cause significant strain.

    I am aware that Protools is one industry standard DAW. I am sure they are watching the innovations of another industry standard DAW, that is Apple Logic. The latter have managed to implement realtime SRC for recording and playback a while ago. And Aggregated Driver, to combine two or more audio interfaces. To me, this developement was obvious, and just a matter of time for such big companies. Protools will have to follow, if they feel the request of the users.

    I would feel a bit old-school to fill this gap on our side, while a much more intelligent solution is obvious and visible.

    It's one thing if the unit isn't capable of 48k. However, there are a number of valid reasons for the higher sampling rate, including the construction of the low pass filter necessary on the back end. For one thing, 44.1 requires a much steeper filter, where 48 can use a gentler slope. You can rely on the SRC in your particular DAW to handle the conversion, but not all SRCs are created equal and the conversion can introduce artifacts. (That's the best reason for setting everything to the same sample rate rather than relying on conversion after the fact.) Now, if Kemper simply relied on SRC to produce a 48k signal then that puts the responsibility on them to deploy a high-quality SRC - so again, if the unit is actually designed to operate at 44.1 only then it's debatable as to whether that's really the best thing for them to do.

    All that is said was written before, and was very true until the early or mid 90ies.

    But not for today.

    The good age started with terms like oversampling, 1 bit conversion and noise shaping.

    Todays AD and DA converters run at sample rates in the MHz region. They utilize digital filters that can be easily designed as steep as needed, without drawbacks.

    The same is true for digital sample rate converters, that use a similar kind of filtering.


    Would be very nice if was possible. Protools don't accept open a 48 session with Kemper. I have to open with my onboard audio then save a new session with 44.1 to open with Kemper.


    As mentioned, there are DAW's out there that do exactly that.

    If ProTools doesn't feature this very helpful and smart method, it might be time to ask them to improve, not us.

    There is only a handfull of relevant DAWs out there, while many dozen audio interface solutions are available.

    It would be a better world, if all DAWs would take any sample rates independend of the chosen project sample rate.

    Especially for musical instruments, where the audio interface feature is an accessory rather than the main purpose, it is very inefficient to circumvent those shortcomings of DAWs.

    DAW makers have a much larger workforce and different economy of scale to provide the appropriate solution.