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Page 2: Kemper Profiler Stage

Floorboard Guitar Amp Emulator By Dave Lockwood
Published December 2019

Well Connected

The automatic voltage-sensing IEC power input sits at the opposite end to the guitar input, and in between lie the main stereo outputs on both XLRs and TS jacks, stereo TS jack monitor outs, two mono send/stereo return effects loops (that's one more than the 'toaster'), S/PDIF digital I/O, USB (types A and B), MIDI in and out, and four pedal inputs that accept expression pedals or switches to address the impressive array of real-time control functions in the Kemper Profiler Stage.

While there's no built-in expression pedal (not necessarily a bad thing) there's support on the rear for connecting up to four external ones.While there's no built-in expression pedal (not necessarily a bad thing) there's support on the rear for connecting up to four external ones.

The main XLR outputs are phantom protected, but avoidance is recommended where possible. Personally, I'd be inclined to always carry my own DI box — it's not exactly uncommon with modern digital desks without obvious per-channel phantom switching for FOH guys not to know for certain if they have it activated or not. Main and monitor outputs can be ganged to the Master Volume control, or separated so you can tweak a stage monitor cab level without affecting the FOH feed. There's lots of output level flexibility and soft-switched earth-lifting available — trying every complicated hook-up I could think of, I didn't encounter a single scenario where I couldn't achieve hum-free, level-optimised interfacing. Impressive!

Equally impressive are the comprehensive internal routing options that allow you to hive off the reverb and delay signals as a 'wet' stereo pair whilst sending an amp or amp/speaker signal, complete with all other effects, out of a different output. This can be used on stage to give you the classic 'wet-dry-wet' setup, or in the studio, recording wet and dry tracks separately to allow re-balancing in the context of the mix. You can also get the dry, un-effected guitar signal as a separate output via Send 1: ideal for recording a re–amping safety track, which can of course be 're-virtual-amped' through the Kemper. The four return inputs, all TRS (balanced) jacks with level control, needn't be just effects returns — returning post amp and cab, they could also be used to feed in a recorded backing track for practice or even performance, provided that you are using full-range amplification rather than a guitar speaker. Effects loops can be made footswitchable by assigning them to effect slots, and then to effect footswitches, or they can be recalled with a stored state within a Rig.

In the Profiler Stage, the four expression pedal inputs are assigned by default to Volume, Morph, Wah, and Pitch control, but can of course be reassigned if you have other requirements. If you are not familiar with the Kemper Morph feature, it allows you to simultaneously change a number of parameters within a Rig, either by switch (with a variable ramp-time setting) or by expression pedal, which gives you continuous variation between the two extremes. For example, you might set up a semi-clean rhythm sound that you can gently slide into a more sustaining distorted lead sound with more gain and delay just by leaning into the foot controller. Morphing works for any parameter that can be continuously controlled within a Rig, so you can't morph between two completely different profiles. It's nevertheless an immensely powerful feature and I feel like I have only just begun to scratch the surface of its creative possibilities.

I must admit, when I first started to encounter Kempers, I had some initial resistance to the use of unfamiliar terminology for many of the parameters. Working with parameters called Definition, Clarity, Pick, Tube Shape, Character, Pure Cabinet, Clean Sensing etc. felt somewhat at odds with my desire to precisely understand the functions I was adjusting at a technical level. I find it much easier now to just experience what these parameters do, and decide if I like the result. In general, I find the Kemper system gives the best results when you find (or create) a profile that does exactly what you want from an amp/speaker setup, and then have to do very little to it in the way of further adjustments, treating the 'amp' EQ as if it were 'control room' EQ in a mixer, and not trying to totally re-shape the sound with it. Reducing gain tends to work much better than increasing the gain of a profile, in my experience. There are further EQ options in the output module to make 'environmental' adjustments to all your Rigs simultaneously. Or not, if you prefer, because there's a nifty Lock function that can keep any part of the signal chain in place as a permanent fixture while other elements are changing. The Monitor output, with or without cab sim activated, is independently EQ'able without affecting the FOH signal at the main outputs.

One exception to my preferred 'choose a profile and don't mess with it too much' strategy is the Pure Cabinet function. This seeks to remove from the signal any sonic contribution introduced by the microphone used for profiling — a similar trick to removing the speaker cabinet from a combined-amp-and-speaker Studio profile. It's one of those Kemper things that you think shouldn't work and yet does. I find I like to leave the mic element in the signal for recording, and dial it out substantially for live playing, for more of an 'amp in the room' sound.

The Profiler Stage's chassis is both stepped and raked to keep the footswitches comfortably clear of the other controls.The Profiler Stage's chassis is both stepped and raked to keep the footswitches comfortably clear of the other controls.

Whether these sorts of options matter to you may well depend on your preferences for amplifying your Kemper and indeed whether or not you ever intend to use it for live performance with a band. The 'live' user base seems to divide sharply into two camps: those who are content to use full–range, PA-style amplification, and those who think that using a real guitar cab, with the Kemper's speaker emulation switched off, gives the best playing experience. I tried both methods at length and found I could be content to work with either, but particularly in respect of working at louder volumes, the real guitar speaker just wins out, provided you're not looking to radically change your sound — the real cab obviously remains a common sonic factor in that configuration even when you select different amp profiles.

If you do want to take full advantage of the sound of different speaker profiles, Celestion's 'full-range, live-response' (FRLR) F12-X200 coaxial speaker (reviewed in SOS August 2019: https://sosm.ag/celestion-f12-x200) is certainly a great option, offering the flexibility of authentic profiled tones, but with real-speaker 'feel', too. It's probably no surprise that Kemper's own future cabinet offering seems to be headed in a similar direction.

The question of the sound and feel of modelling and profiling digital guitar-amp emulators really is one of the most highly subjective. I've been fortunate to have had extended access to most of the leading brands, and have inevitably evolved some personal preferences, but they are just personal preferences — not claims of greater or lesser authenticity. I still use tube amps whenever I can, but am now, like many others, quite content to use a digital emulator when it's more convenient or economically necessary, because the leading digital guitar systems are now all really good, in my opinion, even the ones I personally don't particularly enjoy! The Kemper is right up there with the best of the bunch. It feels fast and responsive under the fingers, and I didn't even look up what the latency figure is because the playing experience allows you to just forget about it being a digital unit. Of course, two effects loops means two more A-D converter stages, and that will be compounded if those connect to two digital units, and if you are perhaps monitoring via a digital desk — just something to bear in mind if it starts to feel different at the heart of a bigger system. The biggest compliment I can pay the Kemper Stage is that I found profiles on which I could complete a whole gig using only the controls on the guitar for variation, just as I like to do with a real tube amp. Unlike some modellers, Kemper profiles seem to hang together really well at performance volume, retaining dynamics even within saturated sounds. Another big positive is the very low noise floor in driven sounds, with no gate necessary until you get up to modern-metal levels of distortion.

The Last Word

Kemper have always seemed to me to be a company who are really in touch with their user base. Much of the discussion around the Profiler Stage, however, seems to revolve around both questioning the form-factor — the relevance of a floorboard when you already have a foot controller — and bemoaning the fact that it doesn't represent the big leap forward in Kemper technology that some may have been hoping for. On the former, I've always rather tended to buy into the sense of keeping the 'brains' of any expensive digital unit out of harm's way on stage and using a relatively dumb controller under your feet — at least, I did, until someone pointed out to me that the combined value of the pedals I had on my 'serious gig' board at the front of the stage came to more than the value of the tube amp I had tucked away safely at the back! I can't be certain from examination of the enclosure that the Profiler Stage has been engineered to prevent liquids from entering through the top, and whilst I no longer tend to play many places where a punter might spill beer on it, I do still get rained on sometimes, courtesy of inadequately covered outdoor stages. All in all, I think I'd be inclined to clingfilm it when the weather was looking uncertain. You could, because the unit doesn't get at all hot, especially compared with other digital devices. Whilst there's no fan, there is a small vent in the baseplate on the power supply side, so making sure to keep a stand-off gap would probably be a good idea if mounting it to a board. Despite the Kemper Profiler Stage being very complete in itself, you are still going to end up with a lot of clutter around it on stage if you're using the sends and some expression pedals. For a touring rig, you'd probably want to 'board it all up' and flightcase it with all connections intact. On its own, however, it's an easier carry than a 'toaster' and a Remote, and wouldn't need to be checked luggage on a fly date.

With regard to the 'old tech' question, my favourite guitar amp is 51 years old now. It wasn't especially 'new tech' when it was designed, but I'd say it was certainly still 'effective tech' for the job it is tasked with doing now. In the digital world at large, seven-year old technology is usually considered practically obsolete already, and I understand the desire on the part of some Kemper devotees for the 'next Kemper' to have been something more radical, pushing the boundaries of the profiling technology still further. But the Profiler Stage makes complete sense to me. It profiles, it has all the processing power necessary to sound like a great guitar rig, it now has high-quality effects, and it ships with more great-sounding profiles on-board than most of us will ever need in a lifetime, even if we never actually profile anything for ourselves. The form-factor is clearly one that is preferred by a big chunk of the market and the price is less than the list for a 'toaster' and a Remote. All things considered — completeness, flexibility, playability, sound authenticity, backup strategy and a few more — if I had to take a modeller on a string of live dates, it would probably now be this one.

Audio Examples

Check out the accompanying Audio Examples page at www.soundonsound.com/reviews/kemper-profiler-stage-audio-examples or click below to download the ZIP hi-res WAV audio file and audition it in your own DAW.

Package icon kemperprofilerstage.zip

How To Profile An Amp

To profile an amp with a Kemper, you simply set up the amp with the sound you want to emulate, as heard via the mic that you'll be using for the profile. The last bit is important: a basic 'Studio' profile encompasses the amp, the speaker and the mic used. The Kemper then sends a variety of test signals (in the Stage, these are taken from Send 1) to the amp, which are reproduced by the speaker and returned to the Kemper via the mic. You can use more than one mic, but you have to submix them before they get to the Kemper. Unlike other Kempers, the Stage has a TRS jack rather than an XLR mic input, so you'll need a TRS–to–XLR adaptor, or you could use a small mixer or standalone mic amp if you want phantom power for a capacitor mic. The return signal is patched into the Stage's Return 1 input.

The clever bit is that the Kemper can then determine the sonic characteristics of the profiled rig, in terms of frequency response, dynamics, and distortion. Initial, test-tone profiling is then followed by a 'refining' process, carried out using an actual guitar signal played through the same signal chain. There continues to be much speculation as to how the Kemper process works on a technical level, but users certainly have no specific need to know — at a user level, it's just really simple.

The complete 'Studio' profile, as described above, is the most commonly encountered — most commercial and user profiles are this type — but you might logically be wondering how it is possible for the Kemper to arrive at separate parameters for the amp and speaker, and indeed allow you to change the speaker or disable it in the monitor feed while still sending a speaker–emulated signal to the PA. The software incorporates an algorithm that intelligently deduces what the contribution of the speaker (and mic) is, and deducts it from the profile. It's one of those things that you think shouldn't work and yet it does, and remarkably well in most instances.

There is a further option, however, in the form of the Direct Amp profile. For this, instead of a mic on the speaker, you use a speaker-level-capable DI box to make a profile from the output of the amp alone. Of course, you'll still need a speaker connected to keep the output stage both safe and working normally. If you want to be as accurate as possible in your profiling you should use the actual cab you use with that amp, because only that cab will make the amp behave precisely in the way you are used to. Any other cab may create subtle differences. High–quality, reactive dummy-load boxes such as Universal Audio's OX and the Boss Tube Amp Expander, however, can also offer a good route to a Direct Amp profile, albeit a more generic one, as you can extract a non-speaker emulated signal from both — the OX has a software DI box option, and the TAE has a Direct mix option within the speaker sim control panel. The end result will be a profile of the amp almost completely separate from any cabinet influence. I say 'almost' because the cab/load will still have affected the dynamic behaviour of the output stage to some extent. A Direct Amp profile can then be used with a conventional guitar speaker, ideally via a tonally neutral solid-state power amp.

If you take a Studio (amp and cab) profile straight after a Direct (amp-only) profile without changing any of the settings, you've given the Kemper everything it needs to work out the difference between the two, and thereby make a 'perfect' extraction of the cabinet (and mic) contribution. The resulting two-part profile is referred to as a Merged profile, and will function as a Studio profile that you can digitally deconstruct with absolute authenticity. Having truly separated the amp from the cabinet, you are then also free to employ any speaker cabinet impulse responses (IRs) that you might prefer. Personally, I don't find the speaker to be the definitive element in many Kemper profiles — an idea somewhat supported by the fact that all of the Michael Britt profiles, which curiously seem to be all the ones I really like, are all created using the same cabinet!

Pros

  • A very complete all-in-one package.
  • A good profile sounds and feels very authentically like a real tube amp.
  • Very flexible routing and external control options.
  • High-quality effects and processors.
  • Automatic tempo detection for time-based effects.
  • Works with 'FRLR' speakers or guitar cabs.
  • Excellent DI recording sound.
  • Light and compact.

Cons

  • Will always require a power point at the front of the stage or a long power cable.

Summary

It's a fully featured Kemper Profiler in a floorboard, with all the power and control of a head and a Remote combined into a single unit. Above all, when you find the right profile, it can sound really, really good!

information

£1431.41 including VAT.

www.kemper-amps.com