Polyphonic Aftertouch On The Behringer UB-Xa Synthesizer

In his latest video, Bernd Brüning, aka The Synth King, explores the polyphonic aftertouch of the upcoming Behringer UB-Xa synthesizer.

Polyphonic aftertouch is a keyboard feature that’s, unfortunately, been extremely rare. It brings an added dimension of possibilities and expression to you keyboard performance, because you can add expressive modulation to individual notes. It’s one of the features the promise to make the Behringer UB-Xa more than a cheap knockoff.

“This little piece of music showcases the superb keybed of the UB-Xa,” notes Brüning.  “It provides velocity sensitivity and polyphonic aftertouch, enabling you to play your music with extraordinary expressivity.”

Here’s what Brüning shared about the technical details of his performance:

“In this split performance, filter frequency, volume, LFO speed and intensity of the upper preset (in unison mode employing only one voice) is controlled by poly aftertouch. Moreover volume, VCF and VCA attack is also controlled by velocity.

The lower pad sound uses OB-8 “second page” functions such as LFO rate delay here controlling panorama position. Furthermore LFO rate is influenced by poly aftertouch as well.

This music genre begs for delay and reverb. I´ve used two Lexicon PCM 70 connected to my main mixing desk as send effects.

Everything is played life and recorded in one take without any edits or further audio processing.”

Check out the performance and share your thoughts on the UB-Xa’s polyphonic aftertouch capability in the comments!

40 thoughts on “Polyphonic Aftertouch On The Behringer UB-Xa Synthesizer

  1. I wish there was a way to have an envelope on the polyAT itself. Release time, so it would ring out as you lift your fingers. Is that possible?

    1. The point of polyphonic aftertouch and MPE is that your fingers create the envelope and that envelope can be applied to anything.

      So you can still use standard ADSR envelopes for the VCA if you like, but you’ve got continuous control over expression for each note.

      1. I had the Gem s2 as my masterkeyboard for several years and I found that that was a thing, with pads ringing out…

        1. That is not reachable via polyAT but with Release Velocity. Only a few synths have that. It’s not as rare as Poly AT though.

    2. Could be done with a Slew Limiter modulator.
      Often wished synths would include a Slew Limiter as a modulation modifier..

    3. Hydrasynth has a separate envelope on the polyaftertouch curves for exactly this reason. They are somewhat hidden under the polyaftertouch settings and are separate from the normal envelopes on the synth.

  2. How did I miss this? Polyphonic Aftertouch on the Behringer???!! I thought the HydraSynth was a no brainer given its poly aftertouch and ribbon controller, but this complicates things…

    1. The “hate” as you like to put it towards beringner is based on many good reasons.
      If beringer will start to build instrument that takes the technology farther, doesn’t compromised on development, have a better build quality, will give long support and the take responsibility to refine the finer but crucial details of their products, will make effort to retain the value of their products and contribute to our beloved market with innovation and respect to other brands I’m shore most of us will like that.

        1. I didn’t say anything about “reinvent the wheel” either, I wrote what improvements people would like to see.

      1. There are many guitar companies that build a “Les Paul” or a “Stratocaster.” Do you hate them as well.

        1. I didn’t say anything about copying, I wrote what improvement most people would like to see from beringer.

      1. That, in my opinion, is what is wrong with many peoples’ perceptions of Polyphonic Aftertouch. You don’t realize how much you need it until you have personally experienced it. There was a point where I was very satisfied with channel aftertouch (especially something as lovely as a Fatar TP8s). Then, I received first the Hydrasynth and later the Iridium Keyboard. That latter keybed has changed the way I now view what constitutes an “acceptable” one. Another thing I have come to realize is that just having a keybed with polyphonic aftertouch available isn’t the same as having it as the active keybed for the synth I am playing. For example, the K2700 will respond to polytouch, but playing it from the Iridium keybed is just not the same as being able to directly interact with the synth while I am playing it. Oddly, this is becoming a main reason why I am hesitant to pull the trigger on a Moog One, TP8 keybed notwithstanding. .

        1. Yep, big fan of Poly-AT going back to my Prophet T-8, Ensoniq, Kurzweil MIDIboard; and currently have two Hydrasynths (49 and deluxe), Mellotron 4000D full size; and was early adopter of Haken Continuum. Got my early preorder in for Osmose as well. So, I’m a big PAT nut 🙂

          1. Just out of curiosity, what does polytouch, or even channel aftertouch for that matter, do on a Mellotron?

            1. From a review, not mine”…….. The regular M4000D, the largest digital Mellotron, also has polyphonic depth sensitivity. This means that you can control the volume of each note that is played back in real-time by how deep you press down the key. This technology was developed by Markus to emulate the behavior of a tape being pushed against the replay head. This also gives this instrument Polyphonic Aftertouch via MIDI, which is very unusual for keyboard instruments today.

              1. I had an M400 for a short while in the early 70s. That’s not the way I remember it, exactly. I do remember hating the keybed that felt to me like depressing spring-loaded woodblocks. Also, I seem to remember that what you got when you increased the pressure was more “wow” then loudness because what tended to happen is that the tape got slowed down by the increased friction. That was almost 50 years ago, now, and I’ve lost more brain cells than I care to imagine. I just don’t remember that being a “feature” of a real Mellotron, which is why I asked the question. Also, because of the way they were manufactured, I’m guessing that it would have been a pretty easy mod to get key by key volume control, since there was a one-to-one relationship between the number of keys and the number of tape loops. Such a mod wouldn’t even require any change in contact force between the keys and the tape.

  3. Very simple, haunting, and very effective at demoing polyaftertouch. That downward run at bar 40, or so, says it all. Unquestionably, this is going to be a poly synth to be reckoned with. I’m really surprised, however, that people still rag on Behringer for “build quality”. Clearly, none of these people have ever handled a Poly D or a Deepmind. Personally, I think that the voice architecture of the latter really sucked, but I never could find fault with the “build quality”. As for the Poly D, I really can’t name a synthesizer available today that has what I would consider better “build quality”.

  4. I suspect this is the keybed we will see on the BS80 (because of the PolyAT). Just like when Behringer introduced their MaxiBoog which featured the key assign functionality of the Borg MonoPoly which was still in the pipes at that point.
    So if this new keybed is good, that’s promising for the BS80 playability.

  5. John, what polytouch can do for a DIGITAL Mellotron is the same as it does for synths: individual key control, which means strings and choirs get a lot more internal variety. That’s the obvious use, but it’ll do the same good for any other sound. You have to configure whatever you’re playing, but it’s easily done.

    Real Mellotrons can offer a bit of volume and tone adjustment with pressure, but that’s a different world. We’re also talking $4-5k for that. I’m an M-Tron Pro fan and many people go for Markus Resch’s excellent digital recreations. Good example: Robert Fripp using the M4000D live with King Crimson. Read this and be impressed.
    $2800 may be more ‘tron than you need, but its small and stable. Mmm, smell the lack of tape snarls….


    1. Thanks, Dave. I guess I was thinking in relation to a tape-based Mellotron. I’m sure that you can do a lot with a keybed that sends poly aftertouch. I’ve never seen or played with any of the newer digital ones but I hope they put some kind of modern keybed on them. Putting any kind of aftertouch on a keybed as shitty as the one that was in the M400s wouldn’t do anybody much good. Then there’s the whole reason for purchasing a big white box with the name Mellotron on it. One would hope that realism and fidelity to the originals would be what you were buying (otherwise why not just make due with the Gforce or even Arturia
      clones?). Since anything that you would add to it would detract from its authenticity, I would just ask “Why?”


  6. This is not just a thought on this synth (it does sound gorgeous by the way) but on Behringer’s products in general; personally, I think they are really kind of missing the whole boat in designing synths that are just copies of classic synths and take a hint from the .vst developers and design clones that are a replica of a classic, vintage instrument and then some, make them more. Add additional oscillators, voices, envelopes, LFOs, routings, great keybeds, etc. etc.

    My other thought is adding usb MIDI + MIDI audio and a .vst that can manage your patches from within your DAW so that your DAW sees and manages the synth like a .vst plugin for automatically saving and loading patches and sees it like an audio interface for recording the audio from the synth. I’m not talking about creating software GUI copies of the synths, the physical instrument is where the love is, just managing the patches and handling the audio in to simplify the connection to the computer.

  7. If I’m not totally mistanken they are using the same keybed for this one as the one featured in Hydrasynth Deluxe. It’s playable, albeit a tad too light for my taste. But I have ordered a Hydrasynth Deluxe anyway.

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