Therevox ET-5

Therevox began making instruments in 2004. The ET-5 is inspired by the Ondes Martenot, so the tradition goes way back. The ET-5 has been in development now for two years.

New features with the ET-5 include a patch panel, an FX loop with a place to put and power guitar pedals (on the right in the above photo), pressure sensor on the fingerboard, with improved ringed action on a longer fingerboard. There is also improvements made to the internal spring reverb, and many more new additions.

(The above photo is an earlier ET-5, the front panel is more of a khaki color as shown below, or in the video.)

I like that the controls are so distinctly presented on the top panel. From the video i get the feeling that this synth has a real presence and unmistakable character. It sounds great.

This video gives a demonstration of 10 of the sounds possible from the ET-5, one sound shown a minute:

Therevox ET-5 Website

No price announced yet but it will likely be in the mid 2000 Euro/USD sort of range (my guess based on the last ET-4 price). You can get in line for delivery later this year with a deposit.


Wow, this new version looks really well thought out. I’m a sucker for interesting input mechanisms… I want this, I want an Osmose.

Wondering how MIDI out will work- will the synth being controlled need to be MPE compatible? Might be a great controller for something like that Anyma Phi

Added: that patch board could really open this thing up for some crazy sounds when paired with some CV utilities

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It’s monophonic, so MPE need not apply.

I think it can do two voices

The two intensity keys work on separate channels, allowing the ET-5 to independently control two synthesizers at the same time, or blending separate voices on a single synth.

I guess I was curious about the continuous glide part. Maybe that can be done over standard MIDI? I’m no expert

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I got thinking as i put this thread together of another classic two voice analog, one that i posted an announcement on yesterday, the Oberheim TVS-PRO. That one sounds absolutely awesome too.

This though has a real heft and presence, and perhaps another word that fits is elegance. It gives so many options, and yet there’s a straight ahead simplicity to it too. I was surprised by this.

I don’t want to be buying another synth !

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It’s not two voices, per se. There are two oscillators which have their own VCA - the wooden triggers open or close the VCA like an envelope, but manually. The MIDI implementation does this with I think either channel pressure or a CC on one or the other MIDI channel. But the fingerboard is monophonic and does not produce more than one “note” or note event, and thus MPE is not applicable, neither is dynamic channel assignment or whatever - just 2 standard MIDI channels (and CC/channel pressure messages or however it’s precisely implemented) are needed.

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Sweet, thanks for that clarity! MIDI/MPE are always a bit confusing to me. It does seem to have a mode that I’d classify as two-voice paraphonic? Two notes, two envelopes, one filter

One of our favourite new features is the ability to “freeze” the pitch of Oscillator 2. When this is enabled, pressing down on the fingerboard will grab and hold the pitch in that position allowing for easily changing drone notes and polyphonic melodies.

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Therevox on their website talks about control of this synth in a semi-polyphonic two voice manner.

One of our favourite new features is the ability to “freeze” the pitch of Oscillator 2. When this is enabled, pressing down on the fingerboard will grab and hold the pitch in that position allowing for easily changing drone notes and polyphonic melodies.

ADDED: Hey Affectionate-Bee-781, we both went rght to the same quote.

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I wonder if the MIDI out might be done with Pitch-Bends mixed with Note-Ons / Note-Offs in some way.

So, clearly there’s some confusion about MPE (MIDI Polyphonic expression) and being able to do polyphonic and multi-channel things over MIDI (which does not require MPE). MPE is nothing more than a way to dynamically assign individual notes entire MIDI channels so that the CC values sent only apply to that particular note. This is so that keyboards which play more than one note at a time can then modulate individual notes and not all notes on the channel. Obviously there needs to be a way to assign a given modulation stream to a given note, and since MIDI only has 16 channels and keyboards have way more than 16 keys, this must be dynamic.


The underlying structure of the MIDI expression transmission - that is to say pitchbend, aftertouch, and specific CCs for other continuous values - does not change.


If you’ve already allocated oscillator 1 to channel X and oscillator 2 to channel Y, there is no need for dynamic assignment of the expression data - the channels are already dedicated. Thus, MPE is not applicable.


If your keyboard only generates one note at a time (the assignment of pitch to the drone oscillator is not really a “note” - its more like changing the pitchbend value of an already playing note - which is probably what the Therevox does since it uses pitchbend for the fingerboard too), there’s also no use for MPE since you don’t have polyphonic expression data - the pitchbend from waggling your finger applies equally to both oscillators unless one is droning.

Remember, it’s the expression being polyphonic that applies to MPE, not whether there can be more than one note at a time, which regular MIDI already handles just fine.

Thus, just like for a paraphonic monosynth, in this situation MPE doesn’t offer anything that a simple assignment of MIDI channels doesn’t already, and thus it does not apply.

Therevox’s ET-4 is documented as doing this, so I don’t see why the ET-5 would change it.


Good, so we’ve completely cleared up the MIDI part of this.

A good idea Affectionate-Bee-781, i wouldn’t have thought of that, using the inputs and outputs on the Anyma Phi in FX mode, plugged into the FX Loop section of the ET-5. It just might fit up there with it’s controls, and there is certainly a wide range of FX available with it.

Perhaps even more apropos would be to use the Les diffYUseurs effects emulator that Yves Usson created. That’s a digital FX processor made to simulate the original Ondes Diffuseurs loudspeakers that were used with the original Ondes Martenot. I wrote about the Les diffYUseurs over in this thread. I really like its sound, and short of getting re-creations of the Ondes Diffuseurs, it would be a natural combination.

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I am really digging the sounds of the ET-5. Cool instrument. The patchbay and FX send seem to really open it up.


303 killer for sure! :wink:


You crack me up !

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Therevox has definitely been doing the work, sitting down with customers and listening and then bringing back those ideas and implementing. The pressure sensor is another thing that they added. And the freeze feature, where you can change drone notes is good stuff too.

It’s a solid and compelling update, definitely.

I just put a post about La Voix Du Luthier resonators over in the Superbooth 21 thread. Either of those two resonators would probably be wonderful with the ET-5. I expect they would give a similar effect to the originals, but with less coloring of the sound.

This total package would not be unreasonable cost wise, and would have an awesome “presence”.

Therevox is at Knobcon 2022. ( thread )

ADDED : Here’s a video with SonicState with Mike Beauchamp of Therevox at Knobcon. 2022. Mike shows and talks about the ET-5, and also shows their new Ondes VCO Eurorack module, which he plays with the ET-5. It’s a revelation to me how the ET-5 can now be used as a versatile CV based controller. There is also a good explanation here for the origin of the Ondes VCO, and a simple demonstration for its sound capabilities. Didn’t realize until watching this video that this new oscillator, has completely different circuitry from the ET-5

Fourteen minute video.

Just me on this, but i’ve found myself GASing after watching this video, and in ways i had not expected. The combination of the right hand controls, together with the left hand controls, seem very powerful and natural. Plus adding in all the front panel knob controls and the patch bay, makes this, the sort of instrument that i could learn and grow with, exploring its interesting sound world.

Also got to say, i really respect the integrity of people who will completely drop selling an older version of a product while in the design process for a new replacement version. Especially for three and a half years !