VCA vs LPG | What's so cool about vactrols?

You can't have too many VCA's. But if you like organic, plucky and percussive sounds and don't have a Low Pass Gate (LPG), then you may have too many VCA's after all. Please note that the statement 'musical vactrols are rare' refers to the original Vactec vactrols (where the thing got its name) used by Buchla in the original 292. Today they'll cost more than the module they're intended for, and since they contain Cadmium, they're on the EU import ban list. Sooner or later, the rest of the World will follow. That does NOT mean you can't make an LPG without vactrols. The Rabid Elephant Natural Gate is a perfect example of a 'green' LPG that may sound even better than the real thing.

[@CinematicLaboratory]

Listening to this video after two years gives me the impression that the Pico doesn't like envelopes on the LPG, it's probably designed to strike it with a trigger. An envelope on Optomix' strike input also sounds 'blurry'. Optomix still wins because it can open a vactrol with an envelope and a strike, but Pico may sound much better in real life if you strike it.

[@deadredeyes]

Dig the lighting and the setup for the videos here. Good stuff! Couple things to share, yes, there is a difference between models of vactrols, and even the VTL5C's themselves can be off by a factor of a few milliseconds when analyzing the exponential rise and decay of the vactrols themeslves, but to say a musical vactrol is rare, is being disengenuous at best. I've hand tested easily over several thousand VTL5Cs for eurorack modules and the majority of them were just fine for Low Pass Gates and the rest of the circuitry used for CV. If they weren't inherently musical there's no way in hell Make Noise or any other company would have released products with them. Also, the LPG circuit is not a VCA with a built in Low Pass Filter, it literally IS a LPF that is configured to act as a VCA. When the LPG opens up, that's the filter itself opening up and closing back down.

[@CinematicLaboratory]

Unfortunately I can't update a video when it's on YT but you're right - I should have never written that because it's not true. I added a note in the description a few months ago. I wanted to make this video to show people that a LPG is more organic and woody compared to a plain VCA or even a VCFA and the vactrol is an important ingredient to that magic. Regardless, MakeNoise currently has a very hard time finding the right ones for their products which they describe as 'good old vactrols'. They've become rare one way or another. Also, the latest Doepfer LPG doesn't sound as good as it used to. Endorphin.es ditched the Terminal design because of the vactrols and went completely digital with the Grand Terminal. I clearly showed the Erica Synths LPG sounds blurry and has no coherent organic pluck, not even with Maths.

[@jaeryan1337]

I just realized I haven’t subscribed. Let’s change that right away 😳 You really run a great channel with great content ❤️

[@nasound2473]

Thank you for this. Honestly... I'm still a bit unsure if LPGs are right for my rig, but this has really opened my eyes to both their potential and the need to carefully select the right one.

[@CinematicLaboratory]

It's really a matter of taste, but I could do completely without VCA's and almost never use them. LPG's are alive.

[@HumanMotives]

Very interesting video! Learned quite a bit from it thanks!

[@Zeitstill_music]

Never heard of this! Sounds awesome! Thanks

[@james_44]

Amazing video as always! Please can you explain the signal chain a little for the quad filter > low pass gate? It sounds amazing! (Sorry for being late to this particular party!)

[@CinematicLaboratory]

As far as I know you can do this with any low pass filter. Put the resonance a bit up, and the cut-off completely down. Then apply an envelope to the cut-off and adjust to taste. This works best with an exponential envelope (e.g. Maths).

[@james_44]

@@CinematicLaboratory sorry I don't follow, so it's a low pass filter into the LPG or the Low Pass Gate into the low pass filter? I'm referring to the example near the end where it says "let's connect the quad filter to a low pass gate". Apologies if I'm being stupid and missing something super obvious!

[@gregorio98000]

Amazing ! Thanks for the knowledge

[@disectormusic]

Great video for nerds like me

[@dangayle]

I have the Noise Engineering Sinc Bucina, it doesn’t quite have that “alive” thing you’re talking about here. Feels more like a regular envelope on a filter.

[@CinematicLaboratory]

Imho, the Sinc Bucina is a great piece of design, but indeed it's more a VCFA with a fast response that matches the iteritas family very well. But the iteritas modules also sound magical with a 'buchla style' LPG. In the end it's a matter of taste. Noise Engineering clearly likes the fast response AD envelopes (Pons Asinorum, Percido envelopes, etc).

[@badador]

love the colors in the video and beautiful video thumbnail. what's the difference between LXD nad Optomix? their both vactrol only that Optomix gives you more control? and agreed, random sequences all sound the same :)))

[@CinematicLaboratory]

Hi Balador, sorry for the late response, I somehow disabled notifications in Chrome. The Optomix has two 6dB low pass gates, the LxD has a 12dB (top) and 6dB (bottom), so the top sounds more 'aggressive'. When you have Maths near, the difference between Optomix and LxD is pretty small. However, Optomix makes sound with nothing patched to the Control inputs, while LxD needs voltage on CV otherwise it remains silent. Also, Optomix has an extra 'damp' input to modulate the incoming signal, so the response of the vactrol will change depending on the incoming dampened sound. You can also use it with an envelope on 'control' and a random source on 'damp' so you get more life. So if you love LPG's, then Optomix is a better choice. If you want to just add an LPG to your case next to your VCA's, LxD is a very HP friendly solution. Please note these LPG's all sound different, even on the same model. But I feel the strike inputs on the LxD sound a bit more powerful compared to the Opto. Hope this helps!

[@kenb7540]

Interesting.

[@drahtmachine4601]

Hey, what kind of sequencer do you use? Cheers Peter

[@Hessencemusic]

Thank you very much (as always) for all your videos.. .Just one question in case you could help me. I bought an optomix v2, and I found something two things that I don't fully sure they are right. One is, the Sum output has lower gain that individual outputs. And second is related to the strike knobs. If I don't have anything plugged to it, and I take optomix's mix output to a mixer (befaco stmix), and I move the mix channel knob I heard some sort of noise.. (Like the one you hear when a pot has dust).. But it's not a stmix problem .. (I've check that channel with more sources, and I've even test it with another new stmix). It´s because the strike knob is up without any input!.. If I CCW strike knobs, then I can turn my mixer knob without any noise. Is that normal? Thanks a lot in advance for you help

[@CinematicLaboratory]

if you patch the sum output to a scope you'll notice it will output CV even when nothing's patched. You can actually use just Optomix to send CTRL CV to a different module, or strike it. The sum output will sum the two separate outputs to unity gain which can be less than the output of the individual channels. When you use the strike (trigger) input you'll need to turn CTRL completey CCW. Do not patch normal CV into it otherwise the vactrol will constantly be struck. Normal CV goes to CTRL. I've never really experienced gain loss at the Sum out. I have three optomixes and none of them makes dust noise when I turn CTRL or DAMP. So the noise you're experiencing is not normal and your module may need service. I wonder if the noise is also on both individual channels. It often helps to turn it CCW/CW a lot of times so the pot will 'repair' itself. But if you feel some kind of friction, then the pot may need to be replaced.

[@Hessencemusic]

@@CinematicLaboratory thanks for answering! May be I didn’t explain correctly… noise is not when I turn optomix pots… but when I turn my stmix channel knob (any of them)… if optomix is without anything connected and strike is up.

[@Hessencemusic]

@@CinematicLaboratory btw: I’m really interested in what you mention about strike input. Not use normal cv on it? You mean normal envelope control cv signal? Then , what kind of signal should be the right one there? I use to share an envelope cv to strike and control input. You mean that certain voltage level could damage it? What’s the limit for that? 10v or 5v? You are an endless place of knowledge for me :)

[@CinematicLaboratory]

@@Hessencemusic When you look at an optomix channel, you see a DAMP, CTRL and STRIKE input. DAMP attenuates the vactrol response. CTRL is for regular envelope CV and STRIKE is for a trigger. A vactrol is basically a LED light and a resistor. When you send a trigger to strike, the LED shortly flashes and you'll get a short percussive tick, like hitting on wood. Since it takes some time for the LED to dim, the sound has a natural decay. You'd need to turn CTRL fully CCW (closed) to let the strike come through. DAMP will set the response curve of the resistor to make it sharp or dull, almost like setting the 'material'. This is because Optomix is not just a VCA, it has a low pass filter that's linked to volume level. The filter is off at high volumes, and engages when the volume goes down. If you turn CTRL fully CW, the strike doesn't work, because the LED is always on and the filter is fully open. Then you'd also have voltage on the module's channel- and sum outputs. Opto resistors are also used to glue a mix because of the slow decay. You'll find them in expensive analog mastering compressors too. Vactrols are totally wonderful, but you may need to do some research and try different settings. Using a regular CV on the strike is like 'rolling' a drum kit like with military drums. It's perfectly fine and you can't damage the module with regular modular voltage (+10V). You can also use CTRL CV and STRIKE triggers together when you keep the CTRL knob at noon or set a balance you like.

[@0neTwo0neTwo]

Does that magnetiques have an alternate panel on it to make it look like a make noise qmmg?

[@CinematicLaboratory]

No :). I did this with Photoshop. I think you may be the first one to ever notice this!

[@0neTwo0neTwo]

@@CinematicLaboratory so the QMMG is one module of MN's that you do not own?!!

[@CinematicLaboratory]

@@0neTwo0neTwo I did not own one at the time of making this video.

[@0neTwo0neTwo]

@@CinematicLaboratory ahh darn - how do you find one that is not a million dollars!!! - do you think double Optomix would be a close replacement? or is only one Optomix necessary?