I’ve never really given dedicated drone synths a second look but just lately I’ve been thinking about them, their uses and the headline features folks like to see. Ive seen some with multiple oscillators and some with just one, I’ve seen some with multiple ‘voices’ and others with just one. So I’d love to hear what drone users out there look for, what are deal breakers for you etc. I get that it’s a broad spectrum which some synths having much more features than others so there’s not going to be one answer. Basically, rather than buy one I’m going to build my own and I’m looking to tap into you guys experience of them to help me design my own. Who knows, if it works out I’d be happy to offer boards or kits for the DIY’ers out there if there’s any interest.
I look for modulations that feel like you might be tripping, and modulations of the modulations that you can play. I want to be continually riding the knife edge of the trip.
So plenty of cross modulation between oscillators? Or are you including filter and amp too? Modulated by osc waves? Forgive my ignorance
Look for
- mad science
- abnormal brain
Yeah, I’m trying to think outside the traditional Architectures that I think of as East Coast.
I’m not trolling BTW! I’m just ignorant 
Two drone classics are the Grendel Drone Commander and Lyra-8. Judge them by their sound rather than specs.
On the more conventional side, something like the Hydrasynth with its anything can modulate anything by pressing some buttons interface should also be good. The Virus is a great drone machine, but overkill. If I didn’t have one already, I’d probably go for the desktop Hydra first.
Cheers. I’ve got a HS and a few other synths that would make good drone instruments, I was thinking more of the architecture and features from a building my own point of view. For me the designing and DIY’ing thing is a big part of the fun. Obv not planning on knocking up a HS or Lyra rival on my workbench! It’ll be something a lot more modest. I’ll deffo look into the Lyra tho, I’ve seen plenty of folk singing it’s praises.
Nothing to forgive 
I don’t think it matters what gets modulated. Different tonal starting points get better with different modulations. LFOs applied to pitch, amplitude, or cutoff… LFOs applied to LFO rate… mod wheel controlling some range of depth, or rate, or both. The “trip” comes from the wobble, and the flow of changing rates and depths, of the harmonics that inteoduces.
I try to make all my synths drone, from time to time. I’ve not tried the classics @obscurerobot suggests, but would like to.
There are various Lyra 8 DIY resources out there. I’m heading out the door or I’d look for links.
Look into 555 based circuits and abused digital CMOS designs like the Lunetta series. Lots of good archival material at Modwiggler and electro-music.
Lyra-8 (and -4) DIY info here
I’m just going to assume we live in different countries and “knocking up” doesn’t mean the same thing to each other 
I’ve been playing about with a few different circuits lately and I’m thinking of incorporating those together on the bench as a start point. One is a filter based around the 3350 that can operate in several modes such as LP/BP/HP in both 2 and 4 pole flavours.
Hmm, mixing my metaphors… knock together would have been more apt but I know where you’re coming from
Nothing wrong with a little human-analog love. Just make sure to buy her flowers and confirm consent before getting busy.
it was Studying Lunetta’s many many moons ago that helped my along the learning path.
Well, it is an “organismic synthesizer” after all.
Since you’ve got a Hydra already, that should be a good platform for testing out ideas. Which modulations are you drawn to that aren’t present on other synths?
Hydra’s button press patch mechanism is a lot to DIY, but you can easily substitute banana jacks or posts and alligator clips in your project. The extra noise and crackle from physical connections may be a bonus.
Lyra-8 is very special for droning, others have covered it I think but what makes the Lyra work so well for droning are its cross-modulation, movement and the effects section.
The Lyra is very much a drone instrument though - if you want something that can be left and do its own thing for 10 minutes it’s not what I would use personally, as you can’t automate much on it.
A more traditional synth with lots of LFO’s will probably be more useful there - load it with delays and organised chaos and you got yourself a drone stewing.
I love the sonic territory of Lyra-8 though, it makes such dark drones…
The Grendel mentioned by @obscurerobot is superb. Unique sounding and built into an old ammo canister. It absolutely invites random experimentations. Whack Eventide Space on the output and it’s massive drone heaven. I had one and stupidly sold it, I had to buy the pedal version as a stop-gap. Neither of these are my videos!
Also love the Nyx v1 for drones. Can get quite complex variations from it’s slightly unusual controls. Keep meaning to pair it up with Erebus for 4osc drone action.
I think the two most important characteristics are A. sound quality (i.e. good enough to sustain one note for half an hour and not bore you) and B. slow modulation options. So far the best ones I’ve come across are:
Soma Lyra-4 and 8
Soma Ether (very dependent on the environment and how slowly you move it)
Grendel Drone Commander (pedal)
Moog Minitaur (low frequency)
Digitone (even though I wish it had incrementally longer envelope and LFO times)
Schlappi Engineering modules (similar to Soma stuff soundwise but in eurorack)
I have a Hydrasynth desktop coming which seems pretty ideally suited for “digital sounding” soundscapes.