Now, look, I have like 5,000+ virtual synthesizers (mostly being the random stuff that came with Ableton Live that you can't really do much altering with) but of the plugins I have, there are certain ones that stick out. Obviously Korg's Legacy Collection is incredible. Arturia makes awesome stuff. Native Instruments is industry-leading. But, these are all paid instruments, and if you're like me and working on a budget, you need good sounding free synths.
Free plus good sound usually doesn't work, I know, but there are some that really stand out. Here's my top 12 list in no particular order:
1) Elektrostudio's instruments
Elektrostudio is quite possibly my favourite VST company. All of their instruments model old analogues, like the Minimoog, Moog Sonic Six, Micromoog, Arp Odyssey, Oberheim 2-voice, and the Roland Junos, along with a few others. They all sound great, and model nearly exactly the originals, with a few quirks that you might expect from digital free synths. I really can't stress enough how amazing their stuff is.
2) HERCs Abakos
I don't know what it is with this instrument, but it does the most incredible soundscapes and pads I have ever heard, even trumping giant analogue modulars and certainly any paid softsynth.
http://www.vst4free.com/free_vst.php?id=399 (actual site is under construction, so this is a DL page)
3) Angular Momentum Wavedraw Free
This thing is perfect at everything, mainly because by design it can do everything. It's basically a sampler, but the samples can be drawn waveforms! It uses that sample like a normal oscillator, so you can do all the normal stuff with that, but then it turns into an incredible complete synthesizer with interesting routing and modulation capabilities. AM makes some other neat instruments that I use, as well.
4) DSK VST
This is another free VST company that sounds AMAZING. They cover literally every need, for every genre, ever. I personally use DSK Choir the most, mainly because I don't have many good choir synths. Actually, I don't have any minus this one. If that doesn't show how specialised DSK is, nothing will.
This is more of a VST company post, isn't it? Well, Ugo is yet another VST company that sounds great, but they are different in that no one else makes anything close to what they make. I particularly love their Element of Surprise, which guaranteed WILL give you sounds you've never heard. Just shows that limitation can be a good thing. I also use their Texture and Rez (both great for crazy leads, insane basses, and utter dirty sounds), and String Theory and M-theory, which are beautiful pizzicato synthesizers.
GTG makes a lot of neat stuff. Most of it is normally laid out, but they all have a very unique sound that I personally love. It's not all synths, either; the GTG EP 2008 is an incredible electric piano which sounds almost as good as my DX7. Almost.
You love modular synths? You love them so much you want to make your own? YOU LOVE THEM SO MUCH YOU DREAM OF WIRES??? (lol get the reference?) Well, Kamiooka is for you. It's a fairly simple fully modular synthesizer with a possible total of 10 modules. It has all the normal modules: VCO, VCA, VCF, ADSR, LFO, Sequencer, and a combination RM/Noise/SnH/Inverter. Nonetheless, you'll be patching your way to modular bliss for HOURS. In my case, when I first got it, 14 hours and 37 minutes. No breaks.
8) SP-1000 and Blue Synth
Ok, I'm a bit biased with these two instruments. If you have been with this blog for some time, you'll know that I worked on these two instruments. Search around here, you'll see what I think of them :) Blue is free, SP-1000 is only a demo, but you can buy it for $30 (though if you hit me up we can possibly work out a deal). I worked on the presets and some of the sonic and design ideas for both of these, so you know that they sound at least decent for their architecture.
Along with all the other awesome stuff Togu Audio Line makes, this Juno emulation is just awesome. It sounds like a Juno 106, including all the little idiosyncrasies that exist in the real one. Note that even though there's a buy button, you don't need to buy it to use it. I don't know why that button is there. There's no limitations that I can find, though as you'll see in the next section I have my own ways of dealing with such things :)
10) Muon Tau Bassline (now Tau Bassline 10th Anniversary)
If you're looking for a 303-like sound, scroll down. If you're looking for something like a 303 but different, look no further. Though Tau sounds pretty much nothing like the TB-303 it appears to try to model, it is really good at synthesising bass guitars and other general bass sounds. And, I guess, if you must, you can use it as a fake 303.
Along with a 303-like synth, who doesn't like an 808-like synth for accompaniment? The TS-808 sounds kinda like a TR-808, but you certainly won't fool anyone into thinking you used a real 808. Still, it's useful :)
12) Gunnar Ekornas' Minimogue va
You know this was going to be on the list. This was my first-ever synthesizer, and to this day is one of my favourites (considering it's in this list). It's basically a model of a Minimoog, but with far advanced features, like a dedicated LFO, arpeggiator, delay, and full ADSRs. And, of course, it has a great sound which is unlike a Minimoog but also unlike a cheap Synthedit knockoff. I fking love this instrument.
Now, there are also some not-so-free synths (infinite demos and the like) that I really love, and will now list here:
1) Native Instruments Massive and FM8
I know, these are normally $200 each, but if you are like me and enjoy meddling with technicalities, they're free. No, I'm not saying to hack them. The way these demo versions work is you can't save presets and it only works for 30 minutes at a time. BUT, if you use Ableton Live (or I'd assume most other DAWs), I found that you can reset this timer simply by activating another track. AND, Live has it's own preset save feature, which I found can work with both Massive and FM8. So basically two of the most powerful synths in the industry are free, as long as you need to work on other tracks within 30 minutes :)
I really don't need to talk about sound with these two instruments because if you've heard just about any harder genre electronic or modern metal music, you've heard them. Modern dubstep certainly makes good use of them.
2) Arturia Moog Modular V
This sort of uses the same principles as the NI stuff. It has the added benefit of essentially being a Moog product, as it was produced in conjunction with Robert Moog. Does it sound like a Moog modular? Yes. Does it work like a Moog modular? No. For whatever reason, Arturia makes use of patch bays and preset interconnections. You can't use it like a real modular, but it's the closest you'll get without paying several dozen grand for a similar system.
3) Audio Realism ABL2
I like all of AR's stuff, but I once heard Joel Zimmerman do a side-by-side of the ABL2 and a real TB-303, and they are IDENTICAL, minus decay times. Just don't use the built-in distortion. Please. This is also a demo, but seems to use the same track-switching rule as the above.
4) Native Instruments Reaktor and Kontakt
Now these really are free, but I included them here because to get much interesting out of them you do need to buy stuff. The free versions do sound good and are useful out of the box (er, .zip), though.
Classic synths are always trying to be replicated in software, usually with little success. Aside from what I've already mentioned, here are a few good classic synths in VST form (again, free stuff!):
Know what an EMS Synthi is? No? Well it's basically this really expensive, incredibly hard to use modular synthesizer. Cynthia is the same deal, but if you're up to the challenge it's an incredible free synth.
The EDP Wasp was a very unique synthesizer, using an electro-static keyboard, pre-MIDI connectors, and was a hybrid subtractive synth. Pretty amazing for the time. daHornet is very similar in sound and function, though not quite as technologically impressive for its time :)
3) Voltkitchen Arppe 2600 va
I don't even need to talk about the Arp 2600, do I? Didn't think so. VK did a decent job with it, though the Xeno Digipatch system is kind of a pain to use. Sounds good, though.
You like the CS-80? Well, here's your lucky day. The ME-80 has all the same functions as the CS-80 a somewhat similar sound, and of course DrIfTiNeSs!!! Yes, this thing has oscillators that drift EVEN MORE than the original, if you can believe it. It can be controlled somewhat, though, and no matter what it's fun to play with, especially if you don't have $15k to spend on a real CS-80.
As a side note, Messiah and Memorymoon (from the same site) are also pretty amazing replicas of the Memorymoog and the Prophet. I use those too.
5) Syncersoft Polivoks Station
The Russian Polivoks is incredible. The Syncersoft Polivoks Station is slightly less awesome mainly because it looks totally different, but the sound is raw Polivoks power (note: not a sampler, it just sounds similar) Mother Russia FTW. It also adds a few features which make it even thicker and more raw-sounding.
So, there you have it. This list pretty much makes up the majority of the VST synthesizers I use, minus some of the more random ones which I only use for their overly-complicated synthesis engines and ability to create highly advanced wave-sequenced sounds. Maybe I'll blog about those later.
I should also note that your DAW's built-in synthesizers (like Live's Simpler or FL's Harmless) can also be incredibly powerful if you just sit down and learn them. That's an important fact, here: just because I've listed a bunch of instruments, it doesn't mean that you don't need to learn synthesis. If anything, you should learn at least basic subtractive synthesis to near-perfection before getting any of these. Otherwise we'll have a Soviet Russia deal:
In Soviet Russia, synth plays YOU!
And we don't want that, now do we?
Oh, and one final note: I wasn't paid or otherwise asked to talk about any of these. They really are part of my personal collection, and I really do use them in my songs. Granted, my DX7 sees most of my synthesis action (it's just so damned versatile), but I do occasionally use VSTs, mainly these.
I hope you try a few of these at least, and I really hope you like them as much as I do.