To "live DJ" there's the extremely famous https://virtualdj.com/ To create prerecorded DJ sets https://www.mixmeister.com/ Been using both for at least 10 years, love them both. - Source: Hacker News / 6 months ago

Not open source, but free for "home use" https://virtualdj.com/. - Source: Hacker News / 6 months ago

I started with Virtual DJ to get used to the software latency (I came from turntables) and get my muscle memory on button locations (which is why I stayed with the same brand). VDJ has every feature you need. The software is free to use without a controller from virtualdj.com. Source: almost 2 years ago

A lot of the places that do it from scratch I notice use https://virtualdj.com/. Source: almost 2 years ago

DJ software, like VirtualDJ will have features that are more conducive to what you're trying to do, like live looping functions that help you lock the loop to the beat. It's also cheaper (free for non-commercial use without a hardware controller) than QLab, and it's cross-platform (QLab is Mac-only, if that matters). Source: about 2 years ago

I've also used ZynAddSubFX, which is also a very powerful synth, though its interface (at least to me) is a bit of a clusterfuck. You could also try browsing this index of microtonally capable synths on the xenharmonic wiki. Source: about 1 year ago

The code for this can be found here on shadertoy! The audio was made with an Ibanez bass, Guitarix, Hydrogen Drums, ZynaddSubFX and Ardour! Source: over 2 years ago

Here is an additive synth - https://zynaddsubfx.sourceforge.io/. Source: over 2 years ago

There are VSTs for Linux. Surge, Vital, and ZynAddSubFx are three prominent examples, as well as OxeFM, Dexed, and plenty I'm forgetting. Surge and Zyn also come LV2 and DSSI, which are native Linux formats. For those who don't know, the VST3 SDK supports Linux, and is released under GPLv3 by Steinberg. Source: almost 3 years ago