Carla

Carla is a plugin suite that comes with KXStudio, it comes in VST as well as LMMS plugins for Linux.

Details
Carla is an audio plugin host, with support for many audio drivers and plugin formats. It has features like automation of parameters via MIDI CC (and send output back as MIDI too) and full OSC control.

Carla currently supports LADSPA (including LRDF), DSSI, LV2, VST2/3 and AU plugin formats, plus GIG, SF2 and SFZ file support. It uses JACK as the default and preferred audio driver but also supports native drivers like ALSA, DirectSound or CoreAudio.

There are 4 types of engine processing:

Same as Multi-client, except that all JACK ports belong to a single master client. This is needed when a setup doesn't support multi-client JACK apps, such as LADISH. Every single plugin is exposed as a new JACK client. Audio and MIDI ports are registered as needed. Plugins are processed in order, from top to bottom. Plugins with non-stereo audio channels are not supported, but a forced-stereo option is available for Mono ones.
 * Single-client: (JACK driver only)
 * Multi-client: (JACK driver only)
 * Rack:
 * Patchbay:

Modular patchbay mode, just like in JACK Multi-client and many other modular applications. Every plugin gets its own canvas group and ports allowing you to interconnect plugin audio and MIDI.

Features

 * LADSPA, DSSI, LV2, VST2, VST3 and AU plugin formats
 * GIG, SF2 and SFZ sound banks
 * Internal audio and midi file player
 * Automation of plugin parameters via MIDI CC
 * Full OSC control
 * Plugin bridge support (such as running 32bit plugins on a 64bit Carla)
 * Rack and Patchbay engine modes, plus Single and Multi-Client if using JACK
 * Native audio drivers (ALSA, DirectSound, CoreAudio) and low-latency (ASIO and JACK)