Modular Softsynths with LADSPA Support
The plugins don't do anything by themselves - you need an application that can load and run them - a LADSPA host.
This is a faithful emulation of old analogue modular synthesisers such as those manufactured by Moog, ARP, Oberheim and others in the 60s and 70s. It follows the CV (Control Voltage) convention used by these.
As some of the BLOP plugins use Hz as a unit of frequency, it requires a little jiggery pokery to use them with AMS - you'll need to use the Frequency Modulator plugin to convert AMS‘ CV values to Hz. Here is a simple example patch for AMS.
Graphical Audio LANguage (gAlan)
This features such nice things as a custom GUI builder, sub-patches (‘sheets’) and a nice way of presenting control vs. signal connections.
Ingen (formerly Om)
This is a standalone engine that exposes its interface via OpenSoundControl (OSC). It also supports sub-patching and is fully polyphonic, and comes with an example GTK+ client.
Pure Data (PD)
Incredibly powerful and fairly complicated general purpose audio and multimedia application. It can be used as a modular synth. To use LADSPA plugins, you'll also need to get the plugin˜ external.
Externals repository. The plugin˜ external, amongst many others, can be found here.
A very powerful and flexible modular synthesiser, which comes with its own wide range of native plugins as well as support for LADSPA. Still my favourite for knocking together quick patches.
See the Sourceforge Project Page for details.