Callybeat has released a free synthesizer instrument geared towards 808 kicks and deep bass sounds.
Hum808 is a 4-oscillator synthesizer with 225 waveforms. It features 12-voice polyphony, a spectrum analyzer, 4-band parametric equalizer, ADSR envelope, multi-mode filter and an LFO for modulation.
The synth is available as a free VST plugin (32/64-bit) for Windows.
More information: Callybeat