VST and Plug-ins
Please go to the Live Misc Preferences and be sure you have selected the correct Path for your VST Plug-in Folder. Live's default setting is the VST folder within your Live Folder, with the exception of OS X, which uses the OS X Library/Audio/Plug-Ins/VST folder. If you use an Intel Mac, please ensure that your VST Plug-ins are compatible.
Be sure you have set the Path for your VST Plug-in folder.
MIDI notes in Live are drawn into MIDI clips. If you do not already have a MIDI clip open, you can create one by double-clicking a clip slot in the Session View track containing your instrument. The MIDI Editor, which contains the piano roll and key tracks, is located in the Clip View at the bottom of the screen. It can be toggled with the Envelope Editor by clicking the title bars of the Notes and Envelopes boxes. If you do not see the Notes box, activate the round switch in the lower left corner with the note icon. With Draw Mode enabled, you can draw MIDI notes into the MIDI Editor and then disable Draw Mode to move them around. Zooming and scrolling in the MIDI Editor work the same way as they do in the Arrangement View, by clicking and dragging horizontally and vertically on the piano roll or beat ruler.
The Notes box can be shown/hidden with the switch at the lower left of the Clip View. Use the title bar of the Notes box to open the MIDI Editor.
Set "plug-in buffer length" to "as audio buffer."
If you experience a different sound from Live 4, set the "plug-in buffer length" to "128."
If the latency gets too high, try to set up the plug-in buffer sizes to a half, third, quarter, etc. of the audio buffer size. Do not round the value! it needs to be exact (e.g. if you have an audio buffer of 257 samples, don't select 256/128 as the plug-in buffer).
