The Feedback Send and Return blocks allow you to feedback sound from one point in the routing to any other point.
The Send block has no parameters, while the Return block has a basic mixer. Adjust the MIX control to set the ratio of direct and feedback signals.
Best results are achieved when feeding back a pure delayed signal. If any direct signal is fed back the resulting loop will usually be unstable and/or sound strange due to phase cancellation.
Warning: Use caution with the Feedback blocks as you can easily program an unstable loop and cause internal clipping of the signal and/or very high sound levels which can damage your hearing. Always start with the MIX control on zero and slowly bring it up. If you start to hear squealing or other signs of instability return the MIX control to zero and analyze your routing for possible causes of instability.