Viva la Convolution
FFT based Convolution Reverb processor
4.1.1: bugfix. I found some bugs in the zero latency version, one of which applied to this version. It's hardly noticable here because the FFT's are so much longer here, but better out than in as they say!
New in version 4:
*You can choose different convolution lengths form the front panel (watch your cpu on the longer ones).
*Visual indicators for start and end of the active Impulse response.
*'scale' control lets you tweak the scale of the Impulse response.
*start offset control lets you chop out the start of the impulse - can be useful to get rid of the initial transient.
*pre-delay, add some delay before the reverb kicks in.
*speaker protect - the initialization caused nasty loud noises in some situations - there is now a fade in of the audio on reset.
New in version 3:
* Significant cpu optimization.
something like 30% improvement at the expense of increased latency (about 12% more)
* Two separate versions. Use the 'short' one unless the tail is audibly truncated on longer Impulse responses, in which case load up the 'long' version (it uses more cpu).
* Automatic latency compensation. The delay is calculated automatically, and the through signal delayed. This means no fiddling with knobs to synch up dry and wet sounds.
Convolution can be useful for various things, but it's most often used for reverbs. You need 'Impulse Response' files. There are lots of free ones on the web - look for ones in .wav format. Some are great, some not so - have fun :)
Some things to remember:
This effect causes a big cpu load.
The latency is also fairly high.
...are now on the front panel of the unit.
Thanks to Salamanderanagram for lots of positive input and discussion.
Thanks also to Robin Davies, whithout his awesome FFT library, this would not be possible.