Sorry, replied direct to Robert, not list. ----- Forwarded message from Steve Harris <[EMAIL PROTECTED]
Date: Fri, 10 Jan 2003 09:25:32 +0000 From: Steve Harris <[EMAIL PROTECTED]> Subject: Re: Sidechains, was Re: [linux-audio-announce] [ANN] swh-plugins 0.3.4 To: Robert Jonsson <[EMAIL PROTECTED]> On Fri, Jan 10, 2003 at 09:47:26 +0100, Robert Jonsson wrote: > >SC4 is more-or-less like SC3, but has no sidechain and a subtly different > >algorithm. The sidechain was confusing hosts. > > > > Yes, I was wondering how the 3<-->2 port sidechain compressor plugin > would be handled in hosts... The answer is 'badly'. ;) > What if the sidechain was a separate ladspa plugin that in turn uses > some ipc mechanism to communicate to the plugin being controlled? > I have no idea what kind of ipc is best for this, named pipes seem easy > but they are probably slow, yes? Pipes are non-deterministic, so banned in LADSPA. The only one thats an option is shared memory. > By using one of the controls of the ladspa plugin to select which > sidechain "channel" (e.g. 1-10) they should send and receive on (much > like a comm-radio) you could have several different sidechains up and > running simultaneously. Its an interesting idea. > This construction has a number of interesting side effects (pun not > intended): > * 1-n setups can be produced, one sidechain can control several effects. > * Atleast with named pipes the control would be application agnostic. > The sidechain would not need to be used in the same host as the effect > plugin. The same is true of SHM, but if the hosts are not running in sample sync all hell will break loose. > * I don't know if other types of plugins are applicable to this, but > since the sidechain is a separate plugin you could make _any_ plugin > sidechain aware. mmmm audio controlled room-size for reverbs...mmmm > :-D. Ahh, theres a misundersantding about what sidechains do here, they really are just an audio stream. > Any thoughts? Neat idea. Kinda evil though. Very tempting... > Top priority is a LADSPA stereo delay, I couldn't find one in Steves > collection. > But it would also be nice with: > - stereo autopanner > - auto sweeping filters. > Apologies if these infact are available and it's just my poor eyesight. What do you want from a stereo delay? There is an left-centre-right delay, but thats actually a mono delay that takes stereo input and pans the result. A stereo delay would be easy to implemnt, what controls do you want? There is an auto-phaser (sweeping allpass filter), but no auto wah (sweeping bandpass), or auto panner, true. I tend to build things like that out of SSM or pd. But there should be complete plugins. - Steve
