First, here is the principle of the I/O plugin:
You can add the I/O plugin to any channelstrip you want except dedicated MIDI channelstrips which have no inserts. It works in all other types of channels: audio, software instruments, auxes etc.
You cannot alternatively use audio
or MIDI. Your effect is audio only and MIDI is an option to control the functions of the external device. You know, MIDI events are only numbers, there is no sound at all.
The I/O plugin will work if you have your audio connections. You can operate the external device manually or, in your case, control it by MIDI. This does not replace audio connections. Your MIDI events tell the device what it should do with the sound. Select presets, control parameters, this kind of stuff.
i added an i/o on one of my audio tracks and selected input 1 and output 1&2.
I don't think your Midiverb is connected to your interface inputs and outputs 1-2, correct? This is possible but unusual. In the I/O plugin you have to choose the ins and outs where the Midiverb is physically connected, where you plugged the audio cables of the device in.
the only thing i see happening is the left side of the audio master gets louder or if i select input 2, the right master gets louder. At no time do i see inputs on my midiverb 4?
Quite clear: the Midiverb is not plugged into the physical holes you selected in the I/O plugin. It is somewhere else and you did not reach it.
Actually you mixed something that comes in on input 1 to your main output which I assume is 1-2. Maybe you just doubled the sound which would explain the increased level without any tonal change.
The interface of the I/O plugin may be confusing at the first glance. In the upper menu you select the output of your interface, which leads to the input of the external hardware. The lower menu is the return, where the sound comes back from the hardware. There you choose the corresponding input of your audio interface.
If you know hardware mixers: the I/O plugin works like the insert jack of a mixing desk.
alesis midiverb4 connected by midi ins and out to channel 2 of my 128 motu. I have created an object in the audio/midi setup on my imac and connected the wires accordingly. In logic 8, i have created a multi instrument 16 channels worth in the environment and i can choose the effects processor on the arrange page
Perfect. So you got the MIDI part right. Now you just have to route the audio correctly and you are on your way.
