Hy!
I have a mackie mixer with 4 subgroups but there is a question:They are just two subgroups(1-2 and 3-4).You can assign 4 subgroup on the main stereo out.Is that right or?
Please help!

The subs can be used independently if you have the channels panned hard left or right. A mono mix to the house can be sent from your main outputs and you can assign each of the four sub groups to a separate slider. A good reason to use this feature is if you have several singers and want a single slider to control the volume without changing the rest of the mix. You could have:
Group 1 - singers
Group 2 - drums
Group 3 - instruments
Group 4 - backing trax

You can also use the sub outs to send a monitor feed to a powered speaker ... say, for example, you play with sequences or trax - you could send the drummer a feed with only the necessary parts from the sub group output.
Just a suggestion of one way to use the sub groups. Enjoy!

Thanks a lot!

sure!