anyone? i've searched the forum and scowered the manual! it's not making complete sense to me how it works and i just really want to know?

Hi If you render, all the tracks are summing IN Reaper, it's not getting thru your soundcard. There is an option "Save live output to disk. Then you can sum the analog way, but if you use only two, or one output summing is still In the reaper, just redirected to card output, then to some card input and written.

Well you see i'm using a metric halo 2882 interface , which has its own mixer . so if i send tracks from reaper to my interface it goes to my mixer in the 2882 before the dac. maybe a simplier question is: does selecting a hardware output for a track bypass summing in reaper? in my case i think so. with other sound cards can you send more than one daw track to one hardware output directly?

Here's how I understand it somebody correct me if I am wrong If you send to a hardware output but leave master checked in the i/o window the signal goes both to the master and the harware out. If you uncheck the master the track goes to the hardware output directly. If this is the only signal going out to that output there is no summing. If you send multiple tracks to a hardware out they are summed in reaper on the way to that output. When mixing OTB (Out of the Box) send each track to it's own hardware send. Provided you have enough channels of D/A and enough channels on the mixer. If you do not send stereo stem mixes of some or all the tracks. Route the mixer back into reaper to record your mix on a new track or use some other recorder to record the master. You do not use render to mix OTB you hit play to record in another recorder or record to record the mix on another track in Reaper.

Thanks Fritz, well i use an analog mixer which gets its audio from my 2882, which is fed by reaper. if i want to go directly out to my analog mixer , i would have to send each audio file to its own output and reaper would not sum them. However my situation is a little more complicated, i want to be able to sum in the mio console which can sum 18 channels in its mixer. usually i like to sum stems in the mio console and then out to my outboard and analog mixer etc. I get the recording part fine, its the summing : when is reaper summing? when is it not? if what your saying is right reaper sums when more then one track is sent to an output? why wouldn't mio console do this for me, or why does reaper sum this way (if it does) does it have to?