Assuming you are referring to the Zoom R-16 - it is a stand alone 16 track recorder. If you are recording each track individually,one at a time, there is no need to use two separate units. The R-16 also has a built in metronome with a count in so there is no need to give up a track for a cue track. There are two banks of 8 tracks each. The isolation between tracks is sufficient to record multiple inputs at once for instruments that plug in such as keyboards, electric guitars, electric bass, etc. Mic'd vocals and instruments you want to avoid cross feed may be recorded individually to isolate them. Backing vocals would not be as critical and may actually sound better with some cross feed between tracks. Individual taste.

The R-16 is designed to sync two units together via a USB connection without the need of a computer. It has two usb connections so be careful to use the correct one and that the sync connection is enabled by the menu. If you have two units, you have access to 32 tracks in four banks for your final mixdown.

BIAB Ultra Pak+ 2024:RB 2024, Latest builds: Dell Optiplex 7040 Desktop; Windows-10-64 bit, Intel Core i7-6700 3.4GHz CPU and 16 GB Ram Memory.