Roger what Mac says. However, he has an "L1s" the L1 has no RCA inputs.

Here is a comment from an L1 power user and moderator of their forum.

"I have three BOSE L1s. I have been using these for 6 years. Laptop to Mackie 1204 with XLR cables to the BOSE set at 12 o'clock. I do not use the mixer." (he means he doesn't use the Bose mixer)

So, that is essentially what Mac is doing. The above contemplates XLR cables from the Mackie to the Bose but same difference since XLRs carry stereo.

For those of us who use the L1 (not the "s" variation) there are no RCA inputs on the Bose so I do the same thing that the above commentator does....go OUT of the Mackie with a 1/4 in. XLR (via the headphone OUT which on the Mackie is a FULL MAIN OUT) IN to the Bose so a stereo signal IS hitting the Bose circuits.

As I stated in my other post, you don't get exactly the SAME stereo separation as you would get from running two separated speakers but in most live gig rooms, the sounds have so many reflections that only the closest audience hears true stereo separation and the rest of the crowd is hearing music bouncing off so many surfaces that they aren't getting anything resembling the true stereo separation you would expect from your home stereo systems anyway.

So, as long as you aren't sending the music TO the Bose through a plain mono cable (Tip/Ring instrument cable)I just don't think there is a "sum to mono" problem...at least not one that I can hear or apparently our audiences either who ROUTINELY compliment us on our sound being "better than what we ususally hear."

Also....forgive me for telling most of you what you already know but TRIM is critical with any sound system including the Bose. To get the full impact of the system's capabilities you need to set the channel TRIMS so that at performance input volumes, the green light is on nearly all the time with SLIGHT OCCASIONAL clipping (red light).

THEN adjust output (main and channel) volumes to suit your needs. If you don't, you're running an 8 cylinder engine on 6 cylinders!

Best,
Jim