How do I "compromise" speaker placement

Helps a lot. Thanks. I will research.
I want to take baby steps for now.
Acoustic treatment is not an option.

For step #1 I want to do speaker placement. I have a very small room so there is not that much leeway. I figure there are about 8 positions each main can go. (That's counting 1 inch increments.) I hired a professional to move the speakers and give me response graphs for each placement. He's coming in 2 weeks.

Also, I want to take a few measurements to see if my sub placement near the L main interferes too much with L main. I would give up a flatter bass response for a flatter main response.

I see possibilities:
I can simply take the flattest response.
Or I can take the flattest bass response.
Or I can choose the flattest human voice range response.

Hello, do yourself a favor and search Real Traps bass traps and the Room EQ Wizard at Home Theater Shack. Use the EQ Wizard and do a graph of your romm and post the results on the site and you will recieve all types of suggestions and go from there. It will be the easiest way for you to tune your system with room tratments or without room treatments or with EQ. You need to do your research there.
Bob

Actually your room is not quite that small. A bit narrow but otherwise I'd consider this a smaller mid-size room.

Anywhere you place your speakers is a compromise. The goal of course is to find the least compromising placement. As you can see there are several ways to find this spot. I just do it by ear which can take a very long time. In my previous room it took me about 9 months to find that spot. But I also only moved the speakers maybe 3 or 4 times a month.

But from what I can tell from your picts, I would start by bringing your speakers about 4ft further out from the back wall and perhaps a foot closer to the side walls as the initial starting point.

From there, every so often move the speakers out, in, forward or back in about 2 inch increments. Eventually you'll find that least compromising location.

I would also suggest shutting down the subwoofer while searching for this least compromising location as it will only add to the confusion.

Very cool room BTW.

-IMO

Rule of thumb - speakers placed well out into the room will excite less room modes. Keep away from side walls (at least three feet). Sit at around 40% or room length (do not sit with back against wall - very very bad) Subs are best well out into the room against the left or right wall about 3 feet in front of your mains. Try walking around the room while listening - the best positions or setup will have the broadest sweetspot and most even sound.

You will be surprised but rule of thumb works best - it won't give you that "jaw dropping" sound that you get when something is wrong and one note seems to rumble the whole room - so be careful - best setup is actually the most neutral and the least "sizzle" or "emphasis".

Finally use a PEQ or TACT or PARC to fix the worst of the room modes (notch down the "peaks" and leave the nulls alone and above all DO NOT aim for absolutely perfectly flat with thousands of filters - it often doesn't sound right at all - just "flatten" the bumps to with 3 to 6 db of the average and you may find it the most natural sounding - the lower you go in frequency towards 20 Hz the less relevant it becomes to get absolutely flat - flatish between 40 and 100 Hz is most important to achieve!!)