How do I "compromise" speaker placement

Flat isn't possible except under the most ideal conditions in a fairly large room. Placement of speakers too close to the wall behind them is the biggestest contributor to getting an uneven frequency response below, say, 500 hz.

The next biggest contributor is location of the listening chair. Optimize both and you will still have dips and bumps but there are some room dimensional suck outs or humps you just can't get rid of. BTW frequency response much above 500 hz has more to do with your equipment synergy, speaker toe in, and killing first reflection points on the side walls, floor, and ceiling (if possible).

I'd suggest, if you have not alread done so read so set up theories which will give you some god starting points. Cardas for one, Physic's for another, and look up Rives site - last time I was there he has a CARA program which just might even include your speakers. That program works well, but all of these are just starting points.

With a SPL meter (Radio Shack), a test disc with 1/3d octave test tones (Stereophile) you can pretty much do your own set up work. It takes a lot of time and experimentation so patience will be necessary but the initial frequency response flattening isn't very hard. Its the subsequent fine tuning that takes a lot of small moves and time listening to the results.

BTW, if you do this, buy some graph paper and keep careful notes of your set up distances - it can get a little complex trying to keep all of these in your head, as it will also give you some visual clues about what you can change, cannot change, and whether its lspeakers or listening position that is causing the issues you like or dislike.

Hope that helps a bit.

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