Ok, so here is a bit of a before after (and after part 2) summary. It looks like in this room the "ideal" front wall sub location is somewhere between 1/3 and 1/4 to center of driver from sidewall length. I was not able to test on exactly 1/3 or 1/4 because this footprint is occupied by the speaker stands. I would love to hear peoples input on where their R/L speakers landed in their room. Same general 1/4-1/3 footprint perhaps? I am confident we can assume somewhere in this general region would work well for subs in this room.
No subs. Baseline measurement.
Test 1. Subs inside speakers just larger than a 1/3 from sidewall measurement. (by a few inches)
Test 2. Subs outside speakers just smaller than a 1/4 from sidewall measurement. (by a few inches) I was messing around with louder tests so the the graph Y axis is taller but the range is still in 10 db intervals. Notice the gross low frequency output is higher as they move closer to the corners.
I will do a similar test in the HT eventually to determine where an "ideal" front wall placement outcome exists, but I can hypothesize from this test 1/3 and 1/4 placement is a fantastic place to start.
In this room, with the bookshelf speakers, the measured overall system response is better with the subs located outside of the speakers near 1/4 width. My overall listening preference is with the subs just inside of the speakers as they seem to blend better and decay faster somehow near 1/3 width. A tighter sound. Perhaps this is due to less reinforcement from the corners as the subs move from the 1/4 to 1/3 position.
The Subs lateral move was about 16" for this test. The net sub change from test 2 to test 3 was widening ~32" The difference in output and timing was not subtle.
I learned a couple of things from part 2 of this test:
1. A better measured result does not always mean a superior listening experience.
2. Our ability to hear subtle changes in bass output or nulls is not very good at all. An SPL meter should be used to help set the sub volume where possible. In this test, with 2 listeners, the bass was initially set far too hot before measuring. Almost 10db!
