Last I heard, you all occupy a single listening position.. you are not some omnipresent being who float around in space.. listening from every inch of the room.
Standing waves occur between 2 parallel walls. Hence, look at the wall spots straight in front of you, behind you, to either side and above you.
Dennis Foley's mention of full wall coverage of ACDA, etc could come in handy with multiple listening positions (hometheater, for example). It has some other benefits as well, but, will consume significant real estate in smaller rooms. ACDA is huge and can give you a hernia if you try to move it around too much.
Very few panels out there will do anything under a 100 Hz. His ACDA will get much lower. But, the correct thing to do is to "cancel out" modes in the subwoofer range with strategic placement of subs, phase correction, etc. Use the panels for ranges above the sub crossover.
For SBIR, you can use panels right behind the speaker woofers or pull the speakers out enough so the SBIR frequencies get pushed into the subwoofer range.
Unless you are an omnipresent being with telescopic ears listening in every corner, your corner traps don't mean much.
Stop looking at what some flat earth audiophile did as gospel and get a measurement mic. Thereafter, download a free measurement software known as REW.
God bless.
