so bass traps in corners do nothing, it seems we have been fooled. or are being fooled.

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.

🍿🍿 🍿 

I have GIK corner bass traps. They are very effective in the corners behind my speakers. They didn’t do much in the corners behind my listening position...so I stack two of them in corners behind my speakers.

apparently the bass pressure was greatest in the corners behind my speakers...which makes sense due to closer proximity to speakers than corners behind me.

i would say they are pretty effective down to 60hz...going off memory they start rolling off at 80hz. They have scatter plates attached as i didn’t want to risk having a dead room.

There is also an option to add a range limiter plate, which focuses on absorbing more bass and less mids and highs....which is what you want because due to lengths of wavelengths, there will be a surplus of longer waves (bass) and a shortage of shorter waves (treble).

To answer the question of whether or not bass traps are needed I think it's a function of room size (close reflections vs longer reflections). If you have a 20x30 room bass traps are more of a nice to do but will definitely help. If you have a 12X16 room, bass traps are going to have obvious improvements if you buy the right traps and put them in the right places.  

I spent 4+ years personally building my own dedicated listening room. The room is 13.5’ x 15.5’ x 9’. (I consider this a small room.) The room was originally our separate dining room. I closed it off and stripped down to studs on front and rear wall. All walls and ceiling are acoustically treated. Based on Dennis Foley’s acoustic product design principles, I spent 100s of hours designing and building my own absorption panels/ boxes and diffusers of various types, sizes and weight. It took numerous trials and errors to determine the best way to design and implement acoustic treatment within my room. I watched all of Dennis Foley’s videos as well as read/ watched as many other acoustic treatment related online videos, articles, books and photos, as I possibly could. I’ve learned a lot about room acoustic treatment and design. I’m just a typical audiophile who wants the best sound possible from my room. I agree (somewhat) with Dennis that corner bass traps are not always required. Depending on your specific room size/ shape, speaker placement..etc, sound pressure build-up can be more pronounced in other areas besides the corners. Address those areas first. If the corners end up being the biggest issue, then corner bass traps are likely needed. More often than not, corner bass traps alone don’t entirely fix low frequency issues. I don’t have corner bass traps. My room has a 5/6db variance between 30hz to 14khz - in a small room. I’m very happy. Dennis means well. Whether or not you agree with him, he’s working hard to bring better sound to this hobby that we all care so much about.

I would do some research on Dennis Foley on other audio forums before doing business with him.