Dennis Foley offers highly repetitive advice which seems knowledgeable at a surface level, but serves primarily to sell his own products.
He frequently denounces the usage of mineral wool and multiple subwoofers, despite both being well proven methods to improve sound quality in residential and small studio environments. He also has a rather stubborn mindset of certain room sizes being tied to certain uses, believing that more channels require more space, even though the people who develop surround standard such as Dolby and DTS attach no such caveats.
Room acoustics aren't rocket science. If you can operate a calculator and read a datasheet, you can pretty quickly figure out for yourself which materials to use for isolating and absorbing which frequencies. On this exact forum, I have seen multiple people posting their DIY room treatments which offer major improvements to frequency response and decay rates, often with less than $1000 invested.
