Bass Traps

So I just read this article.  The author suggests that improvement is subtle and it's best to treat the room properly before adding the PSI?

So I just read this article. 

Which article?  My Stereophile article?  If so, I think you drew the wrong conclusion.  What the C214 does is specific to the bass and will not affect anything else.  That means only that it is not a comprehensive solution to room acoustics.

But what is?

I heard the Synergistic Black Box demonstrated at AXPONA a few years ago (I have not heard the PSI). It made a very subtle difference and I actually liked the sound better with it turned off. Some other people in the room seemed to hear more effect than I did and some said they really liked it.

I've always been somewhat suspicious of Synergistic but that demonstration was very interesting. It was conducted by Ted Denney, the founder. I couldn't hear any difference with the HF-Ts but when he demonstrated the FEQ tower gizmos (the older version) I had to pick my jaw off the floor. They made a huge difference in the soundstage - improving it in every way. I hope to hear them again. It was one of the most impressive demonstrations at the show.

I don't think I misinterpreted what the author had to say. 

"In every instance (stereo or multichannel, with or without DiracLive) and with almost every music selection, the effect of the AVAA C214s is beneficial, though in most cases (despite all that I have written) it is subtle"

 

can you not DIY? @fire_water 

Also room treatment is not based on vibes  but rigorous scientific and iterative processes