Jon's recipe is more work than it's worth. There is a better way which I will explain below (after I rip Jon's apart...just kidding...only some friendly constructive criticism here)

Why do Jon's bass traps work?
ANSWER: When soft pink fiberglass is compressed into a more dense/packed fiberglass it will absorb lower frequencies better than the loose pink stuff (which is why pink stuff in the big plastic bags works so well; it's very compressed so it provides more resistance to low frequencies and therefore absorbs them better...converting the soundwaves into low level heat). Sealing Jon's "tube traps" does nothing as the fiberglass itself is porous so it's not really sealed even though Jon wants you to make sure it's "Sealed good and tight so there are no air gaps" (paraphrased from jon's words). There's just no point to that part.
His mid/high frequency traps work fine but again they are way more work then they are worth and don't look that good; kind of like large, overstuffed pillows on your wall. IMHO
Just save yourself tons of trouble and hassle and some money and start making phone calls to your local insulation distributors. Ask for Owens Corning RIGID FIBERGLASS 705 and 706 panels in 2ft x 4ft x either 2" or 4" thickness (the thicker panels are more absorbant). Place these in the corners where you have those wooden framed things with pink stuff in them and stack to the ceiling.
Those are your first corner bass traps. You can do more in the corners behind you, and the corners where the ceiling meets the walls and right in the middle of the walls--those placed on the flat surface of the wall must be placed a few inches away from the wall with some kind of spacer; otherwise they won't be as effective at taming low frequencies.
If you need some mid/high frequency absorbers, and you probably do, just use Owens Corning 703 or 704 panels in 1"-2" thicknesses in the same 2ft x 4ft panels.
Really any brand of RIGID FIBERGLASS will do (it's not as rigid as you think until you start getting into the 705 and 706 panels).
You want lower density rigid fiberglass panels for mid/high absorption. Like the 703 and 704 panels which are 3PCF and 4PCF respectively (
PCF =
Pounds per
Cubic
Foot)
You want higher density rigid fiberglass panels for bass absorption.
705 and 706 are 5PCF and 6PCF rated. What density of fiberglass do you get with Jon's traps? I don't know. That's the problem. There isn't any consistency really in his design. So it's better to avoid it altogether.
AESTHETICS:
Get yourself some speaker grille cloth to cover the rigid fiberglass panels and you're pretty much done.
Maybe move add a few more panels and listen to how they affect the sound. There will be a point probably when diminishing marginal returns kicks in...
So that's it. You're done and you've got yourself REAL bass traps and they are good looking to boot. Plus your mid/high absorbtion panels were much easier and don't look like overstuffed pillows.
