TEKTON IMPACT MONITORS

@bdp24 ya, i built a lot of cabinets with brute force damping, it does work to a point. My $7,500 wonders have a cabinet within a cabinet, constrained layer between them. Point is, science, technology and good ears ( since 1977 ) can yield superb sound. I like Danny also, smart guy.

Hope to see you before we head South, maybe Java near your record shop in Portland 

and 18 layers of MDF nc routed, glued and clamped  is three generations of cabinet technology back…..

As I mentioned long ago, certain makers are covered with the invisibility cloak by the Admin here. If you missed that, wake up!

True…but that cloak can be pierced with a simple tool called screen capture. i am sure that the misguided libel threat was captured by somebody.

 The new modern world comes with a body cam. Ask any “ Karen after the racist rant at Target. They are always so surprised…

like i said, i relish discovery on this subject. By deleting the thread, the threat “ this isn’t over “ hangs over many. Hopefully the powers that be at Audiogon understand the obligation for preservation of evidence in a threatened legal action.

 Or they could publish a retraction from the hot head who made it.

@tomic601: Years ago Danny designed a 2 cu.ft. (I believe) sealed sub enclosure employing double walls, with the chamber between the two filled with sand. I designed my 4 cu.ft. sub enclosures for the Rythmik F15HP DIY Kit using that same idea (with a 1/2" space between walls), provided my cabinet maker with the schematics, and had him cut the panels out of high quality MDF. I made the braces out of Baltic Birch ply.

I ended up abandoning the idea, having realized that at the low frequencies handled by a sub it is wall stiffness that is important, and robust bracing (spaced 4" apart) is enough to achieve that objective. At bass frequencies, the pressure created inside the enclosure by woofer excursion causes the walls to expand and collapse (like inflating and deflating a balloon), the source of sub enclosure resonance.

The unsupported 4" expanse of MDF wall between braces does create a small amount of resonance , but at a frequency high enough above the range handled by the sub to not be a problem. MDF is heavy, a double-walled enclosure measuring 24" tall x 24" deep x 18" wide and filled with sand really heavy, so having a single-wall/no sand enclosure was welcomed by me!

Coffee (or drinks) sounds great, let me know when you'll be passing through Portland. Have you been to Music Millennium? Pretty darn good LP inventory.