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View Full Version : Bracing to self vs cross-bracing



shizzzon
11-22-2009, 10:35 PM
I have a wall that i used 3\4" allthread on. 1 main run from rear to front then 2 smaller runs from rear to front as the box does like a T design.

Anyways, the rear wall flexes like crazy.

I had laid 1\4" thick steel bar, 2 of them, vertically and just used washers and nuts on outer side and it seems as if it did nothing...

So, i was told by a carpenter to keep the steel bars in there and install angle iron on the outside of the box and bolt that through the flat steel bars on the inside... His theory is angle iron can't flex so by using that on the outside and securing it to the steel on the inside... it should prevent the entire back wall from flexing...

Has anyone done this or if you haven't why? lol....

If this method is really this strong, then what's the use of all-thread to begin with...

iamamp3pimp
11-24-2009, 10:11 AM
Angle iron sure can flex.

if i had your number id send you a text of what we did recently in an enclosure....

slam
11-24-2009, 10:16 AM
Angle iron sure can flex.

if i had your number id send you a text of what we did recently in an enclosure....

post it

i use concrete to secure the back of my wall :fyi:

iamamp3pimp
11-24-2009, 10:18 AM
cant post it from my phone

wait i think i have some in my inbox

PV Audio
11-24-2009, 11:20 AM
Most carpenters who aren't audio enthusiasts don't understand the forces at work in a speaker cabinet. While thread all is useful, it is only there to eliminate flex. You still need a properly braced enclosure to eliminate panel resonance, as a metal rod simply cannot do that. You need to couple the panels together with wood, and to fight flex, you can use threaded rod, but please remember that the two are not interchangeable. If the panel is not flexing, it can still easily be resonating, which is where metal bracing becomes useless and you need to start looking at shelf bracing or putting in 2x4s.