Sub box bracing

[CrazyKenKid 64]

Heys guys I will be building my sub box for 2-15inch NS subs come this summer and I had a quick question. first of all here is my box.

see how the subs are firing DOWN and the full weight of the subs is on that one board, well i am going to need to support that board somehow.

The 2 subs weight about 60~lb's each so 120lbs total will need to be supported. a friend told me to just use a piece of wood (dowel) and screw it from both ends and then glue it and not worry about it.

but then i started to think over time due to vibration and temperature change would the screws start to lose their grip and potential come out or something of that nature?

so i thought about threaded rod and some flat head screws to do the job!! take a look at the pic and let me know what you guys thing of it

as you can see with the use of flat head screws and some threaded rod couplers (hex nuts) (the green things) i think that would be a better idea and i can even use 3/8 (0.375") thread rod as it is load rating is around 600lb's

here is what the coupler will look like

and screws

[thebiggmann12 14]

you could also do just a few long threaded rods and then drill a hole through each side of your box, run the threaded rod through and then put nuts and washers on each end to hold it in place. minimal displacement and threaded rod is fairly strong.

[CrazyKenKid 64]

you could also do just a few long threaded rods and then drill a hole through each side of your box, run the threaded rod through and then put nuts and washers on each end to hold it in place. minimal displacement and threaded rod is fairly strong.

um washers and nuts...what would ahppen if the bass hit and moved the rod and the road fell down? this is why i wanted the 2-flat head screws at the top to hold it in place, and to HOLD it together? plus it has to be flush with the surface fo the mdf as this will be goign into my trunk so if there any extrusion i am screwed

[CrazyKenKid 64]

i guess i should have included this pic also

and yes dirty rag-= db's

[thebiggmann12 14]

you could also do just a few long threaded rods and then drill a hole through each side of your box, run the threaded rod through and then put nuts and washers on each end to hold it in place. minimal displacement and threaded rod is fairly strong.

um washers and nuts...what would ahppen if the bass hit and moved the rod and the road fell down? this is why i wanted the 2-flat head screws at the top to hold it in place, and to HOLD it together? plus it has to be flush with the surface fo the mdf as this will be goign into my trunk so if there any extrusion i am screwed

well if u tightened the nuts down together then they would not come loose...but if u dont want it extruding then yea u probably dont want to do that...ur idea would work great then.

[KU40 173]

You can put nuts on both the inside and the outside of the box and the threaded rod won't move anywhere. But I would definitely use the rod over the wood.

[Adrian_D 520]

You can put nuts on both the inside and the outside of the box and the threaded rod won't move anywhere. But I would definitely use the rod over the wood.

x2.

When using threaded rod you always put nuts on both sides of the panel.

[nem 2,019]

You can put nuts on both the inside and the outside of the box and the threaded rod won't move anywhere. But I would definitely use the rod over the wood.

x2.

When using threaded rod you always put nuts on both sides of the panel.

Don't forget the loctite.

[brandonf 9]

Don't forget the locktite.

x2 on the Locktite, I used it on my motorcycle to keep everything tight after a couple parts kept falling off (chinese bike under $2k brand new) and have had 0 problems since.

[Duran 387]

Use a lock washer AND a normal washer together.

[bigrank916 72]

How minimal is the displacement of a normal bracing size threaded rod? I doubt it would vary the tuning, right?

Im liking the idea of these.

[Adrian_D 520]

Use a lock washer AND a normal washer together.

There's no thread lock like cross-thread

CrazyKenKid, you could add some mdf panels to support the baffle against the bottom of the trunk.

[CrazyKenKid 64]

yes a few things i forgot!

lock washers

locktite

and cross threading! (cross threading is almost as good as contact cement or welding LMAO jk)

and i think i will play around with that baffle idea!!

and thanks everyone for your suggestions! they are awesome!!!

Kenneth

[Viperoni 0]

IMO, the screws will pull right through the wood. Definetely a nut, lock washer and washer on each side of the wood.

I would go with MDF or plywood braces 4-6" wide on two sides of each sub, with 2-3x 2.5-3.5" long screws on each end of the brace.

[KU40 173]

How minimal is the displacement of a normal bracing size threaded rod? I doubt it would vary the tuning, right?

Im liking the idea of these.

Well it's just pi*r^2 * length, which for a 3/8" rod about 20" long is only 2.2 cubic inches. I don't think you'd notice that in the sound, haha.

[CrazyKenKid 64]

How minimal is the displacement of a normal bracing size threaded rod? I doubt it would vary the tuning, right?

Im liking the idea of these.

Well it's just pi*r^2 * length, which for a 3/8" rod about 20" long is only 2.2 cubic inches. I don't think you'd notice that in the sound, haha.

? 20" = 20 feet? lol that is alot of rod! the max i will need is about 11.75 which is about 0.00075 ^3 lol

as for the wood idea as a brace i am worried b/c right now my box is about 6.1~ at bestat about 40hz (not build yet but soon to be) so with wood i fear it would be to much and i would lose out on cubic volume. but will a flat head screw pull though the mdf? keep in mind the head is on a taper so it has a lot of surface area.

o well i will keep playing with the idea!

[Duran 387]

How minimal is the displacement of a normal bracing size threaded rod? I doubt it would vary the tuning, right?

Im liking the idea of these.

Well it's just pi*r^2 * length, which for a 3/8" rod about 20" long is only 2.2 cubic inches. I don't think you'd notice that in the sound, haha.

? 20" = 20 feet? lol that is alot of rod! the max i will need is about 11.75 which is about 0.00075 ^3 lol

as for the wood idea as a brace i am worried b/c right now my box is about 6.1~ at bestat about 40hz (not build yet but soon to be) so with wood i fear it would be to much and i would lose out on cubic volume. but will a flat head screw pull though the mdf? keep in mind the head is on a taper so it has a lot of surface area.

o well i will keep playing with the idea!

20" = 20 inches

20' = 20 feet

[CrazyKenKid 64]

ya some nights i am slow! it happens lol! and i also jsut relized he said 2.2 cubic INCHES lol! i guess i was thinking cubic feet lol!!

thanks for the correction though!

How minimal is the displacement of a normal bracing size threaded rod? I doubt it would vary the tuning, right?

Im liking the idea of these.

Well it's just pi*r^2 * length, which for a 3/8" rod about 20" long is only 2.2 cubic inches. I don't think you'd notice that in the sound, haha.

? 20" = 20 feet? lol that is alot of rod! the max i will need is about 11.75 which is about 0.00075 ^3 lol

as for the wood idea as a brace i am worried b/c right now my box is about 6.1~ at bestat about 40hz (not build yet but soon to be) so with wood i fear it would be to much and i would lose out on cubic volume. but will a flat head screw pull though the mdf? keep in mind the head is on a taper so it has a lot of surface area.

o well i will keep playing with the idea!

20" = 20 inches

20' = 20 feet