The do's and dont''s of my first wall....it seems like something isn't right....

[hispls 5,000+ posts]

i know i have the cubic feet to run all three....and because i spent so much on them....well $1000 is alot to me....i know for some of you it's like buying a burger at McDonalds.

You might have enough airspace but you do not have the surface area on your baffle to do a proper flat wall with 3. The theoretical 1.5dB you might gain from the third sub will be lost and then some from box flexing and from doing sub-optimum port.

Google the term "sunk cost fallacy". This is your build right now.

AFAIK 1000$ is real money to virtually everyone here, more importantly no matter how much money someone has they can't buy another 80 hours of life, that's why we encourage you to take care to do things right once.

 

[ferguson621]

I understand lbetts.....im starting to realize what you guys mean about taking my time. I slowed down a lot yesterday and everything seemed to go smoother....i felt better after i finally got the shape i needed.....and i didnt post pictures last night because when i went outside it started raining again......and because i did a big no no and i had to use four layers of 3/4 osb and im doing the 5th layer in plywood because its my last sheet of ply. I've always been against using osb because i know it's shi t.....but im going to attempt it this time....im sure i can make it work with proper bracing because the four layers right now are ridiculously heavy so i think i can make it work. There's a first time for everything.....and thank you hispls for helping me better understand everything. And thank you to everyone else for the positive encouragement! It really means alot to me and i truley appreciate it!

 

[ferguson621]

I guess your right hispls about the skunk cost fallacy

 

[ferguson621]

Ok so i got some extra cash and I'm going to use the osb but I'm adding a layer of ply to the front and back of the osb, and i also put a coat of resin on both sides of the osb, and I'm going to buy a 1 inch diameter poll with two flanges for the baffles bracing. So I'll have 6 layers all together for the baffle with the 1 inch pipe, i think I'll be good to go after that.

 

[hispls 5,000+ posts]

Ok so i got some extra cash and I'm going to use the osb but I'm adding a layer of ply to the front and back of the osb, and i also put a coat of resin on both sides of the osb, and I'm going to buy a 1 inch diameter poll with two flanges for the baffles bracing. So I'll have 6 layers all together for the baffle with the 1 inch pipe, i think I'll be good to go after that.

OSB is fine as far as rigidity, it's actually more rigid than most other sheet wood:

https://www.stevemeadedesigns.com/board/topic/206653-an-experiment-in-box-materials/

I've had good results with it and there's a 157 dB (on two 15s) daily driver in my area that is built with it. Drawback is it's heavy and rather tough to work with compared to ply or MDF.

Not sure about using polyester resin between layers though, the tech at US Composites told me it wouldn't cure right if not open to the air and that epoxy was the correct type of resin. I can vouch for osb layered up with epoxy being very solid, no promises on polyester.

If you still insist on 3 subs, do yourself a favor and plan around how to make removing the baffle as easy as possible, at least if you build top, bottom, back, and sides solid you won't have to re-do that again.

 

[ferguson621]

Lol good point hispls about building everything else...here's an updated picture of what i have so far....what do you think about that? Obviously i have to fix the bottom part lol, I'm going to do that here shortly so it'll go down at an angle and meet the bottom of the front baffle like its supposed to.....and yes i found out that the resin wasn't a good idea...well it was but i got to impatient because i didn't mix enough hardner....so it took all day to dry.....oh well lol. So I've got 5 layers on the baffle and three pieces of 36" threaded rod for bracing. The picture of the rod is next to 4/0 for size comparison. And I'm going to make the right side have a 90 degree and go over the top of the battery on the wheel well

 

[los33 10+ year member]

No port wall?

Sent from my Z970 using Tapatalk

 

[ferguson621]

Well yes....but i have to make them first lol...then I'll shrink it from there

 

[ChaseinBass]

Well yes....but i have to make them first lol...then I'll shrink it from there

Hey buddy, its looking alot better and it looks like you have built it so you can replace the baffle later if need be ? I think hispls knows what he is talking about and you could try it with two subs next and see whats louder. A Lot of these guys been around the block a time or two doing this stuff. I know sometimes we just want to try things too, but sometimes we end up wasting a lot of cash in the failures.

 

[hispls 5,000+ posts]

Well yes....but i have to make them first lol...then I'll shrink it from there

Looking a bit more like you give a **** about things this time. For bracing, just hold off until it is playing and put your forehead to the box, flex problem areas will be obvious and you can brace where needed,

Honestly 2x4 for braces is fine for your goals but doesn't look as pretty, and it's always best to build the thing bomb-proof to begin with as opposed to putting band-aids on after doing it weak.

As far as port depth, you may not need any. The side walls (keep them straight and strong) will "extend" the port. Assuming that port is 20" wide and your baffle is 4" thick, the port will behave as though it is 14" long as you have it. Do take your time to round over those edges on port mouth.

You can lengthen the port by screwing sections of 2X4 to the back of the baffle and lower tuning a little as you go to test if needed.

 

[ferguson621]

Gotcha hispls....lol yes i put alot more thought into it this time like you guys told me to do...I've also been taking my time. And yes i started to round off the outside of the port. I was using my 2 1/2 flush trim bit to make the mounting holes the same cause i was off by just a hair on the alignment...and in the process the piece of **** bearing came off and i didnt realize it and i took a chunk out of it....so I dont know what im going to do now. Cause i really don't want to redo the baffle.

 

[ferguson621]

I have a question....i understand that what im asking does vary.....i know that rounding the port is always the best thing to do...i round off all the ports on the boxes i build for people....but on the mic how much do you usually gain from rounding it off as opposed to not rounding it.....ive never metered before so i was just curious.

Absolutely chaseinbass! I completely understand what you mean! And i wouldn't have a problem running two if i knew i wouldn't fry the coils. Because i can never seem to set my gains right when ive got like triple the amount of watts being pushed to them. I always hear about people pushing 3000 watts to a sub that takes 1300 rms and playing them daily with no problems.

 

[Jeffdachef 5,000+ posts]

I have a question....i understand that what im asking does vary.....i know that rounding the port is always the best thing to do...i round off all the ports on the boxes i build for people....but on the mic how much do you usually gain from rounding it off as opposed to not rounding it.....ive never metered before so i was just curious.

0.1-0.2 db at best.

 

[ferguson621]

Ah gotcha....that's good to know. Im almost done! I'll take a few pictures when i get home in about 30 minutes. I've definitely got alot done in the past few days lol....it looks like a tank lol....i bought some more expanding foam and finished filling the quarter panels, and i had to take out the rear air bags. Well not completely, i just folded them in half and shoved them above the headliner lol. Ive got one piece to attach to the side and then i need to hook up my amps and batteries and finish sealing it off.

 

[ferguson621]

Ok so i put in all my dimensions.....i did 60 wide x 40 tall x 28 deep and that puts me at 34 cubes....i did the port 29 wide x 18 tall x 26 deep and that gives me a 38hz tuning