[custom build] 18" ported sub for my 7.1 system

[hokiealumnus]

Make sure to glue all of your joints properly, as to not rely on screws alone to hold it together. I would also consider sealing all of the joints on the inside of the box with silicone caulk to ensure that it is air tight.

HUGE plus one to that. Even in ported enclosures it is imperative to completely seal the seams well. Less so than sealed boxes, but still important. Back in my car audio days, every installer with half a brain glued and caulked (flexible silicone is best IMHO) every enclosure.

 

[wagex]

That calculator didn't account for the bracing or the port volume. T.

it calculated for them... idk why it doesnt show the exact values in the equasion in the box i think it just does that part in the background

 

[wagex]

HUGE plus one to that. Even in ported enclosures it is imperative to completely seal the seams well. Less so than sealed boxes, but still important. Back in my car audio days, every installer with half a brain glued and caulked (flexible silicone is best IMHO) every enclosure.

+1 to that ive always used fiberglass inside around all the edges and around all the support footings but then again ive always done high spl systems that would shred the box if i didnt plus it makes the box more rigid which means moar volume, but also 1" mdf with 2 or 3 layers helped a bit too ;D man now you guys make me wanna put a real system back in my pickup ugh benching stuff or system hmmm

but im not to sure on the padding inside, i think it would just use up more of the volume of the box, well thats why you usually put the cotton fluff filler stuff (like pillow stuffing) in sealed boxes is to take up some volume

 

[gregmacknass]

but im not to sure on the padding inside, i think it would just use up more of the volume of the box, well thats why you usually put the cotton fluff filler stuff (like pillow stuffing) in sealed boxes is to take up some volume

I was suggesting something like dynamat at least on the rear wall to absorb and dampen some of the vibration of the box. This does help quite a bit.

 

[wagex]

now i understand what you meant, but as long as he gets the box all sealed up good n tight and his supports are nice and tight there shouldnt be any vibrations. but if he does expierence vibrations after its all assembled i could see that a good thing to do

the first variation of my box in my pickup (it went through about 5 rebuilds before i finally got it solid enough) the support wasnt enough it ended up pulling the screws out of the supports and that was some annoying sounds with the box sides flexing and slamming into the supports so i beefed them up and put fiberglass

edit i finally found some pix first one is first revision second is the last i got messy with the fiberglass lol

 

[MIAHALLEN]

Thanks all for the input...the box is tuned low on purpose...FR should be relatively flat from 20-80Hz, which is important for gaming/movies....this won't be used much for music

Looks like my measurements were a little off, the box will only be 750mm wide (instead of 786mm as cut)....which is where I came up with the 12ft3 figure I mentioned yesterday. So I've got to fix the cuts and then I can start putting this thing together!

 

[wagex]

woot ready for pix

 

[MIAHALLEN]

Here is my screen wall....you can see the cubby hole in the lower left area:



Here is a closer view....its quite large I have no idea what its for (I rent this house).



Waiting for batteries to charge:



***tip*** don't use a cheap battery powered skillsaw to cut a lot of thick wood ***tip***

 

[ssjwizard]

***tip*** don't use a cheap battery powered skillsaw to cut a lot of thick wood ***tip***

A cheap corded skillsaw is a better alternative than that even, and I'm talking harbor freight $15.99 cheap. Regardless as always I'm sure your final built box will be good and solid. You might also consider putting something to absorb vibration from the box to the cabinet it should yeild ~ 1.5Db advantage by removing additional directions for the sound to escape and reducing box flex.

 

[MIAHALLEN]

Here some pictures for today's progress:

This is the back of the BASH 300W amp in case anyone wanted to see it...its mounted in a wood panel I used to mount it to the Klipsch sub.


Front panel marked off:


Dry fitting pieces:


Four sides glued & screwed (its a small upgrade )


Front and top pieces dry fitted....all measurements confirmed to be pretty tight fit...looks good


Amp shown for scale:

 

[wagex]

shes a beauty are you using screws as well as glue? i would but since its not a tremendous ammount of power it should be fine, if you do be sure to drill pilot holes, im sure you already knew that but just throwing a bit of helpfull info out ive split too many boxes that way lol and id hate to see such a pretty box messed up

p.s. your as good at building boxes as you are sexy pc's

 

[I.M.O.G.]

Looks like a great start, and an amazing amount of audio knowledge in this thread. I'm impressed.

... and entirely clueless. I just want to hear the thing, and have my own house to vibrate the walls in. (always been renting in apartments, currently in a duplex)

 

[MIAHALLEN]

@ wagex...Yes, I'm using glue and 90mm screws (almost 4 inches) with pilot holes. I'll also be sealing up the inside of the seams with silicon

@ Matt, thanks buddy...back to my roots, I've been doing audio longer than OCing
But this is only the 2nd sub box I've ever built.

 

[gregmacknass]

Looking great miah. Don't you always hate that last little 1/8-1/4" that it doesn't line up. Accounting for the saw blade almost always bites me in the ***. Are you gonna cover it up/paint it? Are you routing and flush mounting the amp? Heres a few pics of one side of my roommates setup for some encouragement. The grills are out of convenience and to keep his cat from exploring into the box.

 

[MIAHALLEN]

All edges are matching up pretty well, at most about 1/8" off....but with a box this size and my crummy tools, I guess that's pretty good

Only the front size will be visible, I'll be making a front baffle 12mm...so the woofer and the amp will actually be inset from the front face. I'll be routing the openings on the baffle.

Those look like 15s right?

 

[gregmacknass]

Those look like 15s right?

The infinitys on top of the 18's are 15's

 

[PanteraGSTK]

I never realized we had so many audio nerds on here. Sure am glad I decided to revisit this forum. Makes me mad I was away so long.

Back on topic: nice build. As others have said I would use screws as well as the glue. better safe than sorry. It may not be a must since is is a ported box. If you were building a sealed box I'd be worried about you splitting the seam. I've seen it done too many times in the past so I'm ultra cautious now.

I was going to build a monster such as yours, but I needed a tiny footprint so I'm going the manufactured route...plus tools are expensive.

What I REALLY want to do is build an IB sub. Maybe one day. I look forward to your review of how it sounds when you are finished.

 

[hokiealumnus]

Edges 1/16-1/8" off? ...That's what speaker box carpet is for!

 

[ATMINSIDE]

I want out of my apartment so I can have something like this!

Already had to turn down the old Mitsubishi system (older than me!) and it only has two 12s

 

[Mpegger]

I don't want to derail this thread (I've always wanted to build a subwoofer myself, so the info here is great), but since there are some speaker heads here, maybe I can get some advise on this.

I have a pair of old Cerwin Vega RE 38's that I haven't used in a long time just sitting there taking up space. I'm tempted to somehow use the 15" woofer in combination with my Polk Monitor 40, as I was never really pleased with the mids or highs from the RE 38's. Should I disconnect the mid/high at the internal crossover of the RE 38 and just wire it to the Monitor 40? Or would that really affect the sound from monitor 40, seeing how the crossover was made for the RE 38 mid/high?

Or maybe go with the passive subwoofer build I've wanted to make, and build a box around the woofers from the RE 38s, although technically, they already have a box that's shared with the mid/high. Maybe build a new crossover that will work with the RE 38 woofer and the Monitor 40?