[Wooderson]

Time to kill off some spare parts. I bought an 8" Dayton a few years ago and never got around to utilizing it. So I'm using some leftover 1/2" MDF and a 20 year old 100W plate amp I ripped out of a 12" Pioneer sub before I chucked it. This will be a little sub to put in my garage along with some AWESOME active Tapco (Mackie) S5 studio monitors I picked up on Craigslist for $100/pr. Man those things sound incredibly good, but they're ported and tuned to ~60Hz. Pretty much zero deep bass.

While I waited for my EP4000 to arrive in the mail, I used this plate amp to run my first big 'ol LLT. I found with REW that the amp has an HPF @ ~25Hz, so that's perfect (the Pioneer I ripped it out of was ported).

Since I'm using 1/2" MDF, the plan is to compensate with lots of bracing. Volume is going to be somewhere ~60 liters (~2.1 ft^3). It's going to be quick-n-dirty construction all the way. I don't want to get involved in another monster project like my 9 month dual LLT build last year.

Even though this thing is going to be tiny by HT standards, I can still see it pushing ~100lbs total weight. I haven't box-noted it, but I'm sure there will be some in-band resonances due to the high aspect ratio. So I'll put some polyfill in the upper two cavities.

Maybe this thread belongs in a more music oriented forum, but HTS is where I live. Not every build has to be based on an 18" 50mm-xmax sheetrock buster, right?

I'll probably start cutting wood a few weeks from now. It'll probably take a month or two to get it done. No rush.

PartsExpress Cyber-Monday had an 8" TC Sounds for $100. Was I tempted? Oh yeh! But I vowed to keep this $0.

** Edited this post to fix a broken image link. This Sketchup rendering is *after* I took Bill's advice to raise the driver up off the floor.

 

[robbo266317]

Sounds like just the thing for the garage. Have you thought about moving the driver a little higher off the floor to keep some of the dust off it?

Cheers,
Bill

 

[Wooderson]

Good point! And now that I think about it, I wouldn't want it to accidentally take a foot to the cone. I think I'll swap the amp down low where it belongs anyway, and put the driver in the chamber above. That should get it out of the kick zone.

This is just the kind of feedback I was hoping to get. Thanks Bill!

 

[Wooderson]

Brace maniac. I couldn't have the amp blocking the airflow into the slot, so I had to move it up a little above rock bottom.

 

[MikeBiker]

Your neighbors will be wondering what the you are doing in the garage when that thing gets cranked up. It's almost large enough to double as a beer fridge.

 

[Wooderson]

Well, like I said, I resisted the urge to buy the $100 TC Sounds Epic 8" baby-monster (2" total throw :yikes. I don't think me and my little 8" x 8mm xmax Dayton are going to cause much of a ruckus. Click my sig to see what the neighbors really enjoy listening to.

Got the final dimensions all tuned up tonight. Grand total outside dimensions will be 0.9 x 0.9 x 4.0 ft. That's not too big :innocent:. I also upped the tune to 28Hz to get a bit more oomph in the bottom.

I'll post my spreadsheet tomorrow night :nerd:.

 

[Wooderson]

Here's my spreadsheet. Shaded cells are direct entry. Everything else is calculated. I tweaked everything until I hit my volume and got the backside port extender to disappear (-2mm). I highly recommend creating a spreadsheet for your build. I had to tweak the numbers for 30 minutes to hit all my targets. I could never do that manually - over and over. For instance, here's the equation for the port backside extender, F6-12.7-G16-F7/2-F7/2. Total working volume takes everything into account - bracing (assuming braces are 60% wood, 40% air), port volume, etc.

https://docs.google.com/spreadsheet/ccc?key=0AjwCXbS5q2UGdG9KaDhwdm11ckNLTHJncEhhbS0zbUE

 

[MikeBiker]

Good use of the computer. Now you need to do an iPad app!

 

[Wooderson]

Puleez :nono:, I would write it for Android like any self respecting nerd. Having WinISD ported to iOS/Android would be pretty cool though wouldn't it?

I think my physical design is pretty generic for someone wanting to build a simple slot ported rectangular enclosure. If there's any interest, I could parameterize a few more things, like panel thickness, number of horizontal braces, etc. Maybe I'll try to do that over the holidays while I'm killin time on the inlaw's couch.

 

[Wooderson]

Here's the first sneak-peek. I still need to make a mountain of sawdust with the sander, and sink about a quart of wood filler into my imperfections. But there's nothing wrong with the sound. I'm really impressed by how much i got out of this little guy. The box is freaky solid. Kuckle raps give nothing but thud everywhere. I accidentally deleted the source photos from my initial posts. I'll get those back up. I have a lot more pictures i'll post when it's all done. Enjoy.

 

[Mike P.]

Looks good!

 

[ALMFamily]

Looks good!

+1 - very nicely done! :T

 

[Wooderson]

Thanks guys. I listened to it some more today. Amazing what that cheapo little Dayton can do in this sweet box design. The only problem is that this project pretty much burned me out on wood-working. I'm sick of it. If I ever get the urge to build another bass machine, I think I'll probably try to find a super cheap pre-built box, or maybe something from Craigslist. Then mod it with bracing, porting, etc. Just having something to start with that already has perfect 90* angles would be a huge time saver. I hate to discourage any new DIYers, but this stuff is a lot of work.

But still, I'm very very happy with this new baby boomer.

 

[Wooderson]

Gather around kids, it's picture time!

I just used some 60grit sandpaper to flare the outer edges of the port (and added a few mm to the total length). I flared one of the internal edges. There's only one internal edge since the rear wall is the other "edge".

I'm planning a post-mortem post on all the stupid things I did. I think one of the biggest is gluing all the bracing in first, since I'm not a human-CNC, all of my bracing corners are != 90*. So what happens when you mega-clamp all these non-90* corners in tight? A curved side wall. The end result will be seen later.

42 bracing holes had to be jigsawed out. Along with 4*42=168 corner holes to drill. :sweat:

After a few days of glue/set/glue/set/glue/.....

Got the front face glued in. I went ahead and added another 1/2" of mdf for the driver chamber of the front baffle. Plenty of wood for the mounting screws to sink their teeth into.

Got clamps? I took a few of my 5' and 6' pipes from the monster-LLT subs build, and sawed them in half. Easier to handle and I was able to utilize two more clamps that I didn't have pipes for yet.

Starting to come together. Yes, that's a monster overhang you see at the top (I actually fixed that up a little with a spreader clamp and some glue wedged in there). I decided to go with plenty of bracing just in case I ever needed anything to put my car on top of.

Via some major malfunction, this edge that was supposed to be tight to the front face wasn't. When life gives you lemoms...

So here's what you get when you don't glue the outer structure together first. Wood filler to the rescue.

Putting the final face on. For those of you that have done this before, you know that this is like getting the two sides of the Golden Gate Bridge to line up in the center. There are no degrees of freedom left. You have to dance with whutchya brung.

But after half a pint of wood filler and sawdusting all of the neighbor's cars, Frankenstein is transformed into The Bride of Frankenstein.

I added a 1/2" sheet on the bottom so that I could drill/hammer in some hurricane nuts to screw feet into. Like everything else, quick-n-dirty!

And then 5 coats later... BTW, I blatantly ignored the 2hrs recommended drying time between coats. For the first 4, I just worked my way around and around. So ~15 minutes of dry time between coats. Then a few hours of drying. Then the 5th coat. It turned out fine. No bubbling, pooling, or anything else I was worried about. I'm actually very happy with this $10 finish, plus a few bucks for the paint brush I chucked - I never try to save brushes that have touched oil based paints. Yes, there are a few big wood filler skid marks. Did I mention that I didn't care how this thing looks? Quick-ndirty all the way. Besides, I like the "homebrew-chic" look. If it were too perfect, it would look like some BestBuy schlock.

Recall, this is a 100W plate amp I ripped out of a 20 year old cheapo Pioneer 12" sub before I tossed the rest of it. It has an internal HPF @ 25Hz. Perfect for my 28Hz tune!!! It can more than overdrive the xmax of this little Dayton. The evil bass-scientist in me still wants to swap it for an 8" TC Sounds some day. A box this nice deserves a better driver. But the extra output is only really needed if this thing is ever pressed into HT usage.

Here are the SWEET Mackie/Tapco 5.25" studio monitors I built the sub for. They are active speakers (built-in bi-amps) w/ active crossovers. I got the pair off CraigsList for $110. I think it's the best price/performance ratio I've ever achieved. *But*, they are ported and tuned to ~55Hz. Ie, no real bass.

Tapco S5 Review

I also threw a little polyfill in there just for kicks. Especially since the aspect ratio is so high (sonotube-like).

So that's it. I already talked about the sound quality/quantity, but I'll say again, this thing has exceeded my expectations. The sound is so clean and "transparent", whatever that means. The "knuckle test" is nothing but dead thuds everywhere. It weighs ~90lbs total. For 1/2" MDF, this thing is a ROCK! And how many commercial 8" subs are tuned this low (28Hz). I doubt very many, if any. That's why we build them ourselves fellas!

After matching the levels to my liking and cranking the Mackies up to gosh--loud, this sub has *plenty* of headroom to keep up, stress free.

I'll mess around with REW at a later date and post some sweeps (seated position, near-field, etc). I'm curious to see if I hit my tune. And I'll take some SPL measurements. I'm guessing ~105dB, but we'll see.

Thanks for checking in :wave:. None of my loser friends care about my sub building escapades. "Why didn't you just buy one?" :doh:

 

[black_z]

Nice!!

 

[BoomieMCT]

Is that the Dayton DVC driver or some other one?

Nice build!

 

[BoomieMCT]

Also - do you hit xmax often? I ran the numbers for your box in unibox and here is what I got for 100 watts. Real world results can vary somewhat.

 

[ßart West-VL.]

BoomieMCT,
I see you forgot to simulate the 25hz HPF

 

[BoomieMCT]

BoomieMCT,
I see you forgot to simulate the 25hz HPF

I'm not sure how that would affect possible overexcursion up to 70Hz.

 

[ßart West-VL.]

You've got a point there but the OP knows this...

...Recall, this is a 100W plate amp I ripped out of a 20 year old cheapo Pioneer 12" sub before I tossed the rest of it. It has an internal HPF @ 25Hz. Perfect for my 28Hz tune!!! It can more than overdrive the xmax of this little Dayton. The evil bass-scientist in me still wants to swap it for an 8" TC Sounds some day. A box this nice deserves a better driver. But the extra output is only really needed if this thing is ever pressed into HT usage...

edit: Why do you dig this up after more then a year?