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Dual 15" "Mofo" build - Page 2

post #31 of 54
Quote:
Originally Posted by top_down View Post

With the sealed cabinet and the 25hz filter on the Oaudio amp you get a little better extension, with an F3 of around 29hz. But you're pushing it big time on the Xmax and amplifier load (VA). If you like it loud you will probably have to add at least -2db of PEQ around 25hz to protect the driver (and amp from clipping) and that will push your F3 back up.

I wouldn't try the other 3 filters at all, from what I see in WinISD they all cause problems unless you baby it. (I don't know about you but I don't have that kind of will power)

Now I'm no expert, but from where I sit if you are willing to do a little rework and add two 4" x ~28" long flared ports (18hz tune) to each cabinet and change some resistors in the amp you can get an F3 of 18hz and run the amp at near full output. The difference in output at 20hz is remarkable (10db if I am modeling things right). I realize this means reworking some of your bracing, but I think this is worth doing if this is for home theater.

If you decide to go ported, the filter you really want is Fc=18.7hz and Q=1. What you have at the 25hz setting is Fc=23hz and Q=1.42. On the Oaudio amp you need to change two resistors to get the lower Fc and Q - it's described on the Oaudio website in one of the 500w downloads. It's not the easiest thing to do if you don't solder a lot, as the leads are clinched and the clearance between lead and hole is tight.

If you aren't comfortable soldering, you can use the 25hz setting as it is and add -2db of PEQ at 28hz and get pretty close, the F3 would be at 19hz. Still much better low end than with a sealed sub.

Thanks for tipping me off on this driver - I would have never given it a second look before.

sounds good to me, I'd like to see that done... enjoy the 2.3cu ft sealed while you build the big ones :-P
post #32 of 54
Thread Starter 
Merry Christmas! Finished these up late last night! Just in time for an awesome Christmas present for myself. I am extremely impressed so far, I will never run a single sub again.


The pic with the amp was my way of keeping the polyfill off the circuits without the hassle of building an enclosure. A few quick cuts of some dowels, hot glue, and extra "tutu" fabric my wife had to create a net over the amp. Target had queen sized poly pillows for $4 each a few days ago, each sub has 1.5 pillows worth of poly.
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post #33 of 54
Awesome turn out!
post #34 of 54
Thread Starter 
Quote:
Originally Posted by kryptonitewhite View Post

Awesome turn out!

Thanks man!
post #35 of 54
Now lets seem some REW once you get there
post #36 of 54
Thread Starter 
Couple pics of them in their new home. Cabinets are only 12" deep. I dont have a mic to take REW measurements with, but man these things have authority and are very clean. I know that wont mean a lot to most of you guys, but for me upgrading from a single 12" sealed sub I'm impressed.
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post #37 of 54
my receiver came with an Audyssey mic...did your receiver come with one?

man those look so awesome! The one I had sounded awesome, miss it.
post #38 of 54
Thread Starter 
Quote:
Originally Posted by kryptonitewhite View Post

my receiver came with an Audyssey mic...did your receiver come with one?

man those look so awesome! The one I had sounded awesome, miss it.

Good call! I just recently replaced my 10 year old HK AVR8000 with a Yamaha RX-800 and ART SLA4. Just took these with the YPAO mic. I have the 20hz HPF enabled.

This is the uncorrected room response



60hz EQ enabled



I'm pretty happy
post #39 of 54
Thread Starter 
Here's the modeled response. Amazingly close outside of the dip at 50hz.
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post #40 of 54
Thread Starter 
Well after having some time with these I still love them. I have noticed with higher SPL content that there's some vibration with the cabinets, mostly on the top, so I've devised a quick fix. I decided to add numerous dowels with 45 degree cuts in an attempt dampen the panels and tie them into a surface. I've got the cabinets all buttoned up again, but I'm going to wait until tomorrow afternoon to fire them up for the verdict.

I added 2ea front-top-back braces, 1ea side-back brace, and 3ea front-bottom braces. I used copious amounts of gorilla glue with duct tap "straps" pressing them in place. I also took a precaution and squirted a little gorilla glue in each screw hole and let cure/expand just in case the ply wood stripped out. All the screws torqued down good, something to keep in mind.
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post #41 of 54
no poly fill in the box?
post #42 of 54
hey love the way these turned out, quick question for ya

where did u pick up that sprayer for the spray paint cans
post #43 of 54
Quote:
Originally Posted by tprj82 View Post

hey love the way these turned out, quick question for ya where did u pick up that sprayer for the spray paint cans

Not the OP but I got mine at Amazon. Doesn't look as nice as the OP's but it gets the job done: http://www.amazon.com/Can-Gun1-2012-...2773855&sr=8-1
post #44 of 54
Thread Starter 
Quote:
Originally Posted by tundrSQ View Post

no poly fill in the box?

1 1/2 queen sized pillows worth in each box

Also seen in post #32
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post #45 of 54
Thread Starter 
Quote:
Originally Posted by tprj82 View Post

hey love the way these turned out, quick question for ya

where did u pick up that sprayer for the spray paint cans

Thanks! Got the handle at Lowes, on the shelf next to all the spray paint.
post #46 of 54
Thread Starter 
Well the bracng only had a minor effect on the panels, so that type of bracing is definitely not effective. I think once I'm done building all my speakers I'm either going to sand these down and bond another layer of wood around the entire cab, or just build some ported cabs that I've been considering? I'm happy with the SQ so I'm unsure if I want to mess with things that much.
post #47 of 54
jay,

is your top panel really vibrating up/down with those braces inside?

seems like it should be sturdy enough.

i'm suspecting that most of what you are sensing is the torsional vibration from the driver moving back and forth and pulling the cab forward and back.

this can be tested by feeling the top front edge and seeing how much that is vibrating relative to the middle of the top panel. if they vibrate about the same, it is torsional vibration. if the corner doesn't move a bit and the middle of the top panel is vibrating, then the bracing isn't doing the job.
post #48 of 54
Thread Starter 
I'll have to check that out tomorrow afternoon to test what you're describing. I dont feel like the SQ is being compromised, I'm just not satisfied when I put my hand on the cab and I can feel every pulse. Either way, I'm building those PR boxes with complete overkill bracing.
post #49 of 54
Thread Starter 
Alright, the corners are vibrating along with the panels.
post #50 of 54
Ohh Man!!!!!!!!!!

You are great!!!!!!!!!!!!!!
post #51 of 54
Jay1- What are the main speakers in your Photograph? Are they also DIY? They look very similar in design to my Aerial Acoustics LR5's; which are large stand mounted monitors. I often wonder if I could sell my Aerials and build something DIY close in performance and pocket the savings.

I am currently in the design phase (with guidance of Jinjuku- Thanks Mark BTW) of DIY dual opposed 12" subs. Will either build two or four for my large open basement where we have our theater set up.
post #52 of 54
Thread Starter 
Quote:
Originally Posted by jdlynch View Post

Jay1- What are the main speakers in your Photograph? Are they also DIY? They look very similar in design to my Aerial Acoustics LR5's; which are large stand mounted monitors. I often wonder if I could sell my Aerials and build something DIY close in performance and pocket the savings.
I am currently in the design phase (with guidance of Jinjuku- Thanks Mark BTW) of DIY dual opposed 12" subs. Will either build two or four for my large open basement where we have our theater set up.

They're ACI Essence V's, which I originally intended as the start of a full 5 channel set, but then ACI cut all their models except small monitors....

I'm in the process of building new mains to match the center I just finished.

You could modify most floorstanding designs into large monitors by simply modeling the woofers used, and finding a suitable response that uses less volume.
Edited by Jay1 - 6/20/12 at 5:53pm
post #53 of 54
Sick looking build man, I like the looks of those drivers and cabs.
post #54 of 54

These subs actually sound pretty darn good. No fancy work here for me, Just dropped a pair of them in 4 cube ported boxes.
Very nice job on the buiding. smile.gif)
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