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Discussion Starter · #1 ·
After harassing Mark and Mike P. for a few weeks I decided to just go ahead and build something already. Mike tweaked my final crack at box design so I took it and ran!

I know next to nothing about subs, my previous subs were small commercial 8-10" subs, so I'm not even sure what to expect once I finally plug this in. I really just wanted to get something built, get my hands dirty and hear some results. If I have to tear it down and start over that's not really that much of an issue to me.

I wanted to build this quickly and easily... partly because I might be destroying it at some point to try again. I hope I do a good enough job to keep it, but we will see.

Build tools/material:
Table Saw
Router
Cordless Finish Nailer
Few different power sanders
7 - 2' x 4' x 3/4" MDF panels
Glue
1 1/2" 16gauge finish nails (might be a bit big)
Hurricane nuts/bolt set (have a question at the end about those)

Size etc:
25.5"h x 24"w x 25.5"d
5.5L
44" Port tunes to 18hz
3 db boost at 20hz
HPF at 15hz
Reckhorn B-1
EP4000
SDX15!!!

So I got started yesterday, I spent a bit more on the 2' x 4' panels because it gave me less cuts, and more straight edges, since I'm not a pro with the table saws.



Basically I just cut 3 boards in half, created the bottom/top, sides, 2 internal braces. Cut 3 board's to 25.5" for the 2 front plates, and the back, the rest of the bracing and ports comes from the left overs of those boards. Some trimming after the fact to get the boards flush because of the saw blade etc but wasn't bad.



Cut the center braces out with a router, put in the bottom 1/2 of the port.



Here you can see I have the back part of the port on, some more bracing. The bracing is pretty simple, I feel it will be more than enough, but we will find out!



Front view with the sides and bracing and ports in place.



Cut the center holes and port openings out with a router, and then routed all the straight edges. I will smooth out the port edges some more, however I liked the look of the straight edge router bit quite a bit.



You can't see it here, however the top is attached, and the sub bolt holes are drilled. The front isn't attached yet, neither is the back. I don't have a great router bit to countersink the sub... I couldn't bring myself to tack in that 50lb SDX15 into one piece of mdf and just run the 2nd piece around it. I didn't think of a good way to do it before I had the front boards together, so I decided to mount it on the outside. Sitting here tonight I've figured out a way to do it, so I will probably still sink the sub in 1/2 ", so it still gets 1/4" of the second piece of MDF.




So I'm about 10hrs into it, and I need to sort a few things out. I don't actually know how to wire it yet :dontknow:. I'm terrible with watt's etc. Would I wire the dual voice coils in series or parallel for best results with an EP4000? I don't see any reason to not wire it in series so it receives the 2000w @ 2ohms... that's what I've always planned on, however I thought I should float the question since I'm about to do it and I'm not 100%.

Also I gave a hurricane nut a go, but I was having some issues getting it to dig into the mdf it would slide in a bit and spin with the bolt... and I was stressed out about it splitting the mdf...there isn't a ton to work with there. Do you guys countersink the the hurricane nut? I can't see it just forcing into the wood... however counter-sinking the nut seems to negate the reason for it to have teeth... I was planning on countersinking them pretty snug and using epoxy as well... Is there a better way?



Thanks for any and all help... if you want to see how this came about check out the my "noob thread".

All questions and comments are welcome, if you think something is wrong let me know!

http://www.hometheatershack.com/for.../26227-looking-some-answers-css-products.html
 

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Do you guys countersink the the hurricane nut? I can't see it just forcing into the wood... however counter-sinking the nut seems to negate the reason for it to have teeth... I was planning on countersinking them pretty snug and using epoxy as well... Is there a better way?
You already have a marking of the legs of the hurricane nut. So drill some small holes to let them sink into the MDF. Practice on some scrap and you will quickly figure out what size holes work best. Then when you have it all down use some polyurethane adhesive to lock them into place if you want. If your fit is tight enough you probably don't need adhesive.

Nice build. You won't be sorry with what you are building.

As for your amp and the wiring question you probably want to series. That's connecting to one coil and then jumping from that coil over to the other. Stick with your plan to bring out both coils into a bi-wire cup and you can do whatever you want from the outside.



Mark
 

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Nice job thus far:T

I just used hurricane nuts on my project- loved them. I practiced on scrap to find the following: I drilled a hole the diameter of the 'tube' outside diameter, that would allow the nut to fit flush with the material, snugly. I then drilled using a barely-larger bit to allow the outer flanges to fit, though they dug in and held. I then found the depth at which I need to drill that second, wider time to allow the flanges to fit nicely. I used a rubber mallet to smack'em into place :paddle: I didn't use glue, but that's probably not a bad idea, just be absolutely sure not to get it in the threading.

PE REALLY should give the bit sizes needed to do this in the package :foottap: (and I really should have taken notes to share:doh:)
 

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I had to look to!

1.8 + 1.8 Ω

So yep you most definitely have to wire them in series. I don't know of to many amps that will be happy into a 0.9 ohm load and cost less than a good used car!

Mark
 

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Discussion Starter · #6 · (Edited)
As for your amp and the wiring question you probably want to series. That's connecting to one coil and then jumping from that coil over to the other. Stick with your plan to bring out both coils into a bi-wire cup and you can do whatever you want from the outside.

Mark
Awesome thanks, I was bouncing back and forth between just wiring it inside because I have 1 cup already with a single set of posts, I have to order a second one or a bi-wire cup and wait for the shipping... my amp isn't here until this weekend anyhow so I may as well wait it out I suppose!

Mike P. Yes they are 2 ohm voice coils.

Edit: Also from what I've read today if I wire it in series which it looks like I have to, it's going to be at 4 ohms (or 3.6 to be exact I suppose).

Thanks for the tips on the Hurricane nuts, I know what you guys mean, just seemed a little counter intuitive to me a the time and I didn't want to shred any holes. If I had to rotate the speaker and redo holes, I would run into problems with how close the bracing is to the side of the speaker, the nuts wouldn't fit.


Another 2 questions, I was going to email the guys at CSS, but you guys may know.

Is it a good idea to "break" a speaker in before i set it in the box? My friend has some spare 300w Carver amps sitting around i could use. I'm fine downloading some sinewave sweeps and all that, but if it doesn't actually do anything I don't really want to bother. I won't be playing this sub loud enough to properly push any boundaries in normal usage, so it may never get a serious workout while it's in the box... People seem to banter back and for with the pro's and cons so I'm wondering what you guys think.

Also I was planning on using some polyfill. After reading more, most people say it's not needed in a ported sub. To eliminate some standing/back waves people sometimes used Eggcrate foam, however lately it would seem that most people don't think it does very much. Which leaves me with fiberglass/rockwool. I'm not thrilled about using fiberglass or the rockwool in a vented enclosure...I picture millions of particles floating through my movie room! I can still quite easily put in some rigid fiberglass along the sides, even after the sub is built. So my plan right now is to use nothing...and then if I feel I need it I will try some rigid fiberglass. Is this ok or should I be doing something about this now?
 

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Discussion Starter · #8 ·
The suspension will loosen up on most subs, you can break it in in free air or just use the sub when it's built.

As for lining the sub, try it first without anything and see how it sounds.
Alright, sounds good.

It sounds like I'm stressing out on minor details a bit too much!

I found a dual binding post wallplate for $12 in town at lunch, so I think I'm pretty much ready to finish this thing off tonight.

I changed my mind on counter-sinking the driver again for now. I read what I could find today, the decision really seems to be split on whether it's needed or not. The majority of people who said it was needed mentioned the frequency spikes came when you pushed the sub hard, lot's of people just seem to prefer the look.... So I decided to wait and see for myself.

I'm not going to finish the exterior of the sub until I know I'm happy with it, so if I need to counter sink it, I will still have the ability to do it without trashing the finish around the driver.

I had quite a bit of fun building this, I expect to be building another smaller box in the near future, then I will just move the driver over to hear for myself how a different build affects the performance.
 

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It sounds like I'm stressing out on minor details a bit too much!
Hey make music not worries!

And yep you will get all the boom boom you want want.

as for the dual post cup. Well you could force some more power into the driver using your pro sound amp and a channel to each coil. But I doubt that you will ever need that kind of volume. Your gonna be a very happy camper!

Mark
 

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Discussion Starter · #10 ·
I got a bit further through.

Again I changed my mind about countersinking, so I chewed up an hour and a half doing that. I didn't have a bit that I could just run around the outside edge, it wouldn't take enough off, and the one that does is over $100 at home depot. So I had to set up another jig to find the dead center of a 15" hole and then I ran around it twice with a larger cutting bit.




Then I got the front and back glued on without issue, and cut out the hole on the back for the binding post plate. I had to quit it was getting very dark. I have to do all of this at my friends house since I'm still in an apartment, and he doesn't have a shop. Construction is done other than routing down the top edge's from front to back. Hurricane nuts are in without issue, very tight, I also got a strip of the foam down for under the speaker bracket.



I'm pretty confident this thing is rock solid. I can't see any gaps, used a ton of glue and it's nailed solid.

I have a bad nick in the port you can see, where I manage to lift the router a bit, but I should be able to fix that, other than that it should be pretty easy to sand this out and paint. I just used a matt black textured Tremclad paint on my stands, so I will probably go ahead with that. It matches my speakers almost perfectly. I will probably build a mesh grill to cover the entire front section that sticks out as well, I have a few easy idea's for that already.

Also the amp is ordered, I will have it on Saturday. Is it a bad idea to give it a try with my buddies 300watt carver? The only risk is the amp clipping and cooking the driver correct? If I'm careful to watch for it and I'm reasonable with the levels it should be fine right? If I'm happy with what I hear, and I think I will be I will finish it up this weekend.
 

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Is it a bad idea to give it a try with my buddies 300watt carver? The only risk is the amp clipping and cooking the driver correct? If I'm careful to watch for it and I'm reasonable with the levels it should be fine right?
Yep and yep

No problem doing what you are talking about.

Mark
 

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Discussion Starter · #12 ·
nice, I will probably turn it on tomorrow then!

And yeah, I don't need that much power to wire a channel per voice coil! I'm still planning on using the other half of the amp for some transducers eventually.
 

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Looks like away nice build, sure that is your first? I like that you decided to countrsink the sub a little even though it was a pain looks like you pulled it off quite well. As for your nick in the port with the router, if your gonna paint the sub just fill it with wood putty and sand it out you'll never see it or i like to use Bondo, seems to stick to the MDF better. Anyways your the only one that will know it's there (except for all of us shackers that is).
 

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Discussion Starter · #15 ·
You should prime the box before you paint it as the end cuts of MDF really soak up paint.
Ha yeah...I learnt my MDF painting lessons on some stands I built 2 weeks ago. My first stand was a painting nightmare, it was cold out, I used some cheap black oil paint as a first coat... it didn't settle at all. Globs/streaks everywhere...I sanded the out of it, to the point where the routed corners were bare again but most of the sides still had paint...then I went ahead with the $10 can of spray paint and the corners just drank it all in...while the sides looked great. Eventually it even's out with enough paint, but I picked a proper primer for my center stand and it worked much better.


As for the nick on the port bambino, I've never used it before but my friend has some "plastic wood" i was going to try. If it's no good I will try the bondo next.... because it will be the ONLY thing I see when I look at it if I don't fix it!
 

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Discussion Starter · #16 · (Edited)
So I screwed in the sub(only 5 of 8 hurricane nuts took :( ), wired it and fired it up.Sorry I was in a rush I didn't get any pictures, I'll grab some next time.

The countersink around the sub is so tight still i don't think the hurricane nuts are an issue. I think I'm going to need meat hooks or something to dig into the bolt holes on the basket to get that thing out!

Again I was short on time, we just flopped it in the center of my friends living room. No time to really set it up. It's a 1500 sq foot bungalow that is basically open concept, there isn't a door in the place other than his bedroom and bathroom.

The smaller amp seemed fine, I wasn't giving it a hard workout with some heavy bass music or anything just some explosions and rumbling...however I was a little stressed out! I've never seen a speaker move like that! It didn't make any mechanical noises or seem to bottom out, but I swore it was going to just explode or fall apart... I guess I'll get used to it, but I was a bit shocked! I youtubed some other sdx15 video's and I guess it's normal... pretty cool.

It was pretty loud for the large open area and sitting in the middle of a room, and you could feel the vibrations through the floor and into the couch...probably partly because I've yet to put any legs/spikes on the sub. A few explosions pushed air into my pant legs from 7-10' away!

Decent amount of air coming out of the port most of the time, not a sound from the cabinet, the only vibrations I heard where various things on the coffee table. So I think the cabinet is fine. I didn't hear anything sound off/wrong like port noise etc, however it doesn't have 1400-2000w behind it yet.

I only had 15 mins with Call of Duty, my buddy didn't have a single dvd or blu-ray in his place...or any 5.1 tracks for that matter...I think something is wrong with the guy but that's a different story. I'm impressed, it's pretty exciting over-all, I don't have any real impressions yet, it's not really fair to rate it based on 1 level of CoD, and it's only getting about 250w, without the reckhorn/boost added in yet!

I'm going to finish it off soon, I'm happy with it already, I'll post some more pics and impressions shortly.
 

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It's all Mikes fault. I take no responsibility what so ever!

He's bigger and ....

Mark
 

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Discussion Starter · #18 ·
haha yeah... look what you guys made me do...

nah this is pretty awesome. I'm definitely going to finish this one up, thenI'm going to build another once I move... probably after I give sound treatments a try.

This A/V hobby I've acquired seems to have a never ending stream of ways to chew up time and money!
 

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So where to Kaboom! There's supposed to be a Kaboom some where?

MArk
 

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Discussion Starter · #20 ·
Ha, it's loud that's for sure... I still haven't picked up my amp yet, hopefully saturday I can go get it.

I have only had about an hour or 2 with it since I built it, still sitting at my friends house. He's watched a bunch of movies and seems to like it.

If the weekend is nice I will take a day to sand it out and get some paint on it. I'll probably bring it home after I get the amp and painting done, but I can't really push it like I can at his house so it might stay there for a bit.

I still don't have a good opinion on the sub, I need to spend some more time with it!

I know it's lots of fun though!
 
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