[Mattman193]

I would like to start off with saying that this is my first DIY audio build and I am really looking forward to learning and exploring the various aspects of DIY audio. It is truly amazing to see what you guys design and build.


For my first build I would like to try a sealed subwoofer. Originally, I bought a ported eD A5-350 and I just didn't feel like it fit well with my system. With a little encouragement from another forum member I decided to look into building a nice musical sub that would integrate well with my Vandersteen 2Ce Signatures. What was suggested to me was a AE 15-X based build in a sealed box driven by a pro amp.


I am going to be using this sub for a 50/50 mix of movies and music. Even though it will be used evenly for music and movies, I would like to focus on musicality.


My room is 25'x12'x8' and my seating position is about 8' away from my speakers. I played around with room placement using the eD sub and found that with my limited placement options, the best spot for it is right next to my mains in front of my seating area. This causes somewhat of a dilemma in that I don't want something monstrous that will stick out into my walkway or look out of place. The size of the enclosure that has been suggested to me is a 18.75" cube. If this is the correct size, it would work out well with the limited room I have.


I am working on a limited budget so I have been piecing together the items I need over time as they go on sale or I find them second hand. So far I have:


- AE 15-X driver

- Behringer EP4000 amp

- Behringer BFD

- 4'x8' piece of 3/4" Cherry veneered plywood


What I know I still need:


- Cabling from the amp to the sub (thinking of speakon connections?)

- Internal cabinet wiring

- Cabinet feet

- Polyfill

- T-nuts and screws to hold the driver in place

- Glue or epoxy


Is there anything else I am missing?


I have a friend who is a professional kitchen cabinet maker who is going to help me with this build because frankly my woodworking skills are horrendous. He should have all the tools we need to build it but I need to find out how to do this correctly. I'm guessing there are some differences between a kitchen cabinet and a speaker enclosure.

From what I've noticed, it seems that just about every build and builder designs and assembles their cabinets a little differently. Are there any general rules that I should follow when building this?


For example:


Is there a certain joint style that I should use for the corners? I would like to make it look as nice as possible while still being strong.


How about glue? I see some people use a good quality wood glue while others use a two part epoxy. Which is better?


Should I support the magnet with the internal brace?


As far as wiring goes, I am looking at using speakon connections. They seem to be rugged and fairly inexpensive. Will the two pole connectors work or should I use four pole? It looks like the four pole style are a little more common and will give me greater flexibility.


I would like to get most of my supplies ordered this week or early next week so I can get a start on this build soon. Any suggestions for good parts suppliers would be very welcome.


Sorry for my many random questions but I want to make sure I build this correctly so it can last me a long time. Any tips, suggestions, and links to more information would be greatly appreciated.

 

[jeff76]

A properly wood glued joint will be extremly strong. No need for epoxy.


I always use two peices of 3/4 for the baffle. One peice that will fit between the side walls and the other that overlaps them. I glue and screw them together.


Magnet/motor support is more of a personal touch. Not really needed in my opinion, but it's not going to hurt anything.


One four sided brace in the center should be good for an enclosure that small. You could also run a 3-4'' strip horizontal or vertical on the back wall.

 

[spanish68]

In a small box of that size, I would go with the AV15H sub, it works a little bit better in that size box than the AV15X model. The AV15X sub does a little better in bigger boxes.


Any quality wood glue is fine. You can use screws and glue to hold the panels together or if you have clamps and glue, it will work fine. If you have a double front baffle to mount the sub driver, you don't really need a brace to hold the magnet of the driver.

 

[Nuance]



Quote:
Originally Posted by spanish68 /forum/post/18112646


In a small box of that size, I would go with the AV15H sub, it works a little bit better in that size box than the AV15X model. The AV15X sub does a little better in bigger boxes.

It seems he already has the AV15X.

Quote:
Originally Posted by mattman193 /forum/post/0


I am working on a limited budget so I have been piecing together the items I need over time as they go on sale or I find them second hand. So far I have:


- AE 15-X driver

- Behringer EP4000 amp

- Behringer BFD

- 4'x8' piece of 3/4" Cherry veneered plywood

 

[Mattman193]

Yep, I already have a 15X so I would like to tailor the build around it. Do you think I should make the box larger or would using some polyfill compensate for a smaller box?


Thanks for the tips on the bracing. I think I have a good idea in my mind of how it's going to work. Since I don't really want to use my Cherry ply for internal bracing would I be better off using some MDF or another type of plywood?

 

[spanish68]

My bad, I should have read your post better (you having a AV15X sub). I have the AV15X sub in a 7cf with 18" PR's and it rocks in my big room, you will be happy with its good low end and even better mid-bass response. Use any wood for the bracing, MDF, ply, etc., just try to keep it three-quarters of an inch thick. I have a feeling that you'll have leftover ply to do some bracing in your box from your 4' x 8' ply sheet.

 

[spanish68]

Also, If I were you, I would try to make the box as large as posible. If you end up with 3.5-4cf (internal dimensions), you should be good. I would add 1-lb of polyfill per 1cf of box which would make your enclosure some 15% bigger. So if your box is 3.5cf and you add 3-4lbs of polyfill, it should make your box about 4cf or so.

 

[Mattman193]



Quote:
Originally Posted by spanish68 /forum/post/18119414


Also, If I were you, I would try to make the box as large as posible. If you end up with 3.5-4cf (internal dimensions), you should be good. I would add 1-lb of polyfill per 1cf of box which would make your enclosure some 15% bigger. So if your box is 3.5cf and you add 3-4lbs of polyfill, it should make your box about 4cf or so.

Thanks Spanish! I did some more measuring and I should have room for a 20" cube box without it getting in the way. According to a calculator that I used that should give me a 3.66 cf box without bracing figured in. Do you think that will make a difference?

 

[spanish68]

You'll be good with that size box. Even with some bracing added, you'll end up with a box of 3.5cf or so. Add up some stuffing and you're set.

 

[Nuance]



Quote:
Originally Posted by spanish68 /forum/post/18126544


You'll be good with that size box. Even with some bracing added, you'll end up with a box of 3.5cf or so. Add up some stuffing and you're set.

Agreed. That's the size boxes I use with my TC2000 drivers. Combined with the polyfill, you will be thumpin'


Spanish, do you glue the polyfill to the sides, back and top of the box (inside), or just stuff it in there, not blocking the driver vent?

 

[spanish68]

I just packed (stuffed) the polyfill all over the box without using any glue, it's tight enough that it doesn't move, it worked great for me. In my 7cf box, I put 5-lbs of polyfill, which makes it more like a 8cf box. I did leave some free air space (a few inches) around the PR's and the sub driver.

 

[Nuance]

Very cool, spanish. I'm still planning on adding polyfill to my subs. We didn't realize how beneficial it was when we built them, but I can just pull the driver out and stuff both cabinets. Thanks for the info.

 

[spanish68]

Just add about 1-lb of polyfill for one cubic feet of sub and that should make your box some 15% to 20% bigger.

 

[Nuance]

Will do, thanks. Sorry to hi-jack the thread, Matt.

 

[A9X-308]

Mattman, what are you using for a xover?

Plenty of excursion available for EQ.

 

[A9X-308]



Quote:
Originally Posted by jeff76 /forum/post/18112601


I always use two peices of 3/4 for the baffle. One peice that will fit between the side walls and the other that overlaps them.

That will be needed anyway as the flange is 0.62" thick. I usually build the same way.

 

[Mattman193]



Quote:
Originally Posted by Nuance /forum/post/18129587


Will do, thanks. Sorry to hi-jack the thread, Matt.

It's all good. Every bit of info helps!

 

[Mattman193]



Quote:
Originally Posted by A9X-308 /forum/post/18129929


Mattman, what are you using for a xover?

Thanks for the graphs. From what I can tell it looks like this sub will be able to play plenty loud. Wow!


As far as a xover, I used 60 Hz with the eD. I currently don't have a sub so I am running my mains full range right now. My mains can play pretty low but they really aren't able to shine due to the lack of power my AVR puts out. Once I am done with this build I am going to start saving for a decent amp.

 

[Nuance]

Matt,


Once you've completed the build and have integrated the BFD and subwoofer into the system, you should be able to use REW (and your ears) to determine which crossover point is best (100, 90, 80, 70, 60, etc). For me it was 80, even though my speakers go down to 38Hz, but it sounds fantastic!

 

[Mattman193]

I am almost ready to order my parts but I am still unsure what I should do about a grill. I don't need to build a grill right away but I would like to drill the holes for the mounts before the box is assembled and finished. I was thinking of using a magnetic grill but I'm not sure if that's the route I should go or not. So far the plastic mounts I have found look pretty flimsy.


How far from the corners should I place the holes? I was thinking of making a grill that covers the whole front of the box.