DiyMobileAudio.com Car Stereo Forum banner

1 - 20 of 97 Posts

·
Registered
Joined
·
2,438 Posts
Discussion Starter · #1 ·
Some of you might remember that I was planning on building a home theater setup for a frend of mine that just got married as a wedding gift. He's basically paying for material costs and I'm building it all. We wanted to keep it somewhat frugal but still wanted an audiophile sound as well. I always like to make things look nice too when it doesn't get in the way of functionality. The system needs to be a capable 5.1 with the ability to pound when called upon and still sound great for listening purposes. Also, it would be run off a receiver so my loads all needed to be 8 ohm at the least. My choices on equipment were things I had never tried on my own and this was the perfect time to do so! :D

I had bought a DIYMA R12 a few months ago and it was the PERFECT candidate for this project. For the main speakers, center, and surrounds I chose some Mark Audio CHR 70's found here. CHR 70 (Pair)
I don't know dick about crossover design so that was a big reason I went full range on this project. I had heard great things about these little drivers and they were on sale for $55.25 a pair! I could wire them in series for an 8 ohm final load too! Perfect!!!

The Mark Audio drivers are in the mail and I'm still drawing up designs for the speakers. I'll start them here in a couple days once I get my designs solidified.

While I was deciding on drivers for the surround system I have been working hard on the sub. This was my first application for the DIYMA sub and I wanted it to be special. I think I got my wish because the final product really brings a smile to my face. :)


Here is what we are starting with. The DIYMA sub, a pile of hardware, solid 4ga copper and not shown is an ED LT550 plate amp and a pile of wood.



Here is my quick mock up while clamping the front baffle. Let me take a moment to explain my deign. The sub mounts to the front double baffle and is countersunk to be flush with the front. The small chamber on the left side in the picture below is for the plate amp. I didn't want to have the amp in the subs' airspace because I don't want to compromise a side of the box by cutting out the wall for the amp. Also, I wanted to let this amp breathe and cool off which posed a problem since the heatsink is on the INSIDE of the amp...retarded I know. I'll show you how I accomplished this in a bit. Lastly, the DIYMA motor structure is too beautiful too hide so I'll be using a plexiglass window on the top to allow it to be seen.



I'm all about the threaded inserts now. These things are waaaay better than T-nuts!



I wanted to use solid copper instead of wires. Why? Because it looks five million times cooler that's why! I needed to find a way to straighten the copper since it came rolled up. I decided to roll it between two sheets of MDF with all 145lbs of me (cross country runner) on top of it. It worked very well to my surprise!



So now that my copper was straight I needed to find a way to make uniform bends so I could get around the subs' motor structure. I first zip tied the copper pieces together at a few intervals so I could bend both pieces at the same time and get both of them the exact same shape. I used a can of 3M 90 spray adhesive as a guide around the magnet. It was the perfect diameter and actually stuck to the bottom of the magnet which was great since I didn't have to hold it.




Now that I had made my bends I had to test fit to see if it works....perfect fit!
 

·
Registered
Joined
·
2,438 Posts
Discussion Starter · #2 ·
Here is the box with the top being test fitted. You can see here how big the window will be. At this point in the build stage I had to build the rest of the box around the copper so I couldn't remove it. I decided to cover it with a bag so it wouldn't get junk on it. Note the threaded inserts used here. I freakin love these things.



Here is the rear compartment where the amp will mount. I drilled some holes in the bottom of the compartment so air could flow up through the bottom and out the top vent that I had made. Here is where I terminated the copper leads too so they could be connected to the amp.




Here is the box after some round overs and some sanding.
 

·
Registered
Joined
·
2,438 Posts
Discussion Starter · #3 · (Edited)
After some primer and more sanding I did a coat of paint. Let me first admit that I suuuuuuuuuck at painting and I loath it. But, this time I was using some foam paint rollers that worked well. I wanted a smooth finish but yeah...that didn't happen. What did happen was actually even cooler. The rollers left a sort of texture that I ended up liking quite a bit. The second picture is with the paint dry after two coats.




After the paint had dried I connected the amp wires to the copper leads and mounted the amp. More threaded inserts were used. Check out the vent at the top. I think it came well. :)



I couldn't use plolyfill on this box since you could see into it. This meant that I was going to use some acoustic foam that Mir and I had ordered last summer. All walls except for the plexiglass (for obvious reasons) were lined with the foam. I used carpet tape which is my newest favorite toy. It's like duct tape that is double sided. It's strong as hell and keeps two things stuck together flush. Pretty cool stuff! It was perfect for what I wanted to do and I'm glad it was suggested to me.



Now with everything finished all I had to do was pop the sub in and seal up the glass top. I used speaker gasketing tape on the plexiglass because I refuse to build a leaky box.



Here she is all finished up!


 

·
142 fastest gun in town
Joined
·
483 Posts
56k crap I am running 4.5k BEST but worth it. Thumb up.
 

·
Registered
Joined
·
2,438 Posts
Discussion Starter · #7 ·
Thanks for the kind words guys. I'm really looking forward to the CHR's too. Nifty little buggers and they were cheap! I've read that even though they are small they have some balls so I'm excited to see what's what.



I had a chance to finally listen to the sub tonight and I really like it. I put some music on it for about 20 minutes and then the girlfriend and I watched Hit Man. By the end of the movie I think the sub had broken in quite a bit and was starting to disappear. Room placement wasn't optimal by any means. I pretty much just set it down, plugged it in, and let her rip. I'll be running it till my friend takes delivery :D
 

·
Registered
Joined
·
2,438 Posts
Discussion Starter · #9 ·
I started Wednesday of last week and finished this afternoon around lunch. I didn't get to work Saturday though so I think it took me about 6 days. Two of those days were pretty much just waiting for primer/paint to dry though.
 

·
Registered
Joined
·
374 Posts
Freaking awsome man! You're seriously making me want to use my DIYMA 12 when I get it for home audio rather than car audio. One of the best looking (and I'm sure sounding) home subs I have ever seen. I love the copper tubes, the "pyramid" foam, and the plexi glass. My questions is what's the airspace on the box and the dimensions?

Thanks!

Ryan
 

·
Registered
Joined
·
2,438 Posts
Discussion Starter · #12 ·
So your going to run the mark audio drivers with 2 on the front baffle, or more of a bipole configuration?
Two drivers on the front baffle in a BR.
Freaking awsome man! You're seriously making me want to use my DIYMA 12 when I get it for home audio rather than car audio. One of the best looking (and I'm sure sounding) home subs I have ever seen. I love the copper tubes, the "pyramid" foam, and the plexi glass. My questions is what's the airspace on the box and the dimensions?

Thanks!

Ryan
The sub is in 1 cube after driver displacement. I had read that if you were putting it in a sealed box with a decent amount of power it needed to be about 1 cube to keep from folding the cone. The entire sub is 17.25x15x15
 

·
Registered
Joined
·
343 Posts
Great work man!. This is the motivation I needed to do something similar.

What threaded inserts are you using and where did you get them?

And I use the hell out of carpet tape too. Great stuff! sometime a PITA to get the backing off but still works great. I also use it for wrapping fleecing or vinyl or grill cloth on things.
 

·
Registered
Joined
·
2,438 Posts
Discussion Starter · #15 ·
Wow, that looks sweet man.

Wanna make me one, lol :)
I could make another for the right price $$$$ :D

Great work man!. This is the motivation I needed to do something similar.

What threaded inserts are you using and where did you get them?

And I use the hell out of carpet tape too. Great stuff! sometime a PITA to get the backing off but still works great. I also use it for wrapping fleecing or vinyl or grill cloth on things.
I'm using the ones that Lowes has in their hardware department. Nothing fancy. The biggest concern with them is that they go in straight. If not it's hard to thread a bolt into them if the tolerances are tight.

+1 on the backing being hard to get off! It's worth the trouble though.

PS: Dude, 311 just released their new single last night on the internet!
 

·
Registered
Joined
·
343 Posts
Youtube is blocked at work :( but yeah can't wait for new album.
 

·
Registered
Joined
·
2,438 Posts
Discussion Starter · #17 ·
The CHR-70's came in the mail yesterday. Great looking little drivers. I'm looking forward to hearing them but I have to decided on a design first.






 

·
Registered
Joined
·
1,308 Posts
1 - 20 of 97 Posts
Top