Welcome to Mr Crackers Website
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Welcome to Mr Crackers Website |
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DIY Subwoofer After deciding to build a Home theater system I was discussing some speakers options with a friend, Nyxnox. We both thought it would be a fun project to build some speakers. So I made the decision to try to build a subwoofer for my system. Here are some of the pictures of the subwoofer at various stages. I didn't take pictures right when I started the project. Since some friends were wanting to know what I did I took some pictures to help explain. I am by no means an expert, if you want really good advice try LoudSpeaker 101 or DIY Audio These are really good starting points.
Revision 3 I really didn't know what I was doing when I started this project. If I was a little more patient I would have realized you can't use car audio subwoofer for home system. The car audio subwoofer rely on the air inside of the car to help produce the bass. In Home Theater subwoofers you need really big boxes, typically 2.5 - 3.5 cu/ft. for sealed boxes and 3.0 - 5.0 cu/ft for ported boxes. That is a subwoofer approximately 18x17x17in internal dimensions. The first thing to do is pick a good driver and then find/build a box around it. I managed to find a box on close out for $75, normally $175, that is 17x16x15 inches internal. I needed to find a subwoofer to match this box. Here is a link to a DIY subwoofer page that show some comparision of drivers for home use. Here are my observations on some of them: NHT 1259 - To perform well needs a really big box 3.0 - 3.5 cu/ft sealed. Even bigger if you want to port it. It looks like a great driver. Hsu AS 1201 - Wanted a 3.0 cu/ft box or larger ACI's SV-12 - Wanted a 3.0 cu/ft box or larger P.E.Titanic - Couldnt find much specs on it. I also couldnt find anywhere to purchase the driver, so I gave up on using it. Adire Shiva Mark II - This is the one I choose because it wanted 2.5 Cu/ft for a sealed box. This matched the box I purchased really well. The driver also got good reviews on Audioreview.com I need to order the Adire Shiva Mark II and sell my Infinity sub on e-bay. I will put up some pictures after I take them. The box I bought had a cut out for a different amp, 12"x5 along the left side, and vent port. Since I was making a sealed box I had to cut a hole to fit my amp and plug the hole for the vent.
I added some bracing to make the box more solid
I bought a 250w @8ohms and 300watt @4ohms from www.partsexpress.com. Here are pictures front and back. The Adire Shiva II can be setup to 4ohms.
Revision 2 Since the sides of the subwoofer were vibrating I put a brace in the middle of the box to stop the vibrations. I wished I had tested this setup before I moved on.
I read some more tips that suggested lining the insides of the box with some heavy material. I found this "WonderBoard" at Home Depot. It is basically 1/2" concrete in sheets 2x4 for $10. I decided to line the insides of the box with small pieces of the board.
I used Liquid nails to glue the pieces in. That worked really well. I had to use a hammer to knock off the test pieces I glued up. The box was rock solid after gluing in the pieces of the wonderboard. Unfortunately this was the worst setup yet. The Wonderboard is so thick and heavy the box didn't vibrate at all. The sound was terrible. I could turn up the amp to 1/2 and hardly any sound would come out. The sound that did come out was really muffled. I tried stuffing the box with fiberfill but that didn't help either. I think in order to use this stuff in a subwoofer you need a bigger box. You could tell by running it the driver was having problems. At certain frequencies the driver would make weird noises.
Revision 1 I don't have many pictures of this version. I started with the box empty and mounted the amp in back and speaker in front. It didn't sound too bad, but base was really muddled compared to my Promedia 5.1 subwoofer. I then lined the inside with the egg carton foam material and this helped a little. But the sound wasnt what I was looking for. I then read a bunch of articles on the Internet on building subwoofers. The sides of the subwoofer were vibrating really bad. I decided to move on to Revision 2
Some links I have used in this project. Wanted to put them somewhere before I forget them.
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