DIY Subwoofer Building, Repairing, & Upgrading

[liquidice]

fors, if you plan on taking apart your SVS, I will kill you! That is one sub I wouldn't mess with!...I'm sure you don't plan on it.

[Big Daddy]

Originally Posted by liquidice

fors, if you plan on taking apart your SVS, I will kill you! That is one sub I wouldn't mess with!...I'm sure you don't plan on it.

If he doesn't take it apart, I will kill him.

Subwoofers are big toys and are meant to be taken apart. Life would not be as much fun without experimenting and screwing a few things up in the process. It is all part of the learning process.

[Grevlin]

Personally, I would probably take a little peak inside. I've been taking things apart since Christmas mornings many, many years ago. Unless they glued the whole thing together, it should be able to be opened up a bit. But fors- don't blow a hole in the ceiling

[crazyBLUE]

Originally Posted by Big Daddy

If he doesn't take it apart, I will kill him.

Subwoofers are big toys and are meant to be taken apart. Life would not be as much fun without experimenting and screwing a few things up in the process. It is all part of the learning process.

Thats funny !! forsberg you had better take it apart !!

[Newmason]

Sounds like I have a cheap weekend project and a few hours away from the girlfriend! Life keeps getting better!

[liquidice]

alright fine, fors, rip that bastard apart and stuff it like a teddy bear!!!

[crazyBLUE]

Originally Posted by liquidice

alright fine, fors, rip that bastard apart and stuff it like a teddy bear!!!

Just think how much stuffing he will need for that huge sub !!

[Fors*]

The idea of adding polyfill to this thing did occur to me. What I figure I will do is enjoy it for now. However, once I get settled in with it and in need of a tweak ( kinda like a "fix"), I know I will eventually want to do something with it. As far as the amount of polyfill, I think just throwing in an entire pillow should do the trick, right? . If the pillow doesn't work out, then to fix this, all I have to do is get this baby down to the 18-20Hz that the specs say it can handle, and I'll have myself a little canon where I can shoot out the polyfill.

And Big Daddy, looks like I will need to use your method of building a circular sub-riser too someday down the road, as well.

[Aerodude73]

Originally Posted by forsberg21

The idea of adding polyfill to this thing did occur to me. What I figure I will do is enjoy it for now. However, once I get settled in with it and in need of a tweak ( kinda like a "fix"), I know I will eventually want to do something with it. As far as the amount of polyfill, I think just throwing in an entire pillow should do the trick, right? . If the pillow doesn't work out, then to fix this, all I have to do is get this baby down to the 18-20Hz that the specs say it can handle, and I'll have myself a little canon where I can shoot out the polyfill.

And Big Daddy, looks like I will need to use your method of building a circular sub-riser too someday down the road, as well.

- okay, Please tell me you're not Seriously considering doing the Polyfill to your $569 (or so) Sub that you've been raving on & over since you installed it last week??!! Wth. Dude, if it sounds Amazing already - as YOU have said in the short time you've had it - WHY mess with it? Not Everything needs to be tweaked with do they? Oh wait, that's right. I forgot where I am...

[liquidice]

that was my attitude at first too, but BD quickly corrected that. Fors, it's not like you couldn't remove the polyfil if it worked against you for any reason. I do think the riser would be a good idea though. Not a big one, maybe just a couple inches. In fact, I would emulate erict with his super dense foam he used. Riser/Isolator. Can you dig that?

[Fors*]

Originally Posted by liquidice

that was my attitude at first too, but BD quickly corrected that. Fors, it's not like you couldn't remove the polyfil if it worked against you for any reason. I do think the riser would be a good idea though. Not a big one, maybe just a couple inches. In fact, I would emulate erict with his super dense foam he used. Riser/Isolator. Can you dig that?

I still believe I will add the polyfill eventually. I just like the way it sounds right now. When that wears off, I will want to do SOMETHING, and I think a riser would be first, then the polyfill. But that is down the road a bit.

[Aerodude73]

Originally Posted by liquidice

that was my attitude at first too, but BD quickly corrected that. Fors, it's not like you couldn't remove the polyfil if it worked against you for any reason. I do think the riser would be a good idea though. Not a big one, maybe just a couple inches. In fact, I would emulate erict with his super dense foam he used. Riser/Isolator. Can you dig that?

I went back 4-5 pages here, no pics of the Riser/Isolator "Erict" super dense foam, you mentioned. Plus he has no pics in his Gallery (?).

Originally Posted by forsberg21

I still believe I will add the polyfill eventually. I just like the way it sounds right now. When that wears off, I will want to do SOMETHING, and I think a riser would be first, then the polyfill. But that is down the road a bit.

3-6 months. Let it breathe out for a little while 'Fors.

[liquidice]

here is erict's riser/isolator. It was under the riser sticky thread. I'm starting to lose track of where certain posts are myself!

[Aerodude73]

Originally Posted by liquidice

here is erict's riser/isolator. It was under the riser sticky thread. I'm starting to lose track of where certain posts are myself!

oh ok - yes, I remember seeing that. love that hard thick foam with his sub riser/isolator. very cool

[StimpsonJCat]

Originally Posted by liquidice

alright fine, fors, rip that bastard apart and stuff it like a teddy bear!!!

We need a Build-A-Sub store!

[vega2K]

Originally Posted by StimpsonJCat

We need a Build-A-Sub store!

Now that would be awesome! And before you close it up, you can place a dedication in the shape of a heart on the polyfill! (I have three young kids)

[Grevlin]

Its just the thought of little teddy bears locked inside my sub...

[liquidice]

I've got some killer idea's coming up that I can't wait to execute. I've been bouncing some idea's off Brett at ED, and he's digging my idea's, and I'm digging his. One was that I want to use some of ED's sound dampening material to wrap completely around a subwoofer, minus the opening for the woofer and the amp/port of course. Here was Brett's response:

By adding the mass to the walls technically you are helping the panel reverberate less, and taking that energy and displacing it in the butyl rubber of the deadener. (Works great in cars because the metal walls are so thin as compared to a 3/4" EFS wall) It is a theory that if you have an extremely damped cabinet it is supposed to help keep the sound of the subwoofer pure/more natural. Which is why there are subwoofer plans out there that have like 2" of sand in between the inner and outer wall to decouple it and to dampen any type of cabinet resonance.

oh yeah, I'm getting excited now! After after what he said about the sand in some cabinets?....saving that one for my homemade sub in the future!!!

[Big Daddy]

My new subwoofer is unique and kicks butt. It is a hybrid subwoofer that is the result of the marriage between two companies.

I have an old 12" passive Radio Shack subwoofer that has been sitting in the in the garage for a few years. I decided to upgrade its driver and use it in the living room. I ordered a 12" driver from Elemental Designs.

My intention was to upgrade the old sub and decide whether I wanted to use the same driver on a couple of friends’ subwoofers that have blown drivers. I have no idea how I became a subwoofer repair person. I suppose my rates are the best in the world. They don’t pay anything. Occasionally , they take me to dinner and I end up paying half the time.

Anyway, the driver I ordered and received was e3.12 from Elemental Designs for $125 + Free Shipping. This driver is used in the ED A2-300 subwoofers.

These are the pictures of the front, side, and back of the sub driver:

As I was about to change the driver of the old Radio Shack subwoofer, I decided to send a private message to Brett from ED and ask him about the suitability of the driver for non-ED subwoofers in home theater applications. I received a message from him that the driver will work fine in HT subwoofers. OMG, he shouldn’t have said that to a crazy person like me.

I have been wondering for a while how my low cost Acoustic Audio HD-SUB12 would sound with a new driver. The AA is a great subwoofer for less than $200. The message from Brett was enough for me to put the Radio Shack subwoofer back in the garage and take the AA sub apart. These are the specifications for the original AA sub:

Power Output: 400 Watts Nominal RMS to 800 Watts Maximum
Woofer: 12 Inch Front-Firing Long Throw Driver
Complex Fiberglass Cone
Aluminum Voice Coil Former
Parabolic RFL Voice Coil
CEA Cooling Technology
Low Carbon Top and Bottom Plate
Rear Slotted Bass Port
Frequency Response: 20Hz-250Hz
Variable Low Pass Frequency Crossover: 40Hz-130Hz
Efficiency / Sensitivity: 99dB @ 1 watt/1 meter
Built-in Digital Drive High Efficiency Amplifier
Cabinet Design: Advanced RFL Bass Reflex
Dimensions (W x D x H): 14.9 x 15.5 x 17.4 Inches
3 Year Parts and Labor Warranty
Shipping Weight: 47 lbs

This is a picture of the HD-SUB12. As you can see the driver is quite attractive.

When I took the AA driver out, I realized that there were several problems:

1. The wires inside the sub were soldered to the amplifier and to the driver. I couldn’t take the driver out. So I took the easy way out and cut the wires with a pair of scissors.
2. As I tried to put the ED driver inside the box, I realized that it is slightly bigger and doesn’t fit. A sane and normal person would have given up, but not me. For the next hour, I tried my best to increase the diameter of the opening without doing major damage to the cabinet. I believe I succeeded.
3. I was excited and happy that I could finally attach the new driver and run test tones through it and enjoy some movies and music. All of a sudden, I noticed that the original AA driver had 6 screw holes. The new ED driver and almost all other drivers have 8. I was very unhappy and reluctantly went to the garage and got my drill and drilled 8 new holes. Finally, I attached the driver to the subwoofer. The driver has dual 2-ohm voice coils. If connected in series according to the following diagram, the net impedance will be 4 ohms.
   
   
   
   
   
   
   This is a picture of the sub with the new driver.
   
   
   
   
   
   
4. Exhausted and emotionally drained, I carried the sub to the back of the room and connected the power and the sub cable. You think that is the end. Think again. Because of the new driver, the grille did not fit. That is not a major problem as I do like to look at sub drivers.

Finally it was time to test the new beast. The first thing I did was to turn off the other subwoofers in the room. I did not change any other settings. I ran the receiver’s test tone through the new sub and measured it with my SPL meter. It was about 2 to 3dB higher than before. Next, I played one of my favorite subwoofer test CD, Dead Can Dance: Sprit Chaser. Track 3, 4, and 7 give your subs a good workout. I noticed that the new sub sounds deeper and perhaps more detailed. The difference was not night-and-day, but noticeable.

Because the sound was a bit deeper, I automatically assumed that the new driver has better low frequency extension. I decided to run test tones through the sub. To my surprise, it hardly produced any sound at 20Hz. My SPL meter registered 68dB. At 25Hz, the sound was louder around 87dB and they were louder after that. These are the overall responses at 1 meter (3.3ft) in my room:

20Hz, 68dB
25Hz, 87dB
31.5Hz, 97dB
40Hz, 97dB
50Hz, 88dB
63Hz, 92dB
80Hz, 94dB
100Hz, 92dB
125Hz, 92dB

This is the plot of SPL versus frequency.

The original AA driver played much louder at 20Hz. I cannot explain why the new driver sounds deeper. I know that ears are not reliable and sometimes give you misleading results. I plan to run the test tones again after a few more days. Overall, I am very happy with the new driver. The total cost of the original sub (particularly if purchased from their Ebay store) and the new ED driver is still below $300 and a huge bargain. I decided to name my subwoofer the AA/ED-SUB12.

Was it necessary to change the driver? No, not really. The old driver was fine and very satisfactory.

Why did I do it? Because the sub was there and I had to do something new and different. After all, I could not allow Driver King to show off with his DIY subwoofer and the ED driver.

Furthermore, I had to take the title of the craziest person on Blu-ray.com away from CrazyBlue. He is the one who bought 3 subwoofers and a receiver on the same day. A few of us, including me, belong to an institution.

[crazyBLUE]

CRAZY is A good thing to be Big Daddy !! That was A good read & am glad you like the results ! My upgrades start today with all my RG6U cables being delivered - The box weighs 17.5 lbs . I will get some pics for you soon !!