New Life for an Old Subwoofer - AVS Forum
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post #1 of 10 Old 12-02-2004, 06:58 AM - Thread Starter
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Just wanted to share my recent experience with upgrading a Radio Shack 12" subwoofer. I first thought about purchasing a HSU or an Outlaw model, but then realized the enclosure and the 200 watt rms amp of the RS subwoofer could serve well with a new speaker. I found a 12" Dayton dual voice coil model that most closely fit the size of the existing speaker. The Dayton also had impressive specifications that put it well beyond the OEM speaker that RS used.

I changed the design from vented to sealed and added a pound of the nylon acoustic fill material. The new speaker went in with only some minor work required on the enclosure. The result is in my opinion a much better sounding subwoofer. Not as much distortion as with the original speaker and the vented design. Now I can hear down to 25hz instead of 35hz. Much tighter sound as well.

So, if any of you are experiencing upgraditis (I have had three such attacks myself this year), consider doing what I did for the subwoofer.

And yes, for my listening levels, the 200 watt rms amp has plenty of drive even in the sealed enclosure.

Tom
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post #2 of 10 Old 12-02-2004, 07:14 AM
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Nice job Thomas, glad to hear your experiment went well. Now when you want to upgrade again you can just buy a bigger amp and build a better box. Voila! New subwoofer!
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post #3 of 10 Old 12-02-2004, 09:37 AM
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You are going to be driving the amp too hard to achieve decent listening levels without the port. Sealing the port *doubles* the power required for the same SPL. Don't be surprised when the amp melts.

Why not try it with the port open? You can leave the stuffing.

No matter where you go. ... There you are.
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post #4 of 10 Old 12-02-2004, 10:21 AM
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pictures?
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post #5 of 10 Old 12-02-2004, 12:50 PM - Thread Starter
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DMF:

I realize that a sealed enclosure requires more power, but at my listening levels the 200 watts rms should be fine. I am driving old AR-4x acoustic suspension speakers for the front channels and they work fine with the 100 or so watts the Denon 2803 supplies them. If the amp does melt, then it will be back to Parts Express for a larger amp. I like the sound of the sealed enclosure and found the sound better even with the "old" speaker temporarily put back before the new one arrived.

jermy4:

No pictures since the sub looks exactly as it did before the modification.

Tom
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post #6 of 10 Old 12-02-2004, 01:39 PM
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I meant pictures of your modifications ...
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post #7 of 10 Old 12-02-2004, 02:10 PM
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Why not try it with the port open?
I'd rather have a sealed design (with not a lot of power) than a grossly underported design (i.e. fart box).
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post #8 of 10 Old 12-02-2004, 04:49 PM - Thread Starter
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jermy4:

I don't think pictures would show much. Basically I had to remove about 1/16 of an inch of the opening to allow the new speaker to fit flush. I emoved the tuned port and cover the opening with a piece of 3/4 plywood glued and screwed to the bottom inside of the enclosure. Packed the acoustic nylon material into the enclosure and mounted the new speaker. Actually not much to show.

The new Dayton has a heavier magnet and longer excursion than the OEM speaker. The new speaker does go about 10hz lower (to about 25hz) than the original and sounds much tighter with both music and LFE such as opening scene in Star Wars Episode II.

Basically gave my sub a new lease on life without much cost.

Tom
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post #9 of 10 Old 12-02-2004, 07:37 PM
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Thomas, you have my interest ...

What is your room size? What do you run the sub gain at? Is the sub able to play loud enough for your listening volumes? Does the amp run really hot?

You might have found the prefect sub for your room or it might die tomorrow.
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post #10 of 10 Old 12-03-2004, 12:21 PM - Thread Starter
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Jermy4:

The room size is 11.5 x 15 with seven foot ceiling. Wall material is paneling. Since I live in a townhouse with neighbors on either side, I rarely play loud music or movies, but when I do the sub amp never broke a sweat. Now running as a sealed enclosure, that might change and I will poke my hand in the back of the sub to feel the heat sink to see how hard it might be working.

I do notice even at my moderate listening levels how much tighter the bass is, for both music and movies. I have a CD that has some various test tones and from my very unscientific measurements (my ears) it seems that the new speaker can reach another 10 hz lower (from 35hz to 25 hz).

I liked the front firing design of the sub woofer and figured rather than replicate the enclosure and amp I would try a new driver. So far so good.

Tom
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