DIY Subwoofer Building, Repairing, & Upgrading

[Driver_King]

I can imagine. I like your wheel idea though...

[Big Daddy]

Originally Posted by Driver_King

I can imagine. I like your wheel idea though...

I hurt my back severely a few years ago. I prefer to have casters under TVs, Receivers, Refrigerators, Sofas, Blu-ray players, etc. If I could, I would have attached a pair of wheels to my children's feet (when they were smaller) so I didn't have to carry them.

[Driver_King]

Wasn't that in a movie once?

[Big Daddy]

Originally Posted by JJxiv1215

Shoot, I've been needing a bedroom setup, and what better project over my winter break than to assemble it myself??

JJ, since you are an architecture student and you need speakers for your bedroom, you should make a smaller version of this speaker/subwoofer for yourself. Ask your professors to see if you can turn in this for your final project. This is the plan http://www.parts-express.com/project...m?project=hoss

This is a larger picture:

[Big Daddy]

I had an old 15" DBX subwoofer that I had purchased in late 1980s. It hadn’t been used in a long time and was pretty worn out. A few weeks ago I decided to completely refurbish and upgrade this subwoofer. A few days ago I finished the project and posted the pictures. Go to the original post and see how I refurbished the old monster.

[JJ]

I wish I could've turned that in as my final project - my main design course this semester centered around affordable, mass-produced housing that wasn't the typical boring mobile home. This was the final model I built:







3/8" scale - the base is 3'0" x 1'-0".

I'll get to those speakers, maybe over the summer. I think - it can be done. Best start with the subwoofers first, though,



And !!! I just read through your new adventure with the DBX. Well done - you need a logo though, company names are so bland these days. Just wait until I make mine, we'll see who moves the most units!

[Big Daddy]

Originally Posted by JJxiv1215

I wish I could've turned that in as my final project - my main design course this semester centered around affordable, mass-produced housing that wasn't the typical boring mobile home. This was the final model I built:







3/8" scale - the base is 3'0" x 1'-0".

I'll get to those speakers, maybe over the summer. I think - it can be done. Best start with the subwoofers first, though,

They look beautiful. Make sure you create a small home theater room for every unit.

If you have the tools to cut wood, particularly a nice round 11" cut, you can easily build the cabinet. People at Home Depot or Lowes will cut the large pieces for you.

[prerich]

Big Daddy - I've actually though of attaching a subwoofer to each of my speakers via the preouts and use crossovers on each channel - full range every channel and use 2 more subs for LFE. That would be a total of 9 woofers - but I realized something....I need a place to live ! Great job on the titanic retrofit!!! My son has that subwoofer powered by an outboard amp. I'm actually running 4 subs - and you are right - its not about shakin' the walls (even thought they can) or how loud they can get (even though they can - but that doesn't sound good - does it) its about smooth bass response and if its mixed properly - you can have low bass in all channels - bass thats directional (don't tell me that all bass is non-directional - most bass is, but some you can tell show me a sub crossed over at 100 hz - I can find it, I can usually locate ones at 80hz - now 50 and below that's another story).

[Big Daddy]

Originally Posted by prerich

Big Daddy - I've actually though of attaching a subwoofer to each of my speakers via the preouts and use crossovers on each channel - full range every channel and use 2 more subs for LFE. That would be a total of 9 woofers - but I realized something....I need a place to live ! Great job on the titanic retrofit!!! My son has that subwoofer powered by an outboard amp. I'm actually running 4 subs - and you are right - its not about shakin' the walls (even thought they can) or how loud they can get (even though they can - but that doesn't sound good - does it) its about smooth bass response and if its mixed properly - you can have low bass in all channels - bass thats directional (don't tell me that all bass is non-directional - most bass is, but some you can tell show me a sub crossed over at 100 hz - I can find it, I can usually locate ones at 80hz - now 50 and below that's another story).

You are correct. The thought of attaching a subwoofer to each speaker has been bugging me lately. If I can find a way of attaching them to the ceiling, then I won't have to worry about tripping all over them.

Building a speaker is very addictive. I already have requests from family members to build one for them.

[JJ]

So one of my female friends, I visited her house today, and her father had some unused speakers lying around, and I claimed them for a Jackson, and they will become my FIRST reclamation project! A pair of Yamaha NS-A220 three-way towers from the 80s. Might need to do a little veneer work, and the tweeters are blown - but I might just replace all the drivers, install binding posts instead of the spring clips - will have to open them up to see the condition of the wires and crossovers - but looking forward to having something to do over my Winter Break!

They look like, the first image of this search results:
http://images.google.com/images?gbv=...0&start=0&sa=N

They appear to have been part of a rack system.

[Samsang]

Will you guys please critique my plan?

I want to follow BigDaddy's idea for his 12" inch sub with the store-bought cabinet:



I've got a couple of 12" drivers from a pair of KLH speakers I picked up for next to nothing. Anyway, I intend to build two and power them with my former stereo amp (100 watts pre channel.) Since these "new" subs are not engineered for optimal performance, they will likely exhibit system resonance at one point or another in their useful range.

My idea is to build one with plenty of polyfil stuffing and the other with little or none. This should result in different resonsnce points for each, smoothing out the overall bandwidth when they are driven in parallel.

So I ask of you sub gurus:

1. Does this strategy make sense?

2. Do you think it could work well enough to sound good?

3. Any pitfalls to watch for and engineer out?


P.S.: I'm going to build these for the fun of it and to learn just a little. Still, it would be good to know what to expect. Thannks in advance.

[Blu-Dog]

Originally Posted by Samsang

My idea is to build one with plenty of polyfil stuffing and the other with little or none. This should result in different resonsnce points for each, smoothing out the overall bandwidth when they are driven in parallel.

So I ask of you sub gurus:

1. Does this strategy make sense?

2. Do you think it could work well enough to sound good?

3. Any pitfalls to watch for and engineer out?

They both need to be stuffed. The purpose of stuffing is not to alter resonance; it's to defeat standing waves, which reflect off the walls of the box back onto the driver.

Probably a better way to alter resonance would be to modify the size of the port on one of them slightly. Basically, it's time for you to look up the Thiele-Small parameters of your speaker, to see what the size of the box and port should be.

This one is pretty good:

http://www.radiocollection.net/tsp_calc.html

Once you know the box and port size, it's a lot easier to tune your box.

[Big Daddy]

I agree with Blu-dog. Poly-fill is for dampening the cabinet, not for altering the resonance.

If your plan is to experiment, go ahead and do it. You can always remove the driver and add some poly-fill to it later.

[crazyBLUE]

Originally Posted by Big Daddy

You are correct. The thought of attaching a subwoofer to each speaker has been bugging me lately. If I can find a way of attaching them to the ceiling, then I won't have to worry about tripping all over them.

Building a speaker is very addictive. I already have requests from family members to build one for them.

YOU KILL ME SOMETIMES Big Daddy !!!!!!!!!!!!

[Samsang]

Originally Posted by Big Daddy

I agree with Blu-dog. Poly-fill is for dampening the cabinet, not for altering the resonance...

My daughter (a mechanical engineer) looking over my shoulder chuckled at that one. She suggested a water injection system for even more "dampening".

Just poking fun. Thanks for the advice, guys.

[Big Daddy]

Originally Posted by Samsang

My daughter (a mechanical engineer) looking over my shoulder chuckled at that one. She suggested a water injection system for even more "dampening".
Just poking fun. Thanks for the advice, guys.

Actually, putting a large 2.5 gallon plastic water container inside a subwoofer cabinet may not be a bad idea. Wal-mart sells them for only a few dollars. Your daughter should apply for a patent.

[Big Daddy]

Originally Posted by crazyBLUE

YOU KILL ME SOMETIMES Big Daddy !!!!!!!!!!!!

My primary job with Blu-ray.com is to entertain.

[crazyBLUE]

Originally Posted by Big Daddy

My primary job with Blu-ray.com is to entertain.

you do it vary well !!

[xtop]

alright so i inherited my parents older subwoofer, which was decent at the time, and way better than the one i have..that i found free well anyways..its falling apart and sounds terrible. all the foam is falling out...similar to this

http://farm3.static.flickr.com/2067/...fdd011.jpg?v=0

now i keep seeing these cheap kits to repair them..is that the route i want to go? does that even work?

[Big Daddy]

Originally Posted by xtop

alright so i inherited my parents older subwoofer, which was decent at the time, and way better than the one i have..that i found free well anyways..its falling apart and sounds terrible. all the foam is falling out...similar to this

http://farm3.static.flickr.com/2067/...fdd011.jpg?v=0

now i keep seeing these cheap kits to repair them..is that the route i want to go? does that even work?

No, replace the driver. See how I upgraded my DBX subwoofer in the original post. It may cost more, but you will have a great subwoofer for many more years. You don't need to buy the most expensive driver.