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Crazy cheap sonosub build

post #1 of 12
Thread Starter 
Hey I need someone to point me to a sonosub build guide that I can use as a reference. I am planning to build a super small budget sonosub plant stand as an xmas gift for my dad. I pulled this plate amp off of an old sub from a kenwood htib subwoofer. It claims 100 watts on the back, I'm not sure how true that is but it's heavier than my bash 300. So I was thinking of using this cheap dayton driver since it has a 120 watt rms, and it's cheap.

http://www.parts-express.com/pe/showdetl.cfm?partnumber=295-488

I guess I would tune it around it's fs of 24hz. I figure if this plate amp can put out 60 watts, then I'm only short 3db's of this drivers potential output. The model number on the amp says sw-36ht.

Hmm I downloaded the manual and it says 120 watts rms, who knows...

DSC01276.jpg
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post #2 of 12
hi,

any driver can't just be plopped into any enclosure. the driver parameters must be matched to the enclosure.

you are in luck though because sonosubs are as easy to design as ported enclosures.

for the lowest cost possible, here is what to do:

1 piece of 18" diameter sonotube that is 48" long
1 piece of 6" diameter sonotube that is 24" long
2 pieces of wood 3/4" thick, circular, that fit exactly into each end of the 18" sonotube
1 piece of wood, circular, a little larger than 18" for the top

glue the 18" endpieces into the sonotube. make sure they are air tight.

mount the driver on one end and the port on the other end.

add some 1" dowels that are at least 2" long for the feet on the bottom and the feet on the top.

to the top "feet" add another round piece of wood a little larger than 18". this is what your dad can put the plant pot on.

this design will work with the driver and amp that you mention and will have a little over 6 cubic feet interior volume and about a 21hz tune.

finish it however you like.

post #3 of 12
Thread Starter 
Thanks for your input LTD02. I didn't mention what else I was using. I have some leftover plywood from my lilmike f20 and was going to use a square top for the enclosure, and have some 4" diameter pvc left over from a ported enclosure. I'm running off of scraps here, to keep the budget low. For the sonotube, I'm not sure how to finish it. He doesn't really care that thing look nice, so I may just spray paint it. I'm under the assumption that I can just run PL on the rim of the sonotube and place a square piece of stained plywood on top of it. I usually use winisd pro, but is there a better program for cylinders? I'm fine with calculating the internal volume with pencil and paper of a cylinder, but wasn't sure if I should be taking a different path.

And what is your opinion on the salvaged amp? I'm going to try it out, and if it doesn't work, I'll just have to up the budget and grab something cheap but better. And do you have any other suggestions for really cheap drivers, this would be used mostly for music to compliment his mains. I'm unsure of the brand, but each tower has 2x 8" drivers, a mid and a tweeter. I'm not sure if it's his amp, but they lack bass compared to some towers that I have with 6" drivers.

And if you're aware of some, could you link me to some threads of successful sonosubs with finishes, because my searches just result in "noobs" asking questions. No offense to the noobs, but I understand how to calculate volume and model a ported sub. I'm used to working with wood / mdf, this cylinder deal is new to me.

Damn that's a lot of questions :P
post #4 of 12
i don't really see many questions there.

mounting the endplates on top/bottom of the tube is fine, just ensure that they are air tight. an expanding adhesive such as pl premium might help.

not sure what to say about your amp. if it works, keep it, if it doesn't ditch it. :-) it should be good power for that driver/enclosure combo.

as for sonosub finishes, wrapped in the cloth of your choice is one option. just painting it black is going to leave the 'spiral' on the tube.
post #5 of 12
post #6 of 12
I wrapped up a sonotube build not too long ago, you can check it out from my sig. There's also an app which calculates sono specific details (like 1st port resonance, height needed above and below,etc) which you can find off the LLT primer.

As finishes go, I went with textured spraypaint. The spiral is there but it does not seem obnoxious in person.
post #7 of 12
4" port?

missed that the first time.

two of them 24" long would work fine and give you a 21hz tune.
post #8 of 12
Thread Starter 

It does look better, but I'm working with 100 watts, so I wouldn't be able to take advantage of that drivers 300 watts rms.
post #9 of 12
No but you could take advantage of it's $10 cheaper. wink.gif It's also got some excursion you might be able to use.
post #10 of 12
Thread Starter 
Alright, I could only find 12"D sonotube unfortunately, so I have to go with the 10" version of this driver:

http://www.parts-express.com/pe/showdetl.cfm?partnumber=295-486

It looks like I can get a 2.5ft^3 enclosure with a 4" diameter, 14" long port, tuned to 28hz. Around the tuning I'm getting 50ft per second for port velocity, so just barely acceptable. I get a flatter response if I up the volume, but excursion really becomes a problem. I'm not used to modeling such a low cost driver... even with the 2.5ft^3 enclosure I'm seeing 9mm excursion at 40hz, which is quite a bit over it's 6mm xmax. I'm not sure what the xmech is, so I hope this isn't a problem. Here's some screens from winisd, this is with 100 watts:

spl-1.png
excursion-1.png
post #11 of 12
Well, that is to be expected with a low excursion driver like that. I don't think you will hit xmech with program material and only 100w though.
post #12 of 12
Thread Starter 
Ok finally getting around to this and have a question. I see most people put the driver on the bottom. The problem is I could only find 12" diameter sonotube, so the port will have to be on the opposite side of the enclosure. So would it be ok to mount the driver on the top side? The top of the "plant stand" will be a few inches above the driver. I'm not sure if this will sound as good as downfiring, and I'm also not so sure about cone sag, because gravity could be helping the driver reach xmech.

I can attach the port to the top instead, I'm just not sure how to secure it, because it would just be hanging there held on by nothing but some PL.
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