Cheap sub project & else

For all those little gadgets that make driving your car more fun and convienent. Big subs, screaming tweets? Got an amp that's on the way out? Need some recommendations? Then this is the place to ask.
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weba
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Cheap sub project & else

Postby weba » Tue Oct 14, 2008 4:43 pm

I never posted any of the audio crap i'v done, how ever i'v build some subwoofers before this and couple sets of home speakers too, since then i'v lost interest to HiFi\Audio, but now i started a new project again:

Cheap small effort subwoofer project

I do not have that much interest on car-audio, since it's heavy what is anti-Go, and i usually listen to engine\tire noice instead. How ever, i ended up getting a 12" subwoofer speaker for free, so i decided to design and build a custom box for it. And cause i don't want to spend money on stuff like this, i'm going the cheapest way  :hammer

Material i'm using is 19MM MDF.
Subwoofer is 12" JBL GT4-series
Inside displacement im going is 65L
Tuning frequency will be set to 25Hz with 10x50cm pipe.

Costs so far:
- Subwoofer 0e
- Wood 23e
- Cutting of pieces 9e
- Paint 5.49e
- Grille 4.99e
- Terminal 3.49e
- Pipe 5.99



Basic start.














I ended up with a box design like this, fills up the trunk really nicely, does not actually even move there (going to bolt it down anyway) and i can add another woofer to it if i want some other day.






Work in progress, more pics coming later. :)






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Cheap sub project & else

Postby weba » Tue Oct 14, 2008 4:54 pm

Just to share some other pictures.



Size compare to my hifi-sub, what i builded in 2002 for Volvo witch was my first car later.
This sub also was sitting in the trunk of my 91 GTZ, unused from since.



What im using in front vs stock speaker. I'v planned to expand this set to 3-way later, that includes adding amp.



And what i have in the rear, Local brand speakers, really good for the price, they are runned by 10 year old amplifier that was pictured in first post. :)

Oh and i LOVE the stock style with hidden speakers so that's what im using with these too, no cutting for me.

The headunit i'm using is Alpine 7892R


It actually was top-of-the-line model back when i bought it, that would be 2003 ish. No MP3 support either but i dont really care about that one.  :p I can hook it up to my laptop to play those if i want.






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Kyle Anderson
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Cheap sub project & else

Postby Kyle Anderson » Tue Oct 14, 2008 8:02 pm

25hz sounds really low for your tuning frequency...

Do you happen to have a link to the T/S parameters for the sub?



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Cheap sub project & else

Postby weba » Wed Oct 15, 2008 1:05 am


(Kyle Anderson @ Oct. 14 2008,21:02)
QUOTE
25hz sounds really low for your tuning frequency...

Do you happen to have a link to the T/S parameters for the sub?

I don't have it online, simulations actually suggested me to go 23Hz, that would require going really long tube witch would take a good share of the interior displacement of the case.

Fast Googling i found these:
* Fs - 24.75 Hz So you can see i'm really close to desired. :)
* Qes - 0.46
* Qms - 6.46
* Qts - 0.43

And i like to go Low with my subs, my heavyest home sub was exprimentally tuned to 19Hz for a while, here's picture of it back then:





This thing blasted insane anmounts of pressure @ lowest frequencys. The woofer i have in this, is good old Peerless XLS-12, the mother of all sub-subs with 18Hz fs :p

i usually use lowpass filter set around 70-80Hz with 24dB\okt slope


And here's a smaller living room sub i made:


This is using Linkwitz correction to go -6dB @ 20Hz in closed case!  :hammer

<- loves sub-bass.






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Postby 6r8ph1X » Wed Oct 15, 2008 1:58 am

where did you get that port weba?



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1996 Beretta Base, GTU conversion, 3400sfi with less than 100,000 miles :)   ==  Traded

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Postby weba » Wed Oct 15, 2008 2:18 am

Shop  ???

seriously, can't remember, i bough the ports in 2002 or something. The brand of those is Aeroport, but i'm sure you can get ones like that from any diy-audio shop.






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Kyle Anderson
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Cheap sub project & else

Postby Kyle Anderson » Wed Oct 15, 2008 2:20 pm

I believe parts-express carries the Aeroport brand. (www.parts-express.com)

I have used a similar port system made by Dayton, also available at the same place.


As long as you know that you like it tuned low, that's all that matters. It should work pretty well going that low with an FS of ~25. I was initially scared because that's normally quite low for the average sub.



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Cheap sub project & else

Postby wicked-irocz » Wed Oct 15, 2008 6:22 pm

Looks good weba.  I personally prefer sealed boxes but to each his own.  I did a ported box for my brother because he likes it loud but thats not me.  

In the beretta I set the rear panel in on top of the speakers and found the tweeter/mid hit it so I took the press board out in that area and it works well, looks like stock.


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3100, auto, crank windows, power locks/trunk, A/C,
To many mods to list
-intercooler :shock:

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1st Turbo 3100
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1st 94+ Turbo

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Cheap sub project & else

Postby weba » Thu Oct 23, 2008 2:58 am

Update.


I bought the cheapest flared 4"\10cm tube i could find, and added some more pipe to it, to get the tuning frequency i wanted.


I had to cut the center supports to make room for the pipe, design flaw right there, well now it can support the pipe too. I chose to run the pipe behind the woofer, other way had the port directly behind the woofer.


Rattle can paintjob right here too, low-effort & low-cost it is ;)





Only waiting for amp and something to attach it to car so it does not move. :)






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Cheap sub project & else

Postby weba » Fri Oct 24, 2008 1:23 am


Holy bad picture Batman!

I still have to bolt it down, already went for a test drive and my ears still hurt night later...  40A fuse i had in line, burned when i turned the level Too high, i need bigger fuse ÂÂÂ :yippie

It definitely provides some Deep sub-bass, maybe not the sharpest tone on it, But it seems to stay controlled on High volumes too. Also it's not window cracking powerfull, need more expensive stuff for that...

I estimate the weight of this thing to around 30Kg (66~ lbs) and that can be felt while driving.. i guess i keep taking this thing out whenever i want to go out to have some fun...

And i gotta do something to filler panels and tails witch rattle like crazy  ???






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Cheap sub project & else

Postby michi » Sun Nov 09, 2008 7:34 am

Lol good work weba, it looks good! :)




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