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Discussion Starter · #1 · (Edited)
I finally sorted my old tube out for my daughters corsa.

Basically I had been tinkering around with shelf speakers in various cars for years and being really disappointed by the results as well as making a mess of the shelf.

Mid and treble are really easy to acquire from a system, you just buy the driver, stick it in to place and wire it up, but big bass and lower frequencies were much harder to come by. I did some work for a friend of mine about 15 years ago, and in return, he gave me a 10" kenwood subwoofer driver. You couldn't just go and buy a sub enclosure back then and people were mounting these speakers in their parcel shelves (or trying to anyway) and they still sounded crap :laugh:
I made a box up for it and it sounded a bit on the crap side considering the amp used and the quality of the driver (which was very good for its day
), so I went down to my local library and got a book out on speaker theory and design for houses.

It took me about 2 months to read it and understand the theory of it enough to have a bash at building my own speaker enclosure which is a bass reflex design.

I settled on 10" diameter yellow gas pipe as a material to make it out of due to its density (weighs a ton), and as the pipe is about 20mm thick and you can screw self tappers into it and calculated that I needed it to be about 550mm long.

For the bass reflex bit, I needed to have a port running up the side of the tube from the back of it to the speaker which takes whats coming out of the back of the speaker, slows it down slightly and adds it to whats coming out of the front for maximum punch from minimum power input (i used 2 ports to get the volume right).
I settled on some 100mm diameter drainage pipe for the ports which I cut along its length into two halves and bonded them to the side of the gas pipe with hot weld, cut ports 100mm deep from the back end of the pipe the width of the drainage pipe so the sound could pass into them.

I blanked the back of the pipe with 15mm mdf, and lined it with acoustic wadding to reduce the reverb. Then I made up an adapter ring out of mdf as the speakers chassis is slightly bigger in diameter than the internal diamter of the pipe, put in some terminals to get the wires to the back of the driver, and carpeted it.

I used it with a small bridged alpine amp in my old Kadett GSi for years and then it sat in my garage gathering cobwebs for about 5 years.

Anyway, my daughter got her Corsa, knew it was in there and after a fair bit of nagging, its now in her car. The Kenwood driver was totally shot, so that was replaced with an aluminium coned Clarion driver (rated to 200 watts RMS) and a couple of days ago, I picked up a 200watt bargain Fusion amp (RMS bridged at 4 ohms) for £50 (ex demo down from £80 in Halfords) and will put in the old alpine amp to run the rear shelf speakers from the low level outputs on this amp.

The tube works perfectly (hurts the ears and blurs the door mirrors), but a couple of minor niggles are that the 12volt remote wire from the head unit isn't sending enough voltage down the wire to turn the amp on so I'll have to use a pick up from one of the ignition wires to resolve it or try the aerial feed out of the head unit and see it this is enough to turn the amp on. In the mean time I'm just bridging a wire across from the main power feed to the remote terminal, and I'll make up and carpet a mounting board to put the amp on once I'm happy with the wiring to tidy it all up.



 

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Discussion Starter · #3 · (Edited)
Cheers for the comment.

I tacked amp to the tube as I didn't want it sliding around on the floor so it does look untidy. I got the remote on wire working now by using the ariel wire off the head unit, so the next job is to make up the mounting board for the amps against the left hand side of the boot. The power wires are short, which is why they all look a bit strained in the current setup.

I may yet re-carpet the tube as I've got a big roll in the garage which is better quality than whats on there
 

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The tube works perfectly (hurts the ears and blurs the door mirrors), but a couple of minor niggles are that the 12volt remote wire from the head unit isn't sending enough voltage down the wire to turn the amp on
I got the remote on wire working now by using the ariel wire off the head unit.
I had exact same problem with mine and also used the aerial wire! lol. Never knew why it wasnt giving enough voltage.
 
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