My Autotuba Build - lots o' pictures

[loudsubz]

I had built a T39 a few weeks before and was very impressed, but also wanted to try out a tuba design since I had bought a bunch of plans. I had 3 X Tangband W8-740C drivers laying in the basement as I had bought them before when I was heavily into car audio. I thought it would be perfect to give them a try in this new fangled contraption they call a folded horn.

My journey started off at Lowes for some Aurocoply 1/2" Plywood. It was $26 for a 4X8 sheet. I had them cut it into rough 14" strips to carry it home (was not able to borrow the trailer this time).

Once home I cut out the last big piece I had for braces and other misc parts (also for a few extra parts on my second T39 I am building).

I built a saw sled that is 8 feet long so I can do a whole panel if need be. I also swapped out the rough cut blade on my 7 1/4" CS for a smooth plywood blade for cleaner cuts.





I use a Drywall T sqaure to get a good clean line on straight panels.





This is my table saw. It is a cheapy 10" B&D saw with shoddy fence and limited rip capacity. I had some stock laying around so I built a table extension and bought a piece of "L" aluminum for the fence and the cuts are great now. Its not fast to setup because I have to measure both ends but once setup it works flawless every time. Only cost me $15 to make.





My cut plans I had made for the 14" wide AT. That cutsheet program is a great time saver, really helps to maximize your stock and have less waste.

The 14" rough cuts from lowes were ok, but most of them varied by 1/8" or so. I setup the table saw to rip them all to the exact width.

[loudsubz]

My first cut was for the driver access panel. I find my dremel multimax does a great job and is easy to work with.





The boards after they were all ripped to the same width.



Doing 2 AT at the same time helps when you don't have to set up the angle cuts more than once.













I skipped ahead and assembled all the pieces with 2 drywall screws per panel to make sure they were all aligned and fitted correctly. I didn't glue them as I would take it all apart when I was done and glue it all up in my basement where it was warm.

Making the braces was fairly easy. Following the plans was spot on and I was able to cut them just right.



Cutting the driver hole was achieved by tracing the outside diameter of the driver, marking the screw holes, finding the centre of the driver, than measuring the gasket width and drawing a new circle for the inside diameter.







Drilling the holes for the T nuts with minimal chipping was done by using a small bit for the pilot hole, than coming in from both sides of the wood with a 1/4" bit.



A little bit of chipping but very minimal.



T nuts fastened and driver test fitted.

[loudsubz]

Gluing it all up.







The gasket on my TB drivers had a slight opening where the gasket pieces connected so I filled it in with some Silicone and let it cure over night. This way I would have a sure seal.







I like to go overboard and apply a layer of DAP to all the interior seams to make sure I am not going to leak. This step doesn't really take long but gives me some extra assurance.





Driver mounted inside, testing for leaks.





Drilling the hole for the speaker terminal.



Test fitting



My soldering iron



Soldering terminals





Applied DAP to the perimeter of the sub, making sure no leaks



I didn't feel like making a recessed access panel as I wasn't looking to win any contents for its looks so I just made a panel and attached it to the outside.



All sealed up running it through some "minimal" testing.





I used my planer to knock down any edges and also cut the extruding baffle at the front that is normally cut down with a router or saw sled. The planer made fast work and turned out great. Also gave it a nice sanding with my random orbital.







Thats it.

I am sure this is not one of the prettiest builts but its what can be accomplished on limited budget and tools. Lots of patience (I went through 2 baffles on my second build because I messed up the hole for the speaker). Its very rewarding when you connect it all up and you listen to it for the first time.

I highly reccomend you give these designs a try if your still pondering.

Thanks for looking.

[digital_chris]

Congrats on the build! Just like mine with the "external" access panel : P

I feel like my AT is the ONLY one that sounds like garbage... : (

[ewetho]

External non flanged is very quick easy and FUNCTIONAL!!!

Nice Build.

[Gregory East]

You're a lot quicker than me. Although you seem to be working with some much nicer plywood. The compound bowing in my AT panels has been taking a lot of wrestling with innovative clamping.

I dunno about all that silicon. I read somewhere on here that silicon fumes eat rubbery type driver cones.

[mems]

I'm just looking to see if I could get one of these to fit in the back of my Wrangler with the rear seat in. Dimensions 10x10x24 sound close?

[Gregory East]

see that burgundy banner at the top? http://billfitzmaurice.net/autotuba.html

[mems]

Musta read right over it. Thanks for the insight.

By the way, nice build. Simple and clean. No frills.

[loudsubz]

You're a lot quicker than me. Although you seem to be working with some much nicer plywood. The compound bowing in my AT panels has been taking a lot of wrestling with innovative clamping.

I dunno about all that silicon. I read somewhere on here that silicon fumes eat rubbery type driver cones.

Most of the wood was pretty good except for the last side panel which was fairly bendy because I left it in the garage. I was able to spray it down with a spray bottle with some water, lay it on the basement floor and place a weight on it for 30 mins and when I lifted it off, it was straight as an arrow.

Try that next time your panels are all out of wack. You should have enough time to glue it all up and secure before it will want to bend again.

As for the silicone, the only silicone I used was to fill the small gaps on the gasket. All that white stuff in the enclosure is DAP which is latex based so theres no harsh fumes and very easy to clean up with water.

[loudsubz]

couple videos

http://www.youtube.com/watch?v=4sqS2oNsX38

http://www.youtube.com/watch?v=G0uznjdEGw8

http://www.youtube.com/watch?v=S9gbOp2Ne18