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Old 27th December 2010, 03:45 AM   #31
Rudy81 is offline Rudy81  United States
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Use of the router was rather experimental for me, so I went all out. I also cut rabbets along the edges in hopes of getting a perfect fit on the side panels. The router bits are rather expensive, but I figured I'd have some good tools when I was done.
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Old 27th December 2010, 03:46 AM   #32
Rudy81 is offline Rudy81  United States
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Based on pictures of other builds, I wanted a convenient access panel to the woofers in case of problems, or if I ever needed to replace a driver. I created another template so I could match both subs and also ensure the access panel location would work.
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Old 27th December 2010, 03:47 AM   #33
Rudy81 is offline Rudy81  United States
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Here is the complete access panel. I then cut a matching piece of BB to create a panel that fit in the slot.
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Old 27th December 2010, 03:47 AM   #34
Rudy81 is offline Rudy81  United States
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Interior almost complete on both units. Still need a little more polyfill near the horn exit. Then I chose to mount the drivers before I permanently mounted the last piece. It just made it easier to mount drivers, wire and check continuity. Wired in series I got 6.6 Ohms, which should be correct.
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Old 27th December 2010, 03:49 AM   #35
Rudy81 is offline Rudy81  United States
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Units finally complete and sanded, waiting for paint. Prior to sanding and working on the exterior I took one of the subs outside and ran some frequency sweeps through the sub.....plot to follow. As you can see, the sweeps were satisfactory and prepped for paint.
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Old 27th December 2010, 03:49 AM   #36
Rudy81 is offline Rudy81  United States
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The first day I ran REW it was raining, so I ran the plot with the sub inside the shop with the mouth of the horn aimed outside. Amazingly, I got a very similar response as I did in this run. The run below was done outside with the sub flat on the ground. Horn mouth pointing up. I used my shop receiver to run the sweep, so nothing with real power. I think it has 70 wpc.
I am pleased with the performance, but can't figure out the dip near 120Hz. I beleive the sub will work well for my LFE channel, from 15Hz to 125Hz. The system delay measured by REW was right at 6 ms. BTW, this is a totally uncorrected plot.
I have already started painting and will have more shots later.
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Old 27th December 2010, 03:51 AM   #37
Rudy81 is offline Rudy81  United States
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While I'm thinking about this, I'll add some comments on the build.

Although it was not complicated, it took much longer than I expected. Partly because I was building two units, and partly due to my lack of skill with woodworking. I certainly learned quite a bit.

I used the PL construction adhesive since I needed a glue that would 'fill' voids well. In retrospect, I would still use it, but only for the interior parts. It is very messy and not easy to remove excess. For the outside seams I should have used carpenters glue since the sides did not need voids filled. The excess I got on the sides needed to be sanded, which was a pain. I figured paint wouldn't stick too well to that product.

The rabbet and dado idea worked very well for the cabinet and the access panel.

I also spent quite a bit of time dry fitting things since I did not trust my skill to be right on every time.

Another issue was taking guesses at the length of the interior panels. I was glad I dry fit everything first since I had misjudged the length of one panel, making one of the turns narrower than the horn width before and after the turn. I figured that wouldn't work, so had to shorten the panel in question.

I chose to ensure the speakon connector and access panel were on the low pressure side of the enclosure to preclude any chance of leaks in the high pressure section.

The biggest problem I had ocurred when I went to put the last large piece on one of the units. I had cut a dado on an end piece too deep ( where the angled driver baffle meets the end piece), so when I screwed the end piece in, it pulled the end in and bowed the BB. When I went to dry fit the large top section....it didn't fit! It took me about two hours to break that joint loose and pull the end piece away enough to allow the top to fit the rest of the enclosure. I could have saved myself a lot of time and stress if I had dry fit the top on WHILE I screwed the sides on. Live and learn.
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Old 29th December 2010, 12:46 AM   #38
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Took a free air impedence measurement of the Tang Band W88-740P. I also ran the measurement for two drivers wired in series with one driver out of phase.
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Old 29th December 2010, 01:51 AM   #39
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Great build, and as far as I'm concerned any build where you don't lose a finger is a good one! Don't forget to do a few impedence measurements of your completed box.
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Old 29th December 2010, 01:58 AM   #40
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Quote:
Originally Posted by hellonwheels View Post
Great build, and as far as I'm concerned any build where you don't lose a finger is a good one! Don't forget to do a few impedence measurements of your completed box.
Amen to that! This was actually my second attempt at a speaker build. My first journey down that road was my DBB main speaker build. I liked them so much, they replaced my Khorns as main speakers. As you can see by my avatar, it is a two way speaker with dual 15" woofers.

Once I get the subs up to my room and set up again, I will run an impedance plot for the drivers in the enclosure.
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