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View Full Version : Tapered transmission line for Exodus DPL-10 build log



Immacomputer
08-17-2008, 11:20 PM
This build is for an Exodus DPL-10 and it is a tapered transmission line tuned to 22hz.

I will be putting it in my room on my computer powered by an Infinity plate amp (once I remove the subsonic filter circuitry on the board).

I had a couple **** ups at the beginning but they smoothed out well and it's looking good so far. It's drying with the first coat of polyurethane and will be sanded and then coated again tomorrow evening.

I built the box in two parts and this is the inside part being clamped down as one piece:
http://i36.tinypic.com/5fp8d4.jpg

Line walls painted:
http://i35.tinypic.com/2namq07.jpg

Line stuffed and awaiting the addition of the top:
http://i34.tinypic.com/2rw3mt2.jpg

Primer on and drying:
http://i38.tinypic.com/212u15u.jpg

First coat of some rustoleum hammered black:
http://i38.tinypic.com/zjcnxg.jpg

Couple coats of the hammered paint:
http://i36.tinypic.com/6p0x0j.jpg

First coat of polyurethane drying:
http://i36.tinypic.com/egpyq9.jpg

The hammered texture is really nice under the polyurethane so I won't be sanding it too much or doing many coats of it but I would like the box to be pretty shiny and feel nice.

Let me know what you all think...

95BlackGA
08-17-2008, 11:21 PM
You need bigger pictures, and show some of the driver itself!!!

Other than that, very nice!

tc3k101
08-17-2008, 11:22 PM
awesome

thegreatestpenn
08-17-2008, 11:22 PM
boom, nice

tc3k101
08-17-2008, 11:22 PM
You need bigger pictures, and show some of the driver itself!!!

yeah i wanna see the moofa. i like exodus, i want to get 2 10s for my work van

Blinkrazy
08-17-2008, 11:23 PM
very nice

tommyk90
08-17-2008, 11:24 PM
I'm curious as to why you completely stuffed the port with polyfill?

Immacomputer
08-17-2008, 11:44 PM
You need bigger pictures, and show some of the driver itself!!!

Other than that, very nice!

You're lucky I resized them as small as I did.

Here are some pictures of the driver:

http://i34.tinypic.com/2c0jzm.jpg

http://i36.tinypic.com/16gix37.jpg

http://i33.tinypic.com/1z31g14.jpg


I'm curious as to why you completely stuffed the port with polyfill?
It dampens the response, flattens the impedance curve (reduces the two peaks like you get in a ported box to make it look like the single peak of a sealed enclosure but with a much smaller rise), and it reduces standing waves which smooths out the harmonics of the resonance point of the enclosure. The line in a transmission line does not act like a port does in a ported enclosure and so having the whole line filled will not hurt like it would in a ported enclosure. It will reduce the peak around resonance (probably going to be around 15hz or so) and it smooths the upper frequencies.

From the limited listening I did, it sounds very smooth and laid back and VERY low distortion to my ears. I can't pinpoint where the bass is coming from while I'm standing two feet away from the cone. At 10hz with all the amp I had, it sounded like a helicopter was landing in my room yet very pure. Hopefully it will finish well and I can get the SSF removed from the amp.

tommyk90
08-17-2008, 11:52 PM
It dampens the response, flattens the impedance curve (reduces the two peaks like you get in a ported box to make it look like the single peak of a sealed enclosure but with a much smaller rise), and it reduces standing waves which smooths out the harmonics of the resonance point of the enclosure. The line in a transmission line does not act like a port does in a ported enclosure and so having the whole line filled will not hurt like it would in a ported enclosure. It will reduce the peak around resonance (probably going to be around 15hz or so) and it smooths the upper frequencies.

From the limited listening I did, it sounds very smooth and laid back and VERY low distortion to my ears. I can't pinpoint where the bass is coming from while I'm standing two feet away from the cone. At 10hz with all the amp I had, it sounded like a helicopter was landing in my room yet very pure. Hopefully it will finish well and I can get the SSF removed from the amp.

Hmm, interesting. Thanks for the explanation. :)

Immacomputer
08-22-2008, 08:11 PM
Small update...

Here is a picture of what the mounting terminals are going to look like:

http://i35.tinypic.com/2lu89qe.jpg

The silver bolt will not stick out past the brass nuts when attached so it should look pretty nice. There was also a nice sale on Monster cable at Walmart so I picked up some of the 12 gauge wires.

The terminals will be on the side facing the wall. That side is the side that I ****ed up. The finish is decent but I put a hole where I wasn't supposed to and it didn't fill well. Oh well.

Here is a picture of it. In the bottom right corner you can see two holes: one goes through and it will be used for the terminals while the other is an 1/8" dip where I filled an almost through hole.

http://i37.tinypic.com/2youb80.jpg

It isn't horrible and shouldn't be a problem when it's all finished. The two large sides (top and bottom in the pictures but not how it will stand in my room) are both finished with polyurethane and just need a rubbing compound and wax in a few days. I'm going to work on the front and back next. The tropical storm hanging around here has really slowed down my progress seeing as it takes a thin coat of urethane 6 hours before I can sand it.

Picture from the front:

http://i37.tinypic.com/15e77zr.jpg

Immacomputer
08-22-2008, 08:54 PM
I flipped it around and now I'm finishing the front of the enclosure. These pictures show the bottom with respect to the images above; it is the first finished side that just needs to be hit with rubbing compound and wax in a few days.

The finish is very nice and I hope all the sides turn out the same:

http://i35.tinypic.com/313siv6.jpg

It's almost pearlescent:

http://i37.tinypic.com/20h6c77.jpg

http://i33.tinypic.com/zvener.jpg

Immacomputer
08-24-2008, 08:22 PM
Here are the pictures of the sub installed and I'm waiting for some epoxy to dry for the terminals. It looks pretty **** good and I have it on some damped slider feet that make this 100 lb move easily without killing myself.

http://i34.tinypic.com/8zinba.jpg

http://i36.tinypic.com/b53cyg.jpg

I will leave it how it is for about a week and then I'm going to hit it with rubbing compound and then wax it. It should have a pretty nice finish by then though I can't complain much about it now.

Farva
08-24-2008, 09:59 PM
Nice work! In the past I have used upholster felt and even fiberglass as damping material in ported, mass loaded pipes and tlines in a few home theater projects. Used polyfill before in some sealed enclosures but not in ported or tline yet, any particular reason to why you choose to do so? Also how did you taper it, Sd to what (i.e. 1.5-2xSd down to half Sd)?

Immacomputer
08-25-2008, 01:19 AM
Polyfil is all I have ever used so it's really all I know. I used it in the transmission line in my car and it worked very well so I used it again here.

As for the taper, it goes from about 1.6 to .53 or so. I needed to save some space and wanted the line tuned low so going with a taper of that scale was used. It also helps tame things below 20hz.

I gave it a quick listen tonight and it is very musical and clean. I am missing a bit in the 25-30hz range but it appears to be a room null as in the other corner it's very potent. I'll get to play with it a little more in a week and I may run a quick FR curve.