Finalist speakers, Tower version. Advice needed concerning TL vs Ported

[Paperweight]

Need to trim the PVC tunnel braces a hair but this looks like it will work. Trying to figure out how to go about adding in a bottom panel. I could thin the bottoms of the PVC tunnel braces to fit in a quarter inch thick panel and glue some half inch ply on either side of the tunnel for some much needed rigidity for adding in some type of mounts to sit on top of the woofer section.

The planes and a shooting board came in very handy for straightening up my amateur woodworking skills. I discovered a green dry crumbly buffing compound that makes stropping these A2 plane blades plenty sharp.

[Paperweight]

Perfect fit of the PVC tunnel brace. Not bad for a first time using a router. Uh, a couple dozen more to go. This will take a while.

[Paperweight]

Started cutting into the 3/4" baltic birch sheet with my new 4 1/2" battery circular saw. I'm new to this so I may need to trim up a few pieces here and there. The battery lasted more than 8 hours and the new fine finish blade did a very good job. The 5 1/4 plane came in handy for smoothing out and flattening the edges I may have goofed up. That thing is stupid handy, I'm glad I invested in a good one and can sharpen it. 12 panels cut out and there's 6 more to go but I'll save that for my next day off.

After I finish the rough out, next will be a lot of circle routing to do.

[Paperweight]

Got the parts cut out on my last two days off. So far, the dry fitting hasn't revealed too many problems. The bottom panel I used is 1/4" thick. I was either going to try trimming the bottom of the PVC tunnel braces further and trying to get a 1/2" thick bottom panel to work or laminating two pieces of 1/4" plywood to fit underneath the PVC tunnel.

[Paperweight]

Paperweight, have you progressed on your build. I’m hoping to copy yours..

Thanks!
Albert

No, I got sidetracked over the last 4 months. I bought a Lie-Nielsen 60 1/2 block plane to true up the edges of the boards as I fit them. From there, I ended up buying a series of sharpening supplies, more handplanes and then chisels. I honestly don't really do woodwoorking but the handtools bug bit me. Then I wanted to build a 30" wooden jointer plane after I discovered a pile of rough sawn oak. I never knew how satisfying a good handplane with a camber on the iron could be when it slices through a piece of wood.

To cut out the maple to make the 30" jointer plane, I learned about different bandsaw blades for resawing lumber. I have some experience using the band saw and it can produce a very thin kerf with the right blade. Tomorrow, I'm going to mark and cut the cabinet kit into the top and bottom halves. This should be interesting.

[Jazzbert]

Paperweight, have you progressed on your build. I’m hoping to copy yours..

Thanks!
Albert

[Paperweight]

Received the second speaker cabinet today. Looks good and fits all the measurments I specified. Now I need to cut the sheet of baltic birch I have marked up for my split cabinet idea and see how that goes. I might split the cabinet kit I just received if I can work out all the kinks first.

I was thinking about using a 3/8" roundover bit on the 1/2" front panel. Getting veneer to conform to that might be a bit tricky.

Several years ago, I bought a large square of Appleply in 1" thickness for a turntable isolation/leveling platform. I applied a wax and colorant finish. With a little bit of sanding and buffing, it turned out decent for something quick and simple. I was thinking about using a 1/2" sheet of walnut Appleply on the front with a 3/8" roundover. Appleply has a really nice edge once you clean it up and smooth it out. The rest of the speaker can just be veneered in walnut to match the front.

I'm still debating on using Osmo hard wax-oil finish.

[Paperweight]

Just going on simple specs, it looks like the aluminum cone version can get away with a smaller enclosure and have a slightly lower f3.

[Steve Lee]

If you want something done right - do it yourself - this is the best advice I can offer you.
Experience isn't cheap to gain but it is invaluable to possess.

Now you have experience in what not to do, some good tools that will serve you a lifetime and some scrap material on hand to continue learning upon.

Take a break from it - rethink your approach and tackle it again once you have the desire/information and confidence.

Be well, brother!

[Paperweight]

It was a great learning experience but extremly frustrating and expensive. If I had known I'd get so worked up and upset, I probably would have never started this project. Now I have $1000 worth of speaker kit sitting in the corner until I get this cabinet situation straightened out. Spent $620 on two cabinets, $310 on plywood, $220 on a plunge router and $80 on a circle jig kit.

[Ryan]

I have noticed that several three-way designs like the Statements, Finalist's and Travellers use the aluminum cone version of the 8" Dayton RS woofer. How would the paper cone version stack up against the aluminum as the bass driver in a three-way design?

[Paperweight]

Thanks. It's not bad for a brain dead grocery stock clerk who hasn't been in a drafting class for 26 years. I do layout drawings for vacuum tube turret boards every once in a while so I kept graph paper around. Old fashioned but it works.

[djg]

Nice drawing.

[Paperweight]

miyami,
The person for which I designed this ML-TL version told me he was okay with me sharing the design. He had intended to be well into his own build of it by now, but storms damaged his house and he's in the middle of effecting repairs.

I've attached a drawing for the lower part of the cabinet housing the folded, ML-TL. Starting with Jim's original cabinet, you simply replace the window brace below the midrange tunnel with a solid divider, and below that you add 31.25" of height for the woofer's compartment. The original cabinet depth and width is maintained as are the locations of all three drivers on the baffle relative to the baffle's top and sides. Using 3/4"-thick panels all around, except for the baffle, makes the external height of the cabinet be 44.5". Previously I said this places the tweeter's center at 36.25" above the floor--that was incorrect. The tweeter's center will be 41.625" above the floor. That may be a bit too high but it's more in line with Jim's preference and it will definitely be better for the guy I designed this for with his HT setup. [When I calculated the tweeter height I got in a hurry and mistakenly used the center location dimension for the midrange driver :oops:] If you're really interested in this for a personal build and would prefer the tweeter to be lower, I can easily re-design the woofer compartment a couple or so inches shorter. This will not negatively impact the resulting ML-TL to any audible extent.

Going on, now that I've embarrassed myself, the folded line is created by the vertical center divider, and the line has a constant cross-section along its 63.25" length that's 9.5"W x 6.375"D. The mass-loading port is on the rear panel with its center 10.25" above the internal bottom. The non-flared port has a 3" diameter and 4.25" length. All of the first half of the line is filled with polyester fiber at a uniform density of 0.75 lb/ft3, requiring a total of ~14 ounces of fiber. With dotted lines I've shown locations for 4 suggested window braces.

The second attachment shows the predicted system bass response (red line) for a 2.83-volt input and measured at 1 meter in an essentially anechoic environment. As you can see f3 is 31-32 Hz.

If you have any questions or would like to see a different model with a shorter cabinet that places the tweeter height lower, I'm game.
Paul
[ATTACH=CONFIG]23180[/ATTACH][ATTACH=CONFIG]23181[/ATTACH]

The stuff that got cut off at the bottom was the same ML-TL and frequency graph Paul K. posted earlier. Did some searching and digging over at the HTGuide.com forums. Thank goodness for vacation to have the time to read through stuff to find this.

Our cabinet dimentions only differ by 1/4" in height which isn't too bad. I came up with 44 3/4" for total height and Paul K. gave 44.5" as his figure. I took the 8 1/4" from the top of the cabinet to the mid center and centered the PVC tunnel braces around that. So half of the PVC tunnel brace height of 7 1/2" is 3 3/4". Add that to 8 1/4" to get 12". The ML-TL cabinet starts right under that. Paul's internal dimentions of 31 1/4" plus the top and bottom panel 3/4" thickness (1 1/2" total) is 32 3/4". Add 12" to that for a total of 44 3/4" for the height. Tweeter center will be right at 41 7/8".

For once in my miserible existance, I got something right. I feel relieved and tired now.

[Paperweight]

He mixed Curt's TL internal cabinet dimentions with Paul K's ML-TL including the center panel, braces and port? I'm still scratching my head on that.

I sent him the cut list and dimentional drawing for the second cabinet. I'm still kind of worried. I'm down the cost of two cabinets. I then spent just as much on four sheets of baltic birch plywood, a plunge router and circle jig kit to redo the first cabinet.

The internal width should be the same at that for the Finalist which I seem to recall is 9.5".
Paul

Paul K.'s ML-TL design is based on the monitor speaker's original internal dimentions, just extended downward. It is not based on Curt's tapered TL cabinet and its internal dimentions which uses 11" width side to side and 13 1/2" length front to back. I don't know where that idea started or why this confusion is so pervasive and persistant. I do believe Paul K. was going on the original Finalist/Traveler monitor internal dimentions of 9 1/2" width side to side and 13 1/2" length front to back.

I would assume someone would always go the simplist, easiest, least resistance route. Taking the already established monitor speaker internal dimentions and working with that. It seems bizarre beyond reason that he would take Curt's TL cabinet and base the ML-TL internal dimentions on that. That seems very out of left field. The ML-TL is something Paul K. came up with in 2014. Curt designed the TL in 2013 but it wasn't posted on Speaker Design Works until 2016. I have no idea if Curt posted it anywhere else before 2016.

I posted a combined drawing and cut list a while back. I do believe it is correct. I'm marking up a sheet of baltic birch plywood and Leland is building the second cabinet, hopefully, based on this as well. I figure in the near future I will be able to say if this works out or not.


Inner front baffle and Back panel: 43 1/4" X 9 1/2" >>3/4" thick, 2 per speaker

Outer front baffle: 44 3/4" X 11" >>** 1/2" thick **, 1 per speaker

Side Panels: 44 3/4" X 15" >>3/4" thick, 2 per speaker

Top and Bottom panel: 9 1/2" X 15" >>3/4" thick, 2 per speaker

PVC support panels: 9 1/2" X 7 1/2" >>3/4" thick, 2 per speaker

Inner Solid panel for top of woofer section: 13 1/2" X 9 1/2" >>3/4" thick, 1 per speaker

ML-TL main center panel: 24 7/8" X 9 1/2" >>3/4" thick, 1 per speaker

Window Braces: 9 1/2" X 6 3/8" >>3/4" thick, 4 per speaker


Paul K., feel free to step in and correct any of this if I'm wrong on any of your dimentions.

Edit: The scanner cut off the bottom dimention showing the total depth, front to back of the cabinet including the 1/2" outer front baffle at 15 1/2". The internal width dimention is 9 1/2". So, overall exterior dimentions are 11" width, 15 1/2" depth, and 44 3/4" height.