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

[Paperweight]

Here are two out of four mostly completed. I'm afraid I'm going to wear the rasp out before I get this done. I'd like to get a French hand stitched rasp sometime in the future. Maybe a coarse number 4 or 5. An 80 grit sanding belt split in half makes quick work of rounding off the edges after a rough out.

I found the round mallet laying around in a shed. Huh this looks like a chisel mallet. Come to find out it was used for making sauerkraut and belonged to my paternal grandparents. I sealed a crack with superglue and gave it a wax and oil finish. I believe it is made of beech like most old school wooden tools.

[djg]

# hashtag braces.

[Steve Lee]

Its a shame all that old-world skill and effort is going to be hidden and never seen again . . .

Impressive work.

[Paul K.]

Not only that but rounding over all those edges will have zero effect on the sound, but if it makes Paperweight sleep better at night, that's fine.
Paul

[Chris Roemer]

Many folks would just replace one of your # braces with a pair (or 2) of dowels.

[Paperweight]

No dowels handy but I did have lots of scrap ply after the failed first cabinet kit. These were experimental so they came out chunkier than I intended. Just rounding over the edges after I pare the thickness down in places. I don't want them to eat up too much of the internal box volume and I don't want to find out what air speed causes whistling through one of the holes.

With the braces all in one piece, I have some confidence I can get the woofer section glued up without too many mishaps.

Gotta remember, I'm just some random dummy that doesn't know what he is doing so I'm winging it. I've worked a retail job for over two decades. I'm a masochist and some quiet time using hand tools is calming and very satisfying.

[Chris Roemer]

Therapy can be good !
We all build cabs differently.
Your braces look nice ;-) .

[bassman_soundking]

Those braces look nice

[Paperweight]

Got the woofer section front panel installed and the center divider glued and clamped in place. It took a minute to figure out how to apply pressure to the center panel but I got it eventually.

This went together way better than expected considering I didn't have the braces in the mix to keep it from falling over. Thankfully, with a hand plane and shooting board, I put nice clean edges on the panel so it stood up square. The pin nails kept it from moving as the clamps were applied.

When I bought the BB ply from The Hardwood Store last year, I picked up a Titebond silicone glue brush. That thing makes a real difference when spreading the glue around. Love my Glu Bot too. The answer to all your problems really is buy more tools.

Fun fact, the BB ply made in Russia has doubled in price since I purchased this last year. Also, I just discovered Appleply is no longer taking orders for their high-end plywood products. Good thing I got a 4' x 4' sheet of 1/2" walnut for the fronts when I did.

Now to trim the braces for a snug fit and glue up on Wednesday.

[Paperweight]

After having a couple of days to sleep on it, dowels would seem like a very easy implementation of bracing. I did not expect to be able to get the center panel so well glued and placed without braces to hold it in the correct position, but I did.

Any suggestions for the diameter of dowel rods and wood or material composition to span a 6 3/8" X 9 1/2" space?

[Chris Roemer]

3/4" or 1" dowels (or spare square stock - or NOT square, even).
Staggered spacing is best. You want to end up (ideally) with slightly different sized "resonant areas" in the end (not all the same size).
I typically use 5min epoxy to set mine - after construction is done.

[Paperweight]

I have the braces in place. Next time I may just go with 3/4" width on the braces. One inch looks too thick once you place it inside the cabinet. Now I'm afraid it will use up more volume than I intended. Hey, at least it's solid.

Found a not quite one inch diameter dowel rod to try.

[Paperweight]

I started making 3/4" square dowels with a chamfer to try using as internal braces in the cabinet. After looking at the hashtag braces in there and all the empty space, I think 8 dowels in one direction and 8 in the other can do a lot more good and cover more area breaking the internal volume into smaller chunks.

The other thing I'm still debating is rock hard maple or oak. The maple is surprisingly easier to work with hand planes versus oak. The maple is more dense with a higher frequency when it is struck together with another maple stick of the same size. The only thing I'm concerned with is if one will twist or warp over time and if the denser maple will be harder to glue in place.

On the top left is the new Lie-Nielsen 5 1/2 jack plane. It is fantastic on the shooting board with just the right amount of weight and a rock solid thick blade. They are stupidly well made and expensive but should last several lifetimes if taken care of. The tote and knob handles are buttery smooth.

Below the 5 1/2 is the pile of square dowels I've been working on. The top one is some scrap maple turned into a dowel. I like working with maple much more than oak. No splinters and it cuts smoother with less tearout.

To the right is a Stanley ripsaw. It works okay as a crosscut saw to quickly trim braces to size. It is fortunately not an induction heat hardened tooth variety saw and I managed a decent first time sharpening on it with a saw file. It's very aggressive and fast cutting with a fresh sharpening. I may invest in a good quality crosscut saw in the future. This is faster than walking it to the woodshop next door to trim it on the bandsaw.

Under the ripsaw is the bench hook I just completed from a scrap piece of oak I had handy. It's a great bench top appliance for quick hand sawing jobs or when you need something to hold a piece against. Christopher Schwarz mentions them in his Lost Art Press workbench book from 2020 named The Anarchist's Workbench. For those interested, he offers the book free in PDF form by visiting the Lost Art Press website and the book's page.

[djg]

You can start your own thread you know.

[Paperweight]

Oh god moving all this would be a pain. My progress is slow as is. Leaving it hang for several months sounds like a bad idea.

[djg]

We would expect faster progress if you had a CNC machine and a robot army of assemblers.

[Paperweight]

I have a question for Paul K. I got the woofer section to a point of stuffing. 14 ounces of material seems like an awful lot in just the first half of the ML-TL. What does the simulations show for stuffing the first half vs. the full length of the cabinet?

[Paul K.]

If you stuff the full length of the line with the same 14 ounces, the bass response will be affected quite negatively and substantially. I use stuffing to create what I believe is the best overall bass response curve, and often use a stuffing density of 0.75 lb/ft3. For an ML-TL, stuffing the first half of the line gives optimum results, whereas in an equivalent tapered TL, stuffing approximately the first 2/3 of the line gives optimum results. Adding stuffing, even at a lower density, beyond those two lengths really impacts bass response (f3 etc.). One of the many things I've learned after modeling and building TLs for ~20 years is to design the best model I can within whatever restraints and goals I have, then build what I modeled.
Paul

I have a question for Paul K. I got the woofer section to a point of stuffing. 14 ounces of material seems like an awful lot in just the first half of the ML-TL. What does the simulations show for stuffing the first half vs. the full length of the cabinet?

[Paperweight]

Fascinating, thank you. I'm trying to teach myself how to use Hornresp and model a ML-TL and a port.

[Paperweight]

Also, for half, should I stop under the driver or can I stuff the top panel as well? The little bit of the back panel behind the driver is very tempting. I assume there should always be a clear pathway for air to flow through the stuffing and never a blockage of any sort.

[Paul K.]

Stuffing is intended to be in the front half of the line, all the way from top to bottom. So there will be stuffing around and behind the woofer. You want to have a uniform stuffing density but you don't need to drive yourself crazy. A little "less here or a little more there" will very unlikely make a measurable difference and definitely not an audible difference.

[Paperweight]

(78) The Travelers speakers, woofer section test. - YouTube

I've never uploaded a Youtube video before and all I had handy was an old Chemical Brothers EP from the late 90s. Sorry if it's not to anyone's taste.

Hung a tissue off the back over the port for a visual indication of the air flow. This $90 driver can boogie. I laugh like an idiot.

I had pretty close to one pound of Acousta-Stuf so I used all of it and stapled it in place which works. You can reuse it simply by removing the staples. Cheaper than glue and holds well.

I consider this cabinet an experimental unit to test what does and doesn't work. It was made with the 2nd kit I purchased with out of round, off center holes that had to be corrected creating less than ideal seals around the speaker and port.