Totally unscientific....I used my KEF LS50 Metas as a reference. They seem like they are a solid! A "knuckle rap" on the side of the KEFs is similar to the Pensils....My KEF103.2, Klipsch RP500m, B&W DM601 and other speakers I have here are are all like drums when knuckle rapped.......🙂
These drivers are indeed 10.2. NOS that I bought from a fellow on this forum. I also modified the size of the cabinet slightly to conserve plywood. The Bamboo plywood was available from Lowes in 2'X4' for $21 a sheet. four sheets if I made them 12" deep and 43" high.....Same internal volume. Took a big chance, but I'm a real cheap Yankee.....Thankfully they turned out great and sound fantastic. I have ten hours of listening is successful. I've built lots of speakers that I listen to for an hour or so and get tired of them. They are then given to grandkids who don't know good speakers from earbuds! But these are very easy to listen to. So far, they don't do anything bad with three different amplifiers.....Thanks for the leads above. I'll check them out.
Bamboo is one of the most easily renewable woods. Grows fast, easily harvested , And EXTREMELY strong. Have you see Asians building scaffolding for sky scrapers with it? It should be one of the least expensive woods. I went back to buy more and they are all out.....
We have used a variety of Bamboo Ply. The best is VERY good.
We should be able to do the same thing with hemp and make it in NA (ie locally) instead of buying fro China.
dave
We should be able to do the same thing with hemp and make it in NA (ie locally) instead of buying fro China.
dave
What varieties, I have bamboo in my backyard, It is growing VERY slowly, and is not a type big enuff to mske plywood from.
dave
dave
I'm not sure about varieties. I just know that in the Southern gardening world, it's unacceptable to ever plant bamboo pretty much, unless you can keep it under control. I think it grows slowly, but can spread fast.
The reason i got mine, in the fertile gardens of Chris’ wife they were getting out of control. My soil is not as nurturing. For the plywoods i have seen you need significantly large bamboo stocks. I’d guess you’d need 10-12mm thick at least.
The best bamboo ply(stranded/fissilized) is a block core with a veneer ply on each side which is composed of bamboo fibres in a bonding substance of some sort. Lesser versions use a veneer made of either vertical or horizontal slices (edge or flat grain).
The stranded veneer can be had by itself. I surmise that one could make their own 15 or 21mm super-plywood using plies of this veneer in orthoganol layers.
Now hemp, grown for fibre, has much longer strands, and should make even better, cheaper material. Maybe not as pretty, i have yet to see this realized.
dave
The best bamboo ply(stranded/fissilized) is a block core with a veneer ply on each side which is composed of bamboo fibres in a bonding substance of some sort. Lesser versions use a veneer made of either vertical or horizontal slices (edge or flat grain).
The stranded veneer can be had by itself. I surmise that one could make their own 15 or 21mm super-plywood using plies of this veneer in orthoganol layers.
Now hemp, grown for fibre, has much longer strands, and should make even better, cheaper material. Maybe not as pretty, i have yet to see this realized.
dave
It shouldn't be long before hemp materials are normalized. I haven't seen much made of it, though it's for sure a wonder material.
Not exactly. I created the pensils primarily for the MA range, although I can certainly do (and have done) others, albeit under a different moniker. As advance warning: one for the W8-2145 would be big; it's a specific alignment, designed for relatively high acoustic efficiency compared to a Small type vented box, which means size. 😉 I'll have a proper look & see what will be needed.
Loosely, my thoughts on a mltl is it is a box twice as large as a 4th order, adding a resonant pipe to go an octave lower.
Am I off base on my thoughts ?
Am I off base on my thoughts ?
As far as the pensils go, maximum extension is not an objective for them (quite the opposite actually), nor are they derived with reference to any Small-based volume alignment, so you're way off as far as they go I'm afraid. But as noted, the pensils are a specific load / alignment rather than a generic enclosure type.
Broadly speaking MLTLs vary just as other types of vented box do, so you can have as much variety within that nominal subset as you would with a sealed, regular vented etc. For e.g., I create a pensil for every MA unit, aside from the 2 1/2in & 3in models. Many of those also have an enclosure in my Antelope / Bovine range, which have different design goals & are usually somewhat smaller & tuned lower -different type of MLTL, with different objectives. And a few also have some 'real' MLTLs, which are longer & use less forcing for a similar Fb. It ultimately depends on what you're aiming to achieve. A point worth keeping in mind about MLTLs / MLQWs is that they don't necessarily mean you can 'go lower' per se than a regular vented box. They might, they might not. In many cases, what they are really allowing is a different alignment for a given Fb to what may be possible using pure cavity resonance.
Broadly speaking MLTLs vary just as other types of vented box do, so you can have as much variety within that nominal subset as you would with a sealed, regular vented etc. For e.g., I create a pensil for every MA unit, aside from the 2 1/2in & 3in models. Many of those also have an enclosure in my Antelope / Bovine range, which have different design goals & are usually somewhat smaller & tuned lower -different type of MLTL, with different objectives. And a few also have some 'real' MLTLs, which are longer & use less forcing for a similar Fb. It ultimately depends on what you're aiming to achieve. A point worth keeping in mind about MLTLs / MLQWs is that they don't necessarily mean you can 'go lower' per se than a regular vented box. They might, they might not. In many cases, what they are really allowing is a different alignment for a given Fb to what may be possible using pure cavity resonance.
Thanks Scott.....Great conversation. What are your thoughts on Open Baffle......I recently, after reading it seems like thousands of folks claiming fantastic sound....Took a board, cut a hole in it, mounted 4" Tang Band speakers......Hooked them up and with a B&W 8" subwoofer, I was very impressed! What have I been missing for 50 years!