Why not much on Pioneer B20 MLTL?

[davidallancole]

Why isn't there much information (or any?) on using the Pioneer B20 in a MLTL? Is everybody to busy working on the Changs? I found the money to buy some of them with the recommended tweeter and was hopeing to build a MLTL for them. Does anybody have a design for one?

[Scottmoose]

http://www.zillaspeak.com/pioneerb20-3cubox.asp

In reality, an MLTL with that aspect ratio. Zdriver wants to be 20.5in from the internal top (I calc. 20.43in actually -just round to the nearest sensible figure). Stuff 0.35lbs ft^3 of material from the top 27in down.

[davidallancole]

Thanks Scottmoose. I will try to build that one.

Has anbody tried building it yet?

What about the slot port at the bottom, does it need to be shorter? That length is based on how it sims up as a bass reflex in WinISD and I see that the port is usually shorter in an MLTL from designs I have looked at.

[Scottmoose]

No-one's built one to the best of my knowledge, which is a pity, as it'd be well worth it IMO. Ironically enough, WinISD's prediction for a reflex is also a pretty good approximation of this MLTL, which doesn't often happen.

[davidallancole]

Sweet, thanks Scottmoose. You are helpful as always. It will be a slow build, I need the time to go home were my dads wood shop is, but hopefully over the next few months I will have built one up.

[GM]

Greets!

I posted a bunch of them some years ago on the old FR forum and AFAIK no one built any, they were more interested in putting them in little boxes, and no one's asked about them here until you AFAIK.

FWIW, here's the one I wanted built:

L = 50.75"
CSA = 127.372"^2 ( prefer 28.5" W x 4.47" D)
zdriver = 19.3"
zport = 4" dia. x 2" long near/at the bottom for T/S max flat

All dims i.d. and approximate, minimal stuffing and add more down at/in the vent if too 'boomy'. Driver mass loaded against the back panel.

GM

[davidallancole]

That looks nice GM. You would have a pretty wide, but not very deep box with that. You wouldn't necessarily need BSC with that up against the wall. I think if I have the time and money, I will try both.

This is what I am working with for a room. The pony wall is 29 inches deep and 46 inches tall. The roof is 80 inches from the floor.

[Scottmoose]

I like! Especially the minimal damping bit. And with that kind of aspect ratio, this is another 2001 style Monolith, if painted black. I didn't know you'd done those / that Greg. Loads of gain, little damping, no BSC -can't go wrong.

If you're feeling insane of course... welcome to my nightmare. I think you're g... (sorry, don't know what came over me). Something I did for fun recently: 2 B20s per channel (lower one rolled off above ~500Hz) with perfect 1:4:9 external dimensions (3/4in material assumed) 8in x 32in x 72in (DxWxH). Vent 4in diameter x 1in long, 3in up from internal bottom. See attached FR. Nobody would ever be insane enough to build a pair, but I couldn't resist it.

Name your poison, Gentlemen:
http://www.youtube.com/watch?v=wcRSwo9bGHQ

[davidallancole]

Another shot.

[davidallancole]

I would think the one GM has proposed would work the best in my room. You guys agree?