Just finished the first of two subs I'm building

[Fatlimey]

Thanks for the update.

[sine143]

no problem my friend. Peak levels were about 130 at the 2 subs themselves, no top support. They carried nicely, but it was tough to fill that space with it being outdoors and all.

[wasapa]

would u still be using a xti2000 to run the otop 12s? what if u wanted to run just one tuba 30, could u down grade to a xti1000?


i just found a summer project!

[sine143]

Many of the members over on the bfm forums use the crown xti 1000 to drive their tubas. If you already have that amp, or you are interested in using it, I would recomend either building two 16" wide Tuba 30 slims, loaded with the eminence bp 102, or Titan 39 slims loaded with the same driver. Most of the bfm designs are not truly designed to run as singles, and like to be paired up with an identical twin, to give them better low end extension.

There are also benifits to running 2 drivers on one channel. When you run 2 drivers in parallel, you drop the impedence from the original 8 ohms, to about half that, which means your amp, can supply more power to the drivers, about twice as much, which means both drivers are still getting plenty of juice. This does follow the law of diminishing returns, and most amps can not safely run things below a 2 ohm load (everytime you double the drivers, you half the impedence, meaning 4 drivers on one channel is usually ~ 2 ohms).


Edit

Hows the build going limey?

[Fatlimey]

Got me a garage full of rectangles. The magic jig for the circular saw makes all things possible, including the plunge cuts for the access panel. Did you make access panels on both sides or just the one?

[sine143]

just one. Its *kind of* a pain to get the driver out, after you finish the sub up, but as long as you use phillips head screws its not a huge deal.

Its best to only do it on one side because

A: air leaks are the bane of the design
B: no matter how square you think you are doing things, if they are off and you have already cut the acces panel on the other side you might have to scrap it.


What are the specs on the boxes you decided to go with?

[Fatlimey]

24" Tuba30's (all panels are 23" wide) with an Eminence 3012LF driver. Got me some Russian Birch ply and no idea what I'm gonna paint it with.

Good point about the access panels. Best to stick with just the one - bought the kit from SpeakerHardware.com so I have hex socket head screws to secure the drivers to the hurricane nuts:

http://www.speakerhardware.com/tuba_...-KT2430Kit.php

Priced it out, that's absolutely the cheapest cost for all those parts.

[sine143]

Yeah man, I know all about Speakerhardware. Leland (the guy who owns the site) is a great guy, ships quick, and has unbeatable prices. Hes pretty active over on the BFM site.

Other than driver, thats exactly the sub I built (I went with delta 12lf). I actually plan on selling this pair (along with 2 otop 12s), and upgrading to a 22" pair of T30s (3012lf loaded), or maybe a 24 inch wide pair of T48s. The 24" t30 is too wide to fit in the back seat of the car, so I have to borrow my roommates suv to transport them).

Hope the build goes well for you! I found it went a lot quicker with 2 sets of hand working on it, and I believe it took us about 4-6 hours per sub.

I would recomend duratex on the subs. I put a coat or 2 of black latex down, and then finished with duratex, and its amazing.


EDIT

I would also recomend cutting the acces panels on oppossite sides for each, which would allow you to lay them on their sides, v coupled, with driver access retained for both. I'll definitely be doing this on my next pair. The Titans are top loaded I think, so this isnt as big a deal though.

[Fatlimey]

Opposite access panels, good tip.

Question: How did you line up the screws with the panels during construction? Did you markup the opposite side of the 30x30 cabinet and use that as a guide for where to drill? Also, did you use screws where the panels join each other as well as through the 30x30 back piece?

There's very little guidance on where to screw, and yes, I get that the screws are not really structural, it's more about the glue. How quickly are the glue joints solid?

[sine143]

Alright, I've attached some images, hopefully they are kind of helpful. Basically, You draw your lines down onto the 30x30 side you have, identical to how they are displayed in the plans. All internal panels are going to be on the INSIDE of these lines (towards the center). Now, take a drill, and throw some pilot wholes into the 30x30 side. Do as many as you think is necessary, as You can see by the pictures, it racks up to a good chunk of screws. Make these holes larger than your screws. Now what you do, is line up your panels, clamp them (or hold them, just do something) and drill small pilot wholes into the panel, through the larger holes already in the side. Remove the clamps. Lay down your glue bead, and go.

If this isnt clear, keep asking... I kinda just blew that onto the reply box hahaha.

EDIT

The glue is pretty much solid after about 20ish minutes. However, I would leave the screws in for 24 hours, or just... dont take them out.