Dual Loaded Table Tuba by a Teenager

[subharmonic]

Oh why did you have to remind me? It's been in the back of my head all day,

I am the pusherman

[Gregory East]

No guarantee on the plates being safe with what you have planned. Bass frequencies have a way of migrating through buildings and popping up elsewhere.

As for the paint trick, you're relying on the paint to wood connection and the PL to paint connection to hold the cab together. Not recommended practice. I'd leave those screws in.

[bassmonster]

As for the paint trick, you're relying on the paint to wood connection and the PL to paint connection to hold the cab together. Not recommended practice. I'd leave those screws in.

That's why I roughed it up with sandpaper before I attached the final side, and why I countersunk the screws below the surface of the wood. I fill in the depression above the screws with PL, sand, and it's ready to Duratex. Also, as it was tempera paint, it's pretty thin watery stuff anyway, I was having trouble keeping it from running down the sides. Again, a plastic sheet and Sharpie might have been better, but this way worked just fine and I did it right the first time.

Seems there are no leaks around the PL'd driver, but I'll double check tomorrow anyway.

[Gregory East]

I seem to recall others shooting PL with latex to get duratex to take

[bassmonster]

I seem to recall others shooting PL with latex to get duratex to take

Sounds like a good idea, but I'll probably just sand it, because...

When sanded, the pores [in PL] will hold Duratex just fine.

[Titanium Hand]

Well Done Bassmonster on completing the Building Phase of your your first BFM cab. Nice to see you've gotten the bass you desired!

I thought the tempera paint was a rather industrious idea - provided you cleaned it all up.

I recall a note in the plans about marking screw points for the internal horn path, immeadiately after drawing the lines on the first piece of timber. I didn't do that either as I was so excited about the build itself and had to rely on my arms being long enough to reach up inside the mouth to mark the screw points.

Nicely done anyway

[UROK]

Get in there, bassmonster! Well done, mate!

That cab will end up looking great with a bit of finish work. DJ Phatman's signature says it all.

Now, I'm worried because you say you won't be able to do a THT until you are on your own. My fear is that may be sooner than you think now you gone BFDing crazy! My mum used to go mental at my shitty Sony when I put on the Sex Pistols (an ancient punk band) up in my room. Nothing like the terror you can unleash! I bet Elvis (Presley - really ancient singer, lived...hahaha..I know you know who Elvis is - don't you?) himself can feel you! Go easy, Master of the Soniverse. Don't piss them off. You need money to buy more drivers...

You might think of doing music events if full-on home and auto sub nuttiness are out. Least you might get paid to wreak bass havoc.

Anyhow, great thread. Thanks!

[subharmonic]

I seem to recall others shooting PL with latex to get duratex to take

Sounds like a good idea, but I'll probably just sand it, because...

When sanded, the pores [in PL] will hold Duratex just fine.

I havne't had any issues with PL and duratex. Just pay attention when sanding and applying the finish. I have had some area much larger than a screwhead too.

[bassmonster]

Quick question. I was playing some tunes on the TT today at about 4-5v, and looking closely at the drivers I can see them "excursioning" (what's the word for it?) at 30-35hz quite a lot for only 5v. I would say it's about 1/4" off a very very rough estimate. It's less than it would be in free air, but from a sealed system I would expect a lot less excursion, especially at such a low voltage. I'm worried about over-excursion at war volume. Is this a non-issue? I wonder what the voltage limit for the two JBLs would be? They would be taking around 150RMS apiece from the Bash at full volume, and if the speakers are "excursioning" that much at a low volume, I'm a bit worried what will happen when running at full bore.

[UROK]

How can you see the driver? You got the access panel off? If so you unloaded the driver. Don't do that! Lucky you only gave it a low voltage. Blown drivers that way leads, young Skywalker.

[bassmonster]

How can you see the driver? You got the access panel off? If so you unloaded the driver. Don't do that! Lucky you only gave it a low voltage. Blown drivers that way leads, young Skywalker.

I don't have an access panel cover, it's not necessary with the TT. The air mass pressure in the long horn path of the TT limits excursion down to 15hz. Plus the driver compartment acts as a second sound source at very low frequencies. IITP

[Gregory East]

I've been confusing this beast with a dual wide auto tuba off and on myself. I wonder why?

You better look into that limiting BM.

[Sydney]

I shared the same confusion as Russ:
I have the original construction article from AudioXpress ( NOT the plans ).
In the article was stated that the open side was to be placed within a couple of inches of a surface ( like slightly off the floor ) to provide additional acoustic load to the back side of the driver.

[67baja]

Ah, what does your dad know? Put that beast in the car! Lol!

[bassmonster]

In the article was stated that the open side was to be placed within a couple of inches of a surface ( like slightly off the floor ) to provide additional acoustic load to the back side of the driver.

The plans say:

To preserve the tuning of the cabinet the side with the access hole should be 1½ to 2
inches away from the boundary, be it a wall or floor. If you lay the cab on the floor
use legs to lift it 1½ to 2 inches.

Could someone clarify this driver access issue? Bill? I won't run mine with an access cover as the plans don't say so. I'm not sure if this excursion issue is a problem, I just don't want to risk ruining my drivers.