1st AutoTuba Build

[DrFunk]

Just bought the Tang Band W8-740P at parts-express. Will be starting and completing this over the long 4th of July weekend. Only need to find some BB around Charleston and I'll be good to go.

[J_Dunavin]

What amp are you using?

[DrFunk]

Sorry for the late reply. Using this: http://www.crutchfield.com/S-qFRGI241Tr ... 4-0-2.html

Just started today with some basic cuts. Something mildly unfortunate is that only 3/4" was available (arauco), so I have that. Where should we adjust for difference (1/2") in thickness?

[67baja]

Where should we adjust for difference (1/2") in thickness?

At the lumber yard. Get 1/2".

[Tom Smit]

Where should we adjust for difference (1/2") in thickness?

At the lumber yard. Get 1/2".

+1
That way you won't have to compensate for the extra thickness.

[DrFunk]

The blatant sarcasm and unhelpfulness echos loudly. Perhaps you didn't read my post, but that was all that was available at the time and therefore it is what I have to work with. Yes, I knew 1/2 was what was needed, however there was no 1/2 available.

[Bruce Weldy]

The blatant sarcasm and unhelpfulness echos loudly. Perhaps you didn't read my post, but that was all that was available at the time and therefore it is what I have to work with. Yes, I knew 1/2 was what was needed, however there was no 1/2 available.

Everyone was trying to be helpful and you mistook humor for sarcasm. The point is - if you want a chocolate cake, you don't substitute strawberries for the chocolate....do you?

To say that there is no 1/2 inch plywood available is hard to believe. Your location isn't listed, but you mentioned you are near Charleston - a couple of phone calls would probably find you some suitable material.

If you are serious about making a quality speaker that performs as it is intended - then you should go the extra mile to do it right. You won't find many here who will encourage you to do it wrong and help you in that endeavor.

Tell us where you are and maybe someone nearby can suggest a supplier.

[Ryan A]

Using 3/4" would change the horn throat area quite a bit and also changes the flare of the horn slightly...its hard to say exactly how it will affect response but give it a try if you wish.

If you're going to use 3/4 (which I wouldn't), try to make the horn's inside dimensions as close to the original as possible, which means adding 1/4" here and 1/2" there to the inside dimensions so as not to remove horn area from the design.

This is not a recommended practice, but you asked...

[67baja]

Okay, sorry about the tongue-in-cheek attempt at humor, but I meant what I said. Call cabinet makers in your area and ask where they get their BB plywood. Also, add your location so someone here can recommend a lumber yard that has BB. You *could* use 3/4", but that is a huge waste of time and energy. These cabs were engineered to use 1/2", the plans were designed and drafted around 1/2", so it is HIGHLY recommended to use 1/2"! 3/4" ply will add 50% more weight to the box, plus you can no longer use any of the dimensions in the carefully produced plans. And, the finished product may not work as it should.

[Tom Smit]

Apologies. No sarcasm meant. But the truth was told.

If you want you can use 1/2" plywood, 5 ply. Spruce, pine, fir. As long as it free of voids, or they are minimal, it will work. I've used it several times.

[Radian]

If you find some 1/2" but are still compelled to make use of the 3/4" you have on hand, how about using it for the outer panels and using 1/2" for the insides?

It'll be complete over-kill as I'm sure you'll figure out once you're under way, but at least the wood won't go to waste and you'll still end up with a horn path that's within spec.

[subharmonic]

Only need to find some BB around Charleston and I'll be good to go.

South Carolina? If it is you are telling us in a metro area you can't find the right wood. Our town is 1/2 the size of yours and in BFE and we still have multiple sources for wood. I would recommend trying a little harder or there is not much point to the build as it will be a crap shoot.

[MissileCrisis]

Holy crap I just laughed so hard. Never seen bfe so I had to look that one up. Anyways I agree, unless you live in sub-saharan Africa or in other words bfe you should be able to find half inch. Even if it has warp and knots it will be less frustrating than if you build out of 3/4 and screw up an internal dimension.

[Bruce Weldy]

Never seen bfe so I had to look that one up.

They just don't teach these kids nuttin' in school anymore.

[MissileCrisis]

Haha. I work with a bunch of PhD engineer and scientists so I'm used to not knowing things.