BillFitzmaurice.info

I'm interested building a mcm loaded auto tuba for my car.

I figured while I was at it, I should make a second one so that I can use the pair for very light sound reinforcement applications (party speakers or acoustic bands) just to round out the bottom of my pa tops.

I know the tuba 18 would be more suited for the job, but I'm only interested in building two cabinets at the moment. I figured a pair of v-coupled autotubas would preform better than one tuba 18. The smaller form factor is also nice.

I'd try to boundary load the pair whenever possible but also use them outside some. Would I be able to get any worth-while performance while outside?

I doubt they would do much good. An acoustic act doesn't need to go much below 90-100hz unless there's a bass. If not, just EQ the tops properly and it's enough. I do acoustic shows with a single SLA Pro at a covered outdoor setting. Works fine.

If your primary interest was a PA sub, Bruce is right, AutoTuba wouldn't be on the list of recommendations. However, as a secondary use... sure, why not. It's certainly been done more than a time or two before. Although, if you only want to build 2 cabs, you'd be better served with one AT for the car and one T39 for the PA. My 16" T39 waaaaaaaaay outperforms my dual loaded AT.

So, can you do it? Yes.

Would it be effective? Yes, better than nothing. As you seem to be aware, it'll be more effective indoors.

Is V-Plating an option? Yes and no. The standard AT is end firing and can't benefit from V-plating. The TAT, just by virtue of it's design MAY benefit from the use of a V-plate. I can't recall any report of it ever being done or any benefit ever being quantified. I don't think it would hurt anything though. It's certainly worth the limited effort and materials to try it out.

I have one 20" wide TAT loaded with 2 MCM 8's. I've corner loaded it in a living room for band rehearsals a few times. It was noticeable and better than not having it. But, due to the size and weight, I switched it out for a cheapo <$100 12" sub from Amazon that's lighter, smaller, and performed well enough given the cost, size, and weight. Neither performed well enough to be super impressed, but they got the job done. Two single loaded TAT's built to max width (V-plated and corner loaded) could possibly have been noticeably better.

I can't find the pic or thread at the moment, but there was someone years ago that used 6 AutoTubas for outdoor live band PA. I recall them being satisfied.

Here's quote from another older thread, SLA's & AutoTuba

RubiconProSound wrote: ↑Sun Dec 30, 2007 2:08 pm ...I ocassionally DJ at small house partys, coffee houses and the like so I need something with a small footprint. One or two AT's works fine. We have a small bar next to the house and dragging in my T30's isn't an option. Two AT's corner loaded on stands works great. People still can't believe all that sound comes from two 8" woofers.

Ah! Found it!
Crappy quality photo file, but you can get the point. 6 AT's to the left of the stage.


From this thread, A sixpack of AutoTuba 10s did well for live sound

The man intends to build 2 and load them with the MCM 8" drivers. The "AT Stack Of Doom" had 6x AT 10". Yeah, the stack pounded freakin' hard, but I think that does not scale down well from 6x 10" to 1x or 2x 8". Is it enough for "very light sound reinforcement applications (party speakers or acoustic bands)"? I think we cannot tell for sure, it depends on so many factors. One would be totally content, an other would be totally disappointed. I would think there is only one way to find out how it works for Mat. Making sawdust is involved.

Seth wrote: ↑Sat Dec 04, 2021 5:27 pm Although, if you only want to build 2 cabs, you'd be better served with one AT for the car and one T39 for the PA. My 16" T39 waaaaaaaaay outperforms my dual loaded AT.

I should have clarified that I have the budget for 2 mcm 8" loaded cabs. $30 per driver is hard to beat.

It seems like the verdict is that two auto tubas will work, but they wont be blowing anyone away. If I have enough wood left over, ill build two. If not, one for my car will be enough.

Keep us posted on progress! Enjoy the build

Years ago I used two HT SLA's and one 14" AT at an outdoor party. The volume was modest (enough for the neighbors to hear clearly but not get annoyed). The AT was good enough outside to fill-out the sound without being too "boomy". Now when I used 2 of them inside a 2 car garage, I wall-loaded them and cranked it up. It shook things in the house and I was told to turn it down. So yeah you could use it outside but don't expect to be impressed by it. It's designed for cabin gain, so even in a house it'll perform better. Now in a car, it'll rattle your brain and make you turn the gain way down.

Well the mcm drivers are out of stock until may. I guess the project will have to wait unless there are other suitable drivers at a similar price. I really wish bill would post a list of compatible drivers for each cab. I know its included in the plans but if I'm building on a budget, I don't want to buy the plans unless I know I can afford the drivers.

matmonster58 wrote: ↑Mon Dec 20, 2021 11:42 am .....I really wish bill would post a list of compatible drivers for each cab. I know its included in the plans but if I'm building on a budget, I don't want to buy the plans unless I know I can afford the drivers.

Read through some of the build posts and you'll find out what driver are being used