Auto Tuba Dual 8

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JamieEE
Posts: 5
Joined: Thu Mar 21, 2019 1:46 pm

Auto Tuba Dual 8

#1 Post by JamieEE » Thu Sep 02, 2021 2:16 pm

Hi BFM Groups

Here I have my 2nd BFM cabinet build. I have already built 6 t24 single 10's. As usual after you build you want to build something else. So an Auto tuba it is. After the T24's I bought myself a small CNC and I've included some of the pics from the machine. I built this cab out of MDF to test all my cnc cuts, fitment and to try out this mini beast before spending on higher quality/priced baltic. The CNC is nice, but the plans are actually faster, and forgiving.


Here are my mouth brace pieces, and a brace for inside in speaker chamber (not really needed but this was a test cab and also a test of my cnc skills)
braces cnc.jpg

These are all the pieces that are in the enclosure. I decided on two long larger braces that you can see in the top. Nothing wrong with the plans braces. I just did it as a test and to also keep the alighment as I put it all together.
I did a .2 inch rabbit for the sides for the panels to slide into for alignment
IMG_4964.jpg



Testing the fittings and only the back piece glued in place. Don't worry to the top piece was not secured with that gap.

test fit 1.jpg
Next testing to make sure the cones were aligned over the screw holes and would not cone rub the baffle before I put the "square blocks" in place
Untitledtest fit sub.jpg
Attached the internal brace which also helped me align my panels. All were very close with the CNC, with just left me to do a tiny bit of sanding edge to make fit perfect. As I already had t24's I was not in any massive rush to build so I took my time. I fitted a piece or two, let dry, then sealed the edges on Both side for any possible air gaps. As the pieces were .2 inch into the panel and fit snug I still sealed to prevent any leaks.

auto8braceinternal.jpg

Here is that looong internal brace that is complete over kill (insert Bill rolling his eye emojie here. ...lol) It was built a little out of sequence than the plan, but on only the back and bottom order . As it was very square and let me do my wiring and connection plate work with the back off. I also did a single piece for each access panel "lip" as you can see ,and it only needed a little sanding to slide right is and very snug.
auto8 open back.jpg
The mouth brace, I copied the look of Functionone bass cabinets as I like that look with the circles

auto b1.jpg
auto8b2.jpg


Here is the raw cabinet prior to me starting the finishing. As you can see I purposely left the top edge longer so I can router it nice and straight and then do a round over. Still need to fill the screw holes on the one side then sanding and paint.

Auto8 dual raw cab.jpg


The final product ran into an issue:

I first set my amp output to 20volts to get the cabinet playing. I was not expecting a T24 output, but was ready for some bass. But no go. as soon as I got little volume it started to make a massive "KAK, KAK" sound. I played with crossover, (no eq was on) check voltage, checked polarity, listened for air leaks everything was good...... but it sounded very bad at 1/3 plus volume. I knew I could not be the design as my t24's sound awesome. Long story short a brand new MCM driver was bad. Luckly I bought 4 of them as the idea was to build 2 Auto8 dual8's and use them for dj monitor cabs, or for bass in small gigs. New driver in and here we go.

On a ground plane (ie my garage) in the middle of the room I'm getting about 110db with music. But place in in my truck, and it maxed at 130.4db playing music. BTW the track I was listening to was Junior Reid -One Blood

auto8 spl.jpg
I will have some more picture up once I start finishing
Jamie
6 X T24 single 10 (3010LF)
1 Autotuba tall twin 8 (MCM)
Toronto Canada

himhimself
Posts: 562
Joined: Fri Nov 13, 2015 9:34 pm
Location: Bloomington IN

Re: Auto Tuba Dual 8

#2 Post by himhimself » Thu Sep 02, 2021 5:44 pm

Wow, thanks for documenting the build. Looks great!
2xT30 (20", 3012LF)
2xT30 (21", 3012LF)
4xOtop J-array (Beta12, melded/straight piezos)
Truck Tuba (MCM)
Next up: 2xJack12 or family of table tubas

jimbo7
Posts: 753
Joined: Fri Dec 28, 2012 10:45 am
Location: St. Louis

Re: Auto Tuba Dual 8

#3 Post by jimbo7 » Thu Sep 02, 2021 6:12 pm

Yay CNC builds!

What size is the cutting area? My friend made a 2'x4' CNC and cut me out some templates for baffles and hand-holes. Made builds so much easier. Worth their weight in dodgecoin
Now you can carve out some killer car audio designs and make amp racks and add lights and other wicked awesome doodly-bobs
BFM builds:
XF212
T24 BP102 24"
2x SLA's 6-5" mids, 9- gt-302's
2x AT 14" MCM 55-2421
TrT 5" MCM 55-2421
AT 18" JBL GTO804
2x OT12 flat array
2x SLA Pro 2-Alpha 6's 2-Goldwoods
2x T39 24" 3012lf
Simplex 10 BP102

JamieEE
Posts: 5
Joined: Thu Mar 21, 2019 1:46 pm

Re: Auto Tuba Dual 8

#4 Post by JamieEE » Fri Sep 03, 2021 10:58 am

My cnc does unto 32X32 inch, so I can cut the side panels of upto a t30 (I bough plans for t30,t24, and autotuba). The cnc I used for the braces, sides, baffle, and speak plate pocketing on the back. All other panels are cut on my table saw. Yes I have made a few other cabinets that are my designs, but just posted the BFM. Saw dust flies again tonight as I start the finishing process.
Jamie
6 X T24 single 10 (3010LF)
1 Autotuba tall twin 8 (MCM)
Toronto Canada

User avatar
AntonZ
Posts: 2574
Joined: Sun May 14, 2006 6:00 am
Location: NL

Re: Auto Tuba Dual 8

#5 Post by AntonZ » Sun Sep 05, 2021 6:47 am

The cab looks more like a T18 than an Autotuba to me. The CNC work looks great. Makes we want a garage and the funds for a cnc setup. Would you mind sharing some pictures of your CNC rig?

JamieEE
Posts: 5
Joined: Thu Mar 21, 2019 1:46 pm

Re: Auto Tuba Dual 8

#6 Post by JamieEE » Thu Sep 09, 2021 11:29 pm

A few update Pictures, and a family picture


Did some filling ,sanding, rounding over the edges and it looks a lot more finished. The final colour will not be black for the brace. Might go silver brace and black duratex for the cabinet.

Shown infront of her bigger brother a T24's single 10 Eminence. 6 t24 cabs in total. Those were all non cnc cut.
post 2 2.jpg
post2 3.jpg
post 2 4.jpg
post 2 5.jpg


Also did some tuning with crossover freq, types, slopes and dialed in voltage. No eq on them. And with music on the garage floor in a non perfect location she was outputting 116.5db at about 1/2 meter on the floor.
post2  1.jpg
Jamie
6 X T24 single 10 (3010LF)
1 Autotuba tall twin 8 (MCM)
Toronto Canada

JamieEE
Posts: 5
Joined: Thu Mar 21, 2019 1:46 pm

Re: Auto Tuba Dual 8

#7 Post by JamieEE » Thu Sep 09, 2021 11:31 pm

Antonz

I have nothing crazy, its a Xxl Shapoko. does exactly what I need, and fits upto a t30 side plate for machining. And I make some side money to pay for audio with signs that are cut cheap and fast.....and sold for decent money.
Jamie
6 X T24 single 10 (3010LF)
1 Autotuba tall twin 8 (MCM)
Toronto Canada

User avatar
AntonZ
Posts: 2574
Joined: Sun May 14, 2006 6:00 am
Location: NL

Re: Auto Tuba Dual 8

#8 Post by AntonZ » Tue Sep 14, 2021 9:54 am

Nice way to pay for the good things in life :cowboy:
I will keep something like that in mind for the day we get to move into a house with a garage.

CarterKraft
Posts: 77
Joined: Thu Oct 22, 2020 1:46 pm
Location: DFW

Re: Auto Tuba Dual 8

#9 Post by CarterKraft » Wed Sep 15, 2021 5:07 pm

I love the precision and thoroughness of your CNC build.

Any reason to build the Dual Auto Tuba over the T24 or others?

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Tom Smit
Posts: 7107
Joined: Sat Jan 05, 2008 1:24 pm
Location: Sarnia, Ont. Canada

Re: Auto Tuba Dual 8

#10 Post by Tom Smit » Wed Sep 15, 2021 9:39 pm

I'm enjoying this, so far.
TomS

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Bill Fitzmaurice
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Joined: Tue May 02, 2006 5:59 pm

Re: Auto Tuba Dual 8

#11 Post by Bill Fitzmaurice » Thu Sep 16, 2021 6:35 am

CarterKraft wrote:
Wed Sep 15, 2021 5:07 pm
Any reason to build the Dual Auto Tuba over the T24 or others?
I would assume to use it in a car.

himhimself
Posts: 562
Joined: Fri Nov 13, 2015 9:34 pm
Location: Bloomington IN

Re: Auto Tuba Dual 8

#12 Post by himhimself » Thu Sep 16, 2021 9:40 am

Interesting look to your T24s. I like it. Any reason for that shape of the grill frames?
2xT30 (20", 3012LF)
2xT30 (21", 3012LF)
4xOtop J-array (Beta12, melded/straight piezos)
Truck Tuba (MCM)
Next up: 2xJack12 or family of table tubas

JamieEE
Posts: 5
Joined: Thu Mar 21, 2019 1:46 pm

Re: Auto Tuba Dual 8

#13 Post by JamieEE » Fri Sep 17, 2021 9:54 am

Carter: I built it for a couple of reasons. If I need a smaller sub for a smaller gig, or a sub for dj monitors, but more about to just try one out. The speakers from MCM cost less that $60 total, so a fun cabinet to test my cncing and build skills. If I used it for a potable sub I would build a baltic birch cabinet as it would weight much less. I can sell the MDF version built here to a car audio fan , to fund that build. I also don't need anymore t24's they do exactly what I want for the gigs I do (in fact they do more than I expected). As per Bills design, the autoT it is unreal when placed in a vehicle.

Himhimself: The grills on the t24's are that way for a number of reasons.

Why Grills:
1: Grills on them because of two things that I have delt with in the past as a sound tech at clubs. They get full of bottles and cans, and a rattling bottle in the mouth of the horn sounds horrible. You would be amazed how loud a bottle can get get when a good subs bounces it around. Regardless of speaker placement cans and bottles seam to really like to find speakers.
2: Winter in Canada includes winter coats. The mouth of the subs usually end up being coat storage. One club I worked at , I was removing coats from some CV horns. A girl told me that "she knows the owner, and he said these cubbies are for coats" lol.

Why the shape:
For sound people that see them I wanted to keep them guessing, so the grills looks like its an 18, with a port at the top. Its funny that some people hear with their eyes apparently. I have had people ask if " are those 18's or 21's ?" when I say its 6 -10 inch woofers they say "in each cabinet?" lol. Because they can't see the speaker thought the grills they think I'm telling stories. They look like they double be 18's because I built a 20 inch wide T24 version.

The grills are also left and right versions just for looks. here a better picture of them with my own tops (prep-finished) the tops have the same grill idea to keep it consistent. The little wave/s bend is purely for looks. I have tested with the grill in place, and off, there is no real world difference in the performance or sound.

I'll have to dig up pictures from my t24 build and make a new post

Ive been busy on some customer projects so I haven't been able to do the paint on this cabinet yet.
IMG_5164.jpg
Jamie
6 X T24 single 10 (3010LF)
1 Autotuba tall twin 8 (MCM)
Toronto Canada

Rich4349
Posts: 715
Joined: Wed Jul 30, 2008 10:18 am
Location: Kankakee, IL

Re: Auto Tuba Dual 8

#14 Post by Rich4349 » Fri Sep 17, 2021 10:49 am

Bill Fitzmaurice wrote:
Thu Sep 16, 2021 6:35 am
CarterKraft wrote:
Wed Sep 15, 2021 5:07 pm
Any reason to build the Dual Auto Tuba over the T24 or others?
I would assume to use it in a car.
Bill, ya KILL me. :lol:
2 DR250s, 2 27" Lab15 T-60s, 2 30" Neo Titan 39s, 1 Autotuba...and looking for more!

CarterKraft
Posts: 77
Joined: Thu Oct 22, 2020 1:46 pm
Location: DFW

Re: Auto Tuba Dual 8

#15 Post by CarterKraft » Fri Sep 17, 2021 12:08 pm

JamieEE wrote:
Fri Sep 17, 2021 9:54 am
Carter: I built it for a couple of reasons. If I need a smaller sub for a smaller gig, or a sub for dj monitors, but more about to just try one out. The speakers from MCM cost less that $60 total, so a fun cabinet to test my cncing and build skills. If I used it for a potable sub I would build a baltic birch cabinet as it would weight much less. I can sell the MDF version built here to a car audio fan , to fund that build. I also don't need anymore t24's they do exactly what I want for the gigs I do (in fact they do more than I expected). As per Bills design, the autoT it is unreal when placed in a vehicle.

Thanks for chiming in, I was just curious but I see the temptation with the low cost drivers.

Can I ask how does it compare to a single T24 in your opinion?

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