T48 garage build

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howiez
Posts: 314
Joined: Sun Mar 16, 2014 5:23 pm
Location: Fox Valley, Wisconsin

T48 garage build

#1 Post by howiez »

SInce Seth requested pictures, I may as well share this. Didn't think anyone would want to see my Frankenstein T48, (mostly don't want Bill beating me with a stick). Years ago, after I built my first BFM, the THT, I bought all the plans because I wanted to try something else. I had a pair of old Radio Shack 15's and a pair of 18's from a post high school 3 way ported build. I had built them at maybe 17 or 18 years old with 15s. Then I upgraded them to 18 a few years later. I still had the T48 sized cabinets in my basement. Decided to break them down, recycle the drivers and burn the wood. The 15s had dry rotted surrounds. So I figured I'd try to squeeze the 18 into the T48 envelope. I did my best to check the specs in HornResp against the BFM design. It was ok, but again, this was for my garage sound while doing woodworking and wrenching on my bike or car.

Turns out if you stretch the baffle just a bit, you can get an 18 in. I slighly modified the path to accomodate. I also shaved off the second corner, or last bend in the mouth. You'll get it when you see the pictures. I can get one full T48 out of two 4x8 sheets of plywood this way also. I've never tried any measurements, but honestly they sounded great with the Realistic 40-1309 driver. I drive them with the 300BASH from PE, at 150w into 8ohms. Plenty for my single car garage/workshop.
The first one built maybe 4/5/6 years ago
The first one built maybe 4/5/6 years ago

howiez
Posts: 314
Joined: Sun Mar 16, 2014 5:23 pm
Location: Fox Valley, Wisconsin

Re: T48 garage build

#2 Post by howiez »

I built this intending to use the Realistic 40-1309. The plan was to build a second one day, because I had 2 drivers. Just. Coz.
Then last summer I came across closeout Parts Express factory buyout B-52 folded horn drivers made by Celestion. Here is the old and the new, and I started building cab 2 last August.
The before and after drivers
The before and after drivers
first panel laid out and pre-painted
first panel laid out and pre-painted
And yes, I modeled this whole thing in 3D and printed a book with layout plans and details for each panel. Turns out our sheet metal program at work can 'nest' wood if you tell it that it is 1/2 steel and the sheet of 'steel' you cut it from is 4x8.

howiez
Posts: 314
Joined: Sun Mar 16, 2014 5:23 pm
Location: Fox Valley, Wisconsin

Re: T48 garage build

#3 Post by howiez »

Here is the baffle doubled up and routed out. I put T-nuts in the back and screws on the T-nuts so they don't come out.
Baffle
Baffle
baffle glued in front
baffle glued in front
baffle glued in back
baffle glued in back

howiez
Posts: 314
Joined: Sun Mar 16, 2014 5:23 pm
Location: Fox Valley, Wisconsin

Re: T48 garage build

#4 Post by howiez »

Panel 3/4 glued on, and a wire channel on the top.
I glued up all the frame pieces for the front, cleats and all, and glued it all together. I also cut the front cover a hair oversize and covered it in wax paper to use as a glue jig. I match marked all the drill holes and used it all to clamp together while glue set and to clamp on to the side.
panel 7 / front frame and cover
panel 7 / front frame and cover
panel 6 /7
panel 6 /7
panel 7 spacers
panel 7 spacers

howiez
Posts: 314
Joined: Sun Mar 16, 2014 5:23 pm
Location: Fox Valley, Wisconsin

Re: T48 garage build

#5 Post by howiez »

We'll call this panel 65 where I cut a corner, literally.
Panel "65"
Panel "65"
Panel 6
Panel 6
Panel 5, 8, 9 and 10
Panel 5, 8, 9 and 10
Routed handles in bottom/back
Routed handles in bottom/back

howiez
Posts: 314
Joined: Sun Mar 16, 2014 5:23 pm
Location: Fox Valley, Wisconsin

Re: T48 garage build

#6 Post by howiez »

Side profile with all panels and corner reflectors/braces in, mouth braces in before side 2 goes on.
side profile of the business
side profile of the business

howiez
Posts: 314
Joined: Sun Mar 16, 2014 5:23 pm
Location: Fox Valley, Wisconsin

Re: T48 garage build

#7 Post by howiez »

Side two goes on, it is not warped now, but yes, i clamped her tight at first!
I also added some spacers to stiffen the front. I think I need these in cab 1.
I had to place and move them several times to make sure I could actually slide the driver in, since the opening is smaller that the frame outside diameter!
side warp or optical delusion?
side warp or optical delusion?
spacers/braces in first bend clamped in
spacers/braces in first bend clamped in
better view of spacers
better view of spacers

howiez
Posts: 314
Joined: Sun Mar 16, 2014 5:23 pm
Location: Fox Valley, Wisconsin

Re: T48 garage build

#8 Post by howiez »

Woofer test fit, some Duratex and corner protectors. Also a shot of my new solder station, that helped me greatly. my 40 year old soldering gun was tired...
test fit and ready for paint and Duratex
test fit and ready for paint and Duratex
corner protectors and duratex
corner protectors and duratex
my new solder station
my new solder station
driver mounted for leak test
driver mounted for leak test
The pair!
The pair!

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Bryan Cox
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Joined: Sun Nov 22, 2015 3:01 pm
Location: Owensville, Mo

Re: T48 garage build

#9 Post by Bryan Cox »

Great looking build! Have you taken any measurements to see what they're putting out? And once Seth sees this he'll be like a kid in a candy store. Haha
Otop 12 x 4 (Delta Pro 12-450a) 2x melded, 2x straight
Titan 39 x 4 (3012LF) 20" wide

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Tom Smit
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Location: Sarnia, Ont. Canada

Re: T48 garage build

#10 Post by Tom Smit »

Looks good!
TomS

howiez
Posts: 314
Joined: Sun Mar 16, 2014 5:23 pm
Location: Fox Valley, Wisconsin

Re: T48 garage build

#11 Post by howiez »

Bryan Cox wrote: Fri May 06, 2022 7:07 pm Great looking build! Have you taken any measurements to see what they're putting out? And once Seth sees this he'll be like a kid in a candy store. Haha
I have not measured anything other than dB of them with my DR200's. Got 110 steady with a pair of 300w BASH amps driving the pair of T48's and 100wpc Onkyo receiver driving the tops. That was painfully loud even at a distance, so that won't be the normal MO unless I have ear protection (my shop earmuffs!). Neighbors 2 houses / 3 city lots down heard them with all windows and doors closed, so there's that.

Material cost
4 sheets of Menards 125-1062 Arauaco 4x8x1/2 5 equal ply $35 at the time (50-90ish during covid) $140
pair of Celestion closeouts 119.60
Reliable Hardware Company RH-9024BK-A Recessed Tilt Caster $7.46 x 4 or 29.84
Reliable Hardware Company Set of 8 Corners RH-1610-8-A for $5 so two sets for $10
Reliable Hardware Company RH-5112BO-A Truss, 50 Count screws $5.25, only need 32 per cab but lets say $10.50
Reliable Hardware Company RH-1606-8-A Rubber Foot, Black, 4 per cab but $5.88 for the 8
Neutrik NL4MPR speakON Connector 4 Pole Round Chassis Mount i paid $5.44 for a pair.

SO not counting PL, paint and Duratex, T-nuts and screws, I have about $320 in the pair, so a conservative round is $350, or $175 per cab, not too shabby. I wouldn't do a pro DJ gig with this, i'd probably spend the extra on Eminence or something. Coupled with my $400 DR200 pair, for a decent garage and family/friend party system for less than $800, I can't complain.

I've finally procured Crown amps for both. I'm hoping to do some outdoor measurements now that the weather may finally be above 50F here in Wisconsin. (Plus I have to figure out how to measure and capture). I did buy the Dayton iMM-6 for Android measuring. If anyone has a link to a good writeup/tutorial on how to set up and measure, i'd be glad to follow it and paste something here.

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Bryan Cox
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Location: Owensville, Mo

Re: T48 garage build

#12 Post by Bryan Cox »

Pretty good value. And 110dB ain't bad. Glad to hear it's all working out.
Otop 12 x 4 (Delta Pro 12-450a) 2x melded, 2x straight
Titan 39 x 4 (3012LF) 20" wide

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Seth
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Location: Sacramento, California, USA
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Re: T48 garage build

#13 Post by Seth »

Aww man, Howie! What a great write up. Way more than I expected. Look at those big girls I'll in there. Wow.

What had you choose to cut that corner? Just felt right and the force was with you?
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

howiez
Posts: 314
Joined: Sun Mar 16, 2014 5:23 pm
Location: Fox Valley, Wisconsin

Re: T48 garage build

#14 Post by howiez »

Seth wrote: Mon May 09, 2022 3:20 pm Aww man, Howie! What a great write up. Way more than I expected. Look at those big girls I'll in there. Wow.

What had you choose to cut that corner? Just felt right and the force was with you?
Thanks Seth.
As for the corner, I was trying to squeeze a cab out of 2 sheets of 4x8 ply. I drew all the paths up per BFM standard, then did all the HornResp. Then I used CAD to draw a corner reflector and scale/transition volume as it turned the corner. I used what Bill had in the next/last 3 corners as an example and tried to hold or match his transition as I went. Technically my inside corner between the last two segments before the mouth is a few inches shorter, so it opens up a bit faster. But HornResp didn't seem to change much. Really those few inches I shaved allowed me to keep it out of two sheets of ply after I lengthened a panel or two for the driver.

I have this parametric sketch in CAD that has each segment, corners included in an 'unfolded' shape. Then I can get text values out of there to poke into HornResp pretty quick and simulate. All my numbers seemed to come out similar. If this had been for a gig, I'd never even think about it. But for fun, the CAD kept me busy over lunch at work a few weeks while I tweaked. I'll try to find a picture of my nest on two sheets and my horn path and upload it (without numbers).

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