T48 Build Thread

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miked
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T48 Build Thread

#1 Post by miked » Fri Aug 02, 2013 10:02 pm

This thread will document my 4xT48 build. Like most of my threads, it's wordy. I learn best by reading very detailed info, so I'm trying to pay it forward. If reading's not your thing you can just stare at the pictures. ;) In either case, thanks for looking.

I'm building 4, 24" T48s (23" internal). I went back and forth about how wide to build them. After staring at chart after chart of "this cab vs. this other cab" I determined that the advice I was initally given was the best way to go. 24" T48s are the best compromise b/t performance and portability...if a T48 can be called "portable." The cabs will use the 3015LF driver and be limited in frequency and voltage by a Driverack PA+. They will be powered by a Berry EP4000, which at roughly 5 ohms per channel (2 cabs per channel) should give me roughly 800-ish watts per channel. More than enough for continual visits from Officer Friendly.

Let's start on a serious note. The two most important pieces of equipment for any woodworking are these:
Image

You're only issued one set of eyes, so cover them. While hearing protection might seem superfluous on this forum, the drone of a saw and a vacuum for hours on end leads to hearing fatigue. Which leads to physical and mental fatigue. Which leads to injuries. Once you get used to wearing glasses/muffs, you don't even know they are there.

My "shop" is in my garage. And my garage is in steamy San Antonio. It is HOT in my garage. "How how IS IT in your garage, Mike?" Glad you asked.

It's this hot. Taken today about an hour after I started work:
Image

And during the summer (which is 6 months long down here) my garage is never below 85F. EVER. I drank almost a gallon of water during the 6+ hours I was in there today and did not use the bathroom, not once. Talk about sweating off a few pounds!

Today was a great day. Not only b/c I got all the panels (including the braces) rough cut, but b/c I discovered that it indeed possible for me to cut 5'x5' plywood on my table saw both accurately and safely. Previously, including earlier today, I was afraid of trying to cut full size sheet goods on my table saw out of fear of injury and jagged cuts...in that order. So I have used circular saw sleds...with horrible results. I build the sled and it's totally straight and accurate but for some reason I can never cut a straight line with it. I build a NEW SLED last night. It was perfectly straight. Clamp it down on my first piece of BB today and run it through and both the panel AND the sled now have a lovely "response curve" line to them. Argh!!! So I was forced to man-up and use the TS. It was not easy, but I was able to manhandle 14 sheets of expensive BB through there with great results. I am quite pleased.

So after 6+ hours of cutting, I wound up with this pile of main cab parts. Notice they are stored flat, particularly with the sides and back on the bottom. If they look small, that table is 8'x4'. The sides are arguably the most important pieces b/c if they are not flat, it could screw everything up. I'm trying to hedge my bets, here.
Image

And this pile of braces:
Image

If you're thinking "Pfft! That's just a few parts!" Here are the main cab parts in piles.

Here:
Image

And here:
Image

IN total, I cut ONE HUNDRED FOUR (104) parts on the TS today. I have Cutlists for both the main cab and the braces, but I am hesitant to post them here out of fear of giving away too much info. So I'll err on the side of caution and won't post them. If I get the OK, I will throw them up here. I printed out the "full size" sheet of each supply piece. IOW, when hitting "Print" in Cutlist, I checked all the boxes. As I cut a main piece, I put an "X" over it's identical piece on the Supply Piece page. Being that most pieces are cut as multiples from one larger cut, as I cut each individual piece, I lined it out on the "Parts" page of the printout. When I was done cutting, I measured EVERY piece for accuracy. After verifying it, I colored it with yellow hilighter on the "Parts" page. Anal? Yes. Thorough? You betcha.

I will cut the braces to shape and lighten them up tomorrow. I also am using the one-piece flange trick, so I've got some measuring to do there. Bruce Weldy will help me with that (hopefully, right buddy? :D ) b/c I have the mathemetical prowess of a 10-year old and Bruce calculates Pi to 200 digits in his head. While sleeping. It helps to know the right people.

The following info/pics are not directly about the cab, but I thought you might find them interesting. If not, you can stop reading now.

I own a table saw and consider myself lucky to do so. I waited 20 years to have one. When I was younger I had neither the money nor the space for one. I built my car stereo speaker boxes with a jigsaw and a lot of sandpaper. I don't think any of them were truly square. Anyway, cutting wood creates dust (duh). It either goes everywhere or you have a vacuum system of some sort. Whether that be a shop vac or a dust collector, anything is better than nothing. I have the Harbor Freight 2HP dust collector (DC) with a Wynn canister filter on it. I also have a homemade Thein Baffle (Filter) (plans easy to find online) in between the tool and the dust collector.

The Thein acts as a pre-filter, collecting the large dust before it reaches the DC. When built correctly, a Thein can separate as much as 95+% of all airborne particles before reaching the DC. Here is my setup. Thein baffle (AKA garbage can Thein)on the left, DC on the right. All connected with 4" flexible hose.

Image

Here is how much dust ("wood flour" b/c it's so fine) was in the bag after cutting all that wood.
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Here's how much was in the garbage can. Bad angle, but the high part of the pile on the right is about 9" deep. The rest around 6". Nuff said here, right?
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Here is what the piping/lid part of the baffle looks like. Again, plans are free and online. There is some science/math involved in this, but I just copied verbatim what I found online and it works perfectly. I'd be happy to point you in the right direction if interested.
Image
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That's all for today. I will try to make the subsequent posts in this thread a bit shorter. Hope you enjoyed reading.
Last edited by miked on Fri Aug 02, 2013 10:21 pm, edited 4 times in total.

Grant Bunter
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Location: Ilfracombe Queensland Australia
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Re: T48 Build Thread

#2 Post by Grant Bunter » Fri Aug 02, 2013 10:16 pm

Hey Mike,
Great story so far :)
Built:
DR 250: x 2 (melded array) with March 2012 plans. 2 more under way with CD horn
T39's: 4 x 20" BP102 , 2 x 28" 3012lf.
WH8: x 3 with melded array.
Bunter's Audio and Lighting "like"s would be most appreciated...

miked
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Joined: Fri Oct 23, 2009 4:18 am
Location: San Antonio, TX

Re: T48 Build Thread

#3 Post by miked » Fri Aug 02, 2013 10:28 pm

Thanks, Grant. I am hoping this build is easier than my OTops. Those compound miter cuts caused me untold frustration...and wasted BB. There are only a few miters on this build, but the panels are large. I'm hoping storing the rough-cut panels flat for a few days in my hot garage, takes any warp out of them. I have the luxury of not facing a deadline with this build, so I'll be slow and careful.

I already have the dual-Speakon input plates built and wired, so that will save a little time. I will not be using any metal handles; only the oblong handle cutouts as per the plans, along with a single handle holes centered in the 6/10 horizontal brace. That's plenty for me.

David Raehn
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Re: T48 Build Thread

#4 Post by David Raehn » Fri Aug 02, 2013 11:30 pm

Great job so far Mike! I, too am getting ready to build 4 24" T48s. So far I have the 3015s and kit materials. I won't get the lumber until my garage is ready for construction to start. Plus I have to drive an hour to get the lumber :cussing: . I will watch this thread with great anticipation!

miked
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Joined: Fri Oct 23, 2009 4:18 am
Location: San Antonio, TX

Re: T48 Build Thread

#5 Post by miked » Fri Aug 02, 2013 11:41 pm

@Draehn: I literally read every thread on this forum I could find before and during my OTop build and it helped me immensely. If for no other reason, the various pics people posted. I'm absolutely a visual learner so when I see detailed pics of how panels are joined together and the angles, etc, it really makes things clear for me. Some people can just visualize how things go together even if they've never built them before. I cannot, so the first time I construct something it's very difficult for me. Subsequent builds are in half the time, if not faster. I don't have a learning curve; I have a learning cliff. LOL!.

Don't worry on the trials and tribulations to get the lumber! Don't worry at all. Building any cab with the real deal, Baltic Birch makes your job 33% (IMO) easier from the start. The stuff is void-free, relatively stable (warping) and most importantly, does not delaminate. The stuff they sell at the big box stores has a 1/32" face on it and it peels off like a newspaper caught in the rain if you look at it the wrong way. You can never go wrong building with the correct materials.

David Raehn
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Re: T48 Build Thread

#6 Post by David Raehn » Fri Aug 02, 2013 11:53 pm

As funny as it may sound, I have been picking up retired children's 'kitchen equipment' from the local public school auctions. Most of the kitchen sets are 9, 12 and 15mm BB. While none of the panels are of sufficient size for big parts, I plan to use this resource for the fiddly bits such as horn throat pieces and braces for OT12s and braces for the T48s. This approach also allows for practice without the guilt of ruining a large portion of an expensive sheet.

Of course, my wife calls me a certified dumpster-diver but this allows me to save money without compromising quality!

miked
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Location: San Antonio, TX

Re: T48 Build Thread

#7 Post by miked » Sat Aug 03, 2013 12:00 am

draehn wrote:As funny as it may sound, I have been picking up retired children's 'kitchen equipment' from the local public school auctions. Most of the kitchen sets are 9, 12 and 15mm BB. While none of the panels are of sufficient size for big parts, I plan to use this resource for the fiddly bits such as horn throat pieces and braces for OT12s and braces for the T48s. This approach also allows for practice without the guilt of ruining a large portion of an expensive sheet.

Of course, my wife calls me a certified dumpster-diver but this allows me to save money without compromising quality!
Dude, I am ALL about saving money. I am the original Cheap Bastard. I will scrounge a 4x8 sheet of plywood if there is at least 2 square feet of usable wood in the middle. I only throw away the smallest and/or oddly-shaped cutoffs. Even old projects or furniture from my house gets disesected. If it is approximately 1" wide, no matter the length, it goes. If it is wider, I mull it over, depending on the quality of the wood. I.E. 5/8" crappy plywood from Home Depot gets tossed, but if it is BB or Oak or other "good stuff" I mull it over. Since purchasing a table saw roughly 2 years ago, I have the luxury of easily cutting down offcuts down to a usable size, and/or cutting off the glued up/ragged edges and parts. I'd rather cut it, save it, and wind up throwing it away 2 years later than not having it when I need it.

It boils down to this: Anything you scavenge or save is materials you don't have to pay for.

Bruce Weldy
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Re: T48 Build Thread

#8 Post by Bruce Weldy » Sat Aug 03, 2013 1:49 am

Mike....looking good.

:clap:

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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Tom Smit
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Re: T48 Build Thread

#9 Post by Tom Smit » Sat Aug 03, 2013 2:57 am

Nice story, Mike. Anticipating the rest. :)
TomS

hifibob
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Re: T48 Build Thread

#10 Post by hifibob » Sat Aug 03, 2013 5:34 pm

Off to a good start buddy! Im subscribed..

miked
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Joined: Fri Oct 23, 2009 4:18 am
Location: San Antonio, TX

Ah! Braces!!!

#11 Post by miked » Sat Aug 03, 2013 10:01 pm

I'm sure a few of you have watched a cartoon called "The Fairly Oddparents" where a young boy, Timmy, has Fairy Godparents. His teacher, Mr. Crocker has an absolute, spasmodic freakout every time the word "fairy" is even mentioned. Like this: http://www.youtube.com/watch?v=4pV_NfTSctI

If you said the word "braces" right now, I'd freak out just like that. :noob: You'd have to peel me off the wall. LOL!

Yesterday I rough cut all the braces to their overall "rectangular size." Today I cut them to shape and lightened them up. I was in the garage for 8 hours. First, cutting them to shape and then removing extraneous material one_brace_at_a_time. Every brace has to be clamped down and there's sawdust everywhere and then it's in your eyes and then there's sawdust in your ear...it was a long day. It's amazing how time-consuming all these small parts are! Granted, I did not have to swiss-cheese the braces (with the exception of the 2/5 braces), but I wanted try to make these cabs as light as possible. I've also been curious since Day 1 of my decision to build some Titans as to "just how much weight do you save if you skinny down the braces...or not?"

Ah, I'm sure that triggered a subliminal thought! You're thinking "You know what, Mike? I've ALSO always wondered just HOW MUCH weight I might have saved by swiss-cheesing the braces! Guess I'll never know."

Ah, but now you will, my friend! I have taken one for the team and actually weighed the braces on a postage scale before and after swiss-cheesing them! Yeah, I'm mental. But we all are our own unique masterpieces, right? :lol:

But first things first. Cutting rectangles into parallelograms (sp?). Big shout out to Bruce Weldy who in his recent T39 build thread, posted his idea for a simple but dead-accurate table saw sled for cutting braces. What you see below (and in Bruce's thread) is simple and it works perfectly. No need to use any other method but this. It just works. Now here's where it gets funny...or sad, depending on your point of view. I started with the smaller braces. Smaller pieces of wood, easier to handle, etc. So I built a small sled and it worked great.

Here we see the small sled I made cutting the final shape of a 2/5 brace.

Before:
Image

After:
Image

It worked great but ATM it never occured to me that "The braces get bigger so it might be a good idea to build the biggest sled you'll need and use it for all the brace." /faceplam.

I built not one, not two, but THREE damn sleds. I felt like such an idiot. I should've just built the big sled right off the bat and used it for everything. I'd have saved about 20 minutes and two pieces of very nice scrap. Here's the final "big sled." I used it to cut the 6/10 braces. They aren't the widest braces, but the angle of the cut is very steep and the board has to be at a sharp angle to make the cut, necessitating the widest sled.

Image

So after all is said and done, I wound up with this lovely pile of lightened parts. Swiss Cheese For Dinner!
Image

On the windowed braces, I wasn't terribly accurate on the straight line cuts b/c I didn't have to be. The braces aren't visible and deviating from the cutline by 1/32" isn't going to affect performance at all.

So now: The Sixty Four Thousand Dollar Question: EXACTLY HOW MUCH WEIGHT DID I SAVE BY CUTTING ALL THOSE HOLES IN THE BRACES?"

Each cab uses two each of:
2/5 Braces
4/6 Braces
3/7 Braces
7/8 Braces

There's also the 6/10 braces (2) and the horizontal brace for them, but aside from a handle hole in the horizontal brace, I'm not deviating from the plans.

I cut all my braces exactly to size, per the Sep11 T48 plans. I decided on a "per cab" weight measurement. Here are two each, 2/5, 4/6, 3/7, 7/8 braces, cut to size and shape but not lightened at all. 7 pounds, 6.5 ounces:

Image

Here are the same count of braces, after lightening. 4 pounds, 12 ounces:
Image

2 pounds and 10.5 ounces is the difference. Is it worth it? That's highly subjective, obviously. If we were using 3/4" material the lost weight would be greater. But being that we're building well-designed cabs, 3/4" material is a thing of the past, thankfully.

So there ya'go. Just shy of 3 pounds, in my case, is the weight savings. Honestly, I hoped and assumed it would be more than that. Sure; you could shave another few ounces off each brace by cutting away more material than I did, but I tried to be conservative and leave enough meat on the braces to ensure their strength and material for fasteners to bite into, particularly on the very large 7/8 braces.

Tomorrow I'll cut the groove in the 6/10 braces and get the spacer rings cut. Monday is back to work and free time gets scarce. Hope to cut access panel holes on Monday, but we'll see how it goes.

Michael Murphy
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Re: T48 Build Thread

#12 Post by Michael Murphy » Sun Aug 04, 2013 9:40 am

Note to self, stock up on microwave popcorn!
Glad to see smooth progress. Luv the filter setup.

byacey
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Re: T48 Build Thread

#13 Post by byacey » Sun Aug 04, 2013 10:15 am

I was much more scientific in determining the need for lightening up the braces. I built the first cabinet without the cutouts on the braces. After it was finished, I lifted it and determined that it wasn't very heavy at all, and then continued to build cabinet two the same way.
Built
T48s
WH8s
SX212

Bruce Weldy
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Re: T48 Build Thread

#14 Post by Bruce Weldy » Sun Aug 04, 2013 11:13 am

I kinda' wonder how it would look to do a mono stack ......

Your 4- T48s on the bottom
Then my 4 T-39s
Then stack up all 8 OT12s......

We can do that, you know? :mrgreen:

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

sine143
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Re: Ah! Braces!!!

#15 Post by sine143 » Sun Aug 04, 2013 12:17 pm

miked wrote: Here are the same count of braces, after lightening. 4 pounds, 12 ounces:
Image

2 pounds and 10.5 ounces is the difference. Is it worth it? That's highly subjective, obviously. If we were using 3/4" material the lost weight would be greater. But being that we're building well-designed cabs, 3/4" material is a thing of the past, thankfully.

So there ya'go. Just shy of 3 pounds, in my case, is the weight savings. Honestly, I hoped and assumed it would be more than that. Sure; you could shave another few ounces off each brace by cutting away more material than I did, but I tried to be conservative and leave enough meat on the braces to ensure their strength and material for fasteners to bite into, particularly on the very large 7/8 braces.

Tomorrow I'll cut the groove in the 6/10 braces and get the spacer rings cut. Monday is back to work and free time gets scarce. Hope to cut access panel holes on Monday, but we'll see how it goes.
Pro tip. wanna really save weight on braces? Dont use Baltic birch, when a lower grade, lighter ply will suffice.
Built:
2x Tuba 30s delta12lf loaded (gone)
4x Otop12 d2512 loaded
8x t48s (18, 18, 24, 24, 30, 30) 3015lf loaded
2x AT (1 mcm, 1 gto 804)
2x SLA Pro (dayton pa6, 6 goldwood piezo loaded)
1x bastard XF208

2x OT212 (delta pro 450a loaded, eminence psd)

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