SLA Pros and 24" T-24 Duallys
Posted: Wed Dec 19, 2012 2:16 am
(Webmaster - I'm photo-posting challenged. Feel free to alter/delete images or text as you see fit.)
Built these for my son's band. A lot of fun and a great way to connect to your kid at any age (he's 21). 24" cubes with two BP102-4's in each, wired for an 8 ohm cabinet. Tops are SLA Pros and their clarity at a distance is amazing.
If I was doing it over again I would have done a Lab 12 T39 over the two T24s. After the first sub was done I actually asked this forum if the next one should also be a T24 or cut my losses and do a T39.
All said to do a T39. Bad form to not follow advice when you've solicited it, but I didn't want to build a third sub, so that would have left me with one T24 and one T39. Additionally, I would have wanted to reuse my already purchased 10" 4 ohm drivers so the T39 would have to be a dually as well if I wanted an 8 ohm cab. That's starting to become a fairly large cab. And I would have been left with only one T24 when they're meant to be used in pairs.
A few minor goofs here and there but generally went together pretty well.
Recommendations to newbies from one of your own kind (only other thing I'd done even remotely close to these is the workbench and cabinet shown in the photos).
1. Follow the plans. Stop asking if this driver or that driver would be an acceptable substitution, or if you can use waferboard wood instead, or would it be okay to ... whatever. If it was okay BFM would have put it in the plans. If you follow the plans you end up with a great PA you (or your son in my case) will enjoy for years.
2. Use Duratex (and buy it, and everything else you can from Leland at speakerhardware.com). It's so easy, looks great, and you can touch up spots as needed over the years. Don't know why anyone would want to wrestle with carpet. (But a nod to those of you who do it, carpet looks great.)
3. Use screws to hold panels together while they dry and consider not removing them. I couldn't see any point. I only removed outside screws prior to finishing.
4. Really consider not going with duallys. If you believe you need the power of a dually consider stepping up to the next bigger sub instead. On retrospect the only advantage I see to building duallys over singles was only having to build two cabs instead of four. Singles give you much more flexability for transport, smalls rooms or big rooms, etc.
5. Speakon connectors are worth the extra cost. You can make your own cables easily and if you do make them two channel. Makes hooking them up a no brainer and less cords to manage to boot.
6. Don't go with a cheap router like I did. Buy something used off Craigslist with more HP than something new from the store with less power.
I'll add more over time if I think of other stuff. Thanks to Bill and the rest of you for answering my questions when I had them. And especially to Leland at speakerhardware.com who was great about returns when I'd ordered the wrong stuff, advice when I didn't know what to do, and assurance that it'll all come together just fine.
SLA Pro under construction. Notice barrel holes for tweeters aren't centered in the array. Swore I wouldn't make that mistake again on the second one. Of course I did. Still not sure how I missed it twice.
One SLA Pro finished, one under construction.
Close up of the finished one minus its grill.
The completed tops. I mounted their top hats on opposite ends so when they're on their poles they'll be mirror images of each other.
Baffle Pic 1 of 2 of a T24 under construction.
Pic 2 of 2.
A rat maze for very tall rats? Tops were 3/8" baltic birch and the subs were 1/2" BB.
Pic 1 of 3 showing bracing. I used leftover 3/8" BB scrap from the tops for the braces. (Plans give the okay for it.) For some reason I had a ridiculously hard time cutting and fitting them. Sometimes its the supposed easy things that can be most difficult. You'll see I cut the classic BFM handholds into the showing braces. Surprisingly useful for wiggling the T24s into position.
Pic 2 of 3.
Pic 3 of 3.
Pic 1 of 2 of first T24 being sealed up.
Pic 2 of 2.
This is the second sub. Notice the white horizontal band on the front panel. That's Bondo where I joined two smaller pieces together. Didn't want to buy another sheet of BB ply for one panel. Of course if I hadn't miscut the piece of wood I was going to use, I wouldn't have had to do that.
Fitting the hardware on a sub.
The first T24 is finished. I touched up the Duratex after I took the picture. Notice it doesn't have any side handles. More on that below.
As shown on Bill's site, T24's can be stacked mouth to mouth which was the plan all along. But with a dually that's a wider box for one person to get their arms around and pretty heavy as well. So I thought I'd add spring loaded side handles to them to make it easier for two people to flip one on top of the other.
The handles are placed so low because I didn't want to put screws anywhere where I couldn't fix a leak if they caused one. Not likely, but it'd be just my luck ... Also didn't want a handle on the access panel.
Driver chamber prior to adding gasket tape to the flanges.
A trial stacking. I rounded all the edges except those framing the mouth. I imagine those edges will get banged up a bit when the cabs are being stacked so didn't want to remove any material from there. (Apologies for the large white margins on some of these photos.)
Pic 1 of 3 of the Four Horsemen of the Apocalypse.
Pic 2 of 3. Yes I know it shows even less detail than the previous one so why did I bother posting it? Because I've read here and there that one can "never post too many pics".
Pic 3 of 3. Subs now coupled under (drop down) workbench.
Went with pretty heavy duty hardware to try and make the cabinets unbreakable for my son.
Fitting the V coupler plate.
Finished! Hard to see but the V coupler is attached to the side of the stack for moving and storage. (And for any Phoenix area residents, that's my U of Oregon Ducks beating up on your Sun Devils in the background.)
Completed subs configured for sound check. I put the Speakon jacks on in such away that when the subs are tipped on their sides for V coupling, the cables of both of them are low to the ground and hopefully less of a tripping hazard.
Finally(!) my 5' 2" daughter standing on the T24s and playing Vanna White with the SLA Pros in a photo greeting to her brother telling him they're finished. A really great experience all around.
Built these for my son's band. A lot of fun and a great way to connect to your kid at any age (he's 21). 24" cubes with two BP102-4's in each, wired for an 8 ohm cabinet. Tops are SLA Pros and their clarity at a distance is amazing.
If I was doing it over again I would have done a Lab 12 T39 over the two T24s. After the first sub was done I actually asked this forum if the next one should also be a T24 or cut my losses and do a T39.
All said to do a T39. Bad form to not follow advice when you've solicited it, but I didn't want to build a third sub, so that would have left me with one T24 and one T39. Additionally, I would have wanted to reuse my already purchased 10" 4 ohm drivers so the T39 would have to be a dually as well if I wanted an 8 ohm cab. That's starting to become a fairly large cab. And I would have been left with only one T24 when they're meant to be used in pairs.
A few minor goofs here and there but generally went together pretty well.
Recommendations to newbies from one of your own kind (only other thing I'd done even remotely close to these is the workbench and cabinet shown in the photos).
1. Follow the plans. Stop asking if this driver or that driver would be an acceptable substitution, or if you can use waferboard wood instead, or would it be okay to ... whatever. If it was okay BFM would have put it in the plans. If you follow the plans you end up with a great PA you (or your son in my case) will enjoy for years.
2. Use Duratex (and buy it, and everything else you can from Leland at speakerhardware.com). It's so easy, looks great, and you can touch up spots as needed over the years. Don't know why anyone would want to wrestle with carpet. (But a nod to those of you who do it, carpet looks great.)
3. Use screws to hold panels together while they dry and consider not removing them. I couldn't see any point. I only removed outside screws prior to finishing.
4. Really consider not going with duallys. If you believe you need the power of a dually consider stepping up to the next bigger sub instead. On retrospect the only advantage I see to building duallys over singles was only having to build two cabs instead of four. Singles give you much more flexability for transport, smalls rooms or big rooms, etc.
5. Speakon connectors are worth the extra cost. You can make your own cables easily and if you do make them two channel. Makes hooking them up a no brainer and less cords to manage to boot.
6. Don't go with a cheap router like I did. Buy something used off Craigslist with more HP than something new from the store with less power.
I'll add more over time if I think of other stuff. Thanks to Bill and the rest of you for answering my questions when I had them. And especially to Leland at speakerhardware.com who was great about returns when I'd ordered the wrong stuff, advice when I didn't know what to do, and assurance that it'll all come together just fine.
SLA Pro under construction. Notice barrel holes for tweeters aren't centered in the array. Swore I wouldn't make that mistake again on the second one. Of course I did. Still not sure how I missed it twice. One SLA Pro finished, one under construction. Close up of the finished one minus its grill. The completed tops. I mounted their top hats on opposite ends so when they're on their poles they'll be mirror images of each other. Baffle Pic 1 of 2 of a T24 under construction. Pic 2 of 2. A rat maze for very tall rats? Tops were 3/8" baltic birch and the subs were 1/2" BB. Pic 1 of 3 showing bracing. I used leftover 3/8" BB scrap from the tops for the braces. (Plans give the okay for it.) For some reason I had a ridiculously hard time cutting and fitting them. Sometimes its the supposed easy things that can be most difficult. You'll see I cut the classic BFM handholds into the showing braces. Surprisingly useful for wiggling the T24s into position. Pic 2 of 3. Pic 3 of 3. Pic 1 of 2 of first T24 being sealed up. Pic 2 of 2. This is the second sub. Notice the white horizontal band on the front panel. That's Bondo where I joined two smaller pieces together. Didn't want to buy another sheet of BB ply for one panel. Of course if I hadn't miscut the piece of wood I was going to use, I wouldn't have had to do that. Fitting the hardware on a sub. The first T24 is finished. I touched up the Duratex after I took the picture. Notice it doesn't have any side handles. More on that below. As shown on Bill's site, T24's can be stacked mouth to mouth which was the plan all along. But with a dually that's a wider box for one person to get their arms around and pretty heavy as well. So I thought I'd add spring loaded side handles to them to make it easier for two people to flip one on top of the other. The handles are placed so low because I didn't want to put screws anywhere where I couldn't fix a leak if they caused one. Not likely, but it'd be just my luck ... Also didn't want a handle on the access panel. Driver chamber prior to adding gasket tape to the flanges. A trial stacking. I rounded all the edges except those framing the mouth. I imagine those edges will get banged up a bit when the cabs are being stacked so didn't want to remove any material from there. (Apologies for the large white margins on some of these photos.) Pic 1 of 3 of the Four Horsemen of the Apocalypse. Pic 2 of 3. Yes I know it shows even less detail than the previous one so why did I bother posting it? Because I've read here and there that one can "never post too many pics". Pic 3 of 3. Subs now coupled under (drop down) workbench. Went with pretty heavy duty hardware to try and make the cabinets unbreakable for my son. Fitting the V coupler plate. Finished! Hard to see but the V coupler is attached to the side of the stack for moving and storage. (And for any Phoenix area residents, that's my U of Oregon Ducks beating up on your Sun Devils in the background.) Completed subs configured for sound check. I put the Speakon jacks on in such away that when the subs are tipped on their sides for V coupling, the cables of both of them are low to the ground and hopefully less of a tripping hazard. Finally(!) my 5' 2" daughter standing on the T24s and playing Vanna White with the SLA Pros in a photo greeting to her brother telling him they're finished. A really great experience all around.
