Another OT12 build
Another OT12 build
With the T39s almost done, I'm starting work on four OT12s. I'm making four based on recommendations from other, senior forumites; seems having a pair on each side smooths out response. Sounds good to me! I have enough electronics on hand for two currently, so the other two might be shells for a short time. Melded piezo arrays, 2512 drivers, Arauco ply. I'll use standard top hats, with the bottom cab having them in both bottom and top, so I can join the top cab securely.
All major panels got cut out last weekend. Today I'm beginning the markup on tops and bottoms!
It would be great to have these up and running (at least the first pair) by our March 5 gig, but that may be too ambitious....
All major panels got cut out last weekend. Today I'm beginning the markup on tops and bottoms!
It would be great to have these up and running (at least the first pair) by our March 5 gig, but that may be too ambitious....
-todd
5 and 8 string bass | SansAmp | Crown | 2 x J110
2 x W8 panel-mount
2 x T39 24" 3012LF
4 x OT12 2512 melded (finally done!)
5 and 8 string bass | SansAmp | Crown | 2 x J110
2 x W8 panel-mount
2 x T39 24" 3012LF
4 x OT12 2512 melded (finally done!)
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- Location: New Braunfels, TX
Re: Another OT12 build
That really isn't necessary. Put the locking chevron corners on 'em and they aren't going anywhere.ctmullins wrote:having them in both bottom and top, so I can join the top cab securely.
6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
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."
Re: Another OT12 build
Baffles are cut. I remember this maddening step from my W8s. Only this time I have four of them to do!
So I decided to do two at a time, by stacking, clamping and cutting. Good idea or foolhardy? Inquiring minds...
After each section I tidy up the blade wander with the fearsome Shinto Saw Rasp. It's one of my favorite tools!
First pair nearly done....
And then there were four!
We'll soon find out if this little shortcut causes any problems....
So I decided to do two at a time, by stacking, clamping and cutting. Good idea or foolhardy? Inquiring minds...
After each section I tidy up the blade wander with the fearsome Shinto Saw Rasp. It's one of my favorite tools!
First pair nearly done....
And then there were four!
We'll soon find out if this little shortcut causes any problems....
-todd
5 and 8 string bass | SansAmp | Crown | 2 x J110
2 x W8 panel-mount
2 x T39 24" 3012LF
4 x OT12 2512 melded (finally done!)
5 and 8 string bass | SansAmp | Crown | 2 x J110
2 x W8 panel-mount
2 x T39 24" 3012LF
4 x OT12 2512 melded (finally done!)
Re: Another OT12 build
Your process is fine if you don't have a router....cuts the work load in half.
If you have a router (and pattern bit), you could make just one of which you could use as a template for the rest.
If you have a router (and pattern bit), you could make just one of which you could use as a template for the rest.
TomS
Re: Another OT12 build
Humph. That's definitely not happening. Too much life stuff lately. Tonight's the first night of progress since writing that...ctmullins wrote: It would be great to have these up and running (at least the first pair) by our March 5 gig, but that may be too ambitious....
Putting the shells together. I deviated from the plans again.... But a big "thanks!" to whomever invented those W clamp thingies!
-todd
5 and 8 string bass | SansAmp | Crown | 2 x J110
2 x W8 panel-mount
2 x T39 24" 3012LF
4 x OT12 2512 melded (finally done!)
5 and 8 string bass | SansAmp | Crown | 2 x J110
2 x W8 panel-mount
2 x T39 24" 3012LF
4 x OT12 2512 melded (finally done!)
Re: Another OT12 build
Bruce Welby posted a few times about them.But a big "thanks!" to whomever invented those W clamp thingies!
TomS
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- Posts: 8317
- Joined: Fri Nov 27, 2009 11:37 am
- Location: New Braunfels, TX
Re: Another OT12 build
Tom Smit wrote:Bruce Welby posted a few times about them.But a big "thanks!" to whomever invented those W clamp thingies!
Just something I found in an old woodworking magazine......I've used 'em for tons of stuff outside of speaker building over the years.
6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
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."
Re: Another OT12 build
Small progress today - got eight throat reflectors cut out, with their angle cuts. The long side 45 degree cuts were easy, then I used this makeshift sled on the small tablesaw for the other cuts. First one side:
Then I rotated the sled over to the other side of the blade, flipped the piece over, and did the second side:
I don't think I have the energy to actually glue them tonight, though...
Then I rotated the sled over to the other side of the blade, flipped the piece over, and did the second side:
I don't think I have the energy to actually glue them tonight, though...
-todd
5 and 8 string bass | SansAmp | Crown | 2 x J110
2 x W8 panel-mount
2 x T39 24" 3012LF
4 x OT12 2512 melded (finally done!)
5 and 8 string bass | SansAmp | Crown | 2 x J110
2 x W8 panel-mount
2 x T39 24" 3012LF
4 x OT12 2512 melded (finally done!)
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- Joined: Tue Apr 30, 2013 5:56 pm
- Location: Colonial Beach VA
Re: Another OT12 build
http://billfitzmaurice.info/forum/downl ... &mode=view
I've found this to be the best and easiest way to clamp those buggers.....
I've found this to be the best and easiest way to clamp those buggers.....
BFM rig:
6 OT12
4 T48
4 WH8
Other:
56 box Electrotec LabQ rig
Way too many cables
6 OT12
4 T48
4 WH8
Other:
56 box Electrotec LabQ rig
Way too many cables
Re: Another OT12 build
Thanks David, that's easier than what I was going to try! Makes perfect sense!
-todd
5 and 8 string bass | SansAmp | Crown | 2 x J110
2 x W8 panel-mount
2 x T39 24" 3012LF
4 x OT12 2512 melded (finally done!)
5 and 8 string bass | SansAmp | Crown | 2 x J110
2 x W8 panel-mount
2 x T39 24" 3012LF
4 x OT12 2512 melded (finally done!)
Re: Another OT12 build
Throat reflectors installed, lots of excess PL trimmed (tedious), and holes cut for top hats. I clamped my little "portable drill press" to the cab and used a 1 9/16" Forstner bit. This way the holes line up just right.
The top hats (the steel Penn-Elcom ones that Leland sells) are a very snug fit. I won't need to use any sealant here.
On the very last one, however, the final layer of ply gave way and separated completely. I'll have to patch that up. I suppose I should have used a sacrificial backer board...
The top hats (the steel Penn-Elcom ones that Leland sells) are a very snug fit. I won't need to use any sealant here.
On the very last one, however, the final layer of ply gave way and separated completely. I'll have to patch that up. I suppose I should have used a sacrificial backer board...
-todd
5 and 8 string bass | SansAmp | Crown | 2 x J110
2 x W8 panel-mount
2 x T39 24" 3012LF
4 x OT12 2512 melded (finally done!)
5 and 8 string bass | SansAmp | Crown | 2 x J110
2 x W8 panel-mount
2 x T39 24" 3012LF
4 x OT12 2512 melded (finally done!)
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- Posts: 8317
- Joined: Fri Nov 27, 2009 11:37 am
- Location: New Braunfels, TX
Re: Another OT12 build
ctmullins wrote:Throat reflectors installed, lots of excess PL trimmed (tedious), and holes cut for top hats. I clamped my little "portable drill press" to the cab and used a 1 9/16" Forstner bit. This way the holes line up just right.
The top hats (the steel Penn-Elcom ones that Leland sells) are a very snug fit. I won't need to use any sealant here.
On the very last one, however, the final layer of ply gave way and separated completely. I'll have to patch that up. I suppose I should have used a sacrificial backer board...
Just put a doghouse on all of 'em....you have to seal 'em anyway....
6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
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."
Re: Another OT12 build
You know, I need to understand this part of the design a little better.Bruce Weldy wrote: Just put a doghouse on all of 'em....you have to seal 'em anyway....
Unlike the Jacks, the space under the throat reflectors is completely isolated from the main chamber. This means that it must not play a part in cabinet tuning, other than serving as part of the horn path.
So why exactly does it need to be sealed off?
-todd
5 and 8 string bass | SansAmp | Crown | 2 x J110
2 x W8 panel-mount
2 x T39 24" 3012LF
4 x OT12 2512 melded (finally done!)
5 and 8 string bass | SansAmp | Crown | 2 x J110
2 x W8 panel-mount
2 x T39 24" 3012LF
4 x OT12 2512 melded (finally done!)
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- Posts: 8317
- Joined: Fri Nov 27, 2009 11:37 am
- Location: New Braunfels, TX
Re: Another OT12 build
ctmullins wrote:You know, I need to understand this part of the design a little better.Bruce Weldy wrote: Just put a doghouse on all of 'em....you have to seal 'em anyway....
Unlike the Jacks, the space under the throat reflectors is completely isolated from the main chamber. This means that it must not play a part in cabinet tuning, other than serving as part of the horn path.
So why exactly does it need to be sealed off?
Well, you made me do some research. I built mine under an older set of plans where the baffle had slots in the top and bottom - only the baffle for the 3012HO was solid. Looks like the newest plans don't show a different baffle for the 3012HO and the other drivers as far as the slots.
I guess you don't need to seal 'em.
Mea Culpa....
6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
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."
- Chris_Allen
- Posts: 3355
- Joined: Wed Jul 11, 2007 2:43 pm
- Location: Huddersfield, UK
Re: Another OT12 build
Yep, they disappeared in the 2011 set of the plans and aren't present in the JArray version either.Bruce Weldy wrote:Looks like the newest plans don't show a different baffle for the 3012HO and the other drivers as far as the slots.
Built:
6xDR200, 2xT39, 2xT48, 2xJack110, 1xOmni10.5, 1xAutotuba, 1xT18, 1xSLA Pro, 1xW8, 1xW10
6xDR200, 2xT39, 2xT48, 2xJack110, 1xOmni10.5, 1xAutotuba, 1xT18, 1xSLA Pro, 1xW8, 1xW10