Titan 39 Build

[Bryan Cox]

I'm probably going to build a couple V plates Friday night and I have a question. The plans say to add a piece of gasket tape to ensure a rattle free joint. When I've placed gasket tape on top of Duratex it hasn't stuck so well. Anyone have suggestions to help with adherence? Should I add some super glue? Staples?

[Bruce Weldy]

I'm probably going to build a couple V plates Friday night and I have a question. The plans say to add a piece of gasket tape to ensure a rattle free joint. When I've placed gasket tape on top of Duratex it hasn't stuck so well. Anyone have suggestions to help with adherence? Should I add some super glue? Staples?

Put a weatherstrip on the V-Plate. It sticks fine to duratex. This is the stuff I used. It's been on my V-plates for several years....of course, they just sit in the trailer because I added two more subs instead of V-plating.

Use this stuff doubled up. Don't rip it down the middle....

https://www.homedepot.com/p/Frost-King- ... /100017014

[Bruce Weldy]

Here's my build thread on my V-Plate design if you don't want to put holes in your subs....

These were pretty easy to use.

viewtopic.php?f=30&t=17802&p=187461&hil ... te#p187461

[Bryan Cox]

That's pretty neat, Bruce. There's a Home Depot nearby so I can grab the padding this week. Also, your variation on the V plate is ingenuitive. I'm gonna remember that. Thank you!

[Seth]

With it being emphasized how important it is to have the cab completely air tight, I always wondered if there was any benefit to sealing up the v-plate and seam where the cabs meet at the point of the "V" as well as reasonably possible. Or, if it just isn't necessary at all. With reports of noticeable gain with just a folding table instead of a proper V-plate, I gotta guess it may not be worth getting too anal about. Curious still.

[Tom Smit]

Here's my build thread on my V-Plate design if you don't want to put holes in your subs....

These were pretty easy to use.

viewtopic.php?f=30&t=17802&p=187461&hil ... te#p187461

+1
I've made them for myself (easy to make), and easy to use.

[Bryan Cox]

With it being emphasized how important it is to have the cab completely air tight, I always wondered if there was any benefit to sealing up the v-plate and seam where the cabs meet at the point of the "V" as well as reasonably possible. Or, if it just isn't necessary at all. With reports of noticeable gain with just a folding table instead of a proper V-plate, I gotta guess it may not be worth getting too anal about. Curious still.

Obviously I'm no authority on this, but I'm sure the +3dB can be gained with something rigid laid on top to create the larger horn, much like a wall could be used. But IIRC, the plans say it is for a "rattle-free joint."

[Bruce Weldy]

With it being emphasized how important it is to have the cab completely air tight, I always wondered if there was any benefit to sealing up the v-plate and seam where the cabs meet at the point of the "V" as well as reasonably possible. Or, if it just isn't necessary at all. With reports of noticeable gain with just a folding table instead of a proper V-plate, I gotta guess it may not be worth getting too anal about. Curious still.

Obviously I'm no authority on this, but I'm sure the +3dB can be gained with something rigid laid on top to create the larger horn, much like a wall could be used. But IIRC, the plans say it is for a "rattle-free joint."

Exactly. Bill can correct me if I'm wrong, but by the time the wave reaches the mouth - airtight isn't that important, you are just extending the horn like when you wall load. And, it will damn sure rattle if you don't have something in between and a tight grip.

[Bruce Weldy]

Another piece of V-plate building advice. It's better to laminate two pieces of 1/2 inch ply together than using one piece of 3/4. It's more rigid.

[Grant Bunter]

Exactly. Bill can correct me if I'm wrong, but by the time the wave reaches the mouth - airtight isn't that important, you are just extending the horn like when you wall load. And, it will damn sure rattle if you don't have something in between and a tight grip.

This has come up a number of times, and, IIRC, Bill once said something like "If there's a gap between the V'ed cabs, then put some foam in the gap".
This suggests one may not get the desired increase if you don't.

My take is this: You're going to the effort to V plate, for extra output, do whatever you can to maximise it. It doesn't take long to try and block the gap with foam...

[Seth]

I can see both sides of it. That's why the curiosity. I see sealing it up could be good. However, the sketchups of the T39 indicate hand holes on that lip as an assembly option. So... maybe it's not all that important. Dunno.

I'll just have to add it to the list of tests to do once I get my cabs together.

[Seth]

Bryan, sounds like your planning on running 2 separate stacks. I'd be curios to hear your impression, or possibly measured results given identical test voltages of; Single stack of 4, Single stack of 4 with V-plate, Single stack of 4 V-plated and corner loaded, 2 stacks of 2, 2 stacks of 2 with V-plates, 2 of 2 plated & corner/boundary loaded

[Grant Bunter]

However, the sketchups of the T39 indicate hand holes on that lip as an assembly option.
Mmm, never did see that as an option really, as, when I built mine, handholds were included into the mouth braces.
So, I don't have the holes you mention. Which means I only have to seal up the gap if I V plate.
It's amazing how making or decision, or not, can raise itself again later when you build...

So... maybe it's not all that important. Dunno.
me either!

[Bryan Cox]

Bryan, sounds like your planning on running 2 separate stacks. I'd be curios to hear your impression, or possibly measured results given identical test voltages of; Single stack of 4, Single stack of 4 with V-plate, Single stack of 4 V-plated and corner loaded, 2 stacks of 2, 2 stacks of 2 with V-plates, 2 of 2 plated & corner/boundary loaded

Sounds like a plan!

[Bryan Cox]

I thought it couldn't get better...I was wrong. Seth, I didn't have the space to do two separate stacks but I did do a stack of four in these configurations: no v plate, with v plate, wall loaded with v plate. Also Seth, you were right about the LR crossover. I had it set at 48 dB slope and it cut out pretty significant content which also lowered my max voltage to 29.9 VAC. I followed your advice and did my test tone at 60 Hz and got 36 VAC. Then I set my crossover to 47 Hz with a LR24 slope. When I tested again, on the bleeding edge of total meltdown, I got 52 VAC. I set the limiters at 50 volts but never hit it. And to be honest, I couldn't imagine needing anything louder unless I'm outside or the room is just super packed and huge.

My test building is 73' x 135' and I was set up on a shorter wall. So here's the data....

All at 52 VAC with a 60 Hz test tone @ 1 meter:
No V Plate or wall: 121.6 dB
With V Plate: 124.9 dB
V Plate and Wall: 128.1 dB

When I played music content the lows just totally kicked me in the chest. But I will say that the Otop 12s outran the T39s at only 60% power.

With the whole system going, faders at unity gain, mains amp at 60%, and subs amp wide open, some songs hit up to 135 dB on their crescendo. This was at about 35' away...close, I know. But I didn't have the ability to get that far away on-center.

I also noticed I had to bump down 100 Hz by 1 or 2 dB (depending on the time) when it was V Plated and wall loaded. But the absolute clarity and power was astounding. It was so powerful that I could only stand it up to about 75% then I had to put ear plugs in.

Needless to say, impressed doesn't do it justice. I will however, build 4 more T39s to try and keep up with the Otops.