4x T48 and 4x OT12 build

[commander_dan]

Question regarding the damping foam inside the OT12s. Looking at the sketch up and build threads I do not see people putting foam on the backs of the horn panels. Only on surfaces facing the back of the driver cone (top/bottom/back/sides). I assume this is just to damp the direct reflections from the cone.

You could, but the dampening on the other panels would null the reflections before they get there.

[dlv]

You could, but the dampening on the other panels would null the reflections before they get there.

Thanks Dan.

By the way, your build inspired me and these critter screens for the handle ports are coming out just perfect.
A roll on Amazon is less than $15 and enough for two speakers. https://www.amazon.com/dp/B09FPTRLHM

[commander_dan]

How good!

[Bruce Weldy]

Just for reference, this is what the plans recommend;

The (compression driver) horn mounts centered in the cab, ½ inch back from the front edge.
Drill pilot holes for mounting screws or bolts through the cabinet top and bottom into the
diffuser brackets.
Install the horn after the cab has been finished.

It sounds to me like it is intended to be removable. Although, if the drivers are still able to be removed if it was permanently glued to the rest of the cab, I don't see a problem with that.

Mine are a part of the cab and the drivers have easy to access to install and take out. Several years ago, Bill suggested putting in the dowels in the middle of the horn, so I took out the whole assembly, built the new supports and installed the diffuser. Glued it back in and they been through a show or two......or a hundred since then.

[dlv]

Finally started on the CD horns. Man those are tiny parts. Definitely glad to have jigs. Cut all the parts for all four while I had it set up.

Stopped before gluing. Was getting tired and wanted to post pictures of the dry fit in case someone sees something wrong. Only issue I see is the reflector angles are a little bit proud. I’m thinking just glue it up and sand that down to fit rather than setting the jig up all over again. That is my plan for the morning.

[dlv]

Bill I ran across a post of yours recommending roofing screws for installing drivers. Thinking of going with these:

https://www.lowes.com/pd/Hillman-12-x-1 ... 1001236078

Either #10 or #12. #12 is probably overkill so maybe get #10's and if one ever strips, replace it with a 12?

Kinda curious if you advise leaving the washer on the screw. Seems to me like a good idea but it does have that rubber weather seal on it.

No matter what MUCH rather use hex head than Philips head. Yep Bruce, I saw your comment too. Def want to avoid putting holes in my speaker cones if at all possible. That is totally something I'd do.

[Bruce Weldy]

Def want to avoid putting holes in my speaker cones if at all possible. That is totally something I'd do.

Use the circle cutouts from the speaker baffles and lay them on the cone before driving in the screws. Good safety precaution.

[dlv]

Def want to avoid putting holes in my speaker cones if at all possible. That is totally something I'd do.

Use the circle cutouts from the speaker baffles and lay them on the cone before driving in the screws. Good safety precaution.

I would totally do that if I hadn't cut them up as various small parts already.

[Bruce Weldy]

Def want to avoid putting holes in my speaker cones if at all possible. That is totally something I'd do.

Use the circle cutouts from the speaker baffles and lay them on the cone before driving in the screws. Good safety precaution.

I would totally do that if I hadn't cut them up as various small parts already.

I've used those cutouts for a variety of things.....I keep a few in my trailer - great for leveling out a speaker stand in half inch increments. Even built a new steering wheel out of one for a little pedal car tractor.

[dlv]

How is this for a crossover layout if I'm keeping it on one board? Bad idea? I know the sketch up shows two separate boards.
There's about 3/4" between coils and they're off axis to each other. I can keep it to about a 5" x 3" board this way.
This could be me over optimizing here. A tendency I have sometimes.

[dlv]

Even built a new steering wheel out of one for a little pedal car tractor.

I'm betting you've got grandkids. That's a proper grandpa thing to do right there!

[Bruce Weldy]

How is this for a crossover layout if I'm keeping it on one board? Bad idea? I know the sketch up shows two separate boards.
There's about 3/4" between coils and they're off axis to each other. I can keep it to about a 5" x 3" board this way.
This could be me over optimizing here. A tendency I have sometimes.

crossover layout.jpeg

I didn't check the wiring scheme, but being on one board isn't a problem and you positioned things properly. Mine are all on one board.

[Bill Fitzmaurice]

There's no advantage to using a single board. There is to using two, which is to reduce the potential for wiring errors, which worst case can result in blown HF drivers or even a blown amp.

[dlv]

I ended up going with two boards. I'm confident in my wiring skills but of course Bill is right this is much simpler. I like flat mounting both coils too.

[dlv]

Before I start final finishing and painting I threw drivers in one of the OT12s and one sub just because I couldn't wait to hear it.

Oh my god! I couldn't hit the limiters in my shop without ear pro on. Sounded pretty dang good without any eq. Though I did have to turn down the top amp about 12db, it was definitely out running the sub.

Can't wait to get the whole herd painted up and test the rig. Gonna have to see if one of the local outdoor venues will let me set up and play with it.

-Dave