4x T48 and 4x OT12 build

[Seth]

I don't remember what I did to seal the jack that I put in the driver chamber of my T39, but I don't have any leakage. I probably used black RTV silicone. It's not like there's a ton of pressure/vacuum in there. A ported cab would experience greater pressure differential than the sealed chamber of theses designes, and every ported cab out there has their jacks mounted into the driver chamber. I don't see a single issue with that location. They just need to be sealed.

[Bill Fitzmaurice]

Ported cabs mount jacks in the driver chamber because there's no other place to mount them. As a result whistling 1/4" jacks are common. Sealing a Speakon is easy enough, but not all Speakons are airtight.

[dlv]

Hi all! Back from a near month long trip around England and Scotland. Great time but now I’m back at the build.

Nearly done with the subs and I’m finalizing the grill design. Decided to go with the suggestion to set the grill In throat. Looking for feedback on how I’m thinking to fasten it. The trim pieces around the outside in this picture are just a dry fit. I’m planning to use perforated steel. I’ll fasten it to the braces and around the edges. I probably don’t really need support all the way around like I’m doing here but I definitely don’t want anything rattling or buzzing.

It’s a bit of work but I also want it to look good if the grill is removed. Let me know what you think or see a better way to do this. Thanks!

[Seth]

Nice! Welcome home.

It seems to me that a full perimeter may make it a little easier to get a tight enough fit to keep the critters out. Another thought that crossed my mind is if you put a slight curve into the side pieces, forcing the grill to bend slightly when screwed down would put tension in the grill and make it more rigid overall. Could be a good thing for avoiding unwanted noises, but will also make it more dent resistant as well as add a slight visual que of sorts.

Just thinking out loud.

[Rich4349]

You may want to consider rubber washers between the expanded metal and the braces (running the screws through the washers) to reduce or eliminate big bass notes rattling it.

[dlv]

Thanks for the suggestions guys. I'm thinking something like this between the grill and the wood. 1/2" wide adhesive foam weather strip. It's cheap enough. https://www.amazon.com/Weather-Strippin ... TP5RR?th=1

[Bruce Weldy]

Thanks for the suggestions guys. I'm thinking something like this between the grill and the wood. 1/2" wide adhesive foam weather strip. It's cheap enough. https://www.amazon.com/Weather-Strippin ... TP5RR?th=1

That's gonna come up through the grill when you tighten it down and look kind'a crappy. Especially where you screw through it.

Just use some rubber washers between the grill and the cab. That'll give it about a 1/8 standoff and look better. Get some that have a small enough hole so that they are snug when you put 'em on the screw. That way, you can put all of the screws through the grill, put on the washers and they will stay in place while positioning the grill. Too big of a hole in the washer and they'll keep falling off while trying to put the grill on.

[dlv]

Ok good point Bruce. Will get some rubber washers!

[dlv]

If your jacks are far enough from the driver, there may be room to build a small dog house behind the jacks to seal them from the main chamber.

Finally got around to doing this. Worked out great. Thanks again for that suggestion Kevin!

[dlv]

After soldering the wiring harness in the first two cabs with it glued in the cab I had the realization I could make it up and glue it in after testing it. So much easier!

I think by the time I’m done with all 4 of these subs I’ll have a decent idea how to do it!

[Seth]

I'm looking at the preassembled wiring pic and trying to make sense of it. My only intention is to help you avoid mistakes. So, if you're certain it's all good, don't sweat the question. But, if you're not 100% certain or are otherwise willing to humor my curiosity, would you mind walking me through it?

I see four female spade connectors on the left and four on the right, one duplex wire connecting them, and one duplex lead coming off the left set. What it looks like is wiring for two 4 conductor SpeakOn's, yet only one of two pair passed between the two connectors, and a speaker lead off the left set. Am I seeing that right? Maybe it just hasn't been completed when the photo was taken?

Dunno. Just trying to save you headaches down the road. To my eye, it looks like you'll want another duplex, for a total of four conductors between the two SpeakOn's.

Otherwise, it's all looking amazing. I like those doghouses.

[dlv]

Seth your right. Though I’m using NL4 connectors I chose not to wire these for the second (2+/-) terminals. All my speaker cables are two conductor (1+/-) and I don’t plan to change them out for 4 conductor cables. My amp rack is wired similarly. It was a compromise from how most might wire them I know but a conscious decision. If for some reason I find a need to go with 4 conductor cable from the amp I’ll just make a break out box to split them at the speakers.

[Seth]

Seth your right. Though I’m using NL4 connectors I chose not to wire these for the second (2+/-) terminals. All my speaker cables are two conductor (1+/-) and I don’t plan to change them out for 4 conductor cables. My amp rack is wired similarly. It was a compromise from how most might wire them I know but a conscious decision. If for some reason I find a need to go with 4 conductor cable from the amp I’ll just make a break out box to split them at the speakers.

Ohhh, I see what's going on now. Gotcha. Understood. Carry on my good man.

[dlv]

Finally! First cuts on the OT-12s! Have one final side to put on the last T48 and then some sanding and finishing before painting. Also still need to make the grills.

But I need some tops to test these things out with!!! lol

Very first thing is make some circle templates and a template for the baffle.

Using a 6" circle template and some scrap to jig out the baffle template:

The finished baffle template:

And a nice clean baffle cut from it! The rest will be a piece of cake. Templates make this so much fun I might cut parts for 6 tops even tho I planned for 4.

One question about these baffles. Is there any need to square out the corners where the router bit leaves a 1/4" radius? I can't imagine it would affect the sound in any way. I like the look of the radius (though it'll be hidden eventually) so I'd rather leave it.

[Seth]

I find creating jigs with that method to be one of the most satisfying parts of a build. To take a bunch of garbage cutoff's and turn out a part that looks like it just came off the CNC table, such a sweet feeling. Especially once all the parts are made and look identical and perfect too. I love it!

Well done! Looks perfect!