Titan 48 for 12v build// No Labs in the UK

[Bruce Weldy]

Use anything you have between 12 and 16 gauge for a run that short.

[Chris_Allen]

She needs more braces captain!

[Chris_Allen]

Incidentally, I found this 15" driver which looks a good fit for a T48: https://www.rcf.it/en/products/product-detail/lf15x401

Assuming the XMAX is real of course...

[Tom Smit]

1.3 mm2 is the minimum cable required, and it could be any multi-strand wire.
I would suggest a block between the baffle and the centre strut, as well as a brace from the baffle to panel 3.

[Seth]

Kairos,

Wow! That's come along further than I expected. Great job.

A closer look at some of the pics and I agree with Chris...

She needs more braces captain!

With a 30" cab width, using only 2 braces perfectly spaced puts them slightly further apart than the maximum recommended distance between braces. They don't need to be perfectly spaced, in fact Bill has said that having them unevenly spaced can help reduce unwanted resonances. But, you want them no further than 9" from the nearest brace or cab side. Too far apart and it allows the panels to flex slightly which reduces output and negatively affects overall response of the cab.

In the picture below, it looks like there's about 12" without a brace where the arrow is indicating. That area of the horn is subjected to greater pressure swings that cause vibrations than the more voluminous portions of the horn path and it's pretty important to have it braced well. Definitely add some bracing there. If you can't sneak a full length brace in from behind, cut the brace into two or more pieces so you can get them in and around the existing brace that may be blocking the way. Slide one piece in, then the other/s. Not an issue if they're not perfectly aligned, spaced, or matched up. If there's more than 9" between the other brace and the other side, add one in there too. Just want to eliminate any possible panel flex there and 4 braces in that spot wouldn't be a bad thing at all. And use at least 3 braces per panel throughout the rest of your build. But don't sweat it if you only used two between panels 3 and 5. Using 3 braces between panels 5 and 8 will sufficiently support panel 5, two on one side, 3 on the other. If you're running low on scrap to make braces, you can use any quality of ply for the braces, doesn't have to be the same as the rest of the cab. The cheapest, ugliest ply you can find is fine for braces. You can even make the braces out of ¼" / 6mm ply.

The threaded inserts weren't a necessity, but I like to add my own little touches too. For anyone else reading this and contemplating a future build, the plans specify the use of screws into retention blocks to attach the drivers in the cabs. Screws are preferred because the more commonly used T-nuts will occasionally lose their bite into the wood and just spin while trying to remove the driver retaining bolts. With no way to access the backside of the baffle with a pair of pliers, it becomes a HUGE pain in the ass when a T-nut strips. With the screw-in style threaded inserts like Kairos has used, if they strip out you can still pull the driver without too much trouble and just repair the hole. Screws are plenty stout to hold even the heaviest of drivers and screws don't back out with vibration like bolts and threaded inserts tend to do over time. Kairos, make sure you pull the access panel annually and check to make sure all the driver bolts are still tight. The use of any thread locker (loctite) increases the risk of the insert backing out instead of the screw if you ever need to remove the driver. Use split lock washers between the bolt head and driver flange to help mitigate loosening.

As the others have said, standard 2 strand zip cord style speaker wire is fine. The plans specify the use of either 14 or 16 gauge.

These 2 12s are heavy ! 15kg together ( 32Ibs ).... ...Theres not that much wood left in that 29" wide baffle after cutting out for the drivers, with this much weight on there do people think i should add some more braces, or will those mentioned in the plan be enough?

A pair of LAB12's is about 22Kg (48lbs). You're safe to follow the plans to a "T". And additional bracing is almost never a bad thing too.

[Mishkin]

thanks all for responses,

i wont splash out on fancy cable then, 2.5mm squared is 14 gauge as far as im aware ...

I will add in that third brace in that 12 " gap between panel 4 and 6 , glad u spotted it !
Those pics were before i put in any braces around the baffle and its framing. I've now got exactly the 4 braces specified in the plans (two flange to baffle - one more or less under each driver cut out. the one between the central vertical and the baffle and the larger baffle to panel three Brace. ive ofset them a bit after reading what your saying about resonances Seth. and i'll add one more little flange to baffle brace too, so its less then 9" unbraced in the centre of the horizontal lower flange .

I did heaftily epoxy all my insert nuts before screwing them into the wood, hopefully that will be enough to stop them stripping out and spinning . but goood point about the bolts wrattling loose, ill be sure to use grippy washers, and check them sometimes!

[Mishkin]

Also, Seth what do you think to using threadlock on the bolts, if the insert nut has been epoxied into the wood ?

[Bruce Weldy]

Also, Seth what do you think to using threadlock on the bolts, if the insert nut has been epoxied into the wood ?

When you say insert nut, I'm assuming that you don't mean a T-nut, but rather one that you see in furniture? Threaded on the outside to for gripping the wood? If so, that is NOT what you want to use. That will most likely spin with the bolt when you try to take it out. Then you're screwed....pun intended.

If you don't use a wood screw, then use T-nuts and lock them in with a screw on the base of each one to keep 'em from turning. Epoxy alone isn't enough.

[Seth]

Also, Seth what do you think to using threadlock on the bolts, if the insert nut has been epoxied into the wood ?

I've never used them, so I really couldn't say. If it did end up unscrewing the threaded insert instead of the fastener, it wouldn't be as big of a deal as a stripped T-nut. It would probably unscrew until the insert hit the driver frame, then the fastener would probably spin out at that point. I really don't know though.

You could test one out. Glue one into a scrap piece of ply, use the Allen wrench to gauge how difficult it is to remove, and use your best judgement on whether you think you can use low strength threadlock or not.

[howiez]

I use T-nuts and epoxy/screw secure them as pictured. I also typically use Loctite 243, as i'm in no hurry to open the cabs back up for screw tightening. I've changed drivers on one of my Titans without any issue. I also used those pound in jagged threaded inserts in my THT access cover with loctite 243. Took that apart several times for amp upgrades and a driver upgrade without issue. BUT those were #8 screws. You start getting #10 or more and like Seth mentioned, there may be enough torque to pull out threaded or pounded inserts. So T-nuts/epoxy and a screw FTW. I like the epoxy to keep the screw in place/tight too.

[CarterKraft]

Nothing helpful to add but "long live the 12volt!"

The SounDigital amplifier line is a Brazilian style (Tatamps) amp that might be more readily available over there.

It sounds though as you have it all sorted out.

[Mishkin]

Life keeps in getting in the way ...

Progress has been crawling along with long gaps between working on this, but the Titan is more or less ready to be painted and loaded with its drivers. The 12v van system will have its debut on the 27th of jan . Nothing like a deadline to make you actually finish something.

Does any one else who has built an angle back titan48 have trepidations about standing it upright, the way that they are stood in the sketchup?
Because of the smaller footprint that way and being top heavy mine feels like it can easily be knocked over backwards. I've thought about putting the 100mm castors on the angle back section low enough that the are just about touching the floor, already before its tilted - to give a bit more footprint when stood in this position, but then again they roll, so that might make the risk of falling backwards greater.

thoughts anyone?

[Seth]

I think it's typical to put rubber feet on the front edge and attach wheels on the rear in a position that results in the cab resting on the feet and wheels when upright. When it's being used, I think I'd be inclined to lay the cab on it's side if I thought it was in danger of being accidentally knocked over.

I'm very anxiously awaiting a performance report!

[Bill Fitzmaurice]

The balance point is well forward of the midpoint due to the placement of the drivers at the front of the cabinet.