BillFitzmaurice.info

Day 6:

I cut and installed the access panel mounting flanges and got the access panels drilled and countersunk. Then I started the sanding/hole filling/finishing process. Having decided on which grill mounting system I'm using, I rounded over the cab edges and went over them with the finishing sander to get everything nice and smooth. Now I'm just waiting on crossovers, tweeter arrays and recessed jack plates to arrive which should hopefully be the week after next!

What a clean build! Can't wait to see the finished product.

I only see one major mistake......you should have built four!

Looking really nice. Well done!

One thing I noticed is that your rear cover flange appears to to be made from one layer of plywood stips. But I believe the plans call for two layers of plywood strips. I am not sure if this is critical, but Bill usually doesn't put unnecessary features into the design.

kkip wrote:Looking really nice. Well done!

One thing I noticed is that your rear cover flange appears to to be made from one layer of plywood stips. But I believe the plans call for two layers of plywood strips. I am not sure if this is critical, but Bill usually doesn't put unnecessary features into the design.

Well I'll be! I did not see that detail. I've read those plans so many times too, just goes to show no matter how well you think you know something, there's always something more to be gleaned. Thanks for the pickup kkip, I shall add the second layer next time I'm in town.. an easy fix at least hey!

I wonder why there are 2 layers of the flanges though, extra rigidity for that area of the cab, and more meat for the access panel screws to bite into perhaps? The T30 flanges are only single layer, which could be the reason I overlooked that detail, just being used to doing single layer flanges. Either way, its easy to put another set in.

And Bruce, yep, I'm hearin' ya! Perhaps the thread should have read "OT12 Build: 1st Pair"... Single pair will have to do for now though. Once the gigs start to pick up down the track, the 2nd pair will undoubtedly follow

commander_dan wrote:I wonder why there are 2 layers of the flanges though, extra rigidity for that area of the cab, and more meat for the access panel screws to bite into perhaps? The T30 flanges are only single layer

Yes, I wondered about this as well. The T39 also has a single layer flange for the access cover, although there is quite a bit of addition bracing in that area.

Day 7/8:

I managed to put a good amount of work in over the past 2 days and got the OT12's finished up Everything went together without issue which was great, even had a sunny day today to get the 2nd coat of duratex on and dry, despite the threat of storms. I had installed the 2nd row of flanges, and then the access panel braces went on, and the mounting blocks for the melded arrays. My box of parts arrived from Leland (Thanks mate) with my pre-built 2kHz crossovers and pre-built melded arrays, beautiful work Leland! I then cut the holes for the speakon jack plates in the access panels and got everything ready for finishing.

I primed both boxes with a flat black paint as I was worried I might run out of the leftover duratex from the T30 builds. As it turns out, even after 2 liberal coats of duratex, I still have enough left over for probably 2 more OT12's... how convenient! The next task was to cut up the accoustic foam for the padding of the inside of the cabs, so I worked out where the best spot for the crossovers was and installed them, then hot glued the padding in. Installed the HF section and the 3012HO's, soldered everything up and buttoned it up for leak testing. Testing turned out all good, no leaks.

I have them currently in my room (there is not enough room for them in its current configuration, I will have a play around over the next few days) and have been playing around with EQ and have them sounding pretty good, I want to get them outdoors though for a true flat tune, as I think there are funny things happening at some frequencies in this room. For the meantime, they sound way nicer than the boxes they're replacing, and are really clean and powerful. I've had to dial them back quite a bit as they pull alot stronger across the board than my old 3-ways.

Anyways, here's some happy snaps

Day 7/8 Continued:

Day 7/8 Continued:

Day 7/8 Continued:

Day 7/8 Continued:

Day 7/8 Continued:

Very nice.....now, start the next pair.

Nice fit and finish.

Thanks very much! They weighed in at 17.8kg, a fraction under half of the weight of one of my T30's. I couldn't imagine trying to lift a 212!