First Build: Omni Top 112s

[ripNdeb]

No slots with the 3012

+1.

- 6" plug, regardless of HF section

-1. If you are building a cab to use with the 3012HO/NSD 2005 HF driver option the circle is 6” diameter; for all other options the circle is 5” diameter
from OTop 12 plans, where it is also italicized in bold print.

OK, got it; but, then there is this sentence:
The 3012HO driver, with a higher Fs and smaller Vas than optimum, needs less chamber volume, so the throat reflector airspaces are isolated from the driver chamber. The same applies to the Delta Pro driver, which has the same 51Hz Fs and 81L Vas as the 3012HO.

I realize now that I'm asking about two different things, the phase plug and the slots. With the phase plug question answered, does the 3012HO with melded array get slots?

[Bill Fitzmaurice]

OK, got it; but, then there is this sentence:
The 3012HO driver, with a higher Fs and smaller Vas than optimum, needs less chamber volume, so the throat reflector airspaces are isolated from the driver chamber. The same applies to the Delta Pro driver, which has the same 51Hz Fs and 81L Vas as the 3012HO.

I realize now that I'm asking about two different things, the phase plug and the slots. With the phase plug question answered, does the 3012HO with melded array get slots?

The 3012HO driver, with a higher Fs and smaller Vas than optimum, needs less chamber volume, so the throat reflector airspaces are isolated from the driver chamber. There is no mention here of the HF section because it matters not which is being used.

[ripNdeb]

10/4; thanks Bill

[ripNdeb]

I keep forgetting (procrastinating) to take pictures but, here's where I'm at on the "Even you can do this with modest skills and VERY modest tools" build:

Double trouble with horn reflectors fitted and ready to glue. (Do you need pressure to hold them down for a good bond or can you just apply PL and set them in there?)


Note the screw in the horn panel and screw hole in the other one; neccessary due to poor clamping strategy.




The weakest link:


Not quite square as it sits on the floor. Neither the carpenters square or the combination square in use here seem to actually be square.


Most of the tools involved. Weakest link = $40 circular saw


Halfway decent freehand Craftsman jigsaw circle.


Biggest lessons so far are these:
#1. If you don't have a table saw, you really should research and invest in a high quality circular saw. The $40 Ryobi has given me fits and is very difficult to work with. Some of this is, of course, due to my lack of experience and skill. But, I wish I had another to work with; a Milwaukee perhaps.
#2. DO NOT under-estimate a sound clamping strategy!!! I had stuff lined up lookin' good and ready to go. Grabbed the glue, laid it on down, then.....slip, slide, panic, mess, start over.

At any rate, it's a joy and a pleasure to be makin' sawdust and see these things come together!

Progress will likely stall due to medical bills and a speeding ticket so I was wondering this:
Is the 10-7/8" 'nominal' size hole good for the Kappalite 3012HO driver? I might not be able to get them for a while to measure presicely but I could continue construction some more if that is the case.

[digi128pci]

Looks very nice

[DJPhatman]

Invest in a better saw blade. Freud Diablo are my favorite.
Square the "shoe" of the saw with the blade installed. This is very important for straight cuts.

More than likely, your floor is not straight and level. Trust your carpenter's square.

[Dave Non-Zero]

More than likely, your floor is not straight and level. Trust your carpenter's square.

+1

man that BB ply looks sweet, so jealous.

[Gregory East]

I'd be very surprised if you can buy a framing square that isn't. Square off in the guts of a sheet and recheck to see it is still lying on the edge, flip sqaure over and go from the other side. Betcha your mark is lining up. If it isn't either your ply isn't cut straight or you have a dud square.

If the ply isn't square to start off with you will wind up in the cactus. I'm building a slightly diamond shaped AT due to that little trick.

Check the diagonal measurements are the same. If it isn't square you need to work off one edge and use the framing square and your sled to trim.

[bzb]

I agree with Phatty - more likely your floor isn't flat. Lord knows not a single surface in my house is.

[ripNdeb]

The 1/4" hole in the throat reflector for the tweeter wire, as per plans, requires another hole in the baffle if using the Kappa 3012HO as there are no slots.
Is a hole in one of the horn panels an alternate option?

[jswingchun]

#2. DO NOT under-estimate a sound clamping strategy!!! I had stuff lined up lookin' good and ready to go. Grabbed the glue, laid it on down, then.....slip, slide, panic, mess, start over.

One thing that it took me a while to learn is that you do not have to hurry once the glue is applied. It takes a while for it to set up. It isn't five minute epoxy. Do a clamping dry run for testing, then apply the glue, line up the joint, clamp it and if you don't like how it looks, unclamp it and try again. No reason to hurry or panic, you have time. Get it right then nail or screw it in. I was saved from a lot of misaligned joints when I finally understood this.

[ripNdeb]

New Diablo blade worked wonders Phatman, thanks.
Could someone confirm the 10-7/8" hole is exactly right for the Kappalite 3012HO driver? I may not have the drivers for a while - to measure exactly - and would like to continue with this step. Thanks,
Dana

[LelandCrooks]

Eminence data sheet says 11.06" 281mm.

[Bill Fitzmaurice]

Eminence data sheet says 11.06" 281mm.

That's for front mounting. I find that 10 7/8 works well for rear mounting, as even at xmax the portion of the suspension that can hit the baffle is that closest to the joint with the cone, and a bit more wood gives the screws more to grab a hold of.

[ripNdeb]

Cool, thanks.
How about the phase plug extensions: The plans say three, 1/2" disks for 1-1/2" but the pictures and the Sketchup model show 4 disks which, of course, would be 2"...sorry, I'm old and confused

Also, how are you folks cutting the disks? Or, is anyone using something else besides little plywood circles? Which reminds me, what is rigid foam? insulation? model building material?