Finally! Omni 12 Tall Boy build

[CarterKraft]

Thanks Bill, I'll shoot for that.

[CarterKraft]

We have progress. My front camera is busted so you are getting reversed back camera images.
You can see there is about a 1/4" of space on each side of the front panel with the APT150 horn and the mid horn edges touching.
I am thinking about doing a flush inlay of the tweeter horn, but I'm not sure If I have the skills or router tools.

[Seth]

That's looking real good Weldon

I'm getting excited to learn how well it does on batteries!

[CarterKraft]

Thanks Seth, the table saw conked out last night before I could get as much done as I wanted.
I hope to get t back running tonight, it's either centrifugal start switch or start cap or both...

After receiving the amp from PE Bruce has me wondering how much power it will really have...
It is small and I am aware of the size vs output of class D topology and with no integrated power supply even less components are on the board.

The battery voltage range seems somewhat problematic at the moment but I am not going to let that bother me for now, I have a 36v power supply to use to confirm the amp output is acceptable before investing time/money into a custom buck-boost converter for it.

[Seth]

Thanks Seth, the table saw conked out last night before I could get as much done as I wanted.
I hope to get t back running tonight, it's either centrifugal start switch or start cap or both...

When my cheapo, secondhand, Craftsman jobsite style table saw went out, it was the switch. Arcing destroyed the contacts. $10 on Amazon and I was back in business. If that one ever goes out I'll look into integrating a solid state relay.

After receiving the amp from PE Bruce has me wondering how much power it will really have...

Hook it up to something, run a sinewave through it, and measure output voltage if you're curious enough. Now that you mention it, I'm curious too.

[CarterKraft]

Thanks Seth, the table saw conked out last night before I could get as much done as I wanted.
I hope to get t back running tonight, it's either centrifugal start switch or start cap or both...

When my cheapo, secondhand, Craftsman jobsite style table saw went out, it was the switch. Arcing destroyed the contacts. $10 on Amazon and I was back in business. If that one ever goes out I'll look into integrating a solid state relay.

After receiving the amp from PE Bruce has me wondering how much power it will really have...

Hook it up to something, run a sinewave through it, and measure output voltage if you're curious enough. Now that you mention it, I'm curious too.

I bypassed the switch last night, no dice.
I have a new start cap today and can clean the contacts of the centrifugal switch easy enough.


When it's time I will do that for sure, I am not scared to fail on this deal, I will dyno it all for you guys.
They have a three way profile already in the DSP so setup should be simple (famous last words).

[CarterKraft]

What an embarrassing screw up.

Start cap was fine so I moved on to removing the motor to disassemble and inspect the centrifugal switch.
As I removed the second mount strap the motor slips out of my hand falling directly on the shaft of the motor, exploding the thrust bearing on the opposite end.
So I had to repair all the damaged parts, machine a new thrust ring and then lubricate the sleeve bearings that caused it too lock up in the first place

I got the woofer baffle glued in with the top and middle brace.

Anyone have any tips for inlaying/recessing the tweeter horn flange?

I bought some guide bushings and I have various router bits just never used these guides to make a inlay.
I think I use the tweeter horn to make a larger negative then use the correct size guide to create the pocket of the exact size to set the horn in.

It's a complete waste of time I'm sure but I think it would look cool being flush beside the mid horn.

[Seth]

What an embarrassing screw up.

For a moment there, I thought you were going to say it wasn't plugged in. Good job on the fix

I think I use the tweeter horn to make a larger negative then use the correct size guide to create the pocket of the exact size to set the horn in.

It's a complete waste of time I'm sure but I think it would look cool being flush beside the mid horn.

I find it's the extra little details, that are otherwise unnecessary, that make the cabs unique to each of us. When I'm having fun with a build, I do the same. When I just want to get it done, I usually talk myself out of additional finishing details in favor of expediting completion.

I used the same method you describe to get my top-hat flanges flush. It worked well. Granted it will likely take a little more doing to create a negative template that's not a circle, I think you're on the right track. I used a digital caliper to measure the flange thickness, added a tiny bit so it sat just a smidge below flush, locked the caliper, and used the depth gauge on the other end of the caliper to set the cut depth on the router with the bit protruding through the negative template. The template had to be made tall enough so that the bearing had a surface to ride on without cutting too deep. I only have a long style pattern bit, so I laminated a few scraps of ½" ply and made my template out of that. I made the bottom (of the three) laminated ½" ply scraps larger than the other pieces so I'd have a flange on the template to shoot brads through to hold it in place.

Cut the hole for the tweeter in the cab, place the tweeter in the hole, square it up, and screw it down in position. Then place the template over the tweeter to positively locate the template, fasten the template in place (screws, brads, however...), remove the tweeter, and make your cut.

* Just remember to set the cut depth prior to securing the template to the cab. (I didn't )

[Seth]

^^
In hindsite, instead of removing the template and starting the process over, I suppose I could have measured the depth of the template, added the flange dimension plus the little smidge extra, and subtracted the thickness of a flat edge placed against the bit to measure off of, to set the cut depth. I guess I just wasn't clever or clear minded enough to come up with that solution in the moment. Oh well. Live and learn.

[CarterKraft]

No joke Seth round is easy peazy with the Jasper jig.

I am going to make a complete mock up to test everything on before even looking at the real deal.
This learning to make accurate templates deal is important so now is a good time to spend the labor to get educated on the process.

[Seth]

I'm pretty sure I learned this method from someone else here on the boards. I apologize to whomever that is, for not remembering.

In a different build than I mentioned earlier, I made some baffle templates by drawing out the measurements on a piece of scrap that I intended to be my template, tacked down strips of cutoff material along the lines, then ran the router around the inner perimeter and cut out the template, which I used to cut all my actual parts identical.

If you place your tweeter face down on some scrap and tack some strips down creating a solid perimeter around the tweeter, you should be able to use that perimeter as your guide for your pattern bit to cut out a perfect size template. Remove the strips, laminate another layer of ply if you need to build thickness in your template, and use the hole you just cut out as the guide to duplicate the hole in the second layer, and on to a third if you need to.

Not sure that makes sense. Let me know if I need to elaborate.

Here's the baffle template I made, before and after routing. Shows how simple it is to just tack some sticks on.

If the corner radius of your tweeter doesn't match the resultant corner radius the pattern bit provides in the template, I suppose you could either sand the corners of the tweeter to match the recess or maybe daintily massage to corners of the recess a little sharper with a Dremel or chisel work. It may just be okay though.

[CarterKraft]

That is the process I was trying to remember! Thanks for showing those pictures, that jogged my mind enough to get the juices flowing.

I need to use a top bearing cutter for that right?
I don't have one at the moment so I'll have to get one of those unless I figure out how to use the guides in lieu of it.

[Seth]

I need to use a top bearing cutter for that right?

I suppose you could use a flush cut bit (bearing on the bottom) to make the template by cutting from the other side. However, you'll need a pattern bit (bearing on the top) to make the actual recess in the baffle for the tweeter.

Since you don't have one already, it may be smart to identify the corner radius of your tweeter and choose a pattern bit with a diameter that would be complimentary.

[AcousticScience]

Because the low bass is crossed over at 400 Hz, the best output will be had with the kappalite 3012lf with 9.1mm Xmax (14mm Xlim). The 3012HO performs similarly in the bass range and I put one of them in my subwoofer cabs just to test before the 3012lf turned up, and with 6 mm xmax not bad if you got them cheap, but if getting new they aren't cheaper. For the jack cab though where you need more sensitive mids they are the better driver.

People talk about "only 3dB". How much level change v is that? Well if you're on 10 and you need that extra push over the cliff, an extra 3dB will take you to "12" in terms of psychological loudness. Samsung smart phone volume clicks are about 3dB apart. On my laptop, between "50" and "100" is about a 10dB difference on headphones.

[Bill Fitzmaurice]

He doesn't have enough power to need more xmax, he does need the higher sensitivity of the HO.