Simplexx 12 Build

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argon
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Simplexx 12 Build

#1 Post by argon »

So I’m finally getting around to building a few Simplexx 12 cabinets for a bass rig. I’ll start with a Simplexx 12 Tilt Back for practices and smaller gigs, and a regular Simplexx 12 to go under it for larger gigs. Since it will probably take me a while (even though it’s an “easy build” cab, it will probably take me longer), I’m planning on starting with the tilt back. I have a more immediate need for the tilt back, but eventually will build the second cab to go with it. Before I start, I have a few questions:

1. Will I need a horn in the second cab? I realize the “need” for a horn is subjective, and I’m planning on putting one in the tilt back. The tilt back will go on top when paired with the second cab. Will a horn in the bottom cab be redundant?

2. What’s up with the prices of Baltic birch? Holy shnikies, I bought one 1/2” 5x5 sheet today for $140. I’m in upstate New York, and the last time I priced it (which, ok, was awhile ago), the price was literally half of what I paid today. The guy at the lumber yard said it’s because it’s a Russian product, and they can’t get it anymore. Supply and demand, I guess. So my questions here are- did I get ripped off, or is this the going rate now? If so, what are some alternatives to Baltic birch, given the price and the scarcity of it. This guy only has two sheets left, so by the time I get around to building the second cab, he might be out. Should I bite the bullet and buy a second sheet now for $140?

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J_Dunavin
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Re: Simplexx 12 Build

#2 Post by J_Dunavin »

Plywood prices are crazy right now, though that seems a little high.
Look on market place, Craigslist, and make some phone calls to local cabinet shops, lumber yards and specialty shops. I found a place to buy Baltic cut offs for a really good price. May not be enough for a full build, but could help reduce how many full sheets you would need for s couple cabs.
Use cut list program to maximize your cuts, if your using multiple size sheets
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Bill Fitzmaurice
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Re: Simplexx 12 Build

#3 Post by Bill Fitzmaurice »

Russian Baltic Birch isn't going to be imported for the foreseeable future, which also pushes up the price of that coming from the Baltic States and Scandinavia.

Bruce Weldy
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Re: Simplexx 12 Build

#4 Post by Bruce Weldy »

As to your first question.....I'd stick with the horn only in the tilt back that you'll put on top.

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argon
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Re: Simplexx 12 Build

#5 Post by argon »

Thanks for your replies. I assembled the main box portion of the cab, next step is the bracing and ports. So far, so good.

I ran into a snag when trying to order a crossover kit from Speaker Hardware. Unfortunately they’re out of stock. I ended up ordering the individual parts from Parts Express. The only issue I came across is that they didn’t have a 6uF capacitor, so I got a 6.2uF with 5% tolerance. Will this work, or should I keep looking?

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Bryan Cox
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Re: Simplexx 12 Build

#6 Post by Bryan Cox »

6.2 uF is fine.
Otop 12 x 4 (Delta Pro 12-450a) 2x melded, 2x straight
Titan 39 x 4 (3012LF) 20" wide

argon
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Re: Simplexx 12 Build

#7 Post by argon »

The ports and bracing are done, and the baffle is installed. In a few days I’ll get back to work on it. In the meantime, another question. If I rout the edges, what size bit should I use? I read another build thread that mentioned using a 3/8” bit. Will that work for mine, or will it take too much wood off?

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Bill Fitzmaurice
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Re: Simplexx 12 Build

#8 Post by Bill Fitzmaurice »

3/8" radius is the correct size.

argon
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Re: Simplexx 12 Build

#9 Post by argon »

As far as the damping material goes, the directions only describe lining the upper and lower back of the cabinet. Am I correct in assuming it’s not applied anywhere else inside it’s cab? Is there any advantage or disadvantage to putting more in?

Also (sorry, I think this was described in another thread on this forum somewhere), is there any real difference in the performance of open cell/acoustic foam vs. pillow stuffing/upholstery batting?

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Bill Fitzmaurice
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Re: Simplexx 12 Build

#10 Post by Bill Fitzmaurice »

Read those plans again: Damping material lines the back... Damping may also be used to line the cab top, bottom and sides. It’s a chore to work around the braces, and the improvement in sound won’t be major, but if you want the best result possible do so. A PA cab will get the most benefit from being fully lined.
is there any real difference in the performance of open cell/acoustic foam vs. pillow stuffing/upholstery batting?
Not enough to be concerned about it.

argon
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Re: Simplexx 12 Build

#11 Post by argon »

Whoops! Thanks!

I plan on installing a strap handle to the top. Should I glue extra plywood inside the cab to reinforce where the screws will go in, or is that necessary?

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Bill Fitzmaurice
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Re: Simplexx 12 Build

#12 Post by Bill Fitzmaurice »

That's a must if you use screws. 2x2 inch pieces will do.

Bruce Weldy
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Re: Simplexx 12 Build

#13 Post by Bruce Weldy »

argon wrote: Sat Jun 04, 2022 9:59 am Whoops! Thanks!

I plan on installing a strap handle to the top. Should I glue extra plywood inside the cab to reinforce where the screws will go in, or is that necessary?
Use T-nuts for the handle....much safer way to do it. And they are cheap and the install is simple. I think I used #10 bevel head bolts and t-nuts on my last ones. And don't get the cheapo strap handle. The covers on those are trash and bend when you try to tighten down hard. Stick with the Penn Elcom.

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"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

argon
Posts: 44
Joined: Mon Jan 17, 2011 5:59 pm
Location: Upstate NY

Re: Simplexx 12 Build

#14 Post by argon »

Thanks!

argon
Posts: 44
Joined: Mon Jan 17, 2011 5:59 pm
Location: Upstate NY

Re: Simplexx 12 Build

#15 Post by argon »

I’ll be assembling the crossover later today. It’s my first time building one, so I have a few more questions:

I’ll be mounting the components on two perf boards, one for high pass and one for low pass. I’m assuming on each perf board I can just solder the component leads together, and that I only need speaker wire to connect the boards. Is this correct?

Also, since the high pass filter has two coils, do I need to keep them a minimum distance for each other, or mount them at 90 degrees from the other? I read something about doing that on another forum, with a different crossover. I don’t see this mentioned in the plans, so is it not necessary?

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