Simplex Back Panel - Why is it not under top?

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Jakevw
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Joined: Thu Nov 25, 2021 8:15 am
Location: Ottawa, ON, Canada

Simplex Back Panel - Why is it not under top?

#1 Post by Jakevw » Fri Nov 26, 2021 10:06 am

Hi Bill & Gang,

I'm about to build a sealed 2x12 Simplex cab.

I see the back panel is not the same size as the front panel, and it does not traditionally sit underneath the top. Typically the top would sit on top of all four sides, for structural redundancy. I understand the PL Premium in the specs is strong, but the craftsmen in me has a difficult time accepting the lack of structural redundancy.

Is there a reason for this the back doesn't support the top?
For example:
-Are the dimensions of the front and back panels intentional different to help diversify the resonance frequencies of the fronts and back?
- Are the joints intentionally a-symmetrical between front and back, to help dampen resonance?

Is there a negative impact to me changing this, so the back panel is more structurally traditional, sitting underneath the top panel? This adds a bit more structural redundancy. Or, does my above proposal generate panels which are too-similar, increasing the risks of undesirable resonance?

If I keep the design as it is in the Sketchup, could I put an additional bracing (aka a ridge) attached to the top the back, to support the top (- 1/2")? If this negatively consumes the internal volume, I could eliminate some the handles, to offset the internal volume.

Thanks for the feedback!

Jake

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Bill Fitzmaurice
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Re: Simplex Back Panel - Why is it not under top?

#2 Post by Bill Fitzmaurice » Fri Nov 26, 2021 10:20 am

In order to build the cab with internal bracing the back must overlap the top, bottom and side edges. There is no strength issue, the wood will fracture before the glued joints will.
Someone will probably bring this up eventually, so I'll say it now: 'Traditional' speaker cabinet construction is not the best way to build cabs, it's the cheapest way. We use the best way.

Jakevw
Posts: 7
Joined: Thu Nov 25, 2021 8:15 am
Location: Ottawa, ON, Canada

Re: Simplex Back Panel - Why is it not under top?

#3 Post by Jakevw » Fri Nov 26, 2021 10:29 am

Thanks for the clear and timely response!

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