Different Fullrange boxes+SB34NRX75-6 bass towers

Hi.Finally i cut birch ply sheets and ready to make the sealed enclosures of SB34 woofers.I will make side firing woofer because of WAF.When i simulate on hornresp there is almost no difference when put SB34NRX75-6 on top and near middle of the box(when stuffed with polyfill).
But i do not know how to measure the needed distance between the drivers.Should i measure between the fullranges middle point to subwoofers middle point?Because of SB34 are big it can not be very close to fullrange boxes.Which crossover point you suggest?340Hz too high?I already have aucharm 4inch fullranges which i like the sound but i also want to try fountek fr89ex and 3 inch fostex too in future.So i want to make crossover point as high as possible.It may also reduce distortion of fullranges i think.
 

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If you put the crossover high, the speakers need to be aligned otherwise you will have phase issues. Side firing subwoofers only work well when crossovered below 125Hz, and preferable even below 100Hz. That is where sound becomes omnidirectional and the position of your woofer is less important.

If you want it higher, you need to put the FR and the woofer on the same vertical line, and as close as possible to avoid those phase issues.
 
Should i measure between the fullranges middle point to subwoofers middle point?

Centre of driver to centre of driver. The idea being to keep that distance below the 1/4 wave frequency at the XO.

...to try fountek fr89ex and 3 inch fostex too ...

Unless you can find an FE83/88 SOL i would recommend FF85wk. I haven’t heard the FR89ex but have gone thru quite a few FE88ex, i’d put them a notch below the Fostex.

dave
 
I find side mounted fine, but i am also using smaller bass drivers (multiples of them). You do want to XO as low as you can get away with. The faster the XO, the lower you can go (or alternatively, the louder you can go).

The poorest HF response of any of them (on-axis) is 1.7 kHz. Some of the others go up to 10k.

I’d be using 2 x 10” (or 8”) push-push loaded. The twin 5.25” woofers were better than a single 7”.

dave
 
Hi.As i read the only benefit of push push woofers is reducing box vibration right? (magnets facing eachother) What about directivity,maybe it has better off axis response?
Box volume remain same at push push?(i think it is same as pulling rope with F force which is connected to the wall or 2 people pulling it with same F force and tension remains same again.Only 1 F force)
Although i am building with birch ply with 4 braces per box and also use dowels with glue(i think box will not vibrate ) if sound quality will be better than one woofer i will also build push push boxes in future.
 
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Hi.As i read the only benefit of push push woofers is reducing box vibration right? (magnets facing eachother) What about directivity,maybe it has better off axis response?

Yes, the big bonus is a significant reduction in box load (i’d estimate 90%).

Given that at the frequencies we are using push-push woofers the sound is omnidirectional so it matters little wher ethe woofers are facing.

if sound quality will be better than one woofer i will also build push push boxes in future.

They will. Due to much less box getting in the way.

Do post a drawing of how you plan the bracing.

dave
 
Do post a drawing of how you plan the bracing.

Hi.Bracing will be like this.I cut more braces by mistake and now i need to recut a plate for top and bottom pieces.
You can see top and bottom pieces has to be closed but they are cut by mistake.
Woofer will be at place of ruler.
 

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That bracing is running the wrong way.

A brace should be such that the subpanels created by the brace should have a higher aspect ratio than the panel they are bracing.

This means that you will have more effective bracing if they run the long way.

dave

I always brace in all directions, today mostly with an internal frame with subdivisions, so no big piece of wood is unbraced. I think it works better than using plates with holes in. But even if you do it with plates with holes, do it in all directions, so horizontal and vertical. Attached is an example how i do it (it's a 77L sealed 10" subwoofer). The internal frame does the bracing and only in the middle it needs some extra horizontal bracing. All wood is 18mm birch ply, and the bracing is 30mm branches made of the remaining pieces of plywood after cutting the main panels (so it's actually very economical also as bonus).
 

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