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Building a superior 2x10 cab

#121
There's a fair amount you can deduce by comparing the "sonogram" image and where directivity seems to collapse with this one of raw driver FR:

8NCX.jpg


They might be using the baffle/box mentioned in the text reference footnotes: "Measurement is in 18 L box enclosure tuned 82 Hz using a 60-2000 Hz band limited pink noise test signal applied continuously for 2 hours." Or not. No mention of directivity; whether active LR24 was used, os some passive network or what.
 
#123
Yeah, for the frequency response they only mention the cabinet size(volume) which is good when you want to show how the driver behaves in a somewhat "real" environment instead off an infinite baffle like all the other manufacturers do. I do not think they used any kind of filtering for the frequency response graph.
But we can not make any conclusions on how the whole concept behaves off-axis. I'll wait until I measure it myself.
 
#131
That's a nice size midchamber; I'm assuming it gets stuffed? Also, will those single triangle braces be enough? Being that the drivers are all in their own chambers, how will you handle connectivity? One jackplate and then wires to each location, I guess? Are you externally biamping or will there be a crossover in there somewhere? Putting a crossover inside will take away airspace from one of the woofers. This is a dumb question, but I think of stuff like this: The midchamber hangs over one edge of each woofer. The woofers are open back. Will that midchamber block any sound/air movement coming from the rear of the woofers? Does it matter?

Looking good so far! It must be exciting to see your idea becoming tangible where you can finally see it in front of you. :) Can't wait to hear it.
 
#132
Arjank said:
Some pics of building the cabinet.
Click to expand...

If I were building that cab, I'd add vertical bracing in the middle of every panel of the tens compartments. That where you are going to need to have the most vibration.

While the triangular braces will tie the sides to the back, there would be more to gain by using vertical braces to reinforce those panels. Otherwise, looking good!
 
#133
If I were building that cab, I'd add vertical bracing in the middle of every panel of the tens compartments. That where you are going to need to have the most vibration.
Click to expand...

I was thinking of adding a vertical brace connecting the bottom and top. But the "knock" test proved that the current bracing is adequate, it's not totally dead, but ok. I could add some bitumen on the top and bottom to lower the panel resonance if needed. I could also add a brace afterwards. The side panels are braced enough, there are two triangles per side panel. The baffle though is dead as a doornail.
I did the "knock" test on a lot of commercial cabs and most of them sounded hollow:D

Edit: I'll add two triangles per compartment that connect the side panel to the top and bottom

That's a nice size midchamber; I'm assuming it gets stuffed?
Click to expand...
Yes, it will get "stuffed" :smug:

One jackplate and then wires to each location, I guess? Are you externally biamping or will there be a crossover in there somewhere? Putting a crossover inside will take away airspace from one of the woofers.
Click to expand...

Just one jackplate(speakon). Internally it is wired via the three-way crossover. The crossoverparts for the mid/high section will be put into the midchamber, this is also better for the crossover parts since there is less pressure inside that chamber. The low section will be put into one of the bass compartments. I will need a good quality inductor for that.

Will that midchamber block any sound/air movement coming from the rear of the woofers? Does it matter?
Click to expand...

No it will not matter, it will not block the sound. The wedge shape inside each basscompartment will actually have two advantages, strenghten the baffle and eliminate standing waves(just a tiny bit, the 1st standing wave node will occur at approx 400hz which is just a tad below the crossover point of the woofer).

It must be exciting to see your idea becoming tangible where you can finally see it in front of you.
Click to expand...
Yes it is!
 
#135
Thanks for answering all my questions; I know I had a lot, but I'm finding this thread interesting. It's good to see that you've thought a lot of the details through pretty thoroughly. Good luck w/the rest of the build and keep the pics coming!
Click to expand...

Thanks man!

Today I hit the woodshed again, added some extra bracing. Now each compartment for the 10's has four triangle braces and one vertical brace in the middle to connect the top and bottom. It seems a bit overbraced to me :D
 

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#137
Arjank said:
Thanks man!

Today I hit the woodshed again, added some extra bracing. Now each compartment for the 10's has four triangle braces and one vertical brace in the middle to connect the top and bottom. It seems a bit overbraced to me :D
Click to expand...

The triangle braces are wasted wood, as they're placed where the cab is already the strongest. Where a cab most needs to be braced is from panel to panel in the middle of their spans: top to bottom, side to side and front to back.
 
#138
The triangle braces are wasted wood
Click to expand...

Indeed, these triangles are part of a " left over" :D
Serious.
Well, these triangles do work though, maybe not as good as crossbracing. At the side panel they work very good, together they span the whole length of the side panel.

panel to panel in the middle of their spans: top to bottom
Click to expand...

Whats on the picture?

Believe me, this cab is pretty dead now.

Lets not discus any further about bracing and stuff, I tried them all from "matrix" bracing to making a concrete enclosure.
 
#139
Arjank said:
Indeed, these triangles are part of a " left over" :D
Serious.
Well, these triangles do work though, maybe not as good as crossbracing. At the side panel they work very good, together they span the whole length of the side panel.



Whats on the picture?

Believe me, this cab is pretty dead now.

Lets not discus any further about bracing and stuff, I tried them all from "matrix" bracing to making a concrete enclosure.
Click to expand...
I'm not pointing that out for your benefit, but for the benefit of others who might be led to believe that there's anything to be gained with bracing the cabinet corners, other than additional weight.
 
#140
anything to be gained with bracing the cabinet corners, other than additional weight.
Click to expand...

If they were only 1x1" I would say yes, then you would only increase the strenght of the corner joint.
In my case I could not brace front to back easily with just a strip of wood it would not make any sense. I could have braced the back of the cab with just one long strip but it wouldn't have done better then the solution I have now.
 

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