After giving this a little more thought, here's what I think.
The purpose of the bracing is to stop cabinet panel vibrations. To do this it needs to be stiff and for a bass cab, it needs to be extensive enough to divide the panels into small enough areas so that their resonant frequencies are higher than the frequencies used in the cab, ie higher than 300Hz and probably its 1st harmonic too, 600Hz.
Given the size of your bottom cab (large) and the amount of bracing you have drawn, my thinking is that the bracing will be neither stiff enough with 10mm nor the panel frequencies high enough. However, instead of just increasing the thickness of the bracing for added stiffness but no change to panel resonance frequencies, it might be a better idea to still use 10mm but add more bracing (like B&W) so now the bracing will be stiffer and the panel resonance frequencies will also be raised. This should be a better solution.
But copy the B&W design - 2 panels front to back and maybe another 2 or 3 horizontal panels. No vertical panels that go from side to side. Adjust cab depth to keep the same net volume and maybe increase the hole sizing in the bracing to do the same.
The purpose of the bracing is to stop cabinet panel vibrations. To do this it needs to be stiff and for a bass cab, it needs to be extensive enough to divide the panels into small enough areas so that their resonant frequencies are higher than the frequencies used in the cab, ie higher than 300Hz and probably its 1st harmonic too, 600Hz.
Given the size of your bottom cab (large) and the amount of bracing you have drawn, my thinking is that the bracing will be neither stiff enough with 10mm nor the panel frequencies high enough. However, instead of just increasing the thickness of the bracing for added stiffness but no change to panel resonance frequencies, it might be a better idea to still use 10mm but add more bracing (like B&W) so now the bracing will be stiffer and the panel resonance frequencies will also be raised. This should be a better solution.
But copy the B&W design - 2 panels front to back and maybe another 2 or 3 horizontal panels. No vertical panels that go from side to side. Adjust cab depth to keep the same net volume and maybe increase the hole sizing in the bracing to do the same.
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if its not too late, here is the most extensive and accurate box modelling by jeff b
Loudspeaker Design Software
cheers
henry
Loudspeaker Design Software
cheers
henry
I can't give you an accurate estimate without knowing exactly how many bracing panels you're going to use, the number and size of the cut-outs and the new internal cab dimensions.
However, roughly, with 2 vertical and 5 or 6 horizontal panels (all 10mm) I think you're looking at about 6L. Roughly. That means your total internal volume should be somewhere around 75 + 1 + 1.5 + 6 = 83.5L, or 32 x 68 x 39cm. Roughly.
You need to sit down, study the B&W bracing and draw something out that works for you. Then do the calculations and fine tune if necessary.
However, roughly, with 2 vertical and 5 or 6 horizontal panels (all 10mm) I think you're looking at about 6L. Roughly. That means your total internal volume should be somewhere around 75 + 1 + 1.5 + 6 = 83.5L, or 32 x 68 x 39cm. Roughly.
You need to sit down, study the B&W bracing and draw something out that works for you. Then do the calculations and fine tune if necessary.
32 x 68 x 39cm thickness?
The drivers are on the way
That's internal dimensions and it's a rough guess. Decide on the bracing first and then try to calculate the necessary volumes. And you have to decide on exterior panel thicknesses too I think.
Henry, English isn't my native language could you help me? For the cab I have in mind:
MDF 2.2 cm
Height 55 cm
Width 32.5 cm
Depth 58.5 cm
Volume in liters 80.4
Bracing plywood 1 cm
Woofer data-sheet http://www.europe-audio.com/document.asp?document_id=2388&link=datasheets\sba\SB23NRXS45-8.pdf
MDF 2.2 cm
Height 55 cm
Width 32.5 cm
Depth 58.5 cm
Volume in liters 80.4
Bracing plywood 1 cm
Woofer data-sheet http://www.europe-audio.com/document.asp?document_id=2388&link=datasheets\sba\SB23NRXS45-8.pdf
You're confusing me now. On page 6 you show a different cabinet depth than 58.5cm. Very different.
Also, I forgot to ask - what is your listening distance to the front of your speakers?
Please read in the same post of image: "Dimensions aren't correct, the image it's only to ilustrate what I want to make." I'm sorry to confuse you.
Aprox. 1,5 meters.
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Felipe,
In order to do correct simulations, I need to have an accurate layout of your speakers and listening position and even your room. The language thing might be a problem here but I'm afraid that I've just completed a load of simulations with incorrect data.
Can you please post a diagram of the front baffle for your completed speaker including all driver positioning and cabinet dimensions when you are able.
Thanks
In order to do correct simulations, I need to have an accurate layout of your speakers and listening position and even your room. The language thing might be a problem here but I'm afraid that I've just completed a load of simulations with incorrect data.
Can you please post a diagram of the front baffle for your completed speaker including all driver positioning and cabinet dimensions when you are able.
Thanks
that is not much with such a big speaker
sounds like you have very little space
sounds like you have very little space
Well, it depends........
How low do you want the speakers to go?
How likely is it that you will be able to use them in a bigger room some time in the future?
And if not, how useful is it to you to sacrifice some low frequency extension for something like 15 to 20cm less depth?
Can you make them a little taller too?
Can I listen 20Hz at 1,5 meters from the loudspeaker?
No I can't have a bigger room in the future.
I only can sacrifice low frecuency extension if I can listen at 1,5 meters.
I'm open to suggestions.
Arrived the woofers
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