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Old 18th September 2013, 11:09 PM   #1
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Default Multiple driver enclosure calculations

When designing a multiple driver cabinet, in my case a closed 4x12, can one simply calculate the appropriate per-driver volume and multiply by 4, or is there some adjustments that should be made to that as enclosure size increases?
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Old 19th September 2013, 11:42 AM   #2
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What is the enclosure for?, if it's just guitar it doesn't really matter as there's not enough bass content for enclosures to make any difference. 'Generally' it's a question of leaving enough wood between the drivers to support them - and a 4x12 with the speakers removed looks really weak.
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Old 19th September 2013, 01:47 PM   #3
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Quote:
Originally Posted by Nigel Goodwin View Post
What is the enclosure for?, if it's just guitar it doesn't really matter as there's not enough bass content for enclosures to make any difference. 'Generally' it's a question of leaving enough wood between the drivers to support them - and a 4x12 with the speakers removed looks really weak.
Thanks Nigel, but I beg to differ. The drivers (Peavey Pro 12s) are rated as going down to 50 Hz, chosen specifically to be able to reproduce a drop D at 73 Hz directly and handle a bass adequately if necesssary. The drivers come with a recommended sealed enclosure volume and I hope to use that to optimize it. After all they need to be *some* size -- might as well make them try to do their best. And although I generally overbuild anyway, this particular box being made of all 3/4" material, your point about construction is well taken. I should think internal baffles between front, sides and back, midway along each wall and extending at least halfway to the center would help support them. Yes, generally 4x12s do look weak and are. They're not often built to acoustic considerations, only to those of adequate structural strength and lowest manufacturing costs. This is why I'm building instead of buying.
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Old 19th September 2013, 03:02 PM   #4
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If you're planning using them for bass guitar it's obviously a very different matter, but in that case why not use a 1x15 instead, which is likely to give better bass response (in a similar cabinet size) to four 12's.

To make a 4x12 (but not for guitar) simply make it four times the internal volume of the 1x12 design.
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Old 19th September 2013, 03:31 PM   #5
Tesla88 is offline Tesla88  Italy
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Having Thiele and Small parameters and a simultaion SW like WinIsd would make it easy...

I play guitar mostly in DropC#, using a 4x12 Engl ... never noticed the lack of bass , somtimes it seems i have more bass content than the bass player xD
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Old 19th September 2013, 03:57 PM   #6
sreten is offline sreten  United Kingdom
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Hi,

Reality and practicality apply to the design of portable musical speaker cabinets.

Here your looking at 0.75 to 1.0 cuft per driver sealed, preferably stuffed.

rgds, sreten.
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Old 19th September 2013, 04:09 PM   #7
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Quote:
Originally Posted by Nigel Goodwin View Post
If you're planning using them for bass guitar it's obviously a very different matter, but in that case why not use a 1x15 instead, which is likely to give better bass response (in a similar cabinet size) to four 12's.

To make a 4x12 (but not for guitar) simply make it four times the internal volume of the 1x12 design.
It's primarily for guitar, only a stand-in/support cab for bass should the need arise. Similar cabinet size is irrelevant as I'm only designing now and can build it any size. If I need more power for the bass, I'll instead XLR patch the bass 1x15 combo to the PA powered mixer. The main PA towers each have a pair of these Peaveys plus a Trace Elliot 15, and compression horn crossed over at 2 kHz pushed by 800 W. I'm using the 12s because I have them left over from building the PA. What I'd already built did well enough that I didn't need a second pair of towers. Being PA drivers with excellent clarity I simply wanted to get the most out of them I could.

Thanks for the answer.
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