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1x21" vs 2x18"

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APMAUDIO View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote APMAUDIO Quote  Post ReplyReply Direct Link To This Post Topic: 1x21" vs 2x18"
    Posted: 27 March 2009 at 7:45pm
Anyone had the chance to compare a 1x21" reflex against a 2x18"??
Thinking along the lines of B&C SUB218 or SUB21...
It looks to me like a single 21 will move more air but not generate the same SPL?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ceharden Quote  Post ReplyReply Direct Link To This Post Posted: 27 March 2009 at 10:50pm
The 21" will most likely go lower but the 2x18" will be louder over most of the range.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mykey Quote  Post ReplyReply Direct Link To This Post Posted: 28 March 2009 at 6:11am
2 x 18, more cone/piston area
 
2 x 18'' cone area will be 2450 cm2 (sd)
21'' cone area will be roughly 1680 cm2 (sd)
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Post Options Post Options   Thanks (0) Thanks(0)   Quote APMAUDIO Quote  Post ReplyReply Direct Link To This Post Posted: 28 March 2009 at 10:44am
True,but an 18TBX100 has an x-max of 9mm whereas the 21SW150 is 15mm so if my maths are correct(?) the 21" moves a little more air than two 18's?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mykey Quote  Post ReplyReply Direct Link To This Post Posted: 28 March 2009 at 11:01am
2 x 9 =
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Post Options Post Options   Thanks (0) Thanks(0)   Quote APMAUDIO Quote  Post ReplyReply Direct Link To This Post Posted: 28 March 2009 at 11:11am
I'm no expert but I calculate the VD of an 18TBX100 to be 1089cm2(x2 for two drivers)=2178cm2
21SW150 VD=2520cm2
Or do I have my wires crossed somewhere?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote APMAUDIO Quote  Post ReplyReply Direct Link To This Post Posted: 28 March 2009 at 11:25am
I do have something crossed as those should all have been cm3!!!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mykey Quote  Post ReplyReply Direct Link To This Post Posted: 28 March 2009 at 11:36am
wow, that must be a pretty deep cone, I'll have to check it out
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mykey Quote  Post ReplyReply Direct Link To This Post Posted: 28 March 2009 at 11:45am
have they changed the code?
I have 21sw152 and 21sw115
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Post Options Post Options   Thanks (0) Thanks(0)   Quote levyte357 Quote  Post ReplyReply Direct Link To This Post Posted: 28 March 2009 at 11:58am
Originally posted by APMAUDIO APMAUDIO wrote:

True,but an 18TBX100 has an x-max of 9mm whereas the 21SW150 is 15mm so if my maths are correct(?) the 21" moves a little more air than two 18's?


A few people I know only buy 4 ohm 21"s.

They say the drivers drink uber amounts of power, before they start doing anything usefull.

"Who am I? I'm the guy who does his job.. You must be the other guy".
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ceharden Quote  Post ReplyReply Direct Link To This Post Posted: 28 March 2009 at 1:40pm
Yeah, they've updated the 21SW150 to the 152 and brought out the slightly less meaty SW115.

The B&C ones only come in 4Ohm versions from what I've seen.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote APMAUDIO Quote  Post ReplyReply Direct Link To This Post Posted: 29 March 2009 at 1:37pm
Is it me or have the cab designs vanished from the B&C website again??
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