# two 6.5" subs = one 8" sub in cone area ?



## mikemareen (Apr 20, 2006)

you guys think two 6.5" subs in cone area would equal one 8" sub in cone area? or one 10" sub ?


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## demon2091tb (May 30, 2005)

As far as cone area, a little over an 8. Generally like 2 12's have a little more cone area than a single 15 type of thing.


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## lbridges (Jan 4, 2006)

pi times R squared = area


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## DonutHands (Jan 27, 2006)

its very close to the same cone area of a 9"


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## AzGrower (May 30, 2005)

lbridges said:


> pi times R squared = area


werd...its simple math...


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## JasonH (Oct 27, 2005)

2x6.5=~66
1x8=~50
1x10=~78


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## mikemareen (Apr 20, 2006)

awesome, that I'm at about a 9" ! thanks diy-selfers!


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## JasonH (Oct 27, 2005)

1x9=~63


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## mikemareen (Apr 20, 2006)

so I'm a little above a 9, awesome! I'll let you guys know how my project turns out.


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## Oak244 (Apr 7, 2006)

Thats funny, I was wondering if I should get 2 6.5 midbass drivers per door, or a single 8" myself. Partially because it would allow for more Ohm changes. I could use 2 8 Ohm or 2 4 Ohm to get a 4 or 2 ohm rate respectfully. The only problem I see with 2 6.5's vs 1 8" is proper imaging. Its easier to proper image a single speaker.


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## chuyler1 (Apr 10, 2006)

Don't forget to use XMAX in your calculations. Think of the air displacement of a woofer as a cylinder composed of the outer area of the cone (do not include surround) times the XMAX excursion of the woofer.

I'll give you an example since I'm bored.

Area of an 8" woofer (7" cone) = 154 sq in
Area of a 6.5" woofers (5.5" cone) = 95 x 2 = 190 sq in

Lets say the 8" woofer has an XMAX of .5" and the 6.5" woofer only has an XMAX of .4"...

Volume displaced by 8" woofer in motion = 154 * 0.5 = 77 cu in
Volume displaced by 6.5" woofers in motion = 95 * 0.4 = 38 * 2 = 76 cu in

So in this example, the 6.5" woofers have more cone area but the slight difference in XMAX means they will still perform about the same as the single 8" subwoofer.


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## mikemareen (Apr 20, 2006)

the 6.5" subwoofers I'm using are the JL 6w0, they have over 7mm of xmax each, about the same as most 8" subwoofers.

Oh I'm stoked, can't wait for the outcome.


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## chuyler1 (Apr 10, 2006)

Ok. 7mm is .275 inches. A Image Dynamics ID8v3 has an XMAX of 15mm or .590 inches. That works out to be 52 cu in (2 6w0s) vs. 90 cu in (1 ID8). The difference is bigger than you think. 

Anyone know the XMAX of the eD EU-700? That might be a better option over the 6w0.


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## mikemareen (Apr 20, 2006)

chuyler1 said:


> Ok. 7mm is .275 inches. A Image Dynamics ID8v3 has an XMAX of 15mm or .590 inches. That works out to be 52 cu in (2 6w0s) vs. 90 cu in (1 ID8). The difference is bigger than you think.
> 
> Anyone know the XMAX of the eD EU-700? That might be a better option over the 6w0.


wouldn't it be .520 cu in for two 6w0's vs .590 cu in for 1 ID8 ?


I can't do the eu700's, they are too deep and have the pole vent below the magnet, that requires an additional clearance.

the box I'm getting made is a measely 3.5" thick, super slim. it has to be the slimmest possible for my install location.


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## chuyler1 (Apr 10, 2006)

Yes but I accounted for it later so my numbers are still accurate.

.275 in * 95 sq in = 26 cu in * 2 (for two subs) = 52 cu in
.590 in * 154 sq in = 90 cu in

I understand that some installs have space restrictions. That's why I am running 8" Eclipse subwoofers (0.73" XMAX!) instead of a pair of 10"s or a single 12". However, your pair of 6w0s simply won't be able to compete with a single decent 8" subwoofer. Considering that 8"s are a sacrifice, 6"s are a huge sacrifice and unless you go with a ported design, I don't think you're going to get the bass you expect.


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## mikemareen (Apr 20, 2006)

hey guys, here's another one.

which one setup would be louder.

two 6w0's with 7mm of xmax each or one 10" pioneer shallow sub at 7mm of xmax ?


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## chuyler1 (Apr 10, 2006)

pi * 9^2 = 254 sq in * .275 in = 70 cu in.

It falls somewhere between the ID8 and your 6w0s. It will prolly have a deeper sound at moderate levels than the ID8 since it doesn't rely as heavily on XMAX to create it's sound.


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## mikemareen (Apr 20, 2006)

chuyler1 said:


> pi * 9^2 = 254 sq in * .275 in = 70 cu in.
> 
> It falls somewhere between the ID8 and your 6w0s. It will prolly have a deeper sound at moderate levels than the ID8 since it doesn't rely as heavily on XMAX to create it's sound.


yeah it was between a single pioneer 10" shallow sub vs two JL 6.5" 6w0 subs.

you think I opted for the better combo ?


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## chuyler1 (Apr 10, 2006)

If it will fit, I would go with the single 10".


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## mikemareen (Apr 20, 2006)

yeah, if I knew these calculations then I would have gone with the 10" shallow sub


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