PaulN64

I was wondering if you can subtract the sub displacement from the total air space if I were to invert the sub.

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'StangSlayer

Since the volume of the sub isnt in the box you dont count the displacement of the sub, you do need to compensate for the volume of the cone that now becomes part of the airspoace in your box tho.

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Lynxis

ive always been a little confused here.

how do you run a system with inverted subs... also, do you hook the wiring up backwards so to compenstate for phase shifting with the other speakers in the car.... i dont know why you would but... bleh, who knows

and if you dont have to have as big of a box when you have inverted subs, then why doenst everyone do this? especially in an fbody.... of course though, you have massive subs protruding out now but....


hmm, i guess something new to experiment with...


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97FormulaWS-6

I've seen it done in a few special applications, but normally you want the cone facing out.

This due to most of the sound comes from the face of the cone, and if you have the drive assembly in-front of the cone (as it is when mounted inverted) you block some of the sound, as well as making the surface area smaller due to the VC mounting onto the cone.

Mike

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LS1 RULZ

This is exactly why I don't understand why people do this. Why would anyone want to sacrafice cone area just to show off a basket and a magnet? Makes absolutely no sense to me whatsoever.

Lynxis,
Yes you would reverse the polarity of the sub's wires when mounted in this fassion. At least for starters. It may sound fine wired normally. And that's only if you have an exact 180 degree phase problem. If you don't then reversing the wires won't matter.



[This message has been edited by LS1 RULZ (edited August 06, 2002).]

PaulN64

I'm trying to see what my options are. I'm thinking of a vented box instead of sealed, and I'm trying to see if I can get away with a smaller box with an inverted sub.

rthompson

I see there is a lot of misconceptions about inverse mounting....
Most of the sound DOES NOT come from the front of the cone.

First of all there is absolutly NO decrease in SPL, or degredation in SQ.

As we all know SPL is produced from the swept volume of the woofer compressing the air in the cabin of the car. the reason that you will not have any decrease in SPL from loss of cone area is because you still have the EXACT same swept displacement no matter which way the sub is mounted. The cone still moves the same amount and due to the porous spider and often a vented pole piece, you lose NOTHING in terms of swept volume.... Displacement is the name of the game boys.

If you are talking high frequency like a tweeter, the motor structure would block some of the direct sound, but since Bass in nondirectional it doesn't matter.... simple experiment, try to block the sound from your sub with your hand... doesn't work does it.

Yes when you inverse mount your sub, you have to reverse the polarity, and you do gain a marginal amount of space, depending on the concavity of the cone... it is probably small enough that it won't matter, but the displacement of the motor structure plus the extra (cone concavity area and cutout area) might do something... my sub is .17 cubes sub displacement, add that to the (pi*R^2*.75=.05) cutout of a 12... that is .22 cubes extra if you inverse mount my sub....

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PaulN64

the sub I'm looking at requires 2.5 cu ft for a ported box and the sub displaces .27 cu ft. What's the smallest air space would I require?

rthompson

If it requires 2.5 cubes and the sub displaces .27, then if you use a standard mount, you will have to make the box 2.77 cubes. If you inverse mount then just 2.5, and if it has a nice basket then you can show it off.....

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