Inverted subwoofers

[dkmesa 10+ year member]

I have never heard a sub inverted in an enclosure but I was considering doing it for my sister's car so I can use as little depth as possible. Any idea how different a 12" Type R would sound in 1.2 cubes inverted rather than normal?

Thanks for any help and insight

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[bri487 5,000+ posts]

it shouldnt sound any different. just reverse the polarity.

 

[Crown_amps]

it shouldnt sound any different. just reverse the polarity.

why

 

[dkmesa 10+ year member]

Really? thanks b/c I would have thought it would make the sound different. Also I'm too much of a noob to have remembered to reverse the polarity, thanks

 

[PatFitz9 10+ year member]

do you have to reverse the polarity for just one sub? i thought that if there were multiple subs you had to wire them on a 180 phase shift, but one sub doesn't matter if you wire normally.

 

[jujumantb 10+ year member]

do you have to reverse the polarity for just one sub? i thought that if there were multiple subs you had to wire them on a 180 phase shift, but one sub doesn't matter if you wire normally.

No, you dont have to switch the polarity, but you might want to try to see what sounds better. The only time you have to is when you have one sub inverted and another mounted normally, you would switch the polarity on one or the other sub so they will play in unison.

 

[PatFitz9 10+ year member]

The only time you have to is when you have one sub inverted and another mounted normally, you would switch the polarity on one or the other sub so they will play in unison.

yeah, thats what i meant. what would change if you reversed the polarity with only one sub in the enclousure?

 

[neonrt 10+ year member]

you may get some mechanical noise, but it should sound(the bass) the same. maybe lower because of the increased box size.

 

[jujumantb 10+ year member]

yeah, thats what i meant. what would change if you reversed the polarity with only one sub in the enclousure?

Reversing the polarity means that the sub will be on its 'out stroke' when it used to be on its 'in stroke'. Of course, since the sub is moving back and forth anywhere from 20 to 100+ times per second, you wont be able to see the difference, but you may hear one. Basically, all the soundwaves in your car interact, this is most evident at crossover frequencies where multiple drivers are playing the same frequency (aka around 70-150hz where the sub and midbass are both playing).

Say your subs were lowpassed at 80hz and your midbass highpassed at 80hz, then you play an ~80hz tone. Since the sub and midbass are both playing this tone, the soundwaves will interact dramatically. Ideally, you want the two waves to be in total sinc with eachother when they reach your ears. If they are not in sync, they can effectively cancel eachother out and that 80hz tone will sound VERY quiet. (You can dublicate this effect by playing a tone on a CD shelf system with movable speakers. When you move one speaker closer to you, you will notice the tone gets quieter at certain intervals. This is cancellation.)

If, in fact, the two waves are out of phase when they reach your ears, by reversing the polarity on the sub, you can now make those waves in phase when they reach your ears and everything will sound much better. Since its hard to know whether your subs and mids are in phase with eachother, its a good practice to go ahead and try reversing the phase to see if it sounds better. It may sound better, worse, or really no difference at all.