For the longest time I ran my SPL15 inverted due to my box being just under 4 cubic feet net. I also made sure to reverse the polarity on my pioneer HU when I ran inverted . A few days ago I got bored and decided to mount the sub in the "normal" non-inverted fashion. HU sub polarity setting was set back to normal rather than reversed. The sub sounds much louder now and low end reproduction is much more powerful. I thought by putting the motor in the box would decrease net volume therefore raising the tuning a bit. Doing so seems to have had the opposite effect. Box is tuned to 37ish with sub mounted inverted. Can anybody explain why this happened?

did you try NOT reversing the polarity while inverted?

did you try NOT reversing the polarity while inverted?

Yes. It didn't make a difference either way. I never did try reversing the polarity using the speaker wires themselves. Maybe the control on the HU doesn't work as it should.

taking up space inside the box does not always raise the tuning, it can in fact lower the tuning depending on the length and size of the port

I thought I read some where that inverting a sub drops the efficiency of it. I SWEAR I read that some where...

i always thought inverting a sub was more of a "look how pretty it is type of thing"

taking up space inside the box does not always raise the tuning, it can in fact lower the tuning depending on the length and size of the port

I can't think of any situation where that could happen.

I've honestly never heard of that before either. Begs for further testing...

I thought I read some where that inverting a sub drops the efficiency of it. I SWEAR I read that some where...

Its possible that inverted results in less surface area of the woofer... Just a guess.

I did do some more testing. I inverted sub again and left the phase setting on the HU to normal. I switched the polarity by switching the + and minus at the amp. No change in sound either way. I did the same test with my Fi BL and it did the same thing. When I put either sub non inverted and reversed the polarity it sounded similar as to how it sounds inverted. When I wired normally, both subs sounded much better. Just to clarify, I'm only running 1 sub at a time. I'm not mixing 2 different kinds.

One thing I did notice today is I can actually make the SPL15 bottom out when mounted normal. This only happened at near max non distorted volume (48/60 on my HU). It doesn't bottom out when mounted inverted. I'm guessing this is happening because of the higher tuning due to driver displacement.

is the sub firing up??

Arent the SPL's Bottomless motors???

I have heard that inverted- the cone disperses the air because of the shape- conical, as opposed to having the basket in the box and the cone facing outward- where its concave and has a larger surface area of the 'funnel' and directs the air movement forward, rather than outwards. DECWARE on line, has a floor standing speaker model they sell, with A CONE inverted on top of the original cone, so it disperses evenly in a 360 degree spread to make a non-localized bass presence.

I Totally believe subs SOUND Louder when the basket is in the box! MAYBE, when testing, the pressure waves in a controlled, confined chamber result in the same DB in either configuration??

PPI and others played with the honeycomb Flat cone subs many years ago, hit pretty hard and increased the stiffness of the cone and resisted fatigue in the paper cone styles causing a wrinkle and compromising the integrity of the cone rigidity. They dont make em any more- Hmmm, perhaps the funnel cone IS the best design- so it Should be facing outward ? )

How doesn't it make sense to you? There is more air displacement on the inside of the enclosure when inverted so you LOSE output on the outside of the enclosure, because all the "power" is in the inside of the box, and you never hear the rear sound wave.

How doesn't it make sense to you? There is more air displacement on the inside of the enclosure when inverted so you LOSE output on the outside of the enclosure, because all the "power" is in the inside of the box, and you never hear the rear sound wave.

This ^ doesn't make sense at all. I've read it 3 or 4 times and I still can't understand it.

All the power in the box ? You never hear the rear wave ?

How doesn't it make sense to you? There is more air displacement on the inside of the enclosure when inverted so you LOSE output on the outside of the enclosure, because all the "power" is in the inside of the box, and you never hear the rear sound wave.

This ^ doesn't make sense at all. I've read it 3 or 4 times and I still can't understand it.

All the power in the box ? You never hear the rear wave ?

Essentially yes, it does sound weird but it works... In essence you are putting all the sound in the enclosure, and you really won't hear much of it, the sound is meant to come from the front of the cone not the back. The rear sound wave never leaves the enclosure, is that what you don't get?

How doesn't it make sense to you? There is more air displacement on the inside of the enclosure when inverted so you LOSE output on the outside of the enclosure, because all the "power" is in the inside of the box, and you never hear the rear sound wave.

This ^ doesn't make sense at all. I've read it 3 or 4 times and I still can't understand it.

All the power in the box ? You never hear the rear wave ?

Essentially yes, it does sound weird but it works... In essence you are putting all the sound in the enclosure, and you really won't hear much of it, the sound is meant to come from the front of the cone not the back. The rear sound wave never leaves the enclosure, is that what you don't get?

Sound is not meant to 'come from the front', it is meant to come from a perturbation in the air, which can be cause by a cone moving back and forth, 2 wings flapping, a door beeing shut etc.

The subwoofer is not a fan or hose which moves air in one direction which is what can be understood from your explanation. The cone oscillates back and forth and produces sound. It does not shoot air forward. Or backward.

How doesn't it make sense to you? There is more air displacement on the inside of the enclosure when inverted so you LOSE output on the outside of the enclosure, because all the "power" is in the inside of the box, and you never hear the rear sound wave.

This ^ doesn't make sense at all. I've read it 3 or 4 times and I still can't understand it.

All the power in the box ? You never hear the rear wave ?

Essentially yes, it does sound weird but it works... In essence you are putting all the sound in the enclosure, and you really won't hear much of it, the sound is meant to come from the front of the cone not the back. The rear sound wave never leaves the enclosure, is that what you don't get?

Sound is not meant to 'come from the front', it is meant to come from a perturbation in the air, which can be cause by a cone moving back and forth, 2 wings flapping, a door beeing shut etc.

The subwoofer is not a fan or hose which moves air in one direction which is what can be understood from your explanation. The cone oscillates back and forth and produces sound. It does not shoot air forward. Or backward.

Not air, sound waves.

How doesn't it make sense to you? There is more air displacement on the inside of the enclosure when inverted so you LOSE output on the outside of the enclosure, because all the "power" is in the inside of the box, and you never hear the rear sound wave.

This ^ doesn't make sense at all. I've read it 3 or 4 times and I still can't understand it.

All the power in the box ? You never hear the rear wave ?

Essentially yes, it does sound weird but it works... In essence you are putting all the sound in the enclosure, and you really won't hear much of it, the sound is meant to come from the front of the cone not the back. The rear sound wave never leaves the enclosure, is that what you don't get?

Sound is not meant to 'come from the front', it is meant to come from a perturbation in the air, which can be cause by a cone moving back and forth, 2 wings flapping, a door beeing shut etc.

The subwoofer is not a fan or hose which moves air in one direction which is what can be understood from your explanation. The cone oscillates back and forth and produces sound. It does not shoot air forward. Or backward.

Not air, sound waves.

If the sound never leaves the enclosure then why wouldn't you just use a sealed box all the time.

How doesn't it make sense to you? There is more air displacement on the inside of the enclosure when inverted so you LOSE output on the outside of the enclosure, because all the "power" is in the inside of the box, and you never hear the rear sound wave.

This ^ doesn't make sense at all. I've read it 3 or 4 times and I still can't understand it.

All the power in the box ? You never hear the rear wave ?

Essentially yes, it does sound weird but it works... In essence you are putting all the sound in the enclosure, and you really won't hear much of it, the sound is meant to come from the front of the cone not the back. The rear sound wave never leaves the enclosure, is that what you don't get?

Sound is not meant to 'come from the front', it is meant to come from a perturbation in the air, which can be cause by a cone moving back and forth, 2 wings flapping, a door beeing shut etc.

The subwoofer is not a fan or hose which moves air in one direction which is what can be understood from your explanation. The cone oscillates back and forth and produces sound. It does not shoot air forward. Or backward.

Not air, sound waves.

If the sound never leaves the enclosure then why wouldn't you just use a sealed box all the time.

Because there is no release of pressure in the enclosure, there is with a vented enclosure and they are more efficient because of it.

How doesn't it make sense to you? There is more air displacement on the inside of the enclosure when inverted so you LOSE output on the outside of the enclosure, because all the "power" is in the inside of the box, and you never hear the rear sound wave.

This ^ doesn't make sense at all. I've read it 3 or 4 times and I still can't understand it.

All the power in the box ? You never hear the rear wave ?

Essentially yes, it does sound weird but it works... In essence you are putting all the sound in the enclosure, and you really won't hear much of it, the sound is meant to come from the front of the cone not the back. The rear sound wave never leaves the enclosure, is that what you don't get?

Sound is not meant to 'come from the front', it is meant to come from a perturbation in the air, which can be cause by a cone moving back and forth, 2 wings flapping, a door beeing shut etc.

The subwoofer is not a fan or hose which moves air in one direction which is what can be understood from your explanation. The cone oscillates back and forth and produces sound. It does not shoot air forward. Or backward.

Not air, sound waves.

Sound waves are transmitted by oscillation of air mollecules.

http://en.wikipedia.org/wiki/Sound

Sound is a travelling wave which is an oscillation of pressure transmitted through a solid, liquid, or gas,

And

http://hyperphysics.phy-astr.gsu.edu/Hbase/sound/soucon.html#soucon

Sound waves are not something magical and independent of the medium. Read the links.

Duran, you are getting closer a warn for spreading mis-information.

How doesn't it make sense to you? There is more air displacement on the inside of the enclosure when inverted so you LOSE output on the outside of the enclosure, because all the "power" is in the inside of the box, and you never hear the rear sound wave.

This ^ doesn't make sense at all. I've read it 3 or 4 times and I still can't understand it.

All the power in the box ? You never hear the rear wave ?

Essentially yes, it does sound weird but it works... In essence you are putting all the sound in the enclosure, and you really won't hear much of it, the sound is meant to come from the front of the cone not the back. The rear sound wave never leaves the enclosure, is that what you don't get?

Sound is not meant to 'come from the front', it is meant to come from a perturbation in the air, which can be cause by a cone moving back and forth, 2 wings flapping, a door beeing shut etc.

The subwoofer is not a fan or hose which moves air in one direction which is what can be understood from your explanation. The cone oscillates back and forth and produces sound. It does not shoot air forward. Or backward.

Not air, sound waves.

If the sound never leaves the enclosure then why wouldn't you just use a sealed box all the time.

Because there is no release of pressure in the enclosure, there is with a vented enclosure and they are more efficient because of it.

There is no 'realease' of pressure in a vented enclosure. The vent acts like a sound source because the air in it is excited by the waves in the box.

More reading material :

http://en.wikipedia.org/wiki/Helmholtz_resonance

How doesn't it make sense to you? There is more air displacement on the inside of the enclosure when inverted so you LOSE output on the outside of the enclosure, because all the "power" is in the inside of the box, and you never hear the rear sound wave.

This ^ doesn't make sense at all. I've read it 3 or 4 times and I still can't understand it.

All the power in the box ? You never hear the rear wave ?

Essentially yes, it does sound weird but it works... In essence you are putting all the sound in the enclosure, and you really won't hear much of it, the sound is meant to come from the front of the cone not the back. The rear sound wave never leaves the enclosure, is that what you don't get?

Sound is not meant to 'come from the front', it is meant to come from a perturbation in the air, which can be cause by a cone moving back and forth, 2 wings flapping, a door beeing shut etc.

The subwoofer is not a fan or hose which moves air in one direction which is what can be understood from your explanation. The cone oscillates back and forth and produces sound. It does not shoot air forward. Or backward.

Not air, sound waves.

Water waves, air waves, electrical waves ALL follow the same parameters. The Physics behind them all is identical.

You need to rethink your statement. Perhaps start with why a speaker is in the box in the first place, then explain with your theory above how a speaker in a box is going to be louder than one just sitting on the ground free air.

edit: opened this thirty minutes ago so my comment would be more clear up a bit. considering it is still valid though I will leave it

I feel I should apologize. I didn't mean to jack the thread. Somehow my theory works in my head, it's more difficult to type it for you to understand it. Sorry guys.

The theory isn't correct, although it may seem like it works for you, it isn't the way it happens.