upside down subs?

Dragon2

http://www.billkatz.com/images/ces_pics/ces_subwoofers.jpg like these.Can it be done with any subwoofers, or do they have to be certain ones?

michael_w

Are you talking about how they are mounted with the motor on the outside and firing into the box ? If so then yes I belive you can do it with pretty much any sub but it's more of an asthetic thing.

exalted512

any sub can be mounted like that, its called inverted. Mostly for aesthetics, sometimes for space issues. When youre building the box, make sure to compensate for the fact that the sub is no longer taking up any space in the box so the box will need to be made smaller
-Cody

MacLeod

If you mount your subs inverted though youre not legally allowed to use a good quality sub like a Polk Audio cause its pointless and stupid. Audiobahn is all you can use.

Speaking of pointless and stupid, Car Audio and Electronics had an Audiobahn demo car that actually had the mids inverted in the doors. :rolleyes:

1996blackmax

Then I will go pick me up a couple of those there Auglybahns .

Toxis

Plus, if you do mount them like that, be sure to wire them out of phase so they still play out and not into the box.

MacLeod

But thats irrelevant cause if you mount your subs inverted youre not concerned with SQ anyway so it would matter if theyre firing backwards or not!

Still learning

Ok so i may be wrong and confused about this but i thought the bass came out the back end of the sub....what the hell im so confused, no wonder why im still learning?

neomagus00

yeah, i'm pretty sure that the reversal of phase comment was a sarcastic remark, cause it's wrong... for a sub, there's very little audible difference between normal and inverted mounting, it's all aesthetics...

1996blackmax

You hit the nail on the head .

Toxis

so phasing doesn't effect the sound? Wow... news to me.

If I was being sarcastic and that comment was wrong, why did you also agree with it by saying there is a little difference?

spwuinmk67

I think the way that it was read/understood was that if you didn't switch the phase, you wouldn't hear anything. But I dunno, I could be wrong.

Still learning

Well what i said was not a joke? hum i understand that it is all acustics and such but damn i was way wrong...hum thamks for the knowledge, but i still have a question, whitch is, can you "invert" with the actuall in door speakers, because i would think that the "noise" came out of the front of the speaker, (please forgive me for my ignorance im new to all of this)thanks.

1996blackmax

Toxis wrote:

so phasing doesn't effect the sound? Wow... news to me.

If I was being sarcastic and that comment was wrong, why did you also agree with it by saying there is a little difference?

Reversing the phase on the subs will effect the blending of the sound with the rest of the system. I do not think that if you mount the subs inverted that you have to reverse the phase. If reversing the phase would offer an improvement in sound, it would do the same with the sub mounted in the traditional way.

Toxis

no because it's mounted inverted. If a sub has to play into the trunk to be in phase, firing into the box is out of phase no matter how the subs are mounted. Period. So if you mount the subs inverted and wire them the right way, they'll be firing into the box first meaning they're 180* out of phase. This can effect the sound quality. Do you agree?

exalted512

toxis is right
-Cody

VR3

I like phase knobs.

180 degrees out of phase always sounds better (in home) so just chaulk it up as a blessing.

Subs facing out of the box look retarded...

1996blackmax

Toxis wrote:

no because it's mounted inverted. If a sub has to play into the trunk to be in phase, firing into the box is out of phase no matter how the subs are mounted. Period. So if you mount the subs inverted and wire them the right way, they'll be firing into the box first meaning they're 180* out of phase. This can effect the sound quality. Do you agree?

The more I think about it............ If the system and sub are already in phase and then you turn your subs to fire into the box, I can now see having to reverse the phase.

However just saying that a sub has to play into the trunk to be in phase is not 100% correct. A subwoofer can be out of phase with the rest of the system even if it is firing into the trunk too, that is why many manufacturer's offer a switch for reversing the phase on their amp, as well as giving that as an option on their head units. On some of my systems reversing the phase would help out the sound. This was before I had time alignment and reverse switches. You had to actually switch the wires around :eek: .


I've never tried the inverted thing. I thought about it before, not for the looks thing, but for an isobaric setup. Having one of the subs this way was part of the function of this enclosure.

MacLeod

Ive never really thought about this but bass is omni directional so I would think it wouldnt matter if its inverted or not. Since its not actually firing in any direction you wouldnt have to switch the phasing. Right?

1996blackmax

The little things that make us go huh? It seems pretty simple, but..........

Toxis

only reason I know this is because I built a system years back with the subs inverted and there were severe dead spots in the car. Reversed the phase and BAM!

VR3

Macleod...

Phasing is very important in a system...

Lets say your mains are doing a 50hz signal IN PHASE... where as your sub is doing a 50hz signal OUT OF PHASE. All this will cause is one huge cancelation.

This is true with every frequency. This is why dipole loudspeakers are extremely hard to place and can cause huge nulls in the frequency response. They send out an inphase signal in the front with the same exact signal sent out of phase out the back.

MacLeod

Oh I agree 100% Sid. Phasing is also a very valuable tool in staging. Say your tweeters are too much for your mids, slap em out of phase and that added delay can help.

I was just wondering that since bass is omnidirectional, if you mount a sub with the cone in the box would it matter if it was in phase? You wire a midrange out of phase so that it will fire a split second later than the rest of the system but if a sub is firing in all directions, would it matter?

Take corner loading for instance. You place a sub in a corner even with the cone facing out and itll back build against the corner and increase output cause the wave is going in all directions at once. This wont happen with a midrange or tweeter.

VR3

Bass is not really Omni-directional. Well it is, but it isnt.

The room loads the bass, and there is certain cancelations and peaks throughout the room, you may be walking around the room and get hammed with bass, then move a little bit and experience nothing at all. Just the way it works.

Bass itself is omni-directional, but what is producing the bass is not omni-directional, the cone distortion, distortion in general localizes subs. But I am just saying something you already know!

But, I personally think subwoofers are directional, I mean it is a mechanical design firing a certain direction... makes sense to me...

But, putting the sub in or out of the box could change alot as far as phase but wouldnt really effect your system overall. It would just need to be tested to see which phase was better for your particular setup.

MacLeod

That does make sense. Ive always wondered how, if bass was omnidirectional, downfiring really increased output and changed the overall SQ.

Where's a phyisicist when you need one?

VR3

Down-firing subs increasing output is actually a very simple concept...

Adire explained this very effectively...

When you put a driver in a vertical position, it is moving out and in against gravity (pushing down) thus limiting what the driver can do overall. I think they said the difference was around 3 or so DB.

Putting the driver in the downward position makes it work with gravity in a way, moving up and down - allowing for more excursion.

The way I picture a down-firing sub is sound radiating in every direction, all sides - where as a vertical firing subwoofer is just firing in one direction relying on one wall to load it, while a down firing subwoofer is using everything around it directly, instead of by reflections.

MacLeod

I dunno about that. I know its easier to fire with gravity but I think its actually building off of the floor and adding to the output thats increasing the volume. I would think that firing with gravity as opposed to perpendicular to it wouldnt really matter that much.

VR3

Actually, depending on the sub design - firing in the floor can cause you to lose bass. (This would be a slab home... as slab homes add nothing to the bass.)

Since carpet is padded and not a reflective surface, it absorbs sound, so if you are buying a sub that is firing directly into carpet - the floor isn't helping all that much.

Of course a foundation home with a wooden floor will add on to it, but you also have to account for all the bass that is being transferred under the house by extreme margins. Trust me, I've experienced this - it is very uncomfortable to be under my house with my system on... very loud.

Wooden floors, btw, act as a trampoline to your subwoofer and really add alot of output to the bass, usually causing it to be boomy. Alot of people put slabs under their subs to fix this. Isolating it from the floor.

Anyways, the floor helps, BUT - you also have to account for gravity, which does help. (According to Adire)...

If anything, the fact the woofer is sending the soundwave in a 360 degree pattern would help more than anything.

A front firing woofer would rely on reflections in each direction to load the bass. So lets say you are firing away from the corner facing another corner - the bass is going directly to the opposite corner...

Another thing is vertical firing drivers lose about 3db of output due to the loss in the rear reflection. The same goes for Direct Radiating loudspeakers. (Maybe we need Bipolar subs)...

Anyways, you put a down firing sub in a corner... not only is it radiating off the walls behind it, beside (directly), but it is sending direct soundwaves infront and beside of it - along with all the reflected soundwaves left.

To me a down-firing sub would spread the signal in alot more directions and wouldnt rely on reflected signals.

VR3

Lets look at this in ANOTHER senario...

Say you took a subwoofer outside, far far from everything else...

Ok, now that we have this image... imagine the subwoofer playing at max output - a forward driver with no reflective surface... it would be firing in one general direction... YOu would also have to measure it from the direction the driver is firing for correct results...

Now you take a down firing sub outside in that same spot and it will be radiating sound in alot of directions, filling more area and you could probally measure it from any side of the sub.

I guess that is why vertical drivers, firing in one direction are called direct radiating.

audiobliss

^ Hmm. Interesting.

CrBoy

So I mounted my sub "inverted" for the sake of the forum and personal testing...

Believe it or not it plays a little harder... why? I guess because i'm using a smaller amp than the recommended for the Dx-12 and by inverting the sub the box appears to be bigger (no speaker displacement)... SQ seems to be the same... small amp + bigger box = more ouput... right?

If this doesn't make sense my ears are screwed up!