Question For Audio Gurus

[jott5555]

ok why is it or isnt it benifficial to install a sub like the ones pictures below
(thanks Thomas91169 ) as opposed to the other origional way??

just curious

 

[eclipse13]

By original way do you mean in a box? Mounting it with the backet out is just for show. Having a trunk and a convertible makes it hard to hear subs, and having them right behind your head would help make it louder.

 

[62-1gsx]

i think he means by the way the magnets are facing........ive never really noticed a difference in sound myself, but other than show i dont know all the technical reasons.....

 

[Chuckster]

Obviously, we can only see two subs. If there are four in a clamshell arrangement, then it increases the speakers efficiency substantially.

Before installing a speaker upside down, it's best to calculate the sag to make sure it's less than 5% of the sub's xmax. If your algebra skills are still intact, here's the formula:
http://www.adireaudio.com/Files/TechPapers/DriverOrientation.pdf

 

[UnderPrssureDSM]

It's for show.

 

[arson]

It's for show.

for as long as it takes someone with a razor knife to get through the convertible top. i would never put that much money into a convertibles interior. thats just SCREAMING steal me! steal me!

 

[Mack]

Technically, it adds a small amount of internal volume to the enclosue that you would otherwise lose. It's called mounting them inverted. To do it correctly you also need to change the wire polarity. For the bling bling subs it's for looks.

 

[ShadowWulf]

Ive thought about doing this with my 2 12" Comp Kickers. Now bling-bling subs really (at least not the back of em anyways). Ive been wondering how much of a difference it would make on an unported box (no holes)...this is all sitting in the back of a 2g eclipse, not a rag-top, with the seat sitting down and the speakers currently facing up.
Mounted normally it turned the car into a nice audio-enclosure when the windows are rolled up, but what if i reverse the facing of the speakers? More bang for my buck? Or just a waste of time? And why?

 

[arson]

Ive been wondering how much of a difference it would make on an unported box (no holes)

the difference is the kind of music you listen to. a ported(bandpass) box (usually an enclosure like mine (

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)or just one sub in a smaller box) is made for more bass, like rap, hiphop, that hit hard. non-ported boxes, like truck boxes are made for more rock, country, that kind of music, but still sound pretty good when you put in twista.

...this is all sitting in the back of a 2g eclipse, not a rag-top, with the seat sitting down and the speakers currently facing up.
Mounted normally it turned the car into a nice audio-enclosure when the windows are rolled up, but what if i reverse the facing of the speakers? More bang for my buck? Or just a waste of time? And why?

i'm not positive about this, but if the speakers were originally meant for a non-ported box, magnet inside, and were switched, wouldnt the air pushed by the cone on the inside of the box tear something? maybe one of the big dogs can answer that one. just my .02, im sure it'll sound nice however you decide.

 

[sjwelna]

It is basically only to show off a cool magnet. You can also do that if your space tolerances are really tight, and need to keep every tiny bit of enclosure volume that you can get; by mounting it "inverted" as stated above, you basically don't have to subtract the woofer displacement, and can thus gain a little (almost negligible) amount of airspace.

You don't need to check the sag of the xmax with mounting inverted, meaning having the magnet on the outside of the box, but if you were going to mount them downfiring (having the woofer cone pointing towards the ground) then you need to do this. If you have the woofer still "upright" so the cone of the woofer is stille essentially perpendicular to the ground, it won't matter, but if you end up having a down firing woofer inverted (magnet on the outside) you need to check the sag.

Mounting woofers like this (magnet inside vs. outside the box) will have no noticeable affect on the sound that you hear. If you want to do it, go for it.

Hope this helps.

-Steve

 

[Chuckster]

Sealed, vented and bandpass boxes are all different.

A bandpass box has a sealed portion from which the sub fires into a ported box. It only allows certain "band"s to "pass" through the ports. Looking inside Arson's box, you can see the two subs are facing toward the center sealed portion of the box. The frequencies allowed out are controlled by the remaining size of the enclosure and its port sizes.

Both sealed and bandpass use their sealed portion to trap the moving air and cause a resistance to prevent over excursion. (I said prevent!) Inverting the speaker and the signal polarity will still prevent over excursion. The same as yours does, Arson.

A ported box is tuned to highlight frequencies. It takes a little work to make one with a flat response and they don't offer the protection from over excursion.

I don't think inverting speakers in a sealed enclosure would hurt the speakers. If the box was made to the manufacturer's specifications, it would create a larger enclosure size and ~probably~ wouldn't sound as good. Of course this is car audio and nothing happenes by the book inside of a car.

 

[Chuckster]

I believe Steve is right about my sag tolerances. I spend too much time with home audio.

To bite off a little of what Steve also said, "cool magnet": having the magnet outside would also offer a little cooling of the voice coil.

 

[FutureGSXOwner]

Just something to add: Some subs will sound like ass mounted like that. If any of you are thinking about doing something like this, look for "free air" subs which are designed specifically for this type of setup. Use Cardomain.com to check the subs out that you like because they specifically give a "free air recommendation" for each sub they sell.

 

[jott5555]

no my car is a full race setup so i have no desire to do something like that, ive just seen it quite a few times and was curious.

thanks for clearing it up guys

 

[Thomas91169]

thats actually my sub box. i let jott use my pics cause he was curious as to why i would reverse/inverse mount them. theres just the 2 subs mounted inverse.

they can scream steal me all they want, but those suckers are being bolted in to the enclosure, and unless you know exactly how to get the enclosure out youre not getting to the bolts for the subs or the amp. plus its a 2 person job to remove the enclosure and take the subs/amp out cause you really cant extend your arm through my little acess port and hold one bolt while trying to ratchet the other, and even if they rip the top they cant move the box unless the actual converti top is down and they knew where the bolts are.plus im getting a alarm with the motion sensor mounted right up there so if anyone rips the top or i have the top down and im gone and reaches inside it goes off.

ive heard them both ways in cars and i cant tell the difference really. i knew a guy that had 2 kicker 12's in a box, one was mounted normal and one was inverse and it hit really hard. the area that the subs are facing into is really big, about twice the volume of a normal sub box inside. im thinking itll be like facing them inside a hatch or something. i dont know yet, my amp gets here tomorrow so ill see which way the subs sound best.

 

[Chuckster]

Hey Thomas, that's a really sexy install! I just hope those smaller speakers have their own enclosure space. Of course it would be fun to watch them try to keep up with the sub pressures.

Those 2 kicker 12's were probably a push/pull configuration too. If yours are in a single chamber, not divided, you might have fun trying that too.

 

[sjwelna]

Just something to add: Some subs will sound like ass mounted like that. If any of you are thinking about doing something like this, look for "free air" subs which are designed specifically for this type of setup. Use Cardomain.com to check the subs out that you like because they specifically give a "free air recommendation" for each sub they sell.

Mounting a sub inverted is totally different than mounting it free air. Free air is mounting a sub with no enclosure to control the movement of the woofer cone. In this case, there is still an enclosure, it's just that the sub is mounted "backwards" so to speak, but it still has the enclosure to limit it's movement. Just clarifying, not flaming in any way.

Car audio is my second hobby and I got started in it a long time before DSM's, but now I have the best of both worlds in mine.

-Steve

 

[Thomas91169]

each sub has its seperate chamber and theres a chamber in the middle for the midranges and amp stuff

 

[arson]

in that pic, it looks like a small tear in something on the bottom right corner. what happened?

 

[Attack Eagle]

generally the sub doesn't "care" which way it is facing as long as one side of the cone is inside one enclosure of the specified volume and the other is in the sealed or semisealed enclosure of the car's interior...
little difference will be heard if the subs are properly crossed over at a low frequency (sub 80 hz) however at higher bass/ midbass notes a minor difference can SOMETIMES be heard with some subs, or whistling around the basket legs if the basket design is not "open".

subs like the diamond audios dx line are not conducive to inverted mounting because of whistle, while "shallow mount subs" like the pioneer 12" have dual cones and lose output when mounted inverted as they lose part of their acoustical lever when inverted...

ALl that is being said is there is little reason to mount them inverted other than aesthetics or in some instances nominal magnet clearance in the enclosure but excellent clearance outside the enclosure. (plus you might have an ugly sub or find that its magnet attracts screws and other ferrous materials like mad!)

 

[Thomas91169]

that tear was actually a perfect inset for the seat belt cover ring that went into the side panels, i cut it out so that i can run the belts in the same place as the stock ones.

i have a new post with the finished project up now.