Inverted subs in a ported box

[Rashaddd 5,000+ posts]

Nothing wrong with it, same as on a sealed

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[audioholic 5,000+ posts]

Two 6" aero's per 15" sub seems like too much.

 

[IDSkoT 5,000+ posts]

I was planning on running two 15's in my wife's SUV.The box I was designing would incorporate 4-6" ports firing to the rear, and the subs inverted facing up..

Has anyone inverted their ported subs...The idea is to be able to run a smaller box and keep some storage room in the rear

Inverted is the same thing as putting them in "the right way."

The driver still pressurizes air. It's doing it's jerb.

Except.

THE WAVES WILL *** @ U IN V WAVES RATHER THAN U WAVEZ SINCE TEH CONE IS A DIFFERENT SHAPE!!!!

BTW 2-6" ports per sub is A LOT. I'd say 1-6" per sub is good.

But... I haven't done the math for that kind of ish.

Anyone want to do the math and post it up? //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[Linkz 10+ year member]

just set the phase on the amp to 180 and you will be fine

 

[rollerdj 10+ year member]

wait, you finally married jennay? //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif I've done it several times without any problems. You don't have to worry about driver displacment. So I vote do it.

 

[Rashaddd 5,000+ posts]

Since when is 56sq in of port too much for two 15's? I just did a box for a single 15 with 80 somethin sq in of port and that bish moved air for a single 15 off 1k...

edit: misread..okay so 56sq in PER 15...I still don't see the problem...if anything, he'll gain output and it'll sound cleaner.

which sounds better, a 6.5" moving 5" peak to peak or an 18" barely moving...? (same output levels)

Only reason to go with less port area is to save space, same reason to go with smaller drivers with more excursion rather than bigger drivers with less excursion

 

[audioholic 5,000+ posts]

Since when is 56sq in of port too much for two 15's? I just did a box for a single 15 with 80 somethin sq in of port and that bish moved air for a single 15 off 1k...
edit: misread..okay so 56sq in PER 15...I still don't see the problem...if anything, he'll gain output and it'll sound cleaner.

which sounds better, a 6.5" moving 5" peak to peak or an 18" barely moving...? (same output levels)

Only reason to go with less port area is to save space, same reason to go with smaller drivers with more excursion rather than bigger drivers with less excursion

We are discussing AERO ports here, not slot ports. The port area required for aero's is considerably less than a slot port, assuming you care about port noise. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif
For an aero port, a single 6" or dual 4's is usually adequate for a 15" sub.

"Only reason to go with less port area is to save space"

The only reason to increase port area, thereby increasing port length and over all enclosure size, is to reduce air velocity and minimize port noise due to turbulence. So I'll reverse your own logic on you and ask if one 6" aero will produce inaudible port noise, why increase port area (and over all box size) just to reduce port velocity even further?

Most people chose the more expensive aeroport route, rather than the cheaper slot port, to save space on the enclosure (less port area = shorter port for a given tuning = less enclosure size). If you arbitrarily decide aero's need as much port area as a slot port, might as well save some buck and just do the slot.

 

[IDSkoT 5,000+ posts]

We are discussing AERO ports here, not slot ports. The port area required for aero's is considerably less than a slot port, assuming you care about port noise. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif
For an aero port, a single 6" or dual 4's is usually adequate for a 15" sub.

"Only reason to go with less port area is to save space"

The only reason to increase port area, thereby increasing port length and over all enclosure size, is to reduce air velocity and minimize port noise due to turbulence. So I'll reverse your own logic on you and ask if one 6" aero will produce inaudible port noise, why increase port area (and over all box size) just to reduce port velocity even further?

Most people chose the more expensive aeroport route, rather than the cheaper slot port, to save space on the enclosure (less port area = shorter port for a given tuning = less enclosure size). If you arbitrarily decide aero's need as much port area as a slot port, might as well save some buck and just do the slot.

Well, I agree. But, I don't think aeroports are expensive enough to note them. A 6" on PartsExpress is like $8 or so dollars.

Or if you go the PVC route, a 2' [FOOT] 4" diameter PVC section cost $6 bucks. So, it costs slightly more, unless you equate the wood down to a dollar amount per cubic feet/inch, and it might be the same amount. Given that most people don't use a full sheet of MDF for a full box. So "waste" will be there.

But I'll digress.

I plan on using Aeroports for my next ported build. (I used round ports for my last build. It came out pretty nice.) As I said before, I don't think they're expensive enough to note differently. Aeroports tend to give more ease of build, as opposed to slot ports.

But, I'm not too sure if Slots are more notorious for port noise vs round ports or not.

 

[audioholic 5,000+ posts]

Well, I agree. But, I don't think aeroports are expensive enough to note them. A 6" on PartsExpress is like $8 or so dollars.Or if you go the PVC route, a 2' [FOOT] 4" diameter PVC section cost $6 bucks. So, it costs slightly more, unless you equate the wood down to a dollar amount per cubic feet/inch, and it might be the same amount. Given that most people don't use a full sheet of MDF for a full box. So "waste" will be there.

But I'll digress.

I plan on using Aeroports for my next ported build. (I used round ports for my last build. It came out pretty nice.) As I said before, I don't think they're expensive enough to note differently. Aeroports tend to give more ease of build, as opposed to slot ports.

But, I'm not too sure if Slots are more notorious for port noise vs round ports or not.

$38.00 actually.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=268-354

 

[Rashaddd 5,000+ posts]

We are discussing AERO ports here, not slot ports. The port area required for aero's is considerably less than a slot port, assuming you care about port noise. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif
For an aero port, a single 6" or dual 4's is usually adequate for a 15" sub.

"Only reason to go with less port area is to save space"

The only reason to increase port area, thereby increasing port length and over all enclosure size, is to reduce air velocity and minimize port noise due to turbulence. So I'll reverse your own logic on you and ask if one 6" aero will produce inaudible port noise, why increase port area (and over all box size) just to reduce port velocity even further?

Most people chose the more expensive aeroport route, rather than the cheaper slot port, to save space on the enclosure (less port area = shorter port for a given tuning = less enclosure size). If you arbitrarily decide aero's need as much port area as a slot port, might as well save some buck and just do the slot.

I'm not saying its at all necessary to go with more, just saying if he can and wouldn't rather not then he might as well. Whether aero's or not, more port area makes a box more efficient and usually sound better (at least in my experience), people almost always gain on a mic by upping port area as well.

OP if you're under the impression that you need more than 2 6" aero's, you absolutely don't, but it's almost never a bad thing assuming you don't mind giving up the extra space and are able to make the ports long enough for your desired tuning still.

 

[bonesninja 5,000+ posts]

whether you invert the subs or not....the subs til take up the same amount of airspace. You gain no space by inverting....actually, you probably take up more usable space in the car by doing so

 

[audioholic 5,000+ posts]

I'm not saying its at all necessary to go with more, just saying if he can and wouldn't rather not then he might as well. Whether aero's or not, more port area makes a box more efficient and usually sound better (at least in my experience), people almost always gain on a mic by upping port area as well.
OP if you're under the impression that you need more than 2 6" aero's, you absolutely don't, but it's almost never a bad thing assuming you don't mind giving up the extra space and are able to make the ports long enough for your desired tuning still.

If he has the room, should he just bump it up to 10 6" aero's? //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif
I get your point. If he's competing and efficiency is key to squeezing out another tenth or two, by all means try two 6" aero's. But most of us will never notice any realistic performance increase by doing it.

 

[audioholic 5,000+ posts]

If it will only net me a tenth of a db I don't think it would be worth it....I thought it would be more like 1 or 2 at least

I was talking about spending the time/testing to find the optimum amount of port area to maximize SPL. Many times this involves building mutliple boxes of different sizes, proportions and layouts just to find out which gives the best results. But that's for the serious competitors. If you have to ask about it, you really dont need to do it.
There is such a thing as too much port area too, the sub unloads too easily. Im not necessarily saying two 6's would do that in this case, Im just saying port area benefits have their limits as well. For most daily systems, it comes down to not choking the sub off, and not displaying audible port noise.

 

[x2o 10+ year member]

whether you invert the subs or not....the subs til take up the same amount of airspace. You gain no space by inverting....actually, you probably take up more usable space in the car by doing so

How do you figure this one? How can the motor displace airspace if it is not in the box? //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif I realize the cone will still be displacing some, but majority of sub displacement is motor/basket, isn't it? I'm not sure, but this is always how I understood it..

 

[audioholic 5,000+ posts]

How do you figure this one? How can the motor displace airspace if it is not in the box? //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif I realize the cone will still be displacing some, but majority of sub displacement is motor/basket, isn't it? I'm not sure, but this is always how I understood it..

He's talking about the idea of inverting your subs in order to save room on internal volume, thereby making your box smaller. That is true, but then you have speaker frames and motors sticking out of the box, making the whole assembly that much larger. Airspace is not utilized as efficiently as when the subs are mounted inside the box, and their volume accounted for in the over all dimensions.
You think he is saying space will be wasted in the box, but he's actually saying space will be wasted inside the car (but outside the box).