Slot Ports vs. Aeroports

[Hintzyboy 5,000+ posts]

It depends on how much port area you need, what the net volume of the enclosure needs to be, what tuning you want, how much trunk space you have, etc.

Slot ports are better for large enclosures. Let's say you're building a box for 2 12s and you want 24 sq in of port area. You can either use 2 4" aeros or a 2 in wide slot port. Since you'll have already bought MDF to build the enclosure and large enclosures don't require much for port length, you'll likely have enough extra MDF to make the slot port (so you basically get the port for free). Or you could by a pair of 4" aeros for around the same price as a full sheet of MDF. Slot ports take a bit of extra work and calculation, but for a large enclosure, the cost savings are definitely worth it.

Aeroports are better suited to small enclosures. Let's say you're building a .5 cu ft (net) enclosure for a single 8" woofer. Since the height of a slot port is dictated by the height of the box, the port area is going to be larger than may be necessary for a small sub (an 8"x1.5" slot port has almost twice the area of a 3" aero). More port area means a longer port length fore the same tuning. A smaller enclosure means more port length for the same tuning. Using a slot port in a small, low-tuned box is going to require a very long port. The mdf used for a slot port also takes up airspace. All of this means that the slot port is going to increase the overall volume of the enclosure by quite a bit, defeating the purpose of buying a small sub suited for small volume. You're also not going to see the same cost savings. A slot port in a small enclosure is going to require a lot more mdf, which will likely mean you have to buy a full sheet. With an aero port, you can use a half sheet, which balances the cost of the port while keeping the overall enclosure dimensions nice and small.

Aeros also have the advantage of ease of use. You just have to cut a hole and mount vs. measuring, cutting, and glueing/screwing in the boards for a slot port. You can also adjust the tuning without ripping the box apart or building a new one.

 

[subzero 5,000+ posts]

is the search button broken? this has been discussed millions of times on multiple forums

Yea, and in that search you find many bullshit refferences that slow down your search, if your lucky, you can find exactly what you want or bits and pieces. but why do all that, when you can just post a new thread and get a simple answer

It depends on how much port area you need, what the net volume of the enclosure needs to be, what tuning you want, how much trunk space you have, etc.
Slot ports are better for large enclosures. Let's say you're building a box for 2 12s and you want 24 sq in of port area. You can either use 2 4" aeros or a 2 in wide slot port. Since you'll have already bought MDF to build the enclosure and large enclosures don't require much for port length, you'll likely have enough extra MDF to make the slot port (so you basically get the port for free). Or you could by a pair of 4" aeros for around the same price as a full sheet of MDF. Slot ports take a bit of extra work and calculation, but for a large enclosure, the cost savings are definitely worth it.

Aeroports are better suited to small enclosures. Let's say you're building a .5 cu ft (net) enclosure for a single 8" woofer. Since the height of a slot port is dictated by the height of the box, the port area is going to be larger than may be necessary for a small sub (an 8"x1.5" slot port has almost twice the area of a 3" aero). More port area means a longer port length fore the same tuning. A smaller enclosure means more port length for the same tuning. Using a slot port in a small, low-tuned box is going to require a very long port. The mdf used for a slot port also takes up airspace. All of this means that the slot port is going to increase the overall volume of the enclosure by quite a bit, defeating the purpose of buying a small sub suited for small volume. You're also not going to see the same cost savings. A slot port in a small enclosure is going to require a lot more mdf, which will likely mean you have to buy a full sheet. With an aero port, you can use a half sheet, which balances the cost of the port while keeping the overall enclosure dimensions nice and small.

Aeros also have the advantage of ease of use. You just have to cut a hole and mount vs. measuring, cutting, and glueing/screwing in the boards for a slot port. You can also adjust the tuning without ripping the box apart or building a new one.

I haz swappable slot ports.....

 

[RAM_Designs 5,000+ posts]

It depends on how much port area you need, what the net volume of the enclosure needs to be, what tuning you want, how much trunk space you have, etc.
Slot ports are better for large enclosures. Let's say you're building a box for 2 12s and you want 24 sq in of port area. You can either use 2 4" aeros or a 2 in wide slot port. Since you'll have already bought MDF to build the enclosure and large enclosures don't require much for port length, you'll likely have enough extra MDF to make the slot port (so you basically get the port for free). Or you could by a pair of 4" aeros for around the same price as a full sheet of MDF. Slot ports take a bit of extra work and calculation, but for a large enclosure, the cost savings are definitely worth it.

Aeroports are better suited to small enclosures. Let's say you're building a .5 cu ft (net) enclosure for a single 8" woofer. Since the height of a slot port is dictated by the height of the box, the port area is going to be larger than may be necessary for a small sub (an 8"x1.5" slot port has almost twice the area of a 3" aero). More port area means a longer port length fore the same tuning. A smaller enclosure means more port length for the same tuning. Using a slot port in a small, low-tuned box is going to require a very long port. The mdf used for a slot port also takes up airspace. All of this means that the slot port is going to increase the overall volume of the enclosure by quite a bit, defeating the purpose of buying a small sub suited for small volume. You're also not going to see the same cost savings. A slot port in a small enclosure is going to require a lot more mdf, which will likely mean you have to buy a full sheet. With an aero port, you can use a half sheet, which balances the cost of the port while keeping the overall enclosure dimensions nice and small.

Aeros also have the advantage of ease of use. You just have to cut a hole and mount vs. measuring, cutting, and glueing/screwing in the boards for a slot port. You can also adjust the tuning without ripping the box apart or building a new one.

I have to disagree completely on the ease of use with smaller volume boxes. With a .5ft^3 box tuned to 35hz, a 3" aero is going to need to be 30" long. Have fun buying elbows and more PVC to fit that inside a box or you can have an ugly external aero hanging out of the box, taking up a lot of space. With a slot, you can easily follow the outside of the box and get the port length needed. Also, using a 3" aero that has a ~4.5" diameter flare is going to require a decent sized box just to make sure you have enough clearance with the port/sub being so close. With that 30" custom aero, it's doubtful you can even fit it inside a box(depending on the sub/port orientation that you needed to do) and still keep your .5ft^3 net volume that you'd be after.

Basically, with a smaller box you're going to need a longer port. And using a smaller volume while trying to tune any lower than 35hz with aeros is going to require you to make them a custom length, which adds to the cost as well. It would be much easier to use an aeroport on a lower power, more efficient setup that utilizes a larger than normal box volume. That way you could rely on a shorter port length and not have to worry as much about internal clearances.

 

[Hintzyboy 5,000+ posts]

I haz swappable slot ports.....

Pics? Obviously that's possible, but it sounds like quite a bit of extra work to do, and I can't picture how you would do it if you had a smaller box (i.e. for a large box you can have shorter lengths, so you don't have to worry about bends in the port).

 

[subzero 5,000+ posts]

Pics? Obviously that's possible, but it sounds like quite a bit of extra work to do, and I can't picture how you would do it if you had a smaller box (i.e. for a large box you can have shorter lengths, so you don't have to worry about bends in the port).

have to find one or take one and post it. Common idea is to build for the highest tunning say for burp boxes, and build port inserts for lower tunnings. Moble and Ram designed some for me that worked out well.

 

[Hintzyboy 5,000+ posts]

I have to disagree completely on the ease of use with smaller volume boxes. With a .5ft^3 box tuned to 35hz, a 3" aero is going to need to be 30" long. Have fun buying elbows and more PVC to fit that inside a box or you can have an ugly external aero hanging out of the box, taking up a lot of space. With a slot, you can easily follow the outside of the box and get the port length needed. Also, using a 3" aero that has a ~4.5" diameter flare is going to require a decent sized box just to make sure you have enough clearance with the port/sub being so close. With that 30" custom aero, it's doubtful you can even fit it inside a box(depending on the sub/port orientation that you needed to do) and still keep your .5ft^3 net volume that you'd be after.
Basically, with a smaller box you're going to need a longer port. And using a smaller volume while trying to tune any lower than 35hz with aeros is going to require you to make them a custom length, which adds to the cost as well. It would be much easier to use an aeroport on a lower power, more efficient setup that utilizes a larger than normal box volume. That way you could rely on a shorter port length and not have to worry as much about internal clearances.

Fair enough. I was just throwing numbers out there. And it really depends on what kind of vehicle it's going in. For example, my Mazda3 hatch allows for a 41" wide enclosure. If I go with an enclosure that's 38w x 9t x 6d, I get ~.56 cubes and I need a 25.6" aero for 35hz. I lose 6" of cargo space, which I can deal with, and I don't have to worry about any bends in the port. Or I could have a 7.5 x 1.5 slot port, which would require more than 40" of port length, would require bends in the port, and would take away more cargo space.

 

[Hintzyboy 5,000+ posts]

have to find one or take one and post it. Common idea is to build for the highest tunning say for burp boxes, and build port inserts for lower tunnings. Moble and Ram designed some for me that worked out well.

Gotcha. Like I said, makes more sense for larger systems. If you're dealing with a smaller enclosure in a daily driver, it becomes less practical.

 

[Bettr n' Revrse 5,000+ posts]

I preffer aeros as well...

 

[knotdrummer88 10+ year member]

which part?

large port area vs small volume

 

[THATpurpleKUSH 5,000+ posts]

large port area vs small volume

Go look up the necessary length for a 4inch aero coupled to .75 cu/ft to give tuning of 33hz. You will need 39 1/2 inches of length. Yes there are some people that can make that work, but for the majority of people out there, that is just not feasible. Say you want even better low end extension and want a 30hz tune, the required port length just went up to 48 1/4 inches. Do you get it now?

By comparison the 4cu/ft box with a 6in pvc port that I'm running now has a 14.5 inch long port that yields a tune of 31.75hz.

 

[knotdrummer88 10+ year member]

Go look up the necessary length for a 4inch aero coupled to .75 cu/ft to give tuning of 33hz. You will need 39 1/2 inches of length. Yes there are some people that can make that work, but for the majority of people out there, that is just not feasible. Say you want even better low end extension and want a 30hz tune, the required port length just went up to 48 1/4 inches. Do you get it now?
By comparison the 4cu/ft box with a 6in pvc port that I'm running now has a 14.5 inch long port that yields a tune of 31.75hz.

Hm. I think i know what your saying, but I don't quit understand why that happens. If that makes any sense, or maybe I just don't get it at all..hmm...

 

[Falcons 5,000+ posts]

I'm building a box right now just to see how te aeros will work. I'm using an 8" sonotube resined on the inside in a 4 cf box. It is going to be half internal half external. I'll be testing on 600 watts on Wednesday. I'll report back which I like more.

 

[THATpurpleKUSH 5,000+ posts]

Hm. I think i know what your saying, but I don't quit understand why that happens. If that makes any sense, or maybe I just don't get it at all..hmm...

Its very simple, the more port area per cu/ft the longer the port needs to be. A 4in round port has 12.56 sq in of area, now divide that by the volume of the box, .75 and you have 16.74666 square inches of port per 1 cubic foot of air displacement. Now compare it to the other box with a 6inch port, or 28.274 sq inches of port area with 4 cu/ft of box volume and you have 7.068 sq/inches of port area per 1 cubic ft of airspace.

Now back to the slot vs aero comparison- just google why pipes are round and not other shapes, it is because they flow the most efficient under PRESSURE.

 

[knotdrummer88 10+ year member]

Its very simple, the more port area per cu/ft the longer the port needs to be. A 4in round port has 12.56 sq in of area, now divide that by the volume of the box, .75 and you have 16.74666 square inches of port per 1 cubic foot of air displacement. Now compare it to the other box with a 6inch port, or 28.274 sq inches of port area with 4 cu/ft of box volume and you have 7.068 sq/inches of port area per 1 cubic ft of airspace.
Now back to the slot vs aero comparison- just google why pipes are round and not other shapes, it is because they flow the most efficient under PRESSURE.

ahhh. ok. hm....maybe I should look into some aeros or what about kerfed ports? I mean, is thats still better than just a regular slot port right? in terms of least resistance to air flow?

 

[THATpurpleKUSH 5,000+ posts]

I'm building a box right now just to see how te aeros will work. I'm using an 8" sonotube resined on the inside in a 4 cf box. It is going to be half internal half external. I'll be testing on 600 watts on Wednesday. I'll report back which I like more.

You aren't using an aero, you are using a plain round port. True aero ports have flared mouths.