@@superpossum78 So your saying from 140db it will take 150db for a human to notice a volume difference? This is totally false. 140db to even 144db is a huge difference in pressure levels you can feel and hear a major difference in sound very easily.
Anybody can feel a 3-4 decibels difference if they are paying attention It might be harder for you to know the difference in a car that somebody just invested money in a box and an amp and some speakers vs. A competition build where the vehicle is gutted and sound deaded and and soundproofing if those two things are if those things are done correctly you would be amazed by the difference I gained almost 24db (23.8db). And that's rather impressive when you consider you can't gain anything on your windows.
@@charlesdeadman-ye7uu I'm sure that's true I'm talking about what we perceive to be twice not what we perceive to be more, when I hook up a second speaker to my amp I gain 3 decibels or more increase, I can hear it being louder but the car doesn't shake "twice" as hard...
If you can fit a large box like that with an aero port, it could help those guys who do not have massive amounts of power due to vehicle electrical restrictions, so this would scratch that itch for bass on lower power applications. Nice work man, thanks for the video.
Nice test! I agree on the size selection sucking for aeros. I 3d printed mine when seeing how much spl i could get from my DB 10" in the daily. Ended up with a 5" aero that metered 138 on music. Was pretty stoked with it
Probably the best comparison video on entire youtube But man, you are the only one that can help us with one video of testing 2 subs lower power VS 1 sub the same power (ex: 2x 1000w VS 1x2000w , same size) that will be a great test
I've had similar results for a 10" sub in about 1.5 cubes tuned to 34Hz. The 4" aero got a lot louder and can push more air but the slot port sounded a lot better.
Try round ports flared vs no flare next. Also the location of the port in relation to the sub matters thats why I almost always do external ports. My philosophy has always been to use the proper amount of port area regardless of the shape though. Also an easy way to determine what port should work best is to calculate its reynolds number for it sure this isnt really a flow and more of an oscillating mass of air but still it applies.
Id love to see a comaprison of watts vs watts to show the DB's for the whole frequency range. This will show what box is more efficient accross the frequency band. One box might be a little louder but is it putting more strain on the amp to get that output vs the other box?
Port compression at its finest. More port area gives more output up to a point until it becomes free air. Aero sounded boomy because it’s not being compressed to a smother response and is therefore peaky at one frequency. The slot port compressed and lowers peak output to smooth response. A higher order box would allow you to two or three peak to smooth response but takes infinitely more box volume to do.
@7Little701 True. Too large and the power handling is greatly reduced. I have an RE AUDIO SE X15 that I am thinking of building a box just to have some fun, but the ported box is quite large. I have considered a sealed box, although it has been a long time since I had a sealed box. Only a 750-watt subwoofer as it is, so I'm trying to be careful with what I do with it.
@7Little701 There are some interesting videos both for and against poly fill. I have always done it, but there are some pretty compelling videos on using it to change the perceived airspace of an enclosure.
I've always wanted to see the difference between aero and slot, to be honest I've tried a slot port box once but still prefer flared ports.I think that a 4 inch aero port would have played better with a single sub.
Thank you so much for the video , i was planning to make my own first subwoofer box and I didn't know which port is better , thank you so much for the video , i appreciate it ❤️🙏
Can you make a video of a regular round pvc 6” tube vs a 6” aeroport in the same tuning and airspace? Curious to see if there’s any db gain and how much.
I have an aero. The width of the box is a borderline issue, but sounds great. It works with a pair of 8s, but looking to get larger cones. A slot is my only option unless I just get a very efficient single 12”
Just get a fat 15”, 6” Aero. You’ll be covered for days. And you can always port out the top or side. (Personally I prefer same face mounting… but I also run my shit cab firing…)
Thank you. Yea I don’t try to max out subs and test for highway SPL numbers. I try and do overall performance of subwoofers and try to let viewers how they sound to help people make a buying decision.
You're aware enclosure dimension (height width depth) is also a factor in ported enclosures. A ported enclosure is not like a sealed enclosure, where shape and dimension is irrelevant. Also clear acrylic should be avoided but should be the same thickness as the surrounding wood baffle.
Not a lot of difference if playing music volumewise and seems like a tradeoff between your goals. That aeroport is using a decent amount more space for 2-4db gain where that slot port box could probably take enough extra power to outdo what the aeroport can handle at its power limits. Probably a size vs power issue.
@@HiFiVectorhow far off has it been for you? And in how many instances? Seems like a good, overall ballpark, but that ballpark, is like wrigley field being it’s own continent.
Ive been trying a few combos on my CT sounds Meso 12. They call for 40 square inches, i have a bout 24 (slot) now and it Slams but trying to get 40 seems impossible in the 1.5 cubic foot box they recommend. I use sub box pro and winisd 40 inches seems ridiculous to me.
A lot of the factory recommended box specs are way off I my opinion. 24sq “ area in a 1.5 net box is a lot of area for that size box and should be more than enough. But….. that subs needs 2 to 2.5 cuft ft . 1.5 is waaay to small for that 12. I think those specs bare a typo.
I wish i understood how to calculate a port. I built a 5.36cf box in the shave of an L to fit my 65 cutlass for a dd9515 but im having a hard time figuring out the size and length aero port i need.
@@HiFiVector net would be right under 5. And yes im looking try a aero port this time around. So think 36-40 on the tune should work fine in a old muscle car.
Ok do you want to use a 6” aero port or 3 4” ports ? If you use a 6” precision port brand then you will cut the center tube to 2.5” long. When you connect the flares it will be 8.5” total length. Or you can use (3) 4” ports on the precision port brand cut center tube to 7” and when you put the flares on total length of each 4” port with the flares on will be 13”. Here are links to the ports. www.amazon.com/dp/B001001KIA/ref=cm_sw_r_as_gl_api_gl_i_A51K590C0R2G734XC3WY?linkCode=ml2&tag=hifivector-20 www.amazon.com/dp/B0002ZPR56/ref=cm_sw_r_as_gl_api_gl_i_K8VGTC58Z6YFFKHV8HA2?linkCode=ml2&tag=hifivector-20
The length of a port dictates tuning frequency only. The area of the port is what you are thinking about and the area needed has a lot of variables depending on box size, what type of sound you are going for (SQ or SPL) and subwoofer specifications.
Wonder what the 5" would be like... Also wonder if the 6" was talking more power than the slot. You should try to get powet # next time... Thats would explain allot.
Damn..... I'm sitting here with a 4.94 cf box and two six inch aero ports trying to figure out how much volume the ports are gonna take away from my box so I can tune it to 30hz I mean is it six cubic inches per inch? hell if I know I've always built slot ports but I wanna try a aero port with this new hooligan X
inn part 1: Slot port did 113.12 @ 20hz , 128.6 @ 30hz and 136.5 @ 40hz inn part 2: slot port did 118.4 @ 20hz , 129.85 @ 30hz and 136.86 @ 40hz I do belive all tests in vid 1 was done on same volume, and you used a different volum in vid 2? Stil got a 136 @ 40 hz in but a almost 5 DB up on 20Hz. And 6" over 4" +9 @20hz, +7.6 @30hz and +3.3@40hz sound quality apart, consistent testing?
It was not the intention to compare part one verse part two videos as they were done on different days, so the volume and SPL levels will be different than the part one video. but that wasn’t the point of the video the point of this video was to compare at the same slot port box with now a larger aero port box and see the differences. So you cannot exactly compare part one verse part two as far as SPL level goes. Compare the differences of the boxes in each video.
These are great compares.....i always try and build to spec....on that driver 22" is what is recommended so you cant get a round port with that area. seems like a 5" aero port is the answer...but then you run into length problems.....gets pricey to turn those things with adapters.....slot port is the same wood you built the box with.
Is that a special app you have? decibel meter I didn't know you could get an app that would read that loud I haven't found anything for less than $700 that'll go over 112 and let's be honest that's nothing
hey man, all new to this, i had single db sa272 but not sure what enclosure to build. aero or slot? considering i have stock alternator/battery and has two 400rms subs (each) now jumped to 1500rms single. usually listen to rap and no decaf songs only original ones. wanted an all rounder enclosure with good lows and highs
The power acoustik brand caliber sub? If so you can use 4” if you are not over powering it. If you are overpowering it go 3” . That woofer doesn’t have a lot of excursion so the 3” would help with power handing and make bass tighter or you can go 4” which would be not as tight bass but be a little louder with slightly less power handling.
@@HiFiVector ah ok but what if you do a curved slot port where the end of the port turns into a horn wouldn’t that in theory increase the volume on the slot port and keep its efficiency at the same time since it’s only the volume of air at the end of the port that actually moves ? (Edit) kerfed
honestly the correct aero port would be abou a 5.25" aero port would be equal to that slot port....i know you cant buy that size anywhere so you need a cnc machine to make it out of wood which i have done numerous times.....
Kind of a false comparision...a 6" aero port is 28 square inches versus your 22 slot port....and aero ports are way more efficient so that 6" is equal to around 36" inches of port.
You missed the whole point of the video. Part 1 had a 4” aero and parts 2 a 6”. Point was to go more are and less area on the Aeros to see what happens compared the a slot. People have said because Aeros are SO much more efficient you can reduce port area by as much as 60% so the whole point was to just see if that’s the case or not. That’s why in part 1. I used a 4” which is less actual port area than the slot. And in part2, video jumped to a 6” aero to see what happened. It was never meant to be a “fair” or equal port area test. Because if aero are more efficient you can not go equal…. Equal will not be equal since aero is more efficient. So if that’s the case for it to be equal you would need to know how much exactly can you undersize and aero to equal a slots area.
@@HiFiVector I thought you were doing a direct compare using a slot and aero....when you described the sound of the slot being louder and sounding better It seemed like a false comparison going from 22" to 12.5" in port area...if you used a slightly bigger aero it would have been a better apple to apples comparison. but I fully understand that you can't go to Home Depot and get a 4.5" aero...I make mine on a CNC machine....maybe I'll do the comparison...great videos BTW. I new the 6" would be muddy as that is way to much port for that driver. Im building a box right now for 4 DD Audio 1506 subwoofers and DD calls for 32" of port area which just feels to big to me although thats a slot port. At 2.0 cubic feet of airspace that 16" per cube for 6.5" subwoofers....In fairness these are pretty beefy but im going with 28" of port area and see what happens. I know it will sound good for sure and chuffing should not be an issue with 2500 watts of B2 Audio Rage power.
on the logarithmic DB scale every 3 DB more is technically double the volume! So 4 db is a huge gain! Especially in the SPL world.
On a human perceptual level it takes 10 to 12 decibels to achieve a doubling of volume
@@superpossum78 So your saying from 140db it will take 150db for a human to notice a volume difference? This is totally false. 140db to even 144db is a huge difference in pressure levels you can feel and hear a major difference in sound very easily.
@@turblown not saying it takes that much to notice a difference saying it takes that much to go wow that's double the loudness
Anybody can feel a 3-4 decibels difference if they are paying attention
It might be harder for you to know the difference in a car that somebody just invested money in a box and an amp and some speakers vs. A competition build where the vehicle is gutted and sound deaded and and soundproofing if those two things are if those things are done correctly you would be amazed by the difference
I gained almost 24db (23.8db). And that's rather impressive when you consider you can't gain anything on your windows.
@@charlesdeadman-ye7uu I'm sure that's true I'm talking about what we perceive to be twice not what we perceive to be more, when I hook up a second speaker to my amp I gain 3 decibels or more increase, I can hear it being louder but the car doesn't shake "twice" as hard...
If you can fit a large box like that with an aero port, it could help those guys who do not have massive amounts of power due to vehicle electrical restrictions, so this would scratch that itch for bass on lower power applications. Nice work man, thanks for the video.
Nice test! I agree on the size selection sucking for aeros. I 3d printed mine when seeing how much spl i could get from my DB 10" in the daily. Ended up with a 5" aero that metered 138 on music. Was pretty stoked with it
Very cool I do a lot of car audio related 3d printing.
Probably the best comparison video on entire youtube
But man, you are the only one that can help us with one video of testing 2 subs lower power VS 1 sub the same power (ex: 2x 1000w VS 1x2000w , same size)
that will be a great test
I've had similar results for a 10" sub in about 1.5 cubes tuned to 34Hz. The 4" aero got a lot louder and can push more air but the slot port sounded a lot better.
Try round ports flared vs no flare next.
Also the location of the port in relation to the sub matters thats why I almost always do external ports.
My philosophy has always been to use the proper amount of port area regardless of the shape though. Also an easy way to determine what port should work best is to calculate its reynolds number for it sure this isnt really a flow and more of an oscillating mass of air but still it applies.
Best comparison video i ve seen. Thank you for sharing and spending time for these tests. I am a aeroport guy, i m building my own aeroports.
Thanks so much it was a fun test
Can you do a watt comparison how many watts takes to do certain spl number on both boxes
Id love to see a comaprison of watts vs watts to show the DB's for the whole frequency range. This will show what box is more efficient accross the frequency band. One box might be a little louder but is it putting more strain on the amp to get that output vs the other box?
Holy crap that's a huge aeroport
Port compression at its finest. More port area gives more output up to a point until it becomes free air. Aero sounded boomy because it’s not being compressed to a smother response and is therefore peaky at one frequency. The slot port compressed and lowers peak output to smooth response. A higher order box would allow you to two or three peak to smooth response but takes infinitely more box volume to do.
exactly, and port being louder due more cone travel on same gain. It is like always a compromise.
Those are incredible gains with the aero port.
Nice comparison. I've been pondering lately on going back to sealed.
Ty sir for sharing 👍🤞
Any time!
Hey friend. I am just curious why you are considering going to sealed. I know the general reasons for every box order, but yours personally
@7Little701
True. Too large and the power handling is greatly reduced. I have an RE AUDIO SE X15 that I am thinking of building a box just to have some fun, but the ported box is quite large. I have considered a sealed box, although it has been a long time since I had a sealed box. Only a 750-watt subwoofer as it is, so I'm trying to be careful with what I do with it.
@7Little701
There are some interesting videos both for and against poly fill. I have always done it, but there are some pretty compelling videos on using it to change the perceived airspace of an enclosure.
Thank you brother you answered ALL of my questions in one video
Appreciate the feedback!
Thank you for all the effort put into the video
Glad you enjoyed it! Thanks so much!
I've always wanted to see the difference between aero and slot, to be honest I've tried a slot port box once but still prefer flared ports.I think that a 4 inch aero port would have played better with a single sub.
Thank you for being so detailed.
Thank you!
Awesome, part 2 went as planned
Sounded like the slot ported sub bounced the voice coil off the back plate at the beginning of the 20 hertz tone. Nice pair of videos.
Thank you so much for the video , i was planning to make my own first subwoofer box and I didn't know which port is better , thank you so much for the video , i appreciate it ❤️🙏
Glad I could help
Would box placement make a difference? Looks like the aero port loads off the rear corner vs the slot port in the middle.
Can you make a video of a regular round pvc 6” tube vs a 6” aeroport in the same tuning and airspace? Curious to see if there’s any db gain and how much.
Can’t promise anything but I’ll keep it in mind. Thanks for the suggestion!
I once was poor with a single 10" in my camaro and used a Pringles can as my port, in a 1.5ft3 box
I have an aero. The width of the box is a borderline issue, but sounds great.
It works with a pair of 8s, but looking to get larger cones. A slot is my only option unless I just get a very efficient single 12”
Just get a fat 15”, 6” Aero. You’ll be covered for days. And you can always port out the top or side. (Personally I prefer same face mounting… but I also run my shit cab firing…)
@@APinTheAK I wish… A ported 15 would need 4-5 cubes. I have a sedan.
Thank you! noone ever talks about quality
Thank you. Yea I don’t try to max out subs and test for highway SPL numbers. I try and do overall performance of subwoofers and try to let viewers how they sound to help people make a buying decision.
Getting ready to build a box for 3 15 American bass elites to go in an extended cab pickup i e debated slot or aero port for a while
Honestly, they can both be good. It just depends on how you build them.
You're aware enclosure dimension (height width depth) is also a factor in ported enclosures. A ported enclosure is not like a sealed enclosure, where shape and dimension is irrelevant.
Also clear acrylic should be avoided but should be the same thickness as the surrounding wood baffle.
I'm glad I started following your channel great content 👍
Thank you so much inappropriate the sub!
Not a lot of difference if playing music volumewise and seems like a tradeoff between your goals. That aeroport is using a decent amount more space for 2-4db gain where that slot port box could probably take enough extra power to outdo what the aeroport can handle at its power limits. Probably a size vs power issue.
great point murray!
great video, thanks for the hard work!
Much appreciated!
What is your take on the accuracy of the triticum port calculator?
Not a fan… there is a lot more information required to calculate the correct port area.
@@HiFiVectorhow far off has it been for you? And in how many instances? Seems like a good, overall ballpark, but that ballpark, is like wrigley field being it’s own continent.
Ive been trying a few combos on my CT sounds Meso 12. They call for 40 square inches, i have a bout 24 (slot) now and it Slams but trying to get 40 seems impossible in the 1.5 cubic foot box they recommend. I use sub box pro and winisd 40 inches seems ridiculous to me.
A lot of the factory recommended box specs are way off I my opinion. 24sq “ area in a 1.5 net box is a lot of area for that size box and should be more than enough. But….. that subs needs 2 to 2.5 cuft ft . 1.5 is waaay to small for that 12. I think those specs bare a typo.
@@HiFiVector I may have to try that 2.5 and see what she does.
You can make a arrow ports out off pvc pip pipe that come in multiple sizes 1/2=8 inch to flare the end use a heat gun . 😊
Cool! I'm thinking about doing that!
Large arrow port bandpass is louder
I wish i understood how to calculate a port. I built a 5.36cf box in the shave of an L to fit my 65 cutlass for a dd9515 but im having a hard time figuring out the size and length aero port i need.
Is that the “net” volume of your box? And you want to use an aero port correct? What do you want it tuned to?
@@HiFiVector net would be right under 5. And yes im looking try a aero port this time around. So think 36-40 on the tune should work fine in a old muscle car.
Ok do you want to use a 6” aero port or 3 4” ports ? If you use a 6” precision port brand then you will cut the center tube to 2.5” long. When you connect the flares it will be 8.5” total length. Or you can use (3) 4” ports on the precision port brand cut center tube to 7” and when you put the flares on total length of each 4” port with the flares on will be 13”. Here are links to the ports.
www.amazon.com/dp/B001001KIA/ref=cm_sw_r_as_gl_api_gl_i_A51K590C0R2G734XC3WY?linkCode=ml2&tag=hifivector-20
www.amazon.com/dp/B0002ZPR56/ref=cm_sw_r_as_gl_api_gl_i_K8VGTC58Z6YFFKHV8HA2?linkCode=ml2&tag=hifivector-20
Nice the 6" arrow port is louder.
It would be nice too if you could cover how long a port needs to be to not unload vs the xmax of the sub used. Is it 4:1 ?
The length of a port dictates tuning frequency only. The area of the port is what you are thinking about and the area needed has a lot of variables depending on box size, what type of sound you are going for (SQ or SPL) and subwoofer specifications.
Wonder what the 5" would be like... Also wonder if the 6" was talking more power than the slot. You should try to get powet # next time... Thats would explain allot.
Damn..... I'm sitting here with a 4.94 cf box and two six inch aero ports trying to figure out how much volume the ports are gonna take away from my box so I can tune it to 30hz I mean is it six cubic inches per inch? hell if I know I've always built slot ports but I wanna try a aero port with this new hooligan X
Can you post link to where you bought the port at? Thx!
Sure here is the port amzn.to/3qIBn16
@@HiFiVectorwhat's the length?
inn part 1: Slot port did 113.12 @ 20hz , 128.6 @ 30hz and 136.5 @ 40hz
inn part 2: slot port did 118.4 @ 20hz , 129.85 @ 30hz and 136.86 @ 40hz
I do belive all tests in vid 1 was done on same volume, and you used a different volum in vid 2?
Stil got a 136 @ 40 hz in but a almost 5 DB up on 20Hz.
And 6" over 4" +9 @20hz, +7.6 @30hz and +3.3@40hz
sound quality apart, consistent testing?
It was not the intention to compare part one verse part two videos as they were done on different days, so the volume and SPL levels will be different than the part one video. but that wasn’t the point of the video the point of this video was to compare at the same slot port box with now a larger aero port box and see the differences. So you cannot exactly compare part one verse part two as far as SPL level goes. Compare the differences of the boxes in each video.
what wood did you make the slot port box out of???
Birch
Where can I get a 15inch aero port? having trouble finding a good enclosure for a VXF
You can use a 6” aero port for a vxf 15. Here is a link.
amzn.to/3MSlVY9
These are great compares.....i always try and build to spec....on that driver 22" is what is recommended so you cant get a round port with that area. seems like a 5" aero port is the answer...but then you run into length problems.....gets pricey to turn those things with adapters.....slot port is the same wood you built the box with.
Try the Resilient Sounds gold v2 on these boxes I’d like to see if it changes with the different subwoofer
in your preference which sounds better a slot or aeroport?
Honestly so many variables and also depends on the sub. But I lean towards slot ports
Is that a special app you have? decibel meter I didn't know you could get an app that would read that loud I haven't found anything for less than $700 that'll go over 112 and let's be honest that's nothing
It’s a meter that displays from an app there is a link in the video description if you want to check it out but they’re around $400
hey man, all new to this, i had single db sa272 but not sure what enclosure to build. aero or slot? considering i have stock alternator/battery and has two 400rms subs (each) now jumped to 1500rms single. usually listen to rap and no decaf songs only original ones. wanted an all rounder enclosure with good lows and highs
For a single SA272 sub 2cuft net, 25 to 32 sq inches of port area and 34 to 36 hz would be good.
@@HiFiVector slot port or aero?
Slot, if you went aero then 4” aero port. I tend to prefer slot.
@@HiFiVector what are your reasons for preferring slot bro? i have seen people going for aero with SPL subs
@@HiFiVector also bro i have seen people using dampening sheets or foam inside the enclosures, how does that effect?
Put a Sundown X in the aero port box
Hi brother., I have 1600 watts CALIBAR woofer double magnet.for my woofer box how big Aero port i have put to get good bass
The power acoustik brand caliber sub? If so you can use 4” if you are not over powering it. If you are overpowering it go 3” . That woofer doesn’t have a lot of excursion so the 3” would help with power handing and make bass tighter or you can go 4” which would be not as tight bass but be a little louder with slightly less power handling.
CAN YOU TRY PASSIVE RADIATOR SUBWOOFER VS PORTED VS SEALED VS 4TH ORDER VS 6TH ORDER 😱😱😱
👍
I’m looking at doing 2 skar vxf-12 with a 6 inch aero port would that work good or should I use smaller or bigger port size I’m tuning box to 33 hz
6” aero will be good for 2 vxf 12’s
Slot port sounds deeper
👍👍👍💯...
I don’t understand how does a hanky prove which is better
It doesn’t it just help people watching the video show how much air each is moving since otherwise view would have no idea.
@@HiFiVector ah ok but what if you do a curved slot port where the end of the port turns into a horn wouldn’t that in theory increase the volume on the slot port and keep its efficiency at the same time since it’s only the volume of air at the end of the port that actually moves ? (Edit) kerfed
Alot of slots gonna be mad..
👍👀👍
They have bigger aero ports then a 6 inch
GO SEALED
big ass ports makes 6 inch, 8 inch and 10 inch ports that can be custom tuned so there are bigger sizes than 3 4 and 6 inch aero ports
honestly the correct aero port would be abou a 5.25" aero port would be equal to that slot port....i know you cant buy that size anywhere so you need a cnc machine to make it out of wood which i have done numerous times.....
Kind of a false comparision...a 6" aero port is 28 square inches versus your 22 slot port....and aero ports are way more efficient so that 6" is equal to around 36" inches of port.
You missed the whole point of the video. Part 1 had a 4” aero and parts 2 a 6”. Point was to go more are and less area on the Aeros to see what happens compared the a slot. People have said because Aeros are SO much more efficient you can reduce port area by as much as 60% so the whole point was to just see if that’s the case or not. That’s why in part 1. I used a 4” which is less actual port area than the slot. And in part2, video jumped to a 6” aero to see what happened. It was never meant to be a “fair” or equal port area test. Because if aero are more efficient you can not go equal…. Equal will not be equal since aero is more efficient. So if that’s the case for it to be equal you would need to know how much exactly can you undersize and aero to equal a slots area.
@@HiFiVector I thought you were doing a direct compare using a slot and aero....when you described the sound of the slot being louder and sounding better It seemed like a false comparison going from 22" to 12.5" in port area...if you used a slightly bigger aero it would have been a better apple to apples comparison. but I fully understand that you can't go to Home Depot and get a 4.5" aero...I make mine on a CNC machine....maybe I'll do the comparison...great videos BTW. I new the 6" would be muddy as that is way to much port for that driver. Im building a box right now for 4 DD Audio 1506 subwoofers and DD calls for 32" of port area which just feels to big to me although thats a slot port. At 2.0 cubic feet of airspace that 16" per cube for 6.5" subwoofers....In fairness these are pretty beefy but im going with 28" of port area and see what happens. I know it will sound good for sure and chuffing should not be an issue with 2500 watts of B2 Audio Rage power.