Aero Ported VS Slot Ported
03-02-2005, 07:54 PM
#1
4000 Watt CAFz'r
Thread Starter
Join Date: May 2003
Posts: 4,655
Aero Ported VS Slot Ported
Someone was telling me the other day that each of these 2 types of boxes were specifically for SQ - SPL
for example Aero (forgive me if im wrong i cant remember off the top of my head the name of it if thats not it) ports are for SPL and slot ports are for SQ.
Which is better for SQ, which is better for SPL? I'm a fan of slot ports personally however I didn't think there was a specific type of port for SQ & SPL [img]graemlins/dunno.gif[/img]
for example Aero (forgive me if im wrong i cant remember off the top of my head the name of it if thats not it) ports are for SPL and slot ports are for SQ.
Which is better for SQ, which is better for SPL? I'm a fan of slot ports personally however I didn't think there was a specific type of port for SQ & SPL [img]graemlins/dunno.gif[/img]
03-02-2005, 08:12 PM
#2
I dont think it matters, but I know Aeroports have it wrote in big letters across the box "INCREASE SPL". Due to an aeroports flares on each end you do get a lot less turbulence, resulting in less or no port noise. This makes them good for SQ aswell as SPL.
I prefer Aeroports. [img]tongue.gif[/img]
I prefer Aeroports. [img]tongue.gif[/img]
03-02-2005, 09:17 PM
#3
Guest
Posts: n/a
For a given cross sectional vent area, an Aeroport will have lower vent noise and slightly more output due to the flare than either a conventional round port or a slot vent of the same area.
Conversely, it is usually easier to get more net vent cross sectional area in a box by using a slot vent and yes if you round the corners with a router it helps with vent noise. You would need a 2" radius roundover to get the same effect as an aeroport though.
Conversely, it is usually easier to get more net vent cross sectional area in a box by using a slot vent and yes if you round the corners with a router it helps with vent noise. You would need a 2" radius roundover to get the same effect as an aeroport though.
03-03-2005, 02:18 PM
#7
50 Watt CAFz'r
Join Date: Jan 2004
Posts: 206
hold on guys..........
The cross sectional area of the port will make the port make noise, and is directional related to drivers displacement ability
To small and what happens is the velocity of the air going in and out of the port ends up being faster than speed of sound in un resticted air and you will get noise. The driver is forcing air out of the port faster than the port can handle without making it self into a compressor.
Do this example:
Take an empty bottle (like a beer bottle) and blow across the lip. You'll get a noise.
Now blow in free air.....no noise.
Now take a large container (like a bucket) and blow across the lip.....no noise.
So whats the solution. I'll just make a large cross sectional vent so air can flow freely in and out of the port.....hold on again
A vent that is to large will produce pipe resonance which is when the vent resonates and starts making some nasty noises. To get around this you need to start making the port smaller in cross sectional size in order to push the resonance freq higher and out of the sub boxes freq range (what range you play it). But be carefull because you'll end up back at #1 when you get to small
So it is a balance of the right size for the driver. For a SQ application any additional information placed into the music results in poor reproduction. Very un-wanted
For SPL guys they may not care, because that noise may help them out. Plus for the driver to reach its xmax without going crazy on power (ie more efficency) they need as little resistance on the the air moving in and out of the port as possible. So thats why you will see massive ports in the really loud SPL vehicles. They really dont care about more noise.......and I guess they encurage the system to make as much noise as possible.If they can match the resonant freq of the port to the note that the speakers are playing thier spl will increase....but thats a hard balance to get rigth......ie alot of work
A side note. You will notice some SPL guys never blow drivers. Other go through them like every run. Thats because they are trying to put more power into the driver to achive xmax, they are having a hard time because of restrictions of thier enclosure (among other things...lol) It does not take crazy power to achive xmax in free air, this is what the SPL'rs that don't blow drivers have achived....very little resistance from thier enclosure. Thus less power to achive Xmax and more SPL.
For an optimally designed port you can not use an off the shelf port. It will work, but not optimaly.
Rounding out the ends can help....but if the port is to small it won't matter.
Take a look a the lip of that beer bottle....its rounded over also.
[ March 03, 2005, 03:26 PM: Message edited by: Impala Builder ]
The cross sectional area of the port will make the port make noise, and is directional related to drivers displacement ability
To small and what happens is the velocity of the air going in and out of the port ends up being faster than speed of sound in un resticted air and you will get noise. The driver is forcing air out of the port faster than the port can handle without making it self into a compressor.
Do this example:
Take an empty bottle (like a beer bottle) and blow across the lip. You'll get a noise.
Now blow in free air.....no noise.
Now take a large container (like a bucket) and blow across the lip.....no noise.
So whats the solution. I'll just make a large cross sectional vent so air can flow freely in and out of the port.....hold on again
A vent that is to large will produce pipe resonance which is when the vent resonates and starts making some nasty noises. To get around this you need to start making the port smaller in cross sectional size in order to push the resonance freq higher and out of the sub boxes freq range (what range you play it). But be carefull because you'll end up back at #1 when you get to small
So it is a balance of the right size for the driver. For a SQ application any additional information placed into the music results in poor reproduction. Very un-wanted
For SPL guys they may not care, because that noise may help them out. Plus for the driver to reach its xmax without going crazy on power (ie more efficency) they need as little resistance on the the air moving in and out of the port as possible. So thats why you will see massive ports in the really loud SPL vehicles. They really dont care about more noise.......and I guess they encurage the system to make as much noise as possible.If they can match the resonant freq of the port to the note that the speakers are playing thier spl will increase....but thats a hard balance to get rigth......ie alot of work
A side note. You will notice some SPL guys never blow drivers. Other go through them like every run. Thats because they are trying to put more power into the driver to achive xmax, they are having a hard time because of restrictions of thier enclosure (among other things...lol) It does not take crazy power to achive xmax in free air, this is what the SPL'rs that don't blow drivers have achived....very little resistance from thier enclosure. Thus less power to achive Xmax and more SPL.
For an optimally designed port you can not use an off the shelf port. It will work, but not optimaly.
Rounding out the ends can help....but if the port is to small it won't matter.
Take a look a the lip of that beer bottle....its rounded over also.
[ March 03, 2005, 03:26 PM: Message edited by: Impala Builder ]
03-03-2005, 04:05 PM
#8
Guest
Posts: n/a
All I could add to that is there is a between 'acceptable' vent velocity and 'organ piping' and that while say a 4" vent may not be the ideal size for a given box/woofer that it will do an excellent job and not be overwhelming to implement.
I strive to keep velocities under 9% and really try to hit 5% but I also try to never exceed about 20" in vent length. If I cannot work within these parameters then there is a problem.
I strive to keep velocities under 9% and really try to hit 5% but I also try to never exceed about 20" in vent length. If I cannot work within these parameters then there is a problem.
