In WinISD, the ABC enclosure (basically 6th order bandpass) I have designed has insanely high air velocities in the port. Well above 20 m/s , while I believe the recomended is <17?
Anyways, to get it right and under control, I have my rear chamber using a slot port, my front chamber using an aero port, and the intrachamber using an aero port. Switching any of those increases the air velocities way too high, not sure why slot reduces in one chamber, while raising in other.
I can't come up with any reason why I couldn't use both styles of ports, as they each offer benefits.
My question is:
Is port length and port area calculated the same? In ABC's, all three ports have to be exactly the same size (or tuned the same, i'm not sure if there is a difference), so is one square inch of slot port worth one square inch of aero port?
Anyways, to get it right and under control, I have my rear chamber using a slot port, my front chamber using an aero port, and the intrachamber using an aero port. Switching any of those increases the air velocities way too high, not sure why slot reduces in one chamber, while raising in other.
I can't come up with any reason why I couldn't use both styles of ports, as they each offer benefits.
My question is:
Is port length and port area calculated the same? In ABC's, all three ports have to be exactly the same size (or tuned the same, i'm not sure if there is a difference), so is one square inch of slot port worth one square inch of aero port?
What is aero port? I did a quick search and it seems that it might be a brand name for a regular heavily flared port. If so you should use those whenever possible, but they are very expensive and you can make your own heavily flared ports from heated abs.
I'm not sure why all three ports would have to be the same size, you simulate until you get a good result and then you use whatever length and diameter you end up with in the sim.
Some people recommend 17 m/s as a good balance between port size and velocity issues, some people are happy with much higher velocity than that, but a lot of people are much more conservative and recommend under 10 m/s. Ports introduce losses into the system unless they are very large, even at 10 m/s there are losses, and as velocity gets higher the losses increase as velocity turns into turbulence, distortion and noise, and when it gets really bad you get severe compression and the port ceases to function at all.
Flared ports need to be a bit longer than straight ports to achieve the same tuning. There are rules of thumb for this but it's best if you can measure impedance and adjust as required.
I'm not sure why all three ports would have to be the same size, you simulate until you get a good result and then you use whatever length and diameter you end up with in the sim.
Some people recommend 17 m/s as a good balance between port size and velocity issues, some people are happy with much higher velocity than that, but a lot of people are much more conservative and recommend under 10 m/s. Ports introduce losses into the system unless they are very large, even at 10 m/s there are losses, and as velocity gets higher the losses increase as velocity turns into turbulence, distortion and noise, and when it gets really bad you get severe compression and the port ceases to function at all.
Flared ports need to be a bit longer than straight ports to achieve the same tuning. There are rules of thumb for this but it's best if you can measure impedance and adjust as required.
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An aero is just a name for a pvc port. slot port vs aero port. if you google that you'll get a better idea. Why they say all three ports have to be the same size idk.
thanks for the info.
say even in a dual reflex, could you see any reason why I could not use a wooden slot port and then a pvc (aero) port?
thanks for the info.
say even in a dual reflex, could you see any reason why I could not use a wooden slot port and then a pvc (aero) port?
I did google image search and it looks like regular heavily flared abs ports. But I think you are just talking about round ports vs slot ports.
You can use whatever you want, including passive radiators. There might be very specific situations where one type won't work but in general flared ports are always preferred to non flared and passives are used where ports won't fit or when the extra price is worth the size reduction. Slot ports are fine too but if the aspect ratio gets too high air won't flow as well as it would in a circular port.
You can use whatever you want, including passive radiators. There might be very specific situations where one type won't work but in general flared ports are always preferred to non flared and passives are used where ports won't fit or when the extra price is worth the size reduction. Slot ports are fine too but if the aspect ratio gets too high air won't flow as well as it would in a circular port.
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