Are kerf ports as efficient as aeroports?

[AmericanLegend]

In a kerfed port design, the radius of the kerf can make or break the box. In any box under 10 cubes, I would use aeros for numbers, over 10 cubes, I am doing a slot port and then test with kerf from PVC to see if it helps or hurts. It isn't a one size fits all once you get to a very large box. That last part was just for a why not mention it lol.

^^This^^

[STEvil]

Depends on your kerf job and final port mouth area and expansion rate. If you build it identical to an aero then of course it will be the same efficiency wise.

A kerfed square or rectanglular port simply cannot be as efficient as a round one because, for a given port area, the square or rectangle will have more internal surface area.

You do realize that the optimal throat expansion rate is not what used for aero ports, right? They just chose a generic exponential curve and said "this looks cool, lets use it."

That said, the performance difference between the two at any point is miniscule and the expansion rates only influence a very small bandwidth beyond the target ported frequency. If you want a big port you go kerfed. If you want a bunch of smaller ports you can go aero. Its personal preference and beyond getting into horn theory there's not much point in discussing the semantics of which is better..

[matt402]

try an octo-port =].

[AmericanLegend]

Depends on your kerf job and final port mouth area and expansion rate. If you build it identical to an aero then of course it will be the same efficiency wise.

A kerfed square or rectanglular port simply cannot be as efficient as a round one because, for a given port area, the square or rectangle will have more internal surface area.

You do realize that the optimal throat expansion rate is not what used for aero ports, right? They just chose a generic exponential curve and said "this looks cool, lets use it."

That said, the performance difference between the two at any point is miniscule and the expansion rates only influence a very small bandwidth beyond the target ported frequency. If you want a big port you go kerfed. If you want a bunch of smaller ports you can go aero. Its personal preference and beyond getting into horn theory there's not much point in discussing the semantics of which is better..

To me, 'aero' refers to the process or application of rounding a port to reduce drag at its leading edges. Whether or not this is of an 'optimal' degree is, like you said, a very insignificant factor as long as laminar flow characteristics are maintained.

However, what is significant is the port geometry itself. The square ports (kerfed or unfinished) are going to have a lot more pressure losses than a round one the same way multiple ports have more pressure losses than a single port. One could technically build a round port out of wood, but almost nobody does. A more appropriate process for constructing an odd-sized round port might be to mock it out of poster and then reinforce it with fiberglass, however this is beside the point.

The point is that there are significant (ie measurable) differences between round 'aero' ports and square or rectangle 'kerfed' (read 'aero) ports.

[AMI CUSTOMS]

Depends on your kerf job and final port mouth area and expansion rate. If you build it identical to an aero then of course it will be the same efficiency wise.

A kerfed square or rectanglular port simply cannot be as efficient as a round one because, for a given port area, the square or rectangle will have more internal surface area.

You do realize that the optimal throat expansion rate is not what used for aero ports, right? They just chose a generic exponential curve and said "this looks cool, lets use it."

That said, the performance difference between the two at any point is miniscule and the expansion rates only influence a very small bandwidth beyond the target ported frequency. If you want a big port you go kerfed. If you want a bunch of smaller ports you can go aero. Its personal preference and beyond getting into horn theory there's not much point in discussing the semantics of which is better..

To me, 'aero' refers to the process or application of rounding a port to reduce drag at its leading edges. Whether or not this is of an 'optimal' degree is, like you said, a very insignificant factor as long as laminar flow characteristics are maintained.

However, what is significant is the port geometry itself. The square ports (kerfed or unfinished) are going to have a lot more pressure losses than a round one the same way multiple ports have more pressure losses than a single port. One could technically build a round port out of wood, but almost nobody does. A more appropriate process for constructing an odd-sized round port might be to mock it out of poster and then reinforce it with fiberglass, however this is beside the point.

The point is that there are significant (ie measurable) differences between round 'aero' ports and square or rectangle 'kerfed' (read 'aero) ports.

The shape of the port makes NO difference in output. This is assuming you are not changing the loading on the driver, meaning you have the same port area and tuning for both applications, one isn't going to work better then the other.

[AmericanLegend]

The shape of the port makes NO difference in output. This is assuming you are not changing the loading on the driver, meaning you have the same port area and tuning for both applications, one isn't going to work better then the other.

^^This is definitely not true, bro.^^ The shape of the port can make a huge difference....

[AMI CUSTOMS]

The shape of the port makes NO difference in output. This is assuming you are not changing the loading on the driver, meaning you have the same port area and tuning for both applications, one isn't going to work better then the other.

^^This is definitely not true, bro.^^ The shape of the port can make a huge difference....

In what? LOL, all the tests I have done show none. Even doing the math behind it, it makes no difference, numbers come out the same.

[AmericanLegend]

This is boring. Maybe we should start a thread to talk about it?

[STEvil]

The shape of the port makes NO difference in output. This is assuming you are not changing the loading on the driver, meaning you have the same port area and tuning for both applications, one isn't going to work better then the other.

^^This is definitely not true, bro.^^ The shape of the port can make a huge difference....

I think you are thinking kerf just means a rounded over lip? Because the surface area of the expansion radius between a kerfed port and an aero port is almost identical when done "properly." Though the difference between a proper and non-proper kerf/aero radius is minimal at best and just increases below-tuning bandwith in the end really.

[AmericanLegend]

Stevil you are full of misinformation lol.