Thanks for the great explanation!
So, if I understand correctly I should use a sloted port with a AR of at least 9:1 (which dials it back to 270mm x 30mm) that it will give me higher air speed... or use a rounded port which is more effcient (friction wise).
Both cases are not ideal because they have long ports with a bend.
When modelling in WinISD, dual 3" rounded port gives me similar performance than the sloted port, better yet when appling a HP @21Hz, air speed dials back to 18 m/s @ full power (250W)...
So, the final question is... sloted port with a 9:1 AR with air speed around 22 m/s or dual 3" rounded port with 18 m/s air speed, both with a bend.
So, if I understand correctly I should use a sloted port with a AR of at least 9:1 (which dials it back to 270mm x 30mm) that it will give me higher air speed... or use a rounded port which is more effcient (friction wise).
Both cases are not ideal because they have long ports with a bend.
When modelling in WinISD, dual 3" rounded port gives me similar performance than the sloted port, better yet when appling a HP @21Hz, air speed dials back to 18 m/s @ full power (250W)...
So, the final question is... sloted port with a 9:1 AR with air speed around 22 m/s or dual 3" rounded port with 18 m/s air speed, both with a bend.
You're welcome!
No, less than [<] 9:1.
Correct, though critically damping the vent ameliorates it as it's slowing down the vent mach.
Dual vents have additional losses Vs a single large one, so have to be longer for a given tuning, hence short of larger flares than sold commercially, any gain from them can be negated if not longer; so you're on the right track, just need to make it a lower AR and at the bend, triangulate it as the excess volume [Vb] in its own little acoustically triangular corner only acts as a source of bend damping.
I assume AkAbak can accurately enough sim it, but otherwise tuning will be whatever it is unless others have more experience with tweaking duct bends.
No, less than [<] 9:1.
Correct, though critically damping the vent ameliorates it as it's slowing down the vent mach.
Dual vents have additional losses Vs a single large one, so have to be longer for a given tuning, hence short of larger flares than sold commercially, any gain from them can be negated if not longer; so you're on the right track, just need to make it a lower AR and at the bend, triangulate it as the excess volume [Vb] in its own little acoustically triangular corner only acts as a source of bend damping.
I assume AkAbak can accurately enough sim it, but otherwise tuning will be whatever it is unless others have more experience with tweaking duct bends.
Re vent 'elbow' description, forgot to post this visual [scroll down]: X-Z-NS 18in Single Sub Enclosure – Sundown Audio
Thanks,
Finally settled in a 6.99:1 ratio and I will implement the elbow slot port you showed.
Cheers
Finally settled in a 6.99:1 ratio and I will implement the elbow slot port you showed.
Cheers
For those interested, here is a klippel measurement for this driver (well, not exactly this, but the 4ohm versión).
https://www.diymobileaudio.com/thre...ac76-4-shallow-subwoofer-klippel-test.115336/
Seems the XMAX is quite lower that the CtoC measured by SBAcoustics --> From 12mm to a usable 6-8mm
https://www.diymobileaudio.com/thre...ac76-4-shallow-subwoofer-klippel-test.115336/
Seems the XMAX is quite lower that the CtoC measured by SBAcoustics --> From 12mm to a usable 6-8mm
Just a follow up...
Also, this driver (one of the three variants) it's used by Triad, Ascendo and Leon. IDK if they are the best nor even good.