Beyma SM212

[Mottlefeeder]

I read a comment about WinISD a couple of years ago, where someone was complaining that shelf ports always came out too long, and the explanation given was that the default calculation was for a port terminating some distance from any obstructions. With a shelf port, one side of the port is obstructed, and this increases the apparent length of the port.

Unfortunately, I posted the links on the now defunct Finnbass site, so I can't direct you the the link.

David

[Mottlefeeder]

 

On 26/02/2022 at 08:14, Phil Starr said:

... You need to look at 'rear port velocity'; that's just a winisd quirk, you can put the port anywhere but it is calculated as rear port...

 

I'm not sure that WinISD was written assuming a given port position. When you move into bandpass designs, the front and rear enclosures have ports labelled as front and rear. I think that they have carried that over into the ported single box designs.

David

Edited March 16, 2022 by Mottlefeeder

[Chienmortbb]

14 hours ago, Mottlefeeder said:

I read a comment about WinISD a couple of years ago, where someone was complaining that shelf ports always came out too long, and the explanation given was that the default calculation was for a port terminating some distance from any obstructions. With a shelf port, one side of the port is obstructed, and this increases the apparent length of the port.

Unfortunately, I posted the links on the now defunct Finnbass site, so I can't direct you the the link.

David

Correct, unless the slot is a slot port where none of the the sides are cabinet sides that a shelf type slot port will calculate incorrectly. ITs proabbly whay DIYers keep away from them. Innthe plus side they add cabinet rigidity but they are also difficult to calculate. With a round port you can "tune" it easily.