21DS115-4 6th order bandpass design - port flares

Hi folks,

I’ve been working on a design for a new 6th-order series bandpass enclosure using the 21DS115-4, and I’m pretty happy so far. The design is relatively compact out of necessity, with a total internal volume of around 200 L including ports, driver, and bracing. -3 dB points are roughly 35 Hz and 110 Hz.

I’ve started looking more closely at the port design. Air velocity isn’t an issue, but I’d like to incorporate something more than simple, straight rectangular ports.

Many commercially available designs, and those from 18 Sound/B&C etc. incorporate angled or flared sections within the ports, both internally and at the exits. Is there a reliable way to sim/calculate how these affect tuning? 

I’m considering an exit with a 10 cm, 45° flare on one side leading onto the front baffle, while the other side remains flush against the side panel. Is there a method to predict how this kind of asymmetric flare would influence the effective port length/vol and tuning frequency?

Thanks in advance