AES Publications
The
Audio
Engineering Society
lists a number of publications that are relevent to flared ports
They offer these for download for a fee of $20 per document for non-members or $5 for members (as of 6 Sept 2005).
Maximizing Performance from Loudspeaker Ports - Preprint Number: 4855
-
Evaluates Compression, distortion and turbulence in ports with different sized flares
- Identifies
differing requirements for inlet and exit streams
-
Examines different cross-sectional profiles
-
Looks at the effectiveness of using a "dimpled" surface to modify turbulence at the boundary
-
Highlights the role of port airflow in driver cooling
- Provides evidence that using a mounting flange on the inside end of the port, dramatically reduces port-generated even harmonic distortion
|
Comment: I have downloaded this document and found it to be quite enlightening. The analysis is mainly about ports that are tapered as well as having radiused ends. It concludes that the radiused ends (what I have been calling "flares") should have a radius of at least 20% of the port diameter. In addition, the optimal port should have a flare radius (what I would call a taper) equal to the length of the port as shown here. |
 |
Analysis and Modeling of the Bi-Directional Fluid Flow in Loudspeaker Ports - Preprint Number: 6194
Authors: Devantier, Allan; Rapoport, Zachary-
Uses Computational Fluid Dynamics to look at performance of six different sized flares.
-
The six ports were built and tested
Comment: I have not downloaded this document
The Nonlinear Behavior of Reflex Ports - Preprint Number: 3999
Author: Backman, Juha
-
Evaluates nonlinear behavior of reflex ports of various shapes
-
Covers noise, harmonic distortion, and flow resistance.
Comment: I have not downloaded this document, however the summary on the AES site, plus comments from discussion forum members state that the document....
"Concludes that careful design yields significant improvements in the dynamic range, however, relatively small irregularities can increase the nonlinearity greatly. Shows how bent ports and unflared ports perform poorly."
Loudspeaker Ports - Preprint Number: 4523
Author: Vanderkooy, John
-
Examines flared ports
-
Identifies a problem with assymetrical flares (different each end)
-
Advice on measuring with nearfield technique
Comment: I have not downloaded this document, however comments from discussion forum members suggest that Preprint 4855 contains much of the results from this paper.
Thanks
go to the members of the diyAudio
forum
for suggesting these references.
