Speakerplans.com Homepage
Forum Home Forum Home > Plans > Ported Enclosures
  New Posts New Posts RSS Feed - Portsize with different port diameter help
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Portsize with different port diameter help

 Post Reply Post Reply
Author
Message
0krizia View Drop Down
Registered User
Registered User
Avatar

Joined: 15 February 2016
Location: norway
Status: Offline
Points: 79
Post Options Post Options   Thanks (0) Thanks(0)   Quote 0krizia Quote  Post ReplyReply Direct Link To This Post Topic: Portsize with different port diameter help
    Posted: 31 January 2018 at 6:29am
Hello. I got a pair of wharfedale impact 15 top speakers im planning to re-tune. The port are 8 cm tall, 45cm wide in the front and 26cm at the rear end. How does this shape impact tuning frequency? Does an ever increasing surface area give a lower or higher tuning than a constant surface area?

The reason why I am asking is because I am curious about how i will extend the port. Shall i continue the decrease of the surface area or increase it for lowering the tuning frequency efficiently.

Edited by 0krizia - 31 January 2018 at 6:36am
Back to Top
stevie View Drop Down
Registered User
Registered User


Joined: 16 March 2008
Location: Dorchester
Status: Offline
Points: 425
Post Options Post Options   Thanks (0) Thanks(0)   Quote stevie Quote  Post ReplyReply Direct Link To This Post Posted: 31 January 2018 at 11:45pm
As far as I know, port shape doesn't really affect the tuning frequency. To lower the tuning frequency, increase the depth of the shelf. Making a port longer tunes it lower.
Back to Top
JonB67 View Drop Down
Young Croc
Young Croc


Joined: 22 April 2016
Location: UK
Status: Offline
Points: 1376
Post Options Post Options   Thanks (0) Thanks(0)   Quote JonB67 Quote  Post ReplyReply Direct Link To This Post Posted: 01 February 2018 at 7:51am
Id extend it at the same size as its narrow point then test for port noise as well as retuned frequency.
Back to Top
mobiele eenheid View Drop Down
Old Croc
Old Croc


Joined: 15 August 2004
Location: Netherlands
Status: Offline
Points: 1568
Post Options Post Options   Thanks (0) Thanks(0)   Quote mobiele eenheid Quote  Post ReplyReply Direct Link To This Post Posted: 01 February 2018 at 4:52pm
Increasing port area over length, increases the tuning frequency.

If you increase port length or port area at the inside of the cabinet, this will lower the tuning frequency. However any decrease in cabinet volume, will partially counteract this, by raising the tuning frequency.

Easiest would be to simulate this in Hornresp.

Regards
Back to Top
airbell View Drop Down
Registered User
Registered User


Joined: 11 June 2009
Location: Berlin, Germany
Status: Offline
Points: 284
Post Options Post Options   Thanks (0) Thanks(0)   Quote airbell Quote  Post ReplyReply Direct Link To This Post Posted: 05 February 2018 at 7:18am
You would lower the tuning frequency most efficiently if you would continue decreasing the surface area, but on the other Hand maybe the surface area at the port beginning would be too small then and cause air noises so, I would keep it the same area and just extend it. 
Back to Top
 Post Reply Post Reply

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.06
Copyright ©2001-2023 Web Wiz Ltd.

This page was generated in 0.157 seconds.