Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Multi-Way Conventional loudspeakers with crossovers

Slotted port vs round?
Slotted port vs round?
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 4th September 2020, 02:45 PM   #1
audio39 is offline audio39  Canada
diyAudio Member
 
Join Date: Nov 2010
Location: Calgary, Alberta
Default Slotted port vs round?

Over the last few years I've built a number of speakers, all have used a round port because most of the info I've found to date suggests that round is better. I'm starting a new project and have an itch to build my own rectangular port...but will I be disappointed?

Any feedback will be most appreciated.
  Reply With Quote
Old 4th September 2020, 04:53 PM   #2
pkitt is offline pkitt  United States
diyAudio Member
 
Join Date: Feb 2009
No, as long as the port's aspect ratio is not overly large which could cause "noise" because of the large "circumference" from a really narrow slot. Some people recommend an aspect ratio not exceeding 5:1 or so, but that may be unnecessarily restrictive. The peak air velocity in a port, which is the primary source of chuffing or noise, depends on the port's area, but as a port moves from round, to square to being a slot, all with the same area, the port's circumference becomes larger and larger, presenting more and more of an edge to cause turbulence. Others may disagree but I'm currently listening to my latest build which has twin slot ports, each 1" x 2", which has no discernible port-related issues.
Paul
  Reply With Quote
Old 4th September 2020, 05:04 PM   #3
tmuikku is online now tmuikku  Finland
diyAudio Member
 
Join Date: Sep 2004
Location: Savo, Finland
Send a message via ICQ to tmuikku
You should build quick and dirty prototype box with both ports and test it out! If there is a difference, you are able to choose the better one and can then move on to worry some other compromise. Have fun!
  Reply With Quote
Old 4th September 2020, 05:24 PM   #4
Galu is offline Galu  Scotland
diyAudio Member
 
Join Date: Apr 2018
A slotted port is different to a rectangular port. Which one are you considering, as your post mentions both?
  Reply With Quote
Old 4th September 2020, 05:33 PM   #5
pkitt is offline pkitt  United States
diyAudio Member
 
Join Date: Feb 2009
For clarification, when I said slotted or slot port, I really meant a rectangular port.
Paul

Quote:
Originally Posted by pkitt View Post
No, as long as the port's aspect ratio is not overly large which could cause "noise" because of the large "circumference" from a really narrow slot. Some people recommend an aspect ratio not exceeding 5:1 or so, but that may be unnecessarily restrictive. The peak air velocity in a port, which is the primary source of chuffing or noise, depends on the port's area, but as a port moves from round, to square to being a slot, all with the same area, the port's circumference becomes larger and larger, presenting more and more of an edge to cause turbulence. Others may disagree but I'm currently listening to my latest build which has twin slot ports, each 1" x 2", which has no discernible port-related issues.
Paul
  Reply With Quote
Old 4th September 2020, 05:57 PM   #6
YSDR is offline YSDR  Hungary
diyAudio Member
 
YSDR's Avatar
 
Join Date: Nov 2013
You can divide a slot port to get more smaller rectangular or square ports.
  Reply With Quote
Old 4th September 2020, 06:06 PM   #7
audio39 is offline audio39  Canada
diyAudio Member
 
Join Date: Nov 2010
Location: Calgary, Alberta
I'm considering a rectangular port, the dimensions at present are 1.5" x 8" x 10.25" deep. This dimension theoretically will deliver 30 cycles.
  Reply With Quote
Old 4th September 2020, 06:21 PM   #8
turk 182 is offline turk 182  Canada
diyAudio Member
 
Join Date: Oct 2012
funny i should come across this thread as i was just recently discussing this very thing with an old guitar player buddy of mine.
the Theile 12 guitar cab with slot port, originally designed for an EVM 12 L and i was wondering if i could find the original plans....then he sends me a link to this 1x12 Front Ported Thiele Guitar Amplifier Cabinet | MESA/Boogie(R)
  Reply With Quote
Old 16th September 2020, 09:30 PM   #9
audio39 is offline audio39  Canada
diyAudio Member
 
Join Date: Nov 2010
Location: Calgary, Alberta
Ok, I've decided to go with the slotted port. When calculating the internal speaker volume do you factor the internal area used by the port and add that?
  Reply With Quote
Old 16th September 2020, 09:47 PM   #10
Indigent Audio is offline Indigent Audio
diyAudio Member
 
Join Date: Mar 2020
Location: Santa Cruz, CA
The BEST Port Video EVER - YouTube

I have built both, unless you have a space restriction necessitating a square port I would stick with a round port, audio results are (sometimes) better with less issues. Slot ratio (H to W) is also important if your going with a rectangular port.
  Reply With Quote

Reply


Slotted port vs round?Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Vertical Slotted Reflex Port monty78pig Multi-Way 18 14th July 2015 12:37 AM
calculating slotted port in winisd butterwitz Subwoofers 13 17th February 2015 05:34 PM
square port vs slotted port portreathbeach Full Range 16 9th October 2013 02:56 PM
Is this sub TL or Slotted Port? buck1138 Subwoofers 1 17th June 2011 08:34 PM
FR125 MLTL slotted port question valleyman Full Range 7 17th September 2008 03:47 PM


New To Site? Need Help?

All times are GMT. The time now is 07:55 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio
Wiki