Any minimum distance from driver to port? - diyAudio
Go Back   Home > Forums > Loudspeakers > Multi-Way
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Multi-Way Conventional loudspeakers with crossovers

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
Thread Tools Search this Thread
Old 26th December 2002, 12:02 PM   #1
diyAudio Member
Circlotron's Avatar
Join Date: Jun 2002
Location: Melbourne, Australia
Default Any minimum distance from driver to port?

At the moment I am considering building a pair of boxes approx 110cm x 50cm x 40cm with an 8 inch driver at one end of the 40 cm x 110cm face. Does it make very much difference where the port is located? The most convenient place for me would be either on the 40cm x 50cm side adjacent to the driver or on the front right next to it. The box is to be laying on it's side so it would be 110cm wide, 40cm high, 50cm deep.

Actually, seeing the driver and port output are in phase at resonance, how would it be if the driver was encircled by 4 to 6 small ports so that the two sound sources were concentric? Worthwile?
Best-ever T/S parameter spreadsheet.
  Reply With Quote
Old 26th December 2002, 03:45 PM   #2
diyAudio Member
Join Date: Oct 2001
Location: 5280'
There is too much air resistance with multiple small ports. It's best to use a single large port
  Reply With Quote
Old 26th December 2002, 10:09 PM   #3
diyAudio Member
lieven's Avatar
Join Date: Aug 2002
Location: Belgium
try the onken-style
1 big port is easiest, but not the only way.
IMHO, Q-factor of 1 big port is high, so one get's more spectacular result but in a much narower frequency-spectrum compared to onken or different tuned pipes with the same resulting airflow resistance than 1 big pipe.

Compare it to the sound of 1 big exhaust pipe for a car, or multiple ones.

on this site is a onken calculator
  Reply With Quote
Old 27th December 2002, 10:39 PM   #4
diyAudio Member
Circlotron's Avatar
Join Date: Jun 2002
Location: Melbourne, Australia
Default Just pushing this post to the top of the stack again... that anyone that hasn't seen it might be able to tell me about port location...
Best-ever T/S parameter spreadsheet.
  Reply With Quote
Old 27th December 2002, 11:23 PM   #5
diyAudio Moderator
pinkmouse's Avatar
Join Date: Apr 2002
Location: Rotherham, England
It's a tweaky answer I'm afraid...

Port position is not normally a problem, because at the wavelengths involved, a port would have to be metres away from the driver to affect the response. But depending on you cabinet/driver/port/stuffing interactions, sometimes placing a port on the side or rear of a box will reduce out of band and turbulence noises, simply because they are not firing towards you.

So it's the old "build a test box and try it" answer, sorry

As for multiple ports all tuned the same, I personally have never heard any difference other than more port noise. Unless you stagger tune the ports, which I don't think is simulatable( new word? ) in normal software, and I have only done it by trial and error.
Rick: Oh Cliff / Sometimes it must be difficult not to feel as if / You really are a cliff / when fascists keep trying to push you over it! / Are they the lemmings / Or are you, Cliff? / Or are you Cliff?
  Reply With Quote


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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Minimum Port Diameter Narcisse91 Subwoofers 18 30th December 2012 04:58 PM
KT88 Minimum Mounting Distance Rob11966 Tubes / Valves 12 22nd October 2007 12:44 AM
How important is minimum port diameter? downward_dog Multi-Way 1 28th February 2005 05:44 PM
Distance of port to back wall? mitch808 Multi-Way 9 10th June 2004 07:51 PM

New To Site? Need Help?

All times are GMT. The time now is 07:09 PM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2