4"x8" Port = two 4"x4" Ports for MLTL??? More Complex??? - diyAudio
Go Back   Home > Forums > Loudspeakers > Full Range

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 16th January 2005, 10:44 PM   #1
diyAudio Member
 
Join Date: Sep 2004
Location: Brooklyn,NY
Question 4"x8" Port = two 4"x4" Ports for MLTL??? More Complex???

Hi, i'm almost done with the sub and the port is the only thing that separates me from it.
It's a Mass Loaded TL and originally i was gonna use 4"IDx8" port with 3/4"flare on both sides but now i only have 2" of space behind the port and back wall of the line. I think it's too little! Yes/no?
What are the rules for breaking port volume in two ports for MLTL.
If only the mass of air inside the port matters then does it mean i can just saw it in half and have 2 4"IDx4" ports side by side?
Or is there a special formula like for regular BR which takes the inside surface area and friction of air into account and the actual volume has to be bigger?
Please advise ASAP, i can't wait to listen to the sub
Thank you very much!!!

PS.Yes, I've searched and haven't found an answer.
Edit: i put this into FR forum because more ppl make TLs here and since it's a general question about ports (not sub specific).
  Reply With Quote
Old 17th January 2005, 03:28 PM   #2
diyAudio Member
 
Josephjcole's Avatar
 
Join Date: Jun 2004
Location: Wisconsin
The two variables are the effective port cross-section and the length of the port. the narrower the diameter the shorter the port can be. The larger the diameter the longer it has to be. Changing one 4"x8" port into two 4"x4" ports doubles the effective cross-section and halves the length. This would raise the tuning frequency of the box by quite a bit. I would suggest using a 4"x8" port with a 90 degree bend in it.
Joe
  Reply With Quote
Old 17th January 2005, 03:58 PM   #3
diyAudio Member
 
Join Date: Sep 2004
Location: Brooklyn,NY
Thank you i think i figured it out
Regular rules apply, Doh! ((C)Hommer Simpson)
I decided to try 7" port with the extension due to close proximity of the back wall.
  Reply With Quote

Reply


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
What makes an amplifier "bright", "warm", or "neutral"? JohnS Solid State 51 13th December 2009 06:42 PM
What makes Nichicon "muse"/"for audio" caps different ? percy Parts 2 3rd October 2009 05:53 PM
Charcoal "Supreem" hi-density foam "enclosure" IG81 Multi-Way 0 23rd April 2009 01:34 PM
Some final pics of "Stacks" revisited and "Askew" with stand Andy G Multi-Way 2 3rd February 2005 06:07 AM
Anyone used Scan-Speak's "Flow Resistors" or "Aperiodic Vents"? Ignite Multi-Way 3 18th November 2001 08:42 AM


New To Site? Need Help?

All times are GMT. The time now is 02:50 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2