RS100-8 Transmission Line - 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 12th April 2012, 05:03 PM   #1
Einric is offline Einric  United States
diyAudio Member
 
Einric's Avatar
 
Join Date: Feb 2011
Location: Bozeman, MT
Default RS100-8 Transmission Line

The resonant frequency of the RS100-8 is 87.5hz.
That would put the 1/4 wavelength at 38.75".
I read somewhere that you should make the pipe slightly shorter than the 1/4" length and lightly stuff the pipe to dampen & slow the wave.
How short should I make the pipe? 36"? 30" anywhere in between?
Here is a picture of my design idea.

Any Thoughts?
Attached Images
File Type: png RS100 transmission tube.png (4.8 KB, 580 views)
  Reply With Quote
Old 12th April 2012, 06:59 PM   #2
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
That length calculation is for an untapered line (as yours looks to be), but does not include the end correction,

A good place to start is with Martin King's free alignment tables. It will generate the appropriate cross-section, length, and driver off-set.

dave
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  Reply With Quote
Old 12th April 2012, 08:50 PM   #3
Einric is offline Einric  United States
diyAudio Member
 
Einric's Avatar
 
Join Date: Feb 2011
Location: Bozeman, MT
I will look those tables over later tonight.
What is End Correction?
Will a flare at the open end mess with this End Correction?
I plan on building a flare at the bottom end.
  Reply With Quote
Old 13th April 2012, 12:33 AM   #4
kctess5 is offline kctess5  United States
diyAudio Member
 
Join Date: Dec 2011
Location: California
Make sure to at least check out the the alignment tables and/or horn resp. Many times some kind of taper will result in flatter response. Also with what looks like a compression chamber on the front end it could further mess with the response if not specifically designed. Also a flare at the end will change response, possibly beneficially but its hard to guess.

Not sure exactly about end correction but I believe it is something to do with the pipe resonates, the maximum of air velocity will not occur exactly at the open end of the tube but a little beyond so the tuning will be not quite exactly the length of the pipe. I believe it is worse the larger the pipe is in diameter relative to length

Good luck!
  Reply With Quote
Old 13th April 2012, 12:36 AM   #5
GM is online now GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
A pipe, tube, horn's acoustic length is longer than its physical length, so the end correction is how much the pipe is shortened for a given acoustic length.

Since the end correction is ~0.613x the effective terminus radius, flaring will affect it. In the scheme of things though, even it if alters tuning as much as a few Hz it won't be audible. That said, any line that requires damping won't audibly benefit from flaring unless it has a huge radius.

GM
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  Reply With Quote
Old 13th April 2012, 12:43 AM   #6
kctess5 is offline kctess5  United States
diyAudio Member
 
Join Date: Dec 2011
Location: California
Quote:
A pipe, tube, horn's acoustic length is longer than its physical length, so the end correction is how much the pipe is shortened for a given acoustic length.
Sounds like I was close
  Reply With Quote
Old 13th April 2012, 01:06 AM   #7
GM is online now GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
Sure does! Resonances of closed air columns

GM
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  Reply With Quote
Old 13th April 2012, 01:23 AM   #8
Einric is offline Einric  United States
diyAudio Member
 
Einric's Avatar
 
Join Date: Feb 2011
Location: Bozeman, MT
The compression chamber will only be as deep as necessary to give the driver a flat surface to mount to (an inch tops).
The pipe is actually a 3/8" wall cardboard tube with a 2.5" internal radius.
  Reply With Quote
Old 13th April 2012, 01:39 AM   #9
kctess5 is offline kctess5  United States
diyAudio Member
 
Join Date: Dec 2011
Location: California
If you have hornresp you should model it real quick, I would but I'm not with my pc

I suppose if you don't like how it sounds its not like it was a huge time investment with that tube
  Reply With Quote
Old 13th April 2012, 01:40 AM   #10
GM is online now GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
Hmm, 8" driver firing into a 5" pipe........ Is this what MJK's tables calculate? If so, a TQWT is called for. Otherwise, a driver offset typically is required to deal with peaky pipe modes. That, or a high stuffing density.

GM
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  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
how to combine Line array and transmission line together Jared Multi-Way 7 15th December 2012 01:20 PM
Help with converting sealed box line array loudspeaker to transmission line enclosure jb0194 Multi-Way 3 7th January 2012 05:08 AM
FS: (4) Dayton RS100-4s + (1) Dayton RS100-8 Fast1one Swap Meet 4 6th January 2010 10:32 AM
line array + transmission line ? zobsky Multi-Way 12 16th August 2006 04:18 PM
Transmission Line for or against? DJ Sense Full Range 5 10th June 2006 08:35 AM


New To Site? Need Help?

All times are GMT. The time now is 04:38 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