Sanity check please - port tuning for a Fane Colossus 18XB - diyAudio
Go Back   Home > Forums > Loudspeakers > Subwoofers

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 25th May 2012, 08:51 AM   #1
pk is offline pk  Denmark
diyAudio Member
 
Join Date: Apr 2003
Location: Aarhus, Denmark
Default Sanity check please - port tuning for a Fane Colossus 18XB

Hi,

I am just about to have a pair of vented bass cabinets build and would really appreciate a sanity check on the port tuning before I make sawdust

Driver: Fane Colossus 18XB

http://www.fane-acoustics.com/downlo...18XB_Specs.pdf

The most important driver parameters are:

Fs = 33 Hz
Qt = 0.337
Vas = 236 liters

The intended use is hifi (not PA).

Frequency range: up to 200 Hz
Tuning frequency: 30 Hz (I know this is below the drivers Fs, but the since it is for hifi and not PA, it should be ok)

Box volume: 220 liters


Using 'WinISD online' I have come up with the following, single rectangular port:

Port area: 346.8 cm2
Port length: 37.1 cm


Now, can these numbers from WinISD be trusted?

What makes me a bit concerned is that Fane's own recommendation for a smaller cabinet (200 liters) with a higher tuning (35 Hz) does NOT correspond to the numbers calculted by WinISD (Fane-port length = 10.1 vs. WinISD port length = 31.1 cm)!?

http://www.fane-acoustics.com/downlo...nch200Lres.pdf


I would like to build the bigger (220 liters) box tuned to 30 Hz. Can I trust the port calculations provided by WinISD??

Thanks a lot!

Best regards
Peter
  Reply With Quote
Old 25th May 2012, 12:48 PM   #2
Xoc1 is offline Xoc1  United Kingdom
diyAudio Member
 
Xoc1's Avatar
 
Join Date: Nov 2008
Location: Devon UK
The Fane recomended box states a frequency response down to 35Hz
This is not to say that the box is tuned to 35Hz.
The Fane box will be tuned above 40Hz to get as much efficiency out of the cabinet as possible - it is not tuned for a flat response.
From my own experience.
Learn how to simulate a ported cabinet in Hornresp. This will get you closer to the correct port length and frequency response.
Use your WinISD frequency generator (Get frequency from cursor option)
connect the pc to an amplifier and connect the speaker to the amp via a DVM current meter - The tuned frequency of the port is where the speaker draws the maximum current. I found this very easy to do and confirmed the port tuning was fairly close to the calculated figure. There are so many variables that effect the tuning that only real testing will confirm that everything is OK
Regards
Xoc1
  Reply With Quote
Old 25th May 2012, 02:14 PM   #3
bjorno is offline bjorno  Sweden
diyAudio Member
 
Join Date: Mar 2005
Location: Jacobsmountain
Send a message via MSN to bjorno
Quote:
Originally Posted by pk View Post
..Driver: Fane Colossus 18XB

http://www.fane-acoustics.com/downlo...18XB_Specs.pdf

The most important driver parameters are:

Fs = 33 Hz
Qt = 0.337
Vas = 236 liters

The intended use is hifi (not PA).

Frequency range: up to 200 Hz
Tuning frequency: 30 Hz (I know this is below the drivers Fs, but the since it is for hifi and not PA, it should be ok)

Box volume: 220 liters...
Hi Peter,

Take a look at this:

b
Attached Images
File Type: jpg port-tuning_Fane-Colossus-18XB.JPG (264.1 KB, 92 views)
File Type: jpg Fane-Colossus-18XB_Ported-versus-T-TQWT.JPG (313.5 KB, 97 views)
  Reply With Quote
Old 25th May 2012, 04:38 PM   #4
pk is offline pk  Denmark
diyAudio Member
 
Join Date: Apr 2003
Location: Aarhus, Denmark
Hi Xoc1 and Bjorno,

Thanks a lot for your elaborated replies!

Xoc1: Thanks for indicating that the suggested design by Fane is not tuned to 35 Hz at all. I am sure you are right about that!

I have tried to model my own suggestion using HornResp, and it looks ok as far as I am concerned! However, one problem is the spike just below 300 Hz due to a rather deep cabinet.

Q: Do you think I will be able to hear this spike when using a 24dB/octave crosover at 200 Hz?

Bjorno: Thanks for the detailed calculations - I am impressed! Since my mid/high combo only reaches just below 200 Hz, I will have to go for a vented solution though.

Best regards
Peter
Attached Images
File Type: jpg HornResp Fane in 220 liter vented cab tuned to 30 Hz.JPG (91.1 KB, 75 views)
  Reply With Quote
Old 25th May 2012, 05:44 PM   #5
bjorno is offline bjorno  Sweden
diyAudio Member
 
Join Date: Mar 2005
Location: Jacobsmountain
Send a message via MSN to bjorno
Quote:
Originally Posted by pk View Post
..Q: Do you think I will be able to hear this spike when using a 24dB/octave crosover at 200 Hz?..Peter
Answer: No. Picture hints:

b
Attached Images
File Type: jpg Fane-Colossus-18XB_Ported-30Hz-tuning.JPG (249.7 KB, 68 views)
  Reply With Quote
Old 25th May 2012, 06:18 PM   #6
pk is offline pk  Denmark
diyAudio Member
 
Join Date: Apr 2003
Location: Aarhus, Denmark
Hi Bjorno,

Thanks a lot for the reply!

Best regards
Peter

Quote:
Originally Posted by bjorno View Post
Answer: No. Picture hints:

b
  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
2-Way Sanity Check wrenchone Multi-Way 8 9th December 2011 07:54 PM
Siezed fane colossus dean ashmore Subwoofers 3 15th November 2008 02:00 PM
Sanity Check ..... please Lostcause Digital Source 0 16th October 2008 06:19 PM
Sanity check planet10 Multi-Way 14 7th March 2004 10:15 PM
Fane Colossus 18 XB subwoofer Karoliina Subwoofers 20 15th November 2002 05:18 PM


New To Site? Need Help?

All times are GMT. The time now is 05:57 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