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 21st January 2012, 02:51 AM   #1
diyAudio Member
 
BP1Fanatic's Avatar
 
Join Date: Jan 2009
Location: Columbus, Ohio
Post Kicker 08S15L74 Double Fold T-TQWT Build

I'm building my 1st T-TQWT. I want to do a double fold to keep the box as square as possible. I used Volvotreter's pdf to design the folds. My question is how do you fellas maintain the correct board angles and have a constant decreasing flare (or for you TH guys, increasing flare) minus any corner deflectors? When I follow the 45* procedure, the top right hand corner increases in flare instead of decreasing in flare.

I got the 3 corner numbers from drawing this spreadsheet on MDF.
Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

Last edited by BP1Fanatic; 25th January 2012 at 01:52 AM.
  Reply With Quote
Old 21st January 2012, 11:37 AM   #2
bjorno is offline bjorno  Sweden
diyAudio Member
 
Join Date: Mar 2005
Location: Jacobsmountain
Send a message via MSN to bjorno
Quote:
Originally Posted by BP1Fanatic View Post
..My question is how do you fellas maintain the correct board angles and have a constant decreasing flare..
Hi,

The horizontal piece labeled 18.19 x 16 should IMO be attached at the ends to 2 perpendicular mounted vertical dividers where one of the latter is labeled 15.69 x 16 in your picture.

I would take an much easier approach to fold by designing a T-TQWP instead. The only drawback I can see is the need for an additional ~23L of volume.

b
Attached Images
File Type: jpg Kicker-08S15-L74_T-TQWP.JPG (265.0 KB, 175 views)
  Reply With Quote
Old 21st January 2012, 01:06 PM   #3
diyAudio Member
 
Join Date: Nov 2007
Quote:
Originally Posted by BP1Fanatic View Post
I'm building my 1st T-TQWT. I want to do a double fold to keep the box as square as possible.
Try the folding scheme here - The Subwoofer DIY Page v1.1 - Projects : A "Proof of Concept" tapped pipe** - introduction

By varying the position of two internal dividers, you can get a T-QWT, T-QWP or even a TH.
__________________
www.diysubwoofers.org
  Reply With Quote
Old 21st January 2012, 01:46 PM   #4
diyAudio Member
 
BP1Fanatic's Avatar
 
Join Date: Jan 2009
Location: Columbus, Ohio
I was hoping you would respond bjorno! Thank you! The inner top piece is drawn perpendicular to the speaker plate and the inner rear piece. It's easier to leave the inner top piece at 6" from the outer top piece in Excel. That's why I have all the corner dimensions labeled so you can visualize the inner and outer top pieces are not parallel to each other. I can't use 600cm2 for a TQWP. The Kicker 08S15L74 has an 8.6875" mounting depth. I did design a 825.8cm2 (8" x16") TQWP, but its 2 feet longer to get the response I want for HT.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.
  Reply With Quote
Old 21st January 2012, 01:55 PM   #5
diyAudio Member
 
BP1Fanatic's Avatar
 
Join Date: Jan 2009
Location: Columbus, Ohio
Quote:
Originally Posted by Brian Steele View Post
Try the folding scheme here - The Subwoofer DIY Page v1.1 - Projects : A "Proof of Concept" tapped pipe** - introduction

By varying the position of two internal dividers, you can get a T-QWT, T-QWP or even a TH.
Thank you for responding Brian! In this shot, the hole on the right of the speaker is the half way point of the horn, in my case would be 7" x 16"?

Click the image to open in full size.
  Reply With Quote
Old 21st January 2012, 02:10 PM   #6
diyAudio Member
 
Join Date: Nov 2007
Quote:
Originally Posted by BP1Fanatic View Post
Thank you for responding Brian! In this shot, the hole on the right of the speaker is the half way point of the horn, in my case would be 7" x 16"?

Click the image to open in full size.
__________________
www.diysubwoofers.org
  Reply With Quote
Old 21st January 2012, 02:23 PM   #7
diyAudio Member
 
BP1Fanatic's Avatar
 
Join Date: Jan 2009
Location: Columbus, Ohio
I see what a did wrong! I worded my question as a statement. Thank you again Brian!

Last edited by BP1Fanatic; 21st January 2012 at 02:41 PM.
  Reply With Quote
Old 21st January 2012, 04:22 PM   #8
tb46 is offline tb46  United States
diyAudio Member
 
Join Date: Jan 2006
Location: Texas
Hi BP1Fanatic,

I use an iterative process based on the data from the Hornresp input screen. It's basically the same process I used BC (before computers):

Use a cad program (in my case AutoCAD) because of the build in measurement capabilities. Example for a TH or a T-TQWT:

1. Draw a horizontal line representing the total length of the horn path.

2. Draw a vertical line for S1 on one end of the horizontal line, and another for S4 on the other end; I arrive at the length of these lines by dividing the respective area values from Hornresp by the choosen internal width of the box.

3. Connect the free ends of the vertical lines. Then I use the dimensioning command to give me the angle between the original horizontal line, and the line connecting the free ends of the vertical lines; this is the taper of the duct.

4. From your original idea of the layout, start drawing the layout using the taper angle from 3. above, and the duct heights derived from the S1/S2 values from Hornresp for the throat end, and from the mouth end the S4/S3 values.

5. When you have the first (almost by definition wrong) drawing, use Soho54's method for drawing cross-section lines into the duct path (the lines called S1/S2/1/2/3... in the example).

6. Then connect the midpoints of these lines (all the way from S1 to S4) with a line representing the total duct length. You can now compare the total length from the first attempt at a layout drawing and the total length from Hornresp, and adjust the drawing until the two values are close.

7. Now you're ready to work through the path of the duct by - for example -connecting the midpoints of the cross-section lines from S1 to #1 (the first change of direction). In AutoCAD you can use the "List" command to give you the length of this line. Transfer this length to your original horizontal line from 1. above, and draw a vertical long enough to intersect the line you drew in 3. above. The length of the vertical line from the horizontal to the taper line is the duct height at this point. You can now position the divider boards respectively. Now, move on to #2, etc....

8. When you're done with that you will have to adjust the layout to correct for length and cross-sectional errors.

It will obviously take multiple iterations to get close, and for a given design a computer solution is the way to go. I haven't kept up with Brian Steele's and Soho54's spreadsheet work on that subject.

It helps to have a number of drawings for different layouts as a starting point, but it sounds worse than it is. By the way, the top horizontal boards in your drawing (31.00x16.00 and 18.19x16.00) should not be parallel.

Regards,
Attached Images
File Type: jpg drawing_notes.jpg (44.1 KB, 159 views)
Attached Files
File Type: pdf Example_dwg.pdf (25.8 KB, 50 views)
__________________
Oliver

Last edited by tb46; 21st January 2012 at 04:29 PM.
  Reply With Quote
Old 21st January 2012, 04:49 PM   #9
diyAudio Member
 
Join Date: Aug 2011
Quote:
Originally Posted by bjorno View Post
Hi,

The horizontal piece labeled 18.19 x 16 should IMO be attached at the ends to 2 perpendicular mounted vertical dividers where one of the latter is labeled 15.69 x 16 in your picture.

I would take an much easier approach to fold by designing a T-TQWP instead. The only drawback I can see is the need for an additional ~23L of volume.

b
Hi Bjorno,

You assisted me with a horn for my B139-how do you get the schematic diagram to "show" you horn sections and final horn as in that picture? I think* I've worked mine out using graph paper and scissors-a way in HR would be far preferable!

*I'm sure that my horn will actually end up losing volume/length and not output as your model suggests

OP-sorry for jumping on your thread-but as I'm having the same issues this could be helpful to both of us!
  Reply With Quote
Old 21st January 2012, 10:21 PM   #10
diyAudio Member
 
BP1Fanatic's Avatar
 
Join Date: Jan 2009
Location: Columbus, Ohio
Quote:
Originally Posted by tb46 View Post
Hi BP1Fanatic,

I use an iterative process based on the data from the Hornresp input screen. It's basically the same process I used BC (before computers):

Use a cad program (in my case AutoCAD) because of the build in measurement capabilities. Example for a TH or a T-TQWT:

1. Draw a horizontal line representing the total length of the horn path.

2. Draw a vertical line for S1 on one end of the horizontal line, and another for S4 on the other end; I arrive at the length of these lines by dividing the respective area values from Hornresp by the choosen internal width of the box.

3. Connect the free ends of the vertical lines. Then I use the dimensioning command to give me the angle between the original horizontal line, and the line connecting the free ends of the vertical lines; this is the taper of the duct.

4. From your original idea of the layout, start drawing the layout using the taper angle from 3. above, and the duct heights derived from the S1/S2 values from Hornresp for the throat end, and from the mouth end the S4/S3 values.

5. When you have the first (almost by definition wrong) drawing, use Soho54's method for drawing cross-section lines into the duct path (the lines called S1/S2/1/2/3... in the example).

6. Then connect the midpoints of these lines (all the way from S1 to S4) with a line representing the total duct length. You can now compare the total length from the first attempt at a layout drawing and the total length from Hornresp, and adjust the drawing until the two values are close.

7. Now you're ready to work through the path of the duct by - for example -connecting the midpoints of the cross-section lines from S1 to #1 (the first change of direction). In AutoCAD you can use the "List" command to give you the length of this line. Transfer this length to your original horizontal line from 1. above, and draw a vertical long enough to intersect the line you drew in 3. above. The length of the vertical line from the horizontal to the taper line is the duct height at this point. You can now position the divider boards respectively. Now, move on to #2, etc....

8. When you're done with that you will have to adjust the layout to correct for length and cross-sectional errors.

It will obviously take multiple iterations to get close, and for a given design a computer solution is the way to go. I haven't kept up with Brian Steele's and Soho54's spreadsheet work on that subject.

It helps to have a number of drawings for different layouts as a starting point, but it sounds worse than it is. By the way, the top horizontal boards in your drawing (31.00x16.00 and 18.19x16.00) should not be parallel.

Regards,
Thank you tb46! Like I said earlier, those top 2 pieces are not parallel in my drawing on mdf. It's just easier to leave them parallel in excel since the top right corner rounds up to 6" & the top left corner rounds down to 6". Notice the different widths stated in each corner.
  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
TL/TQWT conceptual question aceinc Subwoofers 7 26th May 2007 02:19 PM
Quick ML TQWT question Volenti Multi-Way 1 5th February 2006 03:32 PM
ML-TQWT modelling the B102 question amt Full Range 28 16th October 2005 07:43 PM
TQWT Question Rino odorico Multi-Way 8 6th February 2003 01:14 PM


New To Site? Need Help?

All times are GMT. The time now is 07:26 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