Transmission Line Subwoofer - Home Theater Forum and Systems - HomeTheaterShack.com

Reply
 
Thread Tools
post #1 of 20 Old 12-21-07, 12:33 PM
spresser
Inactive
 
Posts: n/a
Transmission Line Subwoofer

Hi Guys,

I'm kind of new to the DIY speaker scene, I've built "The Golden Boys" from PE, and 5 Bargain aluminum MTM's 3 of whish are currently the front speakers for my soon to be 5.1 HT, they produce decent bass already, but I'm ready to build a sub for my 10' by 12' room. I already have a Dayton SD215-88 8" Shielded DVC Subwoofer part number 295-480 and a Dayton SA70 70W Subwoofer Amplifier part number 300-784. After looking around the internet I got interested in the transmission line idea. Will this work well with these products? I wouldn't have to use the sub for music if that makes a difference, I'm mainly interested in gaining dramatic LFE for dvd's. please help! Any comments or suggestions are appriciated!!
Sponsored Links
Advertisement
 
post #2 of 20 Old 12-21-07, 12:41 PM
Senior Shackster
 
BoomieMCT's Avatar
Boom
 
Join Date: Dec 2006
Location: Fairfax, Va
Posts: 863
Re: Transmission Line Subwoofer

I tried making a transmission line sub with that same amp and driver. It worked but my results were less than spectacular. I don't know what went wrong - the driver had the right parameters and it modeled well. It is possible I didn't have enough patience to work with the design.

You can have the enclosure to play with if you want.
BoomieMCT is offline  
post #3 of 20 Old 12-21-07, 01:19 PM
spresser
Inactive
 
Posts: n/a
Re: Transmission Line Subwoofer

Did you try closing the termus up some by adding MDF to each side? From what I've read this "loading" might help the response, also did you stuff this pipe or not? Thanks for the reply I'm interested to hear what you tried
post #4 of 20 Old 12-21-07, 01:55 PM
spresser
Inactive
 
Posts: n/a
Re: Transmission Line Subwoofer

Would anyone be able to give me the best dimensions for this transmission line? What adjustments should I make to Boom's design? Thanks for the help
post #5 of 20 Old 12-21-07, 02:00 PM
Senior Shackster
 
BoomieMCT's Avatar
Boom
 
Join Date: Dec 2006
Location: Fairfax, Va
Posts: 863
Re: Transmission Line Subwoofer

No I did not add MDF to the sides. I'm not really sure what you mean by that anyway. Yes I did stuff the inside. I probably could have experimented more with the stuffing but I lost heart and didn't. I still don't know why the extension was 10 Hz less then modeled. So I took the sub apart and moved on to other things.

It is a shame. I love how transmission lines sound. My omni-speakers I made and my old HTD level 3's are tranmission lines and my TABAQs I made (but not designed) are mass loaded transmission lines. I just couldn't get a TL sub to work. Someday (in another house) I may make a big straight pipe one - we'll see.
BoomieMCT is offline  
post #6 of 20 Old 12-21-07, 02:13 PM
Senior Shackster
 
BoomieMCT's Avatar
Boom
 
Join Date: Dec 2006
Location: Fairfax, Va
Posts: 863
Re: Transmission Line Subwoofer

Maybe I'm being too picky. Here is the modeled graph (red) vs. my measurements (purple). There is a chance I was just taking bad measurments (my room is far from optimal for sub frequencies). To tell the truth I had a lot of projects going on then which could also be why I got distracted. You know, why focus on a 70 watt 8" sub when I was making a 2000 watt 15" one for a friend? Maybe I'll put this back together and play with it a bit.
Attached Thumbnails
Transmission Line Subwoofer-tl-graphs.jpg  

BoomieMCT is offline  
post #7 of 20 Old 12-21-07, 02:35 PM
spresser
Inactive
 
Posts: n/a
Re: Transmission Line Subwoofer

No I did not add MDF to the sides. I'm not really sure what you mean by that anyway.

I simply meant to make the opening smaller because from what I've read if you make the opening smaller it will make the TL seem longer. I don't know if that makes a big difference. Again, I'm a newby to subs and TL's, so I've been trying to learn as much as possible about both at once.
post #8 of 20 Old 12-21-07, 03:13 PM
Senior Shackster
 
BoomieMCT's Avatar
Boom
 
Join Date: Dec 2006
Location: Fairfax, Va
Posts: 863
Re: Transmission Line Subwoofer

Quote:
spresser wrote: View Post
No I did not add MDF to the sides. I'm not really sure what you mean by that anyway.

I simply meant to make the opening smaller because from what I've read if you make the opening smaller it will make the TL seem longer. I don't know if that makes a big difference. Again, I'm a newby to subs and TL's, so I've been trying to learn as much as possible about both at once.
Ah. I could give that a try. As you can see from the pics I took of it, the TL itself is tapered which does reduce the length needed.

My original plan was to make the whole thing from 8" PVC pipe. That lasted until I found out how expensive 8" pipe is.

I guess one thing I noticed is that since TL subs need to be so long, you might as well use large drivers as they won't make the final design that much bigger. If I were to do it again I'd probably use something bigger than an 8". Also, because it is hard to get a really low tune in a small package, I'd take a look at some pro-sound woofers.
BoomieMCT is offline  
post #9 of 20 Old 12-21-07, 11:26 PM
spresser
Inactive
 
Posts: n/a
Re: Transmission Line Subwoofer

Yeah It looks preety good and from that thread it sounds like it worked preety well, what would you suggest I do different if I make a similar setup? I think I'm gonna try to start working on it sometime after new years so anything you think I should try to improve it is appreciated, I could make a simple sealed box, but that seems so boring, I'm ready to branch out and try something different.
post #10 of 20 Old 12-22-07, 12:33 AM
Senior Shackster
 
BoomieMCT's Avatar
Boom
 
Join Date: Dec 2006
Location: Fairfax, Va
Posts: 863
Re: Transmission Line Subwoofer

Suggestions? Make a box with access panels. I can't get to the tight fiddly part of the TL because I glued the whole thing shut.
BoomieMCT is offline  
Reply

Bookmarks

Tags
line , subwoofer , transmission

Quick Reply
Message:
Options

Register Now




PLEASE COMPLETE ALL REQUIRED FIELDS BELOW... THANKS!

REQUIRED FIELDS ON THIS PAGE
YOU MUST COMPLETE ALL OF THESE

Username
Password
Confirm Password
Email Address
Confirm Email Address
Random Question
Random Question #2




User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
PLEASE READ BELOW PRIOR TO ENTERING AN EMAIL ADDRESS!

ATTENTION!

YOU MUST ACTIVATE YOUR ACCOUNT!

Activation requires you reply to an email we will send you after you register... if you do not reply to this email, you will not be able to view certain areas of the forum or certain images... nor will you be able download software.

AN INVALID EMAIL ADDRESS WILL CAUSE YOUR ACCOUNT TO BE DELETED!

See our banned email list here: Banned Email List

We DO NOT respond to spamcop, boxtrapper and spamblocker emails... please add @hometheatershack DOT com to your whitelist prior to registering or you will get nowhere on your registration.


Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may 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 is not allowed!
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

 


For the best viewing experience please update your browser to Google Chrome