SDX12 in a 2.1 (ft3) .....help!!! - Page 2 - Home Theater Forum and Systems - HomeTheaterShack.com

Reply
 
Thread Tools
post #11 of 14 Old 03-26-14, 05:50 PM Thread Starter
Shackster
 
Join Date: Mar 2014
Posts: 8
Re: SDX12 in a 2.1 (ft3) .....help!!!

Quote:
Gioxtream wrote: View Post
What's the perfect ported volume for this driver and the perfect ports length and diameter?

I am wondering if I can get a carpenter to add extra volume to my boxes that's all.

Thanks so much.
Hummmmmm.

If I decide to go with a single passive radiator......could you recomend a better looking one than the css?


A link for a good passive radiator would be awesome.
Gioxtream is offline  
Sponsored Links
Advertisement
 
post #12 of 14 Old 03-26-14, 07:00 PM
Elite Shackster
 
Mike P.'s Avatar
Mike
 
Join Date: Apr 2007
Location: Chitek Lake, Sask.
Posts: 19,397
Re: SDX12 in a 2.1 (ft3) .....help!!!

You would have a net intenal volume of about 1.7 cu.ft. and the port would be 30" long so porting is not realistic. I don't know what other PR's that would work. You should just go with a sealed design.




We're all in this together!


To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.

Mike P. is offline  
post #13 of 14 Old 01-24-15, 04:09 PM
Senior Shackster
tim
 
Join Date: Mar 2007
Location: vermont
Posts: 298
Re: SDX12 in a 2.1 (ft3) .....help!!!

sorry to bimp this thread, just wondering if the OP ever built this box and how it turned out.

I am building almost an identical sized sealed box and was just looking for some input.

i figure after amp ,speaker and bracing are deducted from the volume, i will be at 1.6cuft of actual airspace.
tundraSQ is offline  
 
post #14 of 14 Old 05-11-15, 09:07 PM
Shackster
Steve
 
Join Date: Apr 2014
Location: Johnson City, TN
Posts: 12
My System
Re: SDX12 in a 2.1 (ft3) .....help!!!

For a 1.6 net cubic foot sealed enclosure, you'll have a system Q a little over 0.6. I'd recommend going larger if you can, and try to get closer to 0.5. My box is 3 cubic feet, and stuffed with a pound of Poly-Fil it's right around 0.5. It's very responsive, and handles the opening bass tones of Edge of Tomorrow very well, retains the timbre of upright bass in jazz tracks, and handles a symphonic bass drum with transparency.

If you're interested in vented, you're looking at 2x rear-mounted 1.75" dia x 16 2/3" length ports for a port tuning of 21.2Hz. You can probably manage that going 7" in, 90 degree bend, and another 9" or so down. F3 will be about 25Hz, F6 about 20Hz, and the sub will average about 107dB from 30 - 80Hz at 250W. At 25Hz you'll have about 5dB more ouput with vented than with sealed. If nothing else, you could buy a couple of rubber corks and plug the ports whenever you want to try sealed.

Not a bad system plan, but you give up a small bit of subsonic extension with the smaller size vented box. Be that as it may, it still graphs nicely in that size enclosure.



Notice the dip in the cone excursion centered right at the driver's Fs, and the symmetry between the peaks in the impedance graph with the center also at Fs. Those are a couple of indicators of a solid design.

If you prefer, you could use the CSS 12" passive radiator instead of ports, add eleven of the 45g washers for 495g of ballast, and end up with similar tuning (albeit with a sharper subsonic rolloff).

I think a 2.5cu.ft. box with two 2"x13.5" ports would be slightly better, having an F3 of 20Hz and less likely to require bends in the ports. But truth be told, there's only about a 2.5dB difference between the two at 25Hz, and you might never hear enough difference that it'd matter.

Last edited by calraith; 05-11-15 at 09:47 PM.
calraith is offline  
Reply

Bookmarks

Tags
21 , ft3 , sdx12

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










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