Cardioid subs for home use? - 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 6th September 2013, 05:17 PM   #1
inguz is offline inguz  United States
diyAudio Member
 
inguz's Avatar
 
Join Date: Jul 2005
Location: MA
Default Cardioid subs for home use?

I'm thinking to experiment with (stereo) cardioid subs:

- Pair of 15" drivers
- One at each end of a short 15"-dia tube, both outward-facing
- Delay the rear driver, by the length of the tube.

Maybe this needs two chambers, back-to-back, instead of a single chamber coupling both drivers. But the whole front-back length should be less than 18" to maintain cardioid pattern to a few hundred Hz. So the enclosed volume is really small.

I don't have much knowledge about how to model this sort of thing, so thinking I should just build it and see what happens. For the cost of an afternoon cutting up tubing...

Before I start, does anyone have experience with this sort of build, or other cardioid subs at home? Do they "work" in a smallish room?
  Reply With Quote
Old 6th September 2013, 06:29 PM   #2
diyAudio Member
 
Join Date: Jan 2008
Separate chambers would be required for cardioid subs.
Cardioid subs are used to reduce level behind the sub, but result in a more ragged frequency response and pattern control of a few octaves centered around a specific frequency.
If by "smallish room" you mean smaller than a theater, no, they don't "work", as low frequency waves are long enough to bounce off opposing walls and fill in the reduced level behind the cardioid subs.
  Reply With Quote
Old 6th September 2013, 08:29 PM   #3
inguz is offline inguz  United States
diyAudio Member
 
inguz's Avatar
 
Join Date: Jul 2005
Location: MA
Thanks, that's exactly the answer I expected

For my (smallish) "Standard American Domestic" living quarters, I'm guessing pattern control in the LF will be dominated by room effects as you say.
  Reply With Quote
Old 6th September 2013, 08:35 PM   #4
inguz is offline inguz  United States
diyAudio Member
 
inguz's Avatar
 
Join Date: Jul 2005
Location: MA
Found a useful reference page with some sawdust examples.

Cardioid bass
  Reply With Quote
Old 6th September 2013, 08:58 PM   #5
diyAudio Member
 
Join Date: Jan 2008
Quote:
Originally Posted by inguz View Post
Found a useful reference page with some sawdust examples.

Cardioid bass
He did a lot of work, and as he says:
"Cardioid cannot fight against reflections from back wall".

Oh well.
  Reply With Quote
Old 6th September 2013, 09:06 PM   #6
sine143 is offline sine143  United States
diyAudio Member
 
Join Date: May 2010
Art, the Nexo Ray sub I referenced in my post (the one I'm trying to mimic) offers cardiod out of a single box(one driver chamber)
  Reply With Quote
Old 6th September 2013, 09:08 PM   #7
diyAudio Member
 
Join Date: Nov 2009
Location: Birmingham, UK
No sawdust pictures and no real idea how they do it but the measurements look pretty decent to me:

RL 801K

Click the 'acoustic diagrams' link.

Last edited by Charles Darwin; 6th September 2013 at 09:11 PM.
  Reply With Quote
Old 6th September 2013, 09:45 PM   #8
diyAudio Member
 
Join Date: Jan 2008
Quote:
Originally Posted by sine143 View Post
Art, the Nexo Ray sub I referenced in my post (the one I'm trying to mimic) offers cardiod out of a single box(one driver chamber)
The Nexo Ray subs use two drivers.
Seems unlikely they would have a single chamber when the two speakers are fed different signal to create different polar patterns.
Have you actually opened a Nexo Ray sub and saw only one chamber?
Pictures or it didn't happen .
  Reply With Quote
Old 6th September 2013, 10:01 PM   #9
sine143 is offline sine143  United States
diyAudio Member
 
Join Date: May 2010
ah curse you art! pushing towards the dark side and whatnot. Maybe i'll get you your pics someday... working that venue tommorrow night
  Reply With Quote
Old 7th September 2013, 03:58 AM   #10
puppet is offline puppet  United States
diyAudio Member
 
Join Date: Dec 2011
Location: The Dells, WI
Quote:
Originally Posted by inguz View Post
I'm thinking to experiment with (stereo) cardioid subs:

- Pair of 15" drivers
- One at each end of a short 15"-dia tube, both outward-facing
- Delay the rear driver, by the length of the tube.

Maybe this needs two chambers, back-to-back, instead of a single chamber coupling both drivers. But the whole front-back length should be less than 18" to maintain cardioid pattern to a few hundred Hz. So the enclosed volume is really small.

I don't have much knowledge about how to model this sort of thing, so thinking I should just build it and see what happens. For the cost of an afternoon cutting up tubing...

Before I start, does anyone have experience with this sort of build, or other cardioid subs at home? Do they "work" in a smallish room?
Just for discussions sake: the rear driver can be 6db down to produce the desired effect of wave cancellation. No need to use an identical woofer when an 8-10" would do just fine
  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
Car Subs for Home Use Thread EWorkshop1708 Subwoofers 28 10th September 2011 08:26 PM
Anyone looked at the JL Audio W7's for home subs pjpoes Subwoofers 12 2nd March 2011 05:09 PM
Possibly Cheap home theater subs! UK RobWells Subwoofers 8 31st May 2008 11:56 PM
Car subs for home theatre Vivek Subwoofers 85 8th June 2007 03:42 PM
Using car amp + subs at home? melvinsmiley132 Everything Else 1 17th September 2005 06:32 AM


New To Site? Need Help?

All times are GMT. The time now is 12:04 PM.


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