Why am I getting better bass with my two "subs" out of phase? - AVS Forum
Forum Jump: 
 
Thread Tools
post #1 of 8 Old 08-03-2013, 01:09 PM - Thread Starter
Member
 
zertman's Avatar
 
Join Date: Jul 2008
Posts: 19
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Liked: 10
Here is my setup for my home theater subwoofers. I have a old Harmon/Kardon AVR-25 receiver as my sub's amp. Connected to it are two Cerwin-Vega Re30 with the tweeters and midranges disconnected. So just the 12" woofers are connected. One "sub" is connect to the left channel output and the other to the right. The "subs" are up against a corner of my room facing out. One sub is directly on top of the other, making a "tower of power" as I call it.

My question is why do I get better, more powerful bass with them 180 degrees out of phase? I always thought that if speakers are in phase there output combines but if there 180 out of phase they try to cancel each other's output out.
zertman is offline  
Sponsored Links
Advertisement
 
post #2 of 8 Old 08-03-2013, 03:19 PM
AVS Special Member
 
Bill Fitzmaurice's Avatar
 
Join Date: Nov 2009
Location: New Hampshire
Posts: 9,540
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 1295
Quote:
Originally Posted by zertman View Post

My question is why do I get better, more powerful bass with them 180 degrees out of phase?
One of them must be wired with reverse polarity inside the cab, or you did so with one of the speaker cables. BTW, you'll get a better result with the subs on opposite ends of the room. Search 'smoothing room modes'.

Bill Fitzmaurice Loudspeaker Design

The Laws of Physics aren't swayed by opinion.
Bill Fitzmaurice is offline  
post #3 of 8 Old 08-04-2013, 06:12 AM
AVS Special Member
 
braveheart123's Avatar
 
Join Date: Jul 2011
Location: Lone Wolf McQuade from Islamabad Pakistan
Posts: 1,816
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Liked: 115
Quote:
My question is why do I get better, more powerful bass with them 180 degrees out of phase? I always thought that if speakers are in phase there output combines but if there 180 out of phase they try to cancel each other's output out.

That's coz may be your room acoustics are kicking in. My front right speaker has to be set out of phase (polarity reversed) in order for it to be in phase with the rest of the speakers. Same speaker when swapped with the left main works fine with correct polarity. The right side of my room causes the right main to go out of phase, which I correct by reversing the polarity.

History is written by those who have hanged heroes ...

The best EQ is no EQ ...

Alpine SWR-1223D Slot Ported HT Sub

Dual Dayton RSS390HO-4 Reference 15 Build For HT

Main System: Klipsch RF-82 II, Klipsch RC-62 II, RS-52 II, Onkyo 5010, Rythmik FV15HP, PSB S300
braveheart123 is offline  
post #4 of 8 Old 08-04-2013, 07:53 AM
AVS Special Member
 
Bill Fitzmaurice's Avatar
 
Join Date: Nov 2009
Location: New Hampshire
Posts: 9,540
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 1295
Quote:
Originally Posted by braveheart123 View Post

That's coz may be your room acoustics are kicking in.
Not when this is the case:
Quote:
One sub is directly on top of the other, making a "tower of power" as I call it.

Bill Fitzmaurice Loudspeaker Design

The Laws of Physics aren't swayed by opinion.
Bill Fitzmaurice is offline  
post #5 of 8 Old 08-04-2013, 10:25 AM
AVS Special Member
 
braveheart123's Avatar
 
Join Date: Jul 2011
Location: Lone Wolf McQuade from Islamabad Pakistan
Posts: 1,816
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Liked: 115
Yes you are right. They are already co-located.

History is written by those who have hanged heroes ...

The best EQ is no EQ ...

Alpine SWR-1223D Slot Ported HT Sub

Dual Dayton RSS390HO-4 Reference 15 Build For HT

Main System: Klipsch RF-82 II, Klipsch RC-62 II, RS-52 II, Onkyo 5010, Rythmik FV15HP, PSB S300
braveheart123 is offline  
post #6 of 8 Old 08-04-2013, 11:08 AM
AVS Special Member
 
steve nn's Avatar
 
Join Date: Aug 2003
Posts: 6,207
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 425
Quote:
Originally Posted by braveheart123 View Post

Yes you are right. They are already co-located.

I have only seen Bill wrong once, but that wasn’t related to SW’s. biggrin.gif

Klipsch RB-75
Klipsch C-7
Klipsch RB-35
On-going SW management class
Denon
PS3
steve nn is offline  
post #7 of 8 Old 08-04-2013, 11:29 AM - Thread Starter
Member
 
zertman's Avatar
 
Join Date: Jul 2008
Posts: 19
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Liked: 10
Thanks for the replies.

I guess when I was rewiring the internal speaker wires I could have accidentally connected one woofer wrong. I will check the internal wires.

My receiver has a fixed crossover for the sub out at 120hz. If I move one sub to the back of the room, wouldn't I notice the higher bass tones coming from the rear? Would making the front sub a little louder combat that?
zertman is offline  
post #8 of 8 Old 08-04-2013, 12:02 PM
AVS Special Member
 
Bill Fitzmaurice's Avatar
 
Join Date: Nov 2009
Location: New Hampshire
Posts: 9,540
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 1295
Quote:
Originally Posted by zertman View Post

My receiver has a fixed crossover for the sub out at 120hz. If I move one sub to the back of the room, wouldn't I notice the higher bass tones coming from the rear?
You will. Time for a better receiver.

Bill Fitzmaurice Loudspeaker Design

The Laws of Physics aren't swayed by opinion.
Bill Fitzmaurice is offline  
Reply Subwoofers, Bass, and Transducers

User Tag List

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


Forum Jump: 

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