ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: [1]   Go Down

Author Topic: Cardioid sub  (Read 2202 times)

Joe Seliski

  • Newbie
  • *
  • Offline Offline
  • Posts: 22
Cardioid sub
« on: January 06, 2016, 01:17:20 pm »

I was using a pair of QSC K subs at an outdoor event.  Sounded fine out front.  In the middle of the stage area however was a loud, annoying low frequency thing happening - .  Isn't this the phenomena that using a cardioid sub setup is designed to cure?  If so - can this be accomplished with somehow setting up a cardioid system with lets say a pair of QSC KW18 or other types of powered subs?  (not mentioning the Ksubs as I am getting rid of those anyway)  possible using the delay settings available on the digital boards?

Logged

Jerome Malsack

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1370
Re: Cardioid sub
« Reply #1 on: January 06, 2016, 01:55:58 pm »

No,  It sounds like you had them separated, one to each side. 

Cardioid sub reduces the sound behind the subs and on stage.

When separated one to each side they will have varied interactions that are based on the distance of the separation, and the frequency of the signal.  It will vary between the frequency. 

When in a room the acoustics of the room will also come into play. 

This is why most advice is to place the subs together. 
Logged

Joe Seliski

  • Newbie
  • *
  • Offline Offline
  • Posts: 22
Re: Cardioid sub
« Reply #2 on: January 06, 2016, 02:02:35 pm »

No,  It sounds like you had them separated, one to each side. 

Cardioid sub reduces the sound behind the subs and on stage.

When separated one to each side they will have varied interactions that are based on the distance of the separation, and the frequency of the signal.  It will vary between the frequency. 

When in a room the acoustics of the room will also come into play. 

This is why most advice is to place the subs together.

yes to confirm - the problem was actually on stage and physically behind the subs
so "subs together" means perhaps directly in front of stage??
Logged

Jerome Malsack

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1370
Re: Cardioid sub
« Reply #3 on: January 06, 2016, 02:13:36 pm »

Subs together can mean in front of the stage or off to a side. 
You may also need to delay to get the tops and the subs in time.

Yes the stage can be helped with cardioid subs but this is down outside mostly because the room acoustics will be a problem still.
  It is something you can test on site for best sound.
Logged

Tim McCulloch

  • SR Forums
  • Hero Member
  • *
  • Offline Offline
  • Posts: 21871
  • Wichita, Kansas USA
Re: Cardioid sub
« Reply #4 on: January 06, 2016, 02:35:59 pm »

yes to confirm - the problem was actually on stage and physically behind the subs
so "subs together" means perhaps directly in front of stage??

Center clustering the subs will not reduce the amount of LF wash on the stage, but it will make it somewhat more uniform.  You will still have the strongest lobe right down the center of the deck.

Putting subs (any format of deployment, too) on each side of the stage creates a dipole array with the lobe centered between the speakers in a rather "figure 8" pattern so it's prominent on the stage as well as in the house.  Using a cardioid array reduces the amount of energy on the sides and behind the array in a rather narrow frequency band (about 1/2 octave either side of the desired frequency of cancellation).  This helps the "power alley" affect of dipole arrays but does not eliminate it.  At a show for Michael McDonald we had to delay one side (SR, IIRC) of the cardioid subs to steer the remaining lobe somewhat to the side, as his piano was right in what was left of power alley on stage.

You can experiment with various directional sub arrays with prediction software - Meyer's MAPP, Merlijn van Veen's (moderator of the PSW Measurement forum) prediction software, and others.  For a good time go to the main LAB forum and find the topic about "so much bass the SSD drive skips" and look at the arced sub array in the picture - guaranteed to put the most bass in the back focal point (right where the DJ and his computer were).  Great for the audience but the absolute wrong thing for the talent.

Clustering subs on 1 side will create other issues with the PA mains on the opposite side of the stage - there's no way to align.  None.  Zip, nada, zero.  Also note that any alignment is valid for only 1 spot in the room.  That's physics.  Our job is to make the adult-in-the-room decision about who gets that sweet spot and who (many who) does not.
« Last Edit: January 06, 2016, 02:38:19 pm by Tim McCulloch »
Logged
"Practicing an art, no matter how well or badly, is a way to make your soul grow, for heaven's sake. Sing in the shower. Dance to the radio. Tell stories. Write a poem to a friend, even a lousy poem. Do it as well as you possible can. You will get an enormous reward. You will have created something."  - Kurt Vonnegut

Stephen Kirby

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3006
Re: Cardioid sub
« Reply #5 on: January 06, 2016, 06:05:51 pm »

Also, a floppy stage will make for some boom that the musicians hear.  Worse if the subs are in front of it, worse still if they are under it.
Logged

ProSoundWeb Community

Re: Cardioid sub
« Reply #5 on: January 06, 2016, 06:05:51 pm »


Pages: [1]   Go Up
 



Page created in 0.018 seconds with 19 queries.