cardoid sub array

[walters]

i am offering help to a local band that has accumulated eight qsc hp series powered subs. i had mentioned they probably wont be able to hear their backline on stage. i am sure i can figure out delay times. but since their subs run from 40hz. to 100hz. what frequency do i use to calculate delay. i will probably have one sub under each main on stage. in front of stage two clusters of three, two facing out one facing in. but at what frequency do i set delay? is it at 40hz. or 100hz or somewhere in between?

 

[walters]

and thank you in advance.

 

[walters]

Never mind. I figured it out. Thanks anyway.

 

[turk 182]

would you care to share your solution for the enlightenment of others?

 

[Timo Beckman]

You might check e few of the links below

http://timobeckmangeluid.wordpress.com/2013/09/03/gradient-or-reversed-end-fired-sub-array/

http://timobeckmangeluid.wordpress.com/2013/09/05/gradient-or-reversed-end-fired-as-i-call-it/

http://timobeckmangeluid.wordpress.com/2013/09/04/end-fired-sub-array-first-with-delay-then-with-2nd-order-all-pass-filters/

http://timobeckmangeluid.wordpress.com/2013/09/05/end-fired-sub-array/

http://timobeckmangeluid.wordpress.com/2011/11/16/csa-the-cardioid-sub-array-according-to-some-from-db/

http://timobeckmangeluid.wordpress.com/2011/11/14/the-gradient-sub-array-or-reversed-end-fired-as-i-call-it-english-only/

http://timobeckmangeluid.wordpress.com/2011/11/08/end-fired-sub-array-only-in-english/

 

[walters]

thank you for your interest and links. I do not have the luxury of computer software.
all i have access to is two cheap active x-overs with delay. I was thinking since there is not a 5 string bass I would just cross higher, around 60 hz. delay the front facing, outer speakers slightly less than quarter wave length as a start point. to the rear facing speaker which will be 180 degree's out of phase. now the two on stage may be used as risers for mains. I am not sure if the presonus mixer has all pass filters or not. I am from the analog days and retired. turned out they decided not to do anything. these guys are old rock and rollers. they probably can't hear anything anyway. but I do worry about infants, children standing too close to 140db. subs. this might be for an opening of a new amusement park. thank you again for interest.

 

[Timo Beckman]

You might try to delay the back facing sub to the front facing subs (i.e. match phase measured at the back (stage side) of the array which means you have to delay the one facing the stage side).
After that ø reverse the "stage facing" sub and most problem frequencies will reduce anywhere between -6 to -18db

 

[JonSnell Electronic]

You might try to delay the back facing sub to the front facing subs (i.e. match phase measured at the back (stage side) of the array which means you have to delay the one facing the stage side).
After that ø reverse the "stage facing" sub and most problem frequencies will reduce anywhere between -6 to -18db

If the PA is used in a hall, place the subs together. Outside venues don't matter as there is no reflection to cancel the bass.

 

[walters]

Thanks timo it makes sense to delay one sub per side. I might be able to get some attenuation from subs with the little equipment available to me.