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Author Topic: Cardoid Design for Sub setup.  (Read 1113 times)

Canute J. Chiverton

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Cardoid Design for Sub setup.
« on: January 24, 2017, 10:33:17 am »

I have a question relating to the Cardoid Setup for Subs as seen in the Photo from an EV Roadshow here in Houston.
Does this design give added db because the subs are in a sense "coupled" or is the design strictly for cancellation from behind?  Thanks
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Chris Tsanjoures

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Re: Cardoid Design for Sub setup.
« Reply #1 on: January 24, 2017, 11:37:18 am »

This design offers a bit of both coupling going forward and cancelation in the real. Also referred to as a gradient array, or reverse end fired.

Some trade offs with this array design: it doesn't sound as good as end fired however offers broadband reduction in the rear.

Where, end fired sounds better but only offers max reduction at a target frequency (two deep).

If you have the opportunity, create the two and have a listen.

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

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Re: Cardoid Design for Sub setup.
« Reply #2 on: January 24, 2017, 12:48:05 pm »

When you use directional subs (either endfire or cardioid), the output will be LESS than the same number of subs placed side by side or on top of each other.

So for 2 subs the output in a directional configuration will be greater than a single sub, and less than 2 subs in a normal configuration.

Some people are spreading the false hood that directional subs produce MORE output than the same number normally setup.

Their "theory" (which has no data or evidence) is that the cancelled sound is somehow wrapped around to the front and added to the front sound.

WHere do they get these ideas----------

Just because you "want" it to do that DOES NOT mean that it will :(
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Ivan Beaver
Danley Sound Labs

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Canute J. Chiverton

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Re: Cardoid Design for Sub setup.
« Reply #3 on: January 24, 2017, 02:15:41 pm »

Thank you Ivan Beaver
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Canute J. Chiverton

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Re: Cardoid Design for Sub setup.
« Reply #4 on: January 24, 2017, 02:16:25 pm »

Thank you Chris Tsanjoures
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lindsay Dean

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Re: Cardoid Design for Sub setup.
« Reply #5 on: January 24, 2017, 02:31:41 pm »

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Kevin_Tisdall

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Re: Cardoid Design for Sub setup.
« Reply #6 on: February 17, 2017, 10:50:37 am »

I have a question relating to the Cardoid Setup for Subs as seen in the Photo from an EV Roadshow here in Houston.
Does this design give added db because the subs are in a sense "coupled" or is the design strictly for cancellation from behind?  Thanks


If I have three subs per side and want to use one backward/reversed phased/delayed for rear cancellation, is it best positioned side-by-side in the middle, in the middle stacked vertically, or on the bottom stacked vertically?   Or does it matter at all?

I have tried the setup pictured live and found that there seems to be just a little more in front.  But I didn't really find that much cancellation in the rear.  I'm hoping to spend more time experimenting with these setups but as I don't have any measurement tools like Smaart (and don't really have the know-how to use them) it will be all by ear.

--Kevin


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Ivan Beaver

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Re: Cardoid Design for Sub setup.
« Reply #7 on: February 17, 2017, 12:32:25 pm »


If I have three subs per side and want to use one backward/reversed phased/delayed for rear cancellation, is it best positioned side-by-side in the middle, in the middle stacked vertically, or on the bottom stacked vertically?   Or does it matter at all?

I have tried the setup pictured live and found that there seems to be just a little more in front.  But I didn't really find that much cancellation in the rear.  I'm hoping to spend more time experimenting with these setups but as I don't have any measurement tools like Smaart (and don't really have the know-how to use them) it will be all by ear.

--Kevin
It depends on where you want the cancellation notch to be.

If you want it straight to the rear-then vertically stack.

If you want it a little bit to one side or the other, you put them side by side.

YES, it does make a difference.


There should have been a good bit of reduction in the rear.

Did you have the proper delay-polarity set on the proper cabinets-along with the proper spacing?

It takes all three setup correctly-delay-polarity and spacing to get the idea to work.

Were there any boundaries nearby?  That will start to throw things off a bit.
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A complex question is easily answered by a simple-easy to understand WRONG answer!

Ivan Beaver
Danley Sound Labs

PHYSICS- NOT FADS!

Kevin_Tisdall

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Re: Cardoid Design for Sub setup.
« Reply #8 on: February 17, 2017, 01:08:00 pm »

It depends on where you want the cancellation notch to be.

If you want it straight to the rear-then vertically stack.

If you want it a little bit to one side or the other, you put them side by side.

YES, it does make a difference.


There should have been a good bit of reduction in the rear.

Did you have the proper delay-polarity set on the proper cabinets-along with the proper spacing?

It takes all three setup correctly-delay-polarity and spacing to get the idea to work.

Were there any boundaries nearby?  That will start to throw things off a bit.


Thanks Ivan -

Yes, there were hard 'theater wings' nearby.  I didn't expect much and I got that :).   I'll play with it a bit more, but yes I had the subs (2 per side) positioned as in the first post picture, reversed bottom one, and out of phase and delayed about 3.5ft.  Trying to cancel around 80hz.

Again, seemed to help a bit with stage rumble, seemed to be a tiny bit easier to get more kik and low bass guitar in the house.  Last time at that venue I just used one sub per side. So I had a bit of comparison as it was also the same band and about the same audience headcount. 

--Kevin
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Luke Geis

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Re: Cardoid Design for Sub setup.
« Reply #9 on: February 17, 2017, 01:48:27 pm »

You may have had better luck delaying the forward facing sub for maximum rear rejection.

3.5' is quite a bit considering the drivers are only about 1' apart. Keep in mind the rear facing sub is essentially trying to place energy in the forward direction. So it was at that point roughly 4.5' delayed in respect to the forward direction with 3.5' of delay.

If you delayed the front sub to line up with the sound that would " wrap around " from the rear facing sub, you would have 2' or more of time difference in the rear, but the sound on the front side would be coupled and in phase. If you were to delay the front so it was 180* from the rear, but in phase with it, you would have maximum rear rejection with the sound in the front only being off by part of a cycle. That is to say the sound from the rear facing sub would lead before the front one, but as the sound comes out of the front sub it would be in phase with the rear still. The rear would be 180* out at all frequencies and you should have maximum rejection.

When you delay the rear facing speaker it is usually done in arrays of three. This is because you can use it to tune out a specific range of frequencies in the rear and it's major effect of the front side is not as bad. You can also tune the front to be in time with the rear facing subs forward energy and it would couple in the forward plane, but have reduced or less controlled rear rejection.
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