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Old 4th December 2011, 09:02 PM   #1
Zero D is offline Zero D  United Kingdom
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Question TH Phasing

I havn't seen mention of the way TH's are phased ?

Are most people using drivers with the cones facing inwards towards the throat, connecting the Amps Positive terminal to the Positive driver terminal eg: in phase.

If so, doesn't that mean they are out of phase with the mains ?
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Old 4th December 2011, 09:34 PM   #2
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Originally Posted by Zero D View Post
I havn't seen mention of the way TH's are phased ?

Are most people using drivers with the cones facing inwards towards the throat, connecting the Amps Positive terminal to the Positive driver terminal eg: in phase.

If so, doesn't that mean they are out of phase with the mains ?
You are writing about polarity, phase is different at every frequency.

Positive voltage making the cone go towards the horn throat is "normal" compared to a front loaded speaker.
A delay approximately corresponding to the horn path length then needs to be added to the top cabinet for "in phase" response through the crossover region..
For tapped horns with a path length approximating one wave length at the crossover frequency, one can observe an "in phase" response at crossover, but the TH will actually be lagging by one wavelength and will not sound as "punchy" as it will if the tops are time aligned.

Art Welter
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Old 5th December 2011, 04:57 AM   #3
Zero D is offline Zero D  United Kingdom
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Quote:
Originally Posted by weltersys

You are writing about polarity
Hi yes, but as it's often referred to as Phase Reversed or Out of Phase, when a driver cone is facing that way, that's why i said that.

So TH designs that have the magnet facing the throat, should be Polarity reversed then, either directly at the Amp or Driver/s, or via an Active Xover ?

I've not seen Any mention of this !
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Old 5th December 2011, 06:39 AM   #4
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Quote:
Originally Posted by Zero D View Post
So TH designs that have the magnet facing the throat, should be Polarity reversed then, either directly at the Amp or Driver/s, or via an Active Xover ?

I've not seen Any mention of this !
Agreed.

I use a 4th order LR crossover (active, of course) on mine and found a big suckout at ~80Hz when everything was wired +ve to +ve.
Reversed the wiring of the subwoofers, and all is well.
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Old 5th December 2011, 01:45 PM   #5
Zero D is offline Zero D  United Kingdom
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@ chris661

Quote:
agreed


Glad you were able to eliminate the suckout

Regards
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Old 5th December 2011, 11:19 PM   #6
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Quote:
Originally Posted by Zero D View Post
Hi yes, but as it's often referred to as Phase Reversed or Out of Phase, when a driver cone is facing that way, that's why i said that.

So TH designs that have the magnet facing the throat, should be Polarity reversed then, either directly at the Amp or Driver/s, or via an Active Xover ?

I've not seen Any mention of this !
Yes, polarity is often confused with phase.
Yes, if the magnet was facing the throat, polarity should be reversed.

Positive voltage should make the cone move towards the throat.

Most tapped horns have the magnet facing the mouth, and the front of the cone faces the horn throat, so should use "normal" polarity.

That said, the horn path length still needs to be accounted for by delaying the top cabinets by (approximately) the path length difference between the top and bottom cabinets.

Art
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Old 6th December 2011, 07:15 PM   #7
Zero D is offline Zero D  United Kingdom
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@ weltersys
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