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Old 5th November 2012, 10:17 AM   #11
Moonfly is offline Moonfly  Spain
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Quote:
Originally Posted by muddasirwaheedmalik View Post
Ok. lets not say its pull push. its dual driver in sealed configuration magents facing each other. its more like dipole for reducing distortion and reducing room interaction and to save foot print.
Any one having any idea of KEF KAR S-380 and behringer MP pro 1800 and/or peavey GPS 2600. i am still wondering how the amp clips without the subs bottomin out ?
Just for clarification, push pull works like this:

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Dual opposed is like this (drivers opposite each other in this cab):

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Isobaric is like this:

Click the image to open in full size.

Push pull is the only one that really offers improved distortion reduction over a standard driver config, though how noticeable it is in high end designs is up for debate, I couldnt tell in my own testing unless the subs were really pushed hard. With your clipping issue, its not a given that drivers will be pushed to their mechanical limits when the amp hits its limits. There are drivers out there that when placed in an optimally size enclosure, wont ever hit their mechanical limits, even with their maximum rated input power power available. It sounds like your drivers might fall into that category, assuming your amplifier isnt under rated.
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Old 5th November 2012, 11:28 AM   #12
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Bipole
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Old 5th November 2012, 04:57 PM   #13
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"Thats not push pull though. Push pull requires two drivers to share the same cabinet volume space, and for one driver to face into that cabinet while the other faced out. Then, to ensure the drivers remain mechanically in phase, they are wired out of phase. The isobaric configuration doesnt do this. "

The 2nd harmonic cancellation is what defines P-P, and from that standpoint, yes, you can make a P-P isobaric.

The original isobaric was done by RCA decades ago, it used a 15 on the front and a 12 behind it. This, of course, could not be made P-P (because the drivers were not identical).
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Old 5th November 2012, 05:19 PM   #14
sreten is offline sreten  United Kingdom
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Hi, Its "force cancelling" not "push pull", rgds, sreten.
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Old 5th November 2012, 05:54 PM   #15
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So, back to your original question, given what you plan to do (sealed with magnets touching and both drivers facing outward in dipole config) seems to me you need twice the volume.
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Old 5th November 2012, 08:24 PM   #16
Moonfly is offline Moonfly  Spain
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Quote:
Originally Posted by djk View Post
"Thats not push pull though. Push pull requires two drivers to share the same cabinet volume space, and for one driver to face into that cabinet while the other faced out. Then, to ensure the drivers remain mechanically in phase, they are wired out of phase. The isobaric configuration doesnt do this. "

The 2nd harmonic cancellation is what defines P-P, and from that standpoint, yes, you can make a P-P isobaric.

The original isobaric was done by RCA decades ago, it used a 15 on the front and a 12 behind it. This, of course, could not be made P-P (because the drivers were not identical).
Ye sure iso can be made P-P, and following on from that, dual opposed could also be push pull. The main reason to go Isobaric is to make a cabinet smaller, but its much less efficient as it only really matches single driver performance and needs twice the power, plus your paying for two drivers instead of one.

To help be more specific about the original question, Isobaric would mean a cabinet half the size, for any normal configuration, you have to double the cab volume every time you double the number of drivers. If one driver needs 2.5 cu ft, then every time you add another driver, you need to increase the cabinet volume by the same amount.

@ JMillerDoc, dipole wouldnt work for a subwoofer as in a dipole speaker the drivers are out of phase, which doesnt work for subwoofers.
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