AudioNervosa
Systemic Development => Speakers => Topic started by: WireNut on July 25, 2012, 09:00:17 PM
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In a bass application, which setup of the two below is the better loudspeaker design.
Isobaric: Where each driver faces the same direction.
Push Pull: Where each driver faces opposite each other.
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Isobaric loading can be accomplished in a few variations,, all of which must yield push pull. weather drivers are facing cone to cone or magnet to magnet or magnet to cone doesn't matter.What does matter is that they are wired to operate in the same phase...as in both cones moving in the same direction for the same given input. It is this push pull arrangement with air sealed between the 2 cones that couples them and lowers distortion.also lowering the needed enclosure volume to half that of the volume needed for a single driver. The only penalty is a 3db lowering of efficiency and a greater roll off of the upper range of the bass. These 2 coupled cones can be loaded into any enclosure sealed vented etc.
Push pull in a non isobaric setup is simply 2 drivers loaded into a common enclosure one facing opposite wired out of phase. no coupling is achieved twice the enclosure volume is needed and the efficiency goes up 3db. The other way to push pull drivers is in a dipole "open air" setup like Legacy Whispers or 2 woofers face to face mechanically connected to the same voice coil former like in Vandersteen model 5 and I think the model 7. This will lower distortion. Whatever is better is in the application.If your looking for a smaller enclosure sub woofer and don't need mid bass operation I like isobaric. Greg
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Good info Greg. Thanks for the input.
charles
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They both require deep cabinets. So you get more midrange body and bass bloom out of them. What seperates the cheapos from the good ones are their abilities to dissappear in the soundstage i have found. My k104/2 were awesome for dissappearing, still have them.
I think thats what makes the isobaric so popular since they do that well. I have heard some deep (from front to back in inches) speakers that sat there and you knew it. Paradigm speakers are like that. Except for their reference S4 could dissappear.