I was inspired by another question on this forum and the number of 'surround' speaker drivers I have lying around.
Bass extension vs Cabinet volume: If I was to use a 3" woofer and 3" 'full range' driver in the same cabinet, cross them at say 800Hz, wouldn't the full range driver work as the woofer's passive radiator at low frequencies?
Bass extension vs Cabinet volume: If I was to use a 3" woofer and 3" 'full range' driver in the same cabinet, cross them at say 800Hz, wouldn't the full range driver work as the woofer's passive radiator at low frequencies?
Yes, but unpredictably. The fullrange driver has a voice coil suspended in a magnetic field being shorted through the amplifier. How it reacts will be shaped by the damping of the back EMF. It's going to be bad regardless. A midrange/fullrange sharing the cabinet volume with the woofer is a recipe to severe distortion at the minimum and, likely, mechanical damage.
This reminds me that there have been a handful of commercial designs (small bluetooth speakers) that did use the fullrange driver as its own passive radiator. The driver as a whole was suspended in its own surround with the tune determined by the compliance and the mass of the entire driver. It's not a path to fidelity by far, but I thought it a clever way to go about it to keep things compact and inexpensive.
This reminds me that there have been a handful of commercial designs (small bluetooth speakers) that did use the fullrange driver as its own passive radiator. The driver as a whole was suspended in its own surround with the tune determined by the compliance and the mass of the entire driver. It's not a path to fidelity by far, but I thought it a clever way to go about it to keep things compact and inexpensive.
Will it act as a PR? No. Because the high-frequency driver isn’t passive, nor will be heavy enough to load it properly to actually help with bass, and the top driver will be attempting to play while it is being pumped, poked, and prodded by the low frequency driver, adding lots and lots of intermodulation distortion.
Ageed, although I think the main point is that for practical purposes, the wideband unit will to some extent (details depending on design specifics) end up being modulated by the other drive unit. I may be mistaken, but I don't think the OP is asking if the wideband could be used as a functional PBR, which isn't going to happen (not happily anyway 😉 ) -just whether that would occur in some way or other.
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