Froggy(wawaron), as Jason points out, the internal amplifier in the sub is what is actually powering its driver. As long as it has enough output voltage for the needed sub sound level, that's all it does. The "control" of the sub is determined almost entirely by the parameters of its driver and the tuning of the enclosure. The amplifier damping factor, as long as it's anywhere in the double digits, doesn't significantly affect the sound and shouldn't be a cause for concern.

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Enjoy the music, not the equipment.