Ciao Rhino. The question about the Kef 107 Kube is timely as I just wrote the following for an ad I'm in the process of creating. Hope this helps.
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The Kube's Preset Function
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Each pair of KEF 107s left the factory with a Kube unique to that specific speaker pair, and identified with a serial number identical to each speaker in that pair. An essential function of each Kube is to equalize the midranges and tweeters in their speaker pair to achieve frequency and sensitivity matching to within 0.5db or less. As such, each Kube (with its preset equalization factory customized via internal adjustments) is part of the design of a particular pair of KEF 107s and should be used with that pair in order to meet factory specifications and maximize the fidelity achieved.
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The Kube's User Adjustments
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How low bass response extends, another essential function, is User adjustable via a lower cut-off control with choice of 18Hz, 25Hz, 35Hz, or 50Hz. In addition, users can vary bass reproduction from being quite loose to quite tight and anywhere in-between. Also, the response below 160Hz can be increased or decreased by as much as 3dB. These user adjustments enable controlling speaker output to correlate to one's tastes, room requirements, and the music played.