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My brother owns a 29 and I have owned both the 27.5 and the 23.5. The simple answer is get a 23.5.
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I have Sonus Faber Extremas which also have am 87 db sensitivity. They 29's can not drive the Extremas very well and the 23.5's were far and away better in every way over the 27.5 (which is an incredibly good power amp). This one is a no brainer. Get a 23.5 for between $ 2,500.00 - 2,700.00 and smile.
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Rgds,
Larry
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