The VSM was reviewed in stereophile at the link below, in the measurements section the VSM is seen to have one of the flatest frequency responses I've ever seen. Also, it can be seen that the drivers are connected in positive polarity.
http://www.stereophile.com//loudspeakerreviews/439/index.html
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http://www.stereophile.com//loudspeakerreviews/439/index.html
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