A friend just gave me her husband's ESS Heil Rock Monitor 3 speakers. The AMT tweeters work fine and give a great stereo image but he had replaced the 6 1/2" midrange and 10" woofers with cheap car stereo speakers (Hella Beat for God's sake!!). Does anyone know where I could find the specs for right replacement speakers for restoration? I need to know the cross over points, speaker impeadence, etc. Thanks