I worked for Polk in the late 70's and helped to design the RTA12. I prefered the sound of the Model 7 to the model 10. It would not play as loud, but offered a more clear voice and balanced tone. The 10 could get boomy and the mid-bass a bit defocused. The RTA12 was a better choice over the 10 as a lot more went into the crossover design and a lot more testing to get it right.
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