Hi Tony. welcome to the Shack. I would suggest finding a center with as close a sound signature match to your mains as possible. The front 3 should be voice, timber, etc. matched to present a smooth sound stage on the front. Have fun. Dennis
Thanks for all the advice. I had previously been looking at the Polk CSI A4 center. I went to the store today for a listen. The A6 had a deeper sound that would pair better with the Yamaha's, but is too big for the space I have. Is it worth trying to pair new speakers to those made in the 70's? Should I just buy new Polk fronts to match the new center and move the Yamaha's to the surround position?
Also, any advice on how to best match sound signature between speakers at home and speakers in the store?