As a rough generalization, older records tended to be cut with grooves that went closer to the label. As mastering engineers got better at altering groove spacing to match the groove modulation, more music could be packed into any given space, so the necessity of cutting close to the label went down. Also, narrower profile styli (e.g., Shibata, van den Hul, other line contact) and other cartridge developments have made inner groove tracking less problematic. That means that the issues Stevenson alignment addresses is less of a concern these days.
Curved and Straight Tonearms
Over the last 40 years I have owned 3 turntables. An entry level Dual from the '70's, a Denon DP-52F (which I still use in my office system) and a Rega P3-24 which I currently use in my main system. All of these turntables have had straight tonearms. I am planning on upgrading my Rega in the near future. Having started my research, I have noticed that some well reviewed turntables have curved 'arms. My question: What are the advantages/disadvantages of each, sonic or otherwise? Thanks for any input.