The original foam surrounds are almost certainly rotted. Do not play them until refoamed. Buy a specific 12-inch foam kit. The process takes 2 hours per speaker. Replace the dust caps if they are brittle.
The "Extra Quality" label was justified in 1978, and it remains justified today—provided you find a pair that hasn't been abused. For the collector, the tinkerer, or the revivalist, the Pioneer CS787 is a gateway into high-end vintage audio without the high-end price tag. pioneer cs787 extra quality
The Pioneer CS-787 is a vintage 3-way, 4-speaker bass-reflex loudspeaker system produced approximately between 1977 and 1979. Marketed under the tagline "Extra Quality," it represents Pioneer’s mid-tier "CS" (Component Speaker) series during the peak of the silver-faced receiver era. While not as legendary as the HPM or top-shelf CS series (like the CS-99A), the CS-787 is renowned for a distinct "West Coast Sound" profile—characterized by punchy bass and a laid-back, warm midrange—making it a highly regarded entry-level audiophile choice today. The original foam surrounds are almost certainly rotted