What is the difference between a 4-head VCR and a 2-head VCR?
In a two-head VCR, the heads are utilized in both the SP and EP recording and playback modes. This results in much lower quality EP recordings and special effects. A four-head machine uses two heads for SP and the other two heads for EP. Why: This allows implementation of narrower head-gap room for the EP heads, resulting in higher quality EP recordings and special effects.