The Cross-Field Head System: AKAI used this type of head system in the late 1960's to the mid 1970's. There is a Bias head located under the recording head which is utilized for higher frequency response at the slower speeds like 3 3/4 inches per second. This would mean the tape would sound just like other decks recorded at 7 1/2 inches per second or even better. The following decks used this feature: X-100/D, X-150/D, X-165/D, X-200/D, X-201/D, X-300/D, X-330/D, X-355/D, X-360/D, X-1800SD, X-1810/D, X-2000SD, X-5000W, X-IV, X-V, M-7, M-8, M-9, and M-10. Heres a picture: