MRL Tape Equalization Calculator gives the adjusted signal level and frequency when you have an MRL tape, but you need to calibrate for a different speed and/or equalization
Polartape Tape EQ Calculator is similar to the MRL Equalization Calculator, and also includes some nice graphs and supplemental technical information
Recording the Masters (RTM) manufactures and sells blank open reel magnetic tape; primarily SM900 and SM911. Formerly RMGI or BASF
ATR Magnetics manufactures and sells blank open reel magnetic tape. Historical relationship to Ampex and Quantegy
AES Historical Committee hosts information on the history of audio engineering (including magnetic tape recording)
