willythekid said:
Thank you for all of your replies, it helps a lot. I tend to record pretty long songs, therefore I wonder: how long is a 7" tape/10.5" in Minutes (on normal speed).
A totally different question: Should I even consider the TASCAM 488/688 portastudios or is the soundquality to lousy? I don't have anything against a certain amount of tape noise and so on but I still want kind of professional results....
The narrow track width and low tape speed put me off that idea, but I must confess I always wanted a R2R.
I look at it this way:
1" 8-track (1969+, King Crimson, early Pink Floyd, Genesis etc) is 1/8" per track (minus some for the guard bands). Each TRACK is the width of an entire cassette tape.
1/2" 8-track (Tascam 80-8,38,TSR-8, used by Boston & Kansas) gives 1/16" per track. Generally these are used with DBX noise reduction, although the width is still good enough for use without. 2" 24-track gives 1/12" per track.
1/4" 8-track (Fostex, Tascam 388) gives us 1/32" per track. You can't generally use this without NR, either DBX or Dolby. I tried on my A-8 once, it was awful. The 1/2" 16-track B16 has been used commercially, I think Bill Nelson used it a lot. The actual track width is about the same as for domestic cassette, although the R2R machines usually run about 7 times faster which helps.
Cassette 1/8" 8-track gives us 1/64" per track.. IMHO that's just nasty.
(Oh yes, I forgot.. the TSR-8 has integrated DBX noise reduction, the 38 requires an external unit or two).
Now, for recording time, that depends on tape speed, obviously.
The reel is usually measured in feet, a 10.5" spool usually has 2400', although you can get thinner tape with 3600'. If you multiply the feet by 12, you can get the number of inches on the spool. If you divide that by the tape speed in inches-per-second, you'll get the number of seconds. Many people leave the first and last minute of the tape blank, just in case.
IIRC, a 10.5" spool at 15ips gives you around 33 minutes. For mixing down an album you'll need two. I think with 3600' spools you can get around 48 minutes (which still isn't enough for the 49-minute 'Legend of the Black Sun'), assuming you add leader tape on both ends.
Most machines run at 15ips, the 388 runs at 7.5 ips, but then it has a smaller spool size. The fostex machines run at 15ips and use 7" spools.
For 7" spools you usually get 1200' or 1800' tape (Ampex/Quantegy 456 and 457 respectively. 457 is thinner). 456 will give you around 16 minutes of recording time, 457 will give you around 24.