EQ Calibration Questions

[_brian_]

Hi all, i'm pretty new to analog recording but am wanting to really get into it. I've read a little about calibrating reel to reels but am a little confused . How can you successfully calibrate a machine with reference tape that is several decadeds old (out of tolerance) for rmg tape that will have a different frequency responce from tape made years ago?

 

[Tim Gillett]

Hi all, i'm pretty new to analog recording but am wanting to really get into it. I've read a little about calibrating reel to reels but am a little confused . How can you successfully calibrate a machine with reference tape that is several decadeds old (out of tolerance) for rmg tape that will have a different frequency responce from tape made years ago?

Just being several decades old doesnt necessarily mean the cal tape is incorrect. More likely it's out because it's been used too many times, or run on a machine which damaged it, etc. I guess the older it is the more likely it's been damaged or used too many times.

Older cal tapes as tapes probably had more tape hiss, less output but that's not normally an issue. They still had the reference tones recorded at the levels stated on the box. If the tapes are undamaged, presumably they will still hold true.

When we calibrate a machine to a cal tape we are only aligning the playback section of that machine to a playback standard.
Then we align the machine's record circuits for the tape type we want to use for actual recordings. We are aligning the record section of the machine using that tape, so that it plays back truly on the (now calibrated) playback section of the same machine.
Two different steps.

There are of course different playback standards, with differing levels and differing playback curves. But even with an old standard cal tape you can still use it as a reference and just adjust levels or eq curves a set amount away from that standard.


Cheers Tim