[Radio Wrangler]

It wasn't just the tape, the pole tips of recording heads could go too vlose to saturation and there was a compromise between hardness for wear versus saturation level of the pole material.

At higher tape speeds, on open reel machines there was also the opposite problem of engineering a long enough pole piece contact with the tape to get good LF response. There are two sampling aperture effects, the distance across the gap and the contact length of the pole pieces.

David