There is a recurring question as to what is the best way to set azimuth for playing a tape. Many people assume that using the test-tape alignment is best. Well, that makes another big assumption: The recorder used a proper test tape alignment. While that can be the case, it usually is not.
matching head to tape
Playback of NAB 2-track tapes on a DIN Stereo (Butterfly) head
I received a query from Sweden today asking
I have a Studer machine with butterfly heads with which I’d like to reproduce
tapes recorded with normal two track heads. Theoretically, how much more noise,
in dB, would I get from playing the “empty” part of the tape?
Let’s look at the assumptions.
Tape speed, track width, frequency response, and dynamic range
There are complex interactions between tape speed, track width, frequency response, and dynamic range. This article is an attempt to summarize the major influences.
Playing full-track mono tapes
About ten years ago, when I transferred the oldest tapes in the United States as part of the Mullin-Palmer collection, my good friend Don Ososke pressured me to use a full-track head for the project. I had started transferring these full-track tapes with a Woelke NAB stereo (two 80 mil (2 mm) tracks) head and recording both channels. When I obtained a Nortronics full-track head, the difference was night-and-day. The full-track reproduction sounded fuller, smoother, and quieter. There were no tracking problems to speak of that would cause azimuth wander large enough to create a “flanging” or “phasing” effect of in-and-out high-frequency loss.
Capturing both directions of a half-track mono tape
It is possible to capture both directions of a two-sided half-track mono tape in one pass.
The critical factors are:
- Azimuth
- Direction
- Polarity