REEL ATLASTHE ART & SCIENCE OF TAPE
THE ENCYCLOPEDIA / 02

Tracks & compatibility

Same tape width. Very different recordings.

Half-track stereo →

L →R →

Two broad tracks. One stereo programme in one direction.

Quarter-track stereo ⇄

1 · L →2 · R ←3 · R →4 · L ←

Tracks 1 + 3 in one direction; 2 + 4 on the return pass. Schematic, not to scale.

FormatTypical purposePractical consequence
Full-track monoEarly mono / broadcastOne signal across almost the full width.
Half-track monoTwo mono sidesNot the same programme layout as half-track stereo.
Half-track stereoStudio and modern tape editionsTwo channels use most of the tape width; normally no second stereo side.
Quarter-track stereoDomestic music collectionsTwo stereo sides; greater playing economy, narrower tracks.
Four-track / four-channelMultitrack or quadraphonicFour simultaneous channels require suitable heads and electronics.

Before pressing Play

Does four-track always mean four-channel?

No. Domestic four-track stereo commonly means four physical tracks carrying two stereo programmes in opposite directions. Four-channel recording uses four channels simultaneously.

Can I turn every reel over?

Only when the recording format provides a return programme. Turning over a half-track stereo album does not reveal another stereo side.

Are all two-track machines interchangeable?

Check tape width, track dimensions, mono/stereo configuration, speed, EQ and any timecode or pilot track. Model names alone are insufficient.

Read the references

IASA — deterioration during replay ↗Studer — original A810 manuals archive ↗Akai — original 4000DS operator manual ↗Otari — original 1991 series data sheet ↗