A simple device for the preparation of exactly aligned dichotic tapes

A system is described involving three tape recorders and a control device whereby dichotic tapes can be prepared with onset alignment accurate to a few milliseconds, or to a measured asynchrony if required. No modifications of any sort are necessary for the three tape recorders. The two channels are separately recorded in the speaker’s own time, the only requirement being that the separate words be spoken with an interword interval of 350 msec or more, to provide sufficient time for starting and stopping the system. A tone burst is placed directly on tape on another channel ahead of each word, the latter being delayed by recording in tandem through two tape recorders. The first recorder is set to the delay (echo, NAB) facility, while the tone is recorded directly on the second. Subsequently, when this is done for each item on the two speech channels, the device, described below. utilizes the tone bursts to align the two input recorders. It then rerecords each pair of words on to the third (output or dichotic) machine, to the desired synchrony/asynchrony, and interitem interval. The system can be left to align the two channels automatically. A maximum repetition rate of two dichotic pairs every 1.3 sec can be achieved with Revox A77 tape recorders.