< Actually, if you set the azimuth of the replay head to be the same as th < recording head, you do improve the signal and the HF response. It doesn' Not much at all. We are talking halftrack heads or wider and you get phase cancelation if the gap is not perpendicular to the tape travel on record. if the play back head is narrower say using a stereo playback or one of the quad decks then you can tweek some but it still only buys you a little. Keep in mind that impats the upper limit of the HF response and most tape systems were designed to stay way clear of that. The best upper freqency response you could count on was 9-10khz from your 35-50USD portable that was sold for or commonly used. Most modulations schemes were either modem high pair (~2200hz) or phase encoded data (FM) if you FM data using a data rate of TARBEL (187char/SEC) you were using tones that were around 3000hz and 1500hz. TRS80 was in the same range. So the actual bandwidth needed was far less than 5khz. Kansas CITY format was exactly 8cycles of 2400 or 4cyles of 1200 for one or zero. FYI I droped using audio cassette save for when I needed to get some neat software from one format to mine. I went direct saturation where the NS or SN polar flux change carried the information. The same heads at audio that might work at 9khz audio did respectable 9600 baud using FM encoding. LAter I would find some low impedence heads that would allow me to hit a solid 1600frpi (800 bits/inch). This fixed some of the ills that plague audio schemes. < become perfect, but it does get better. VCRs (certainly UK VHS ones) use < this trick to reduce crosstalk between adjacent video tracks (which are < read by different heads on the head drum) and to allow a stereo audio < signal to be recorded under the video track and then replayed by a < separate head at a different azimuth setting. Different world and heads. Heical scan systems the path across the tape is different from linear travel and since the tape effectively moves in two directions operation is different than a portable audio cassette. Allison