I'm sure that all of the tapeheads on WBF know the importance of repro head azimuth. I was taught this by my good friend Stewart Emmings, who sadly went prematurely to a studio in the sky 2 years ago at the age of 49.
Misalignment of the repro head azimuth leads to loss of high frequency playback, which is much greater on lower speeds and wide tape format, such as reel to reel, and less obvious on 1/8 inch cassette tape. The amount of HF loss is related to track width and tape speed. Hence the HF performance of 15 IPS 1/4 inch 2 track HF replay performance is much more reliant on getting the repro head azimuth correct (see section 3-7 of Morrison's seminal paper in AES) - small errors lead to BIG losses in HF response.
http://aes-media.org/historical/pdf/morrison_stl-manual.pdf
I have about 100 1/4 inch 2 track tapes - some original production masters (2nd gen from stereo mix down) and many dubs from production masters (3/4th gen) - all of these have line up tones at the head, so that I can check repro head azimuth and adjust the frequency response on my repro machine to maximise the sound quality. I do this EVERY time for a new tape coming into my home, which is then copied onto new tape stock as a zero level dub at 15 IPS with Dolby SR (I play the copy and keep the original safe). That's why a studio tape usually has a 15k tone first, so that the engineer can ensure that the tape is played exactly in the manner in which the mastering studio intended.
Repro head azimuth is the same as phono cartridge alignment on a turntable - but imagine that each LP mastering lab might cut the LPs in a slightly different way, so that you would have to align the cartridge on each record to get the maximum out of the groove. Vinyl fanatics (yes I am one of those too) are happy to make sure that cartridge alignment is spot on. Presumably tape heads are the same, or maybe I'm wrong.
Charlie
Misalignment of the repro head azimuth leads to loss of high frequency playback, which is much greater on lower speeds and wide tape format, such as reel to reel, and less obvious on 1/8 inch cassette tape. The amount of HF loss is related to track width and tape speed. Hence the HF performance of 15 IPS 1/4 inch 2 track HF replay performance is much more reliant on getting the repro head azimuth correct (see section 3-7 of Morrison's seminal paper in AES) - small errors lead to BIG losses in HF response.
http://aes-media.org/historical/pdf/morrison_stl-manual.pdf
I have about 100 1/4 inch 2 track tapes - some original production masters (2nd gen from stereo mix down) and many dubs from production masters (3/4th gen) - all of these have line up tones at the head, so that I can check repro head azimuth and adjust the frequency response on my repro machine to maximise the sound quality. I do this EVERY time for a new tape coming into my home, which is then copied onto new tape stock as a zero level dub at 15 IPS with Dolby SR (I play the copy and keep the original safe). That's why a studio tape usually has a 15k tone first, so that the engineer can ensure that the tape is played exactly in the manner in which the mastering studio intended.
Repro head azimuth is the same as phono cartridge alignment on a turntable - but imagine that each LP mastering lab might cut the LPs in a slightly different way, so that you would have to align the cartridge on each record to get the maximum out of the groove. Vinyl fanatics (yes I am one of those too) are happy to make sure that cartridge alignment is spot on. Presumably tape heads are the same, or maybe I'm wrong.
Charlie
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