34B Frequency Response Calibration

[R. D. Davis]

When calibrating a tape deck, such as a 34B, should the
frequency response on all channels, and for both the sync
and repro. heads, be nearly identical, well within 0.50dBV to
1.0dBV?

Also, why is there nearly a 2dBV increase at 63Hz and about a
2dBV decrease on each head/track at 125Hz? Also, I'm getting
less than 1dBV down at 32Hz, which makes me wonder about
why 40Hz is specified as the low-end response... is this
typical?

Lastly, when calibrating the heads for azimuth, should there
be some slight variation at 8kHz and 16kHz? E.g, when
adjusted for as much of a straight line from the lower-left to
upper-right quadrant as possible, it varies from a very slight
hint of the oval to the straight line for both the sync and
repro heads.

Now, if only I didn't have to remove the dx-4d from the rack
stand and then the bottom panel from the 34B for each
calibration. :-) Are pro decks typically less of a hassle, e.g., just
flip a panel or something open to get to the trim-pots, etc.?