Frequency Response Graphs for various cassette decks
Measurement Setup:
AudioTester Software in a sine sweep mode.
RME Digi 96/8 PAD sound card.
HP 3478 RMS multimeter.
Sony UX-Pro or TDK SA Type 2 ("Chrome") tapes for recording and playback.
BASF and STL alignment tapes for setting the speed, the playback level, the azimuth and the playback response.
All measured decks were serviced and aligned.
NOTES:
dB scale on the left is relative and set by the sound card, so the value is dependent on the output level of a particular unit.
Please refer to the legend on the right hand side for the graphs explanation.
All decks are measured at Dolby level ("0 dB") and at +6 dB, -10 dB and -20 dB from Dolby level.
On some graphs there are visible "rises" on high-level high frequency parts.
It is a result of an interference between bias and signal frequencies creating low-frequency tones on the tape.
I did not restrict the sweep for higher signal levels as it shows the HF overload behaviour of a deck.
On the X-axis shown the frequency of the sweep generator signal on the deck's inputs
On the Y-axis shown the RMS level measured by the sound card from the deck's output.
In case of HF interference it may be not the same frequency as on the input!
