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TUBE VITALIZER
The Hi-Mid Freq. control is used to set the starting frequency of
a broad-band shelving filter. In line with the setting of Process
Level control, all frequencies above this value right through to the
end of the audio range are processed.
The control range of the Hi-Mid Freq. control is between 1 kHz
(extreme right) and 20 kHz (extreme left). In practice, common
settings vary between 3.5 kHz and 8 kHz.
As the human ear perceives the range between 1 kHz and 3 kHz
particularly clearly, at all volumes between 0 and 120 phon it
makes sense to adapt this frequency range. You might feel
inclined to say “Yes, but I do that with my graphic EQ as well”. The
main difference is that the graphic EQ really reduces the effective
loudness of the frequency, i.e. cuts out the appropriate frequen-
cies, thus changing the spectral content of the original signal. The
Tube Vitalizer, however, relies on a more subtle method of ampli-
tude-depending phase shifting. This does not involve altering the
spectral composition of the signal but it does maintain the
subjective impression of loudness. Moreover, graphic equalizers
produce comb-filter effects because of the interaction between
adjacent filters, when broad-band frequencies are raised. The Hi-
Mid Freq. filter can raise the broad-band spectrum with a very
linear frequency response, without colouring the signal.
Above the Hi-Mid Freq. value set, the Tube Vitalizer filters create
a linear increase, i.e. one that is adapted to the human ear. This
compensates any inability of our hearing as regards perceiving
frequencies ranging between 5 kHz and 10 kHz. The Hi-Mid Freq.
filter work with a wide bandwidth and always sounds musical,
never ‘bell-like’. Gradually go down from 20 kHz (extreme left) to
lower frequencies. The further down you go, the brighter the
sound image becomes, as an increasing number of frequencies
are included in the process.
The Hi-Mid Freq. control can also be used to tone down excessi-
vely sharp-sounding material, by setting frequencies of 10 kHz or
higher, and setting the Process Level control on Max. Seeing as
the Process Level control is also responsible for deleting domi-
nant mid frequencies, all frequencies are gradually reduced down
to the application frequency, in conjunction with high starting
frequencies of the Hi-Mid Freq. control.
Measurement 1:
Bass = Tight
Bass-LC filter = Off
Process Level = Max
Hi-Mid Freq. =
1 / 1,5 / 2,5 / 3 / 5 / 8 / 14 / 22 kHz
Setting the starting
frequency for the shelving
filter to adapt the frequency
range to the hearing
sensation.
No comb-filtering effect as
with graphic EQs.
Hi-Mid Freq.
Control elements
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