5
Proportional Q
Unlike most other equalizers which use constant-Q filters, the
Q
URE adopts the proportional-Q principle to realize maximum
musicality. Conventional constant-Q designs keep the amplitude
constant,regardless of the adjusted bandwidth (Q).The disadvan-
tage of this is, when it comes to sound creation, frequencies
above and below the center frequency are often boosted so
intensely that they lose their musicality. With proportional-Q it is
quite different; the amplitude of the processed frequency band is
reduced as the bandwidth broadens. Adjusting the bandwidth
back to a narrow bandwidth (high Q), will increase the amplitude
of the center frequency to its former level. Furthermore, with
proportional-Q, there is no need to constantly readjust the
boost/cut control when varying the bandwidth – as is usually
necessary with constant-Q equalizers. It is generally perceived
that equalizers based upon constant-Q designs produce acousti-
cally comparable results, and suffer from limitations in the areas
of sound flexibility and musicality. Often there is only one truly
usable position on the Q-control.
The proportional-Q principle offers a wide range of possible
potentiometer settings and makes it easier to identify the desired
frequencies within the sound spectrum – even subtle nuances
become clearly audible.Equalizing with proportional-Q is therefore
more intuitive and subjectively musical than with constant-Q
equalizers. The Q
URE forms its response curve around the center
frequency with a bell-like response, so that frequencies closer to
the center frequency are emphasized slightly more; frequencies
further from the center are less affected. The development of
these filter curves was the result of extensive listening tests, and
the result is an equalizer that combines technical excellence and
precision with unsurpassed musicality.
The Frequency Bands
The QURE is configured as a two-channel, 3-band equalizer with
a separate hard-bypass switch for each band. The filters are
connected in series. The three filters bands cover a frequency
range from 15Hz to 21kHz. In addition each channel is equipped
with high- and low-cut filters.
Tuning the equalizer is very intuitive because the frequency
control law has been designed to match the characteristics of the
human hearing system.The perfectly linear phase response of the
Q
URE circuitry, combined with its wide bandwidth, contributes to
the sonic excellence of this esoteric equalizer.
The mid-band features the ‘non-reciprocal response’ of the
BOOST/CUT control which qualifies this band to operate as a
notch filter, too. Cutting is allowed to -36dB at high Q (Q5)
whereas the low and high band offer cutting of -15dB. The sonic
advantage of the ‘non-reciprocal response’ design is the vast
dynamic response making the filter sound very open and clear.
With the musical
proportional-Q principle the
amplitude of the processed
frequency band is reduced
as the bandwidth broadens.
Equalizing with
proportional-Q is more
intuitive and subjectively
musical than with
constant-Q equalizers.
The Q
URE is a two-channel,
3-band equalizer with the
filter bands connected
in series
The mid-band features
a ‘non-reciprocal response’
of the BOOST/CUT control
