User Manual

Duende Native User Guide Page 37
Gaussian
N
o ringing or overshoot in the time domain, but slow roll-off in the frequency
d
omain.
Butterworth
Characterised by having a maximally flat magnitude response, ie. no
amplitude ripple in the passband.
Chebychev
Characterised by having an equiripple magnitude response, meaning the
magnitude increases and decreases regularly from DC to the cutoff
frequency.
EQ HISTORY
An Audio Engineer’s Best Friend
The equaliser is the oldest and the most popular sound processing tool. From the earliest days, its main function has been
to correct or enhance sound by boosting or cutting certain frequency ranges. Engineers have developed countless equalisers
for over 50 years and some of them became legendary and were considered bench marks. The most popular type of EQ in
recording and post-production studios is the parametric equaliser or PEQ. It offers maximal flexibility due to direct access to
all relevant filter parameters. Properly used the PEQ is a very powerful tool and the best friend of every sound engineer in the
battle for perfect sound. If misused, it can be the greatest enemy of any recording.
The Best of the Analogue and Digital Worlds
X-EQ is a creative equalising tool combining the best of both the analogue and digital worlds. We recreated the most legendary
analogue equalisers and added a few experimental characteristics only possible the in digital domain. By using proprietary
filter algorithms, we have achieved a huge dynamic range as well as extremely low noise and distortion level, and thus
unparalleled sound purity; impossible with any analogue circuitry.
Analogue Parametric EQ Modelling
In today’s era of digital audio workstations, hundreds of software parametric equalisers are available. Many of them are
intended to be “THE best sounding equaliser ever”. The truth is that only few of them are recognised and adored by the
experts. You may ask why one equaliser sounds great while another does not. This question is almost as old as the equaliser
itself and still is not completely answered. On the one hand there are some obvious rules which must be followed when
designing a good sounding PEQ, on the other hand some never really proven esoteric claims driven by marketing departments
or self-nominated audio evangelists. Especially treasured analogue equalisers are considered by some people as being
absolutely unique and unmatched by any ‘dirty’ digital equaliser. The truth is that with a properly designed, fully parametric
analytic EQ every amplitude and phase characteristic of any other equaliser setup can be recreated. Of course, the contribution
of distortions to the specific sound of a particular analogue equaliser caused by the respective electronics has to be
considered. If the distortions are ‘good’, they may make certain applications sound better. Usually however, ‘bad’ non linear
distortions and other deficiencies like limited dynamic range are surely not responsible for a ‘magic’ sound. Therefore our
policy in digital PEQ design has always been to make the equaliser filters as precise and clean as possible. For controlled
generation of distortions we recommend using enhancers or any other specialised processors with proper built-in anti-aliasing
technology.