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B1-GRQ-2-OpGuide-v1-050125.pmd
S
ECTION
T
WO
: A
NALOG
VS
. D
IGITAL
S
IGNAL
P
ROCESSING
Section Two: Analog vs. Digital Signal Processing (DSP)
The ongoing debate continues: what sounds better, digital or analog signal processing? Audio
engineers ALL have an opinion on this, but the lack of documented research on the topic makes
conclusions tentative. Nonetheless, the audio industry is slowly moving to digital as circuit designs
continuously improve and technology advances into the realm of 24-bit resolution — which provides
finer audio detail, particularly at low levels of dynamic range. The tentative conclusion we would suggest
is that the sound of digital circuits is widely variable, encompassing the capacity to sound remarkably
like analog circuits … and much more. Beyond these considerations, however, there are undeniable
advantages to DSP … and one disadvantage that we believe we have solved with the Graphi-Q2.
THE ADVANTAGES
1.
GREATER PRECISION AND REPEATABLE ACCURACY. Analog circuitry produces less exact
and repeatable adjustment. Identical analog circuits may produce different results when process-
ing an identical audio signal, due to the tolerance of components comprising the analog circuit.
Digital circuits rely on repeatable mathematical calculations and thus are more consistent. For
equalizers, this means that the slope, shape, and symmetry of digital EQs are consistent across
frequencies, and from one application to the next.
In addition to the precision attributable to digital processing, the Graphi-Q2 offers a high degree of
operational precision and repeatability as well. On an analog graphic equalizer, the operator must
infer the value of a knob or EQ fader setting from its position. With the Graphi-Q2 Tweek-n-Peek
feature, the exact value of each knob is visually displayed as each setting is adjusted.
2.
LESS PHASE DISTORTION. All equalizers cause some degree of phase shifting. In analog filters,
this phase shift exceeds the width of the filter — often by a considerable margin. In other words,
the phase shift encompasses frequencies beyond the boost or cut range of the filter. With digital
filters, this phase shift can be restricted to within the filter width.
3.
LESS FILTER DRIFT. Analog circuits rely on components that vary as they age and/or are
subjected to different ambient temperatures. This variation can in turn cause analog filters to drift
from their original settings. In contrast, digital filters are based on mathematical formulas and will
remain constant over time and changing temperatures.
4.
LESS NOISE. As analog parts wear, get dirty, or corrode, readjusting them can introduce noise
into the signal path. All audio engineers are familiar with the sound of a “scratchy fader.” Digital
controls affect the signal, but are not actually in the audio path and thus cannot introduce noise.
5.
RECALL AND STORAGE OF SETTINGS. Because digital filters can be represented mathemati-
cally, settings are easily stored, recalled, and copied to other channels or units. Analog filters are
dependent on the physical position of potentiometers and sliders, and storing and recalling settings
requires servo motors and automated repositioning of controls. This is both more expensive to build
and produces less accurate results.
6.
COST. As technology improves, features increase and prices plummet. Nowhere is this trend more
apparent than in the digital world. DSP circuitry is generally smaller, less costly, and more powerful
than comparable analog circuitry, which means you get a lot more bang for your buck (or
DeutschMark, pound, or peso) with a digital box. Compare the price of the Graphi-Q2 to a high
quality analog graphic equalizer, and you’ll see what we mean — especially when you add a
compressor, delay, FBX and parametric EQ, and software interface to the comparison.
THE DISADVANTAGES
1.
FAMILIARITY AND EASE OF USE. The sole disadvantage of digital processors that few if any
sound engineers will argue has to do with the familiarity and user-friendliness of the digital control
interface. Many powerful DSP products are menu-driven and difficult to use. One very special
feature of the Graphi-Q2 GRQ3122 and GRQ3121 models is the familiar analog-style interface of
the front panel. The control surface looks, feels, and operates like a graphic equalizer from the
1970’s — with the power and features of 21
st
century technology. If you’re a 21
st
century technophile
who loves computers and knobs, then you won’t be disappointed either—just plug in a serial cable,
load up the software, and you’ll find a whole new world of hacker-pleasing software control waiting
for your command.
