I N T R O D U C T I O N
Echobode is a delay effect with a frequency shifter placed inside the feedback
loop. The frequency shifter algorithm is inspired by the classic Bode
Frequency Shifter (named after its inventor Harald Bode). The difference between
a frequency shifter and a pitch shifter is that it shifts the audio spectrum
linearly. E.g. an overtone series of 100, 200, 300 Hz can be shifted by 50 Hz to
150, 250, 350 Hz, making the overtones inharmonic. This effect in itself is
great for creating metallic bell timbres, but putting it inside a delayed
feedback loop opens up many other possibilities.
When a frequency shifter processes audio, two “sidebands” are generated, one
that is shifted upwards and one that is shifted downwards. The challenge in
creating a good frequency shifter
lies in suppressing one of these
sidebands (otherwise the effect
sounds like a regular amplitude
modulator). We are proud to say
that Echobode features excellent
suppression over the range of 40
Hz to 20 kHz. If you want less
suppression, there is a “sideband
mix” parameter that you can
adjust, allowing you to create
amplitude and ring modulation
effects.
Echobode features a unique “anti-
reflection” stage that removes
“negative” frequencies (frequencies
that are shifted down beyond 0 Hz
and would otherwise bounce back
into the audible spectrum). This
