Just as a chorus is a group of singers, the chorus effect thickens the sound to make a single instrument sound like there are actually several instruments being played. This work introduces a variant on the classical chorus effects. The classic design does not simulate spectral differences between the unison parts, and can have too much phase cancellation. The new model includes random bandpass filtering to introduce spectral differences, and gives delay scaling factors that result in an appropriate amount of phase cancellation for unison playing. We also consider how detunings between the voices is controlled in our doubling and chorus effects. We have tested our design on representatives of the woodwind, brass, string, and percussion instruments using excerpts from the standard orches...[ Read more ]

Just as a chorus is a group of singers, the chorus effect thickens the sound to make a single instrument sound like there are actually several instruments being played. This work introduces a variant on the classical chorus effects. The classic design does not simulate spectral differences between the unison parts, and can have too much phase cancellation. The new model includes random bandpass filtering to introduce spectral differences, and gives delay scaling factors that result in an appropriate amount of phase cancellation for unison playing. We also consider how detunings between the voices is controlled in our doubling and chorus effects. We have tested our design on representatives of the woodwind, brass, string, and percussion instruments using excerpts from the standard orchestral repertoire. Our listening tests indicate the unison voices have more independence with our variant than with the classic design.