Radulescu described spectral techniques as "a conceptual reply (2000 years later) to Pythagoras, and a realisation of the intuitions of both Hindu and Byzantine music, which were closest to natural resonance". The wariness of labels stems in part from a mistrust of compositional orthodoxies, serialism in particular, from which many spectral composers were trying to escape. 

The notion of “instrumental additive synthesis” often features prominently in spectral composition. A combination of instrumental sounds with the appropriate frequencies and intensities can fuse into a single timbral entity. In contrast to some approaches to timbral composition, instrumental color tends to be exploited not for its differentiating abilities but for its potential to participate in spectral fusion. Thus individual instrumental timbres are subsumed into larger musical structures.

In some spectral works, harmonic models are derived from characteristic spectra of instrumental sounds. The goal of instrumental additive synthesis is never to recreate, but rather to reveal latent musical potential is pre-exisiting sonic material. The archetypal gesture of instrumental additive synthesis is the arpeggiated spectra which gradually transforms from a series of individual tones to a fused complex.

Pitch and rhythm: continuous rather than discretee

​timbre: mix