Summing many oscillators in additive synthesis accumulates noise floor whereas subtractive synthesis can filter noise away

Each oscillator or partial in an additive synthesis patch contributes a small amount of inherent noise. When tens or hundreds of partials are summed, these noise contributions add together, raising the overall noise floor of the result. Subtractive synthesis avoids this accumulation: a single noisy oscillator passes through a filter that removes frequency content, and the noise is also attenuated where the filter cuts. This is a real engineering trade-off when building additive patches — more partials for realism, more background hiss as the cost.

Examples

A 32-oscillator additive patch on Nord Modular will have measurably higher noise than a single VCO run through a VCF. Keeping gain levels low per partial and summing into a mixer helps; using the sine-bank oscillator (which shares DSP budget) also concentrates noise less than 32 separate oscillator modules.

Assessment

Describe why a 64-partial additive patch is noisier than a 4-partial one, and explain why the same problem does not arise in subtractive synthesis.