In VCV Rack 0 dBFS equals 10 V, and 0 dBVU sits at −18 dBFS by hardware convention

Decibel readings in VCV Rack use dBFS (decibels relative to full scale), with full scale defined as ±10 V peak, so 0 dBFS corresponds to 10 V absolute. Meters may also show two other references: 0 dBV (a 1 V reference, rarely used) and 0 dBVU, which sits at −18 dBFS by the hardware convention inherited from analog studio practice (a VU meter reading 0 with typical programme material leaves about 18 dB of headroom up to full scale). Reading these correctly lets you interpret Rack’s scope and meters and set gain staging sensibly: aim programme levels around −18 dBFS — roughly 1.26 V peak — to keep headroom, exactly as in a hardware studio, rather than running signals up near 10 V where the Audio module would clip.

Examples

A signal peaking at 5 V on a VCV Scope is about −6 dBFS (half of full scale = 6 dB down). Targeting 0 dBVU (−18 dBFS) means aiming for peaks near 1.26 V.

Assessment

A VCV Scope shows a kick peaking at 2.5 V. Express that level in dBFS. Is it a sensible level to feed a mix bus, or would you attenuate it, given the −18 dBFS ≈ 0 dBVU target?