dBu
Definition
A voltage-referenced measurement unit used in professional analog audio equipment. 0 dBu equals 0.775 volts RMS. The standard operating level in professional studio gear is +4 dBu; consumer equipment typically operates at -10 dBV.
In Simple Terms
A measurement used by professional analog gear to describe signal level. Most relevant if you're connecting hardware equipment together — mismatching levels between pro and consumer gear creates noise or distortion.
Common Confusion
dBu and dBV are both voltage references but use different zero points. Mismatching equipment operating levels is a common source of unexpected noise or distortion in hybrid analog/digital setups.
Sources & Verification
- IEC 60268-15 — Sound system equipment — Part 15: Preferred matching values for the interconnection of sound system componentsInternational Electrotechnical Commission
- AES48-2005 — AES standard on interconnections — Grounding and EMC practicesAudio Engineering Society
Last verified: 2026-05-04