How to Tune a Cello Online
Cello is tuned CGDA: same intervals as viola but an octave lower. The C2 string vibrates at just 65.41 Hz, low enough that some laptop and built-in mics struggle to detect it clearly. For best results, use a close mic or plug an electric cello directly into an audio interface. Tune A first using the 220 Hz reference, then work down: D3, G2, C2. Each string is a perfect fifth below the previous.