Why audio gear hums at 60 Hz
Alternating current in North America cycles 60 times per second (50 in Europe, most of Asia, Africa, and Australia). When that AC leaks into an audio signal path - through a ground loop, an unshielded cable running near a power cable, or a failing power supply - it is reproduced as an audible hum at exactly the grid frequency.
Real-world hum rarely appears alone: rectification and magnetic coupling generate harmonics, so a ground-loop problem typically shows energy at 60, 120, 180, and 240 Hz. A hum dominated by 120 Hz usually points at a power supply (rectified AC doubles the frequency); a purer 60 Hz tone points at direct induction or grounding. Get familiar with the sound using the player above, then confirm what your system is doing with our spectrum analyzer - the peak readout will name the frequency.
Fixing hum, in order of likelihood
First, find the loop: disconnect sources one at a time until the hum stops - the last cable removed is carrying it. The most common fix is breaking the ground loop: plug all connected equipment into the same outlet or power strip so their grounds meet at one point. For stubborn source-to-amp loops, an isolation transformer (hum eliminator) in the signal path is the safe solution. Never remove a safety ground pin - that trades a hum for a shock hazard.
Cable-induced hum has simpler fixes: separate signal cables from power cables (cross them at right angles if they must meet), use balanced connections where available, and replace damaged shields. Turntable and guitar hum usually respond to reseating the dedicated ground wire.
60 Hz as a test tone
Beyond hum diagnosis, 60 Hz is a genuinely useful bass test frequency: high enough that most bookshelf speakers and better headphones reproduce it cleanly, low enough to exercise a subwoofer and reveal cabinet rattles. It sits just under B1 (61.74 Hz) - about 50 cents flat, almost exactly a quarter tone.
Play it at moderate volume and listen for buzzing (loose grille or cabinet panel), port chuffing, or the tone dropping out entirely (system cannot reach 60 Hz - common for small speakers). For a full low-end workout, follow with our subwoofer test, which sweeps from 150 Hz all the way down to 1 Hz.