Bass strings are the hardest notes for a phone to tune. The low E on a bass vibrates 41 times a second, and the low B on a five-string just 31 times. Most phone and laptop microphones hear almost nothing that low, so ordinary tuners either show nothing or jump an octave up.
This tuner is built for those notes. A low-string helper reads the strong overtones each string makes and works out the real note underneath, then checks it against your bass strings so a reading an octave too high is pulled back to the right string. In our tests with a simulated phone microphone that filters out everything below 250 Hz, every string from low B upward read within a fraction of a cent.
Choose 4, 5 or 6 strings in standard, drop D, D standard, drop C, low B tunings and more, add a capo if you use one, and tap any string to hear it on a real bass sound. The needle and strobe displays, sensitivity levels and noise filter all work as they do on the guitar tuner.
For the clearest reading, pluck with the soft part of your thumb or finger, let the string ring, and keep the phone close to the bass or the speaker of your amp.