Measuring range +/- 0.256V over 16 bit resolution @ 16x gain, with a 0.0078125mV per step.
One could measure phono cartridge to see if there any magnetic fields present that could affect the sound quality (to get the voltage, multiply the value on the screen with this number, 4k video) Arduino and ADS1115

Related:
https://hackaday.io/project/11865-3d-magnetic-field-scanner
https://hackaday.io/project/12603-3d-vectorfield-scanner-for-magnetic-flux
Also think Hall effect sensors and compas IC's