HUM Suppressor

The measurement of electrical impedance, as well as audio recordings with High-Z input, are prone to power line hum (or mains hum), which is mainly due to the alternating current in the powerline network. HUM Suppressor provides a simple software-based solution to this issue.

The purpose of HUM Suppressor is to isolate the interference signal from the useful one, rerouting the latter to the sound card output device. It targets both the standard 50 Hz and 60 Hz frequencies of the main hum and the harmonic frequencies that go up to 6 kHz.

As for the signal frequency, the application supports a range that goes from 0 Hz to 96 kHz, depending on the sound card in question and the operating system iteration.

Focusing on functionality more than looks, the interface of HUM Suppressor is unsophisticated, enclosing all the options into a single window. You start by choosing the input and the output devices, then you can move on to parameter adjustments.

The sampling rate you select must be correlated to the the signal bandwidth you want to obtain. You can also choose the bit depth from a drop-down list. HUM Suppressor also features a slider to manually control the gain, as well as automatic gain control.

There are two different modes for hum suppression: while the brute force mode is more efficient in hum removal, it produces more pre-ringing effect in comparison with the "normal mode". The difference between the wide and the narrow filters stands in the supported frequency range.

HUM Suppressor enables you to experiment with various levels of the parameters to ensure the input signal gets filtered without compromise on quality. The distortion level must be kept to a minimum, regardless of the type of the input signal.