Extreme Power Line Hum

[alex-m]

Hey there!
Is there a chance to remove or reduce a very bad power line hum (attached sample)?
We'd unwisely used Hi-Gain option on the iRig Mic cast to record an interview.
The location had several industrial refrigerators and smoking equipment, a place where make sausages.

Thank you in advance.
Alex

[kozikowski]

That sounds like you already tried to process it. Do you have a raw clip? Before you did anything to it?

Koz

[Trebor]

Is there a chance to remove or reduce a very bad power line hum (attached sample)?
ATTACHMENTS sample_alex.wav (1.51 MiB)

The interfering frequency is too high to be mains hum.
Notch filters [in Audacity's Nyquist Prompt ] help a bit ...

''alex'', before-after notch filters shown.wav

(1.72 MiB) Downloaded 16 times

Code: Select all

(setf s (notch2 s 1073 20))
(setf s (notch2 s 3384 50))
(setf s (notch2 s 5533 50))
(setf s (notch2 s 6606 20))
(setf s (notch2 s 7680 50))
(setf s (notch2 s 12141 20))

How notch filter code appears in Audacity's 'Nyquist Prompt'.png (9.63 KiB) Viewed 265 times

[alex-m]

Hey there! Thanks for the fast response and suggestions, really appreciate it.

We've finally managed to download the original wav file (please see the attached sample) from iRig (IK Multimedia site).
So if I understand this correctly, there is no way to get a "cleaner" audio, without that interfering frequency?

Regards,
Alex

[Trebor]

... So if I understand this correctly, there is no way to get a "cleaner" audio, without that interfering frequency? ...

The constant tones (which are horizontal lines on the spectrogram) can be removed with notch filters (see my previous post)

Audacity spectrogram of ''sample_uncompr''.png (380.44 KiB) Viewed 247 times

However the constant tones have distorted the voices with a ring-modulator effect, which, IMO, isn't removable.

''sample_uncompr'', notched.wav

(1.68 MiB) Downloaded 14 times