Hello I recently made an audio recording on an Olympus digital recorder. During the recording the record level was accidentally adjusted and the record level appears to be -60db when I looked at it Audacity. When I try and play the recording I can’t hear anything. I downloaded audacity to see if I could move the recording level up so I can hear the conversation. I know the data is there because I had a friend who does forensics look at the file data to ensure it was there. I have Audacity 2.1.2 running on Windows 10. I saved a backup of the file, then attempted to manipulate the audio. I was able to get it where I can hear it but just barely. It took me a week of messing around to get the audio where it sounds like a whisper. The recording was made during an interview in an office so there is not significant background noise just me and the client talking. Is there a way to increase the audio level from -60 db to something I can really hear? If so can you give me some pointers. Much appreciated.
Please note that we do not offer an audio forensics service for uncovering hidden audio or recovering seriously damaged recording, so if you need that, you may be better to ask your friend or consult a specialist in that field.
To increase the level of a recording, use the Amplify effect. The maximum amount of amplification that can be applied in one go is +50dB, but the audio may be amplified more than once if a greater amount of amplification is required.
The Amplify effect works on “peak level”, and by default it will not allow you to amplify peaks beyond 0 dB.
0 dB is “full scale” (the full height of a track), and is the maximum ‘valid’ level for digital audio.
When amplifying a whole track, the Amplify effect will amplify enough to bring the biggest peak in the waveform up to 0 dB, or +50 dB of gain, whichever is less. Thus a single loud peak in the waveform will limit the amount of amplification that can be applied to the rest of the track. If part of your recording is at a high level and part is at a low level, you will need to select just the low level portion and apply the Amplify effect to that portion of the recording.
Note that there is always noise in every recording. The biggest problem with very low level recording is that the recorded signal tends to get buried in the noise. Amplifying does not discriminate between “voices” and “noise”, both will be amplified by the same amount. If, after amplifying, you can’t make out what is being said due to the noise, then it becomes a specialist audio forensics job.