I'm trying to preserve some audio recordings. Unfortunately, whenever there is a lot going in the lower bands (<2kHz), the higher bands are noticeably quieter. Is there any filter/technique to restore such recordings?

Example (6.0 - 6.5 sec):



Have you tried just using EQ? You obviously can't boost what's not there, but if it's just being masked, then you could rebalance with any equalizer.

To get the best sound, I would CUT the lows and mids first. If you still don't have what you want, try to lightly boost the high-end. Try to get by with the least boosting that you can. In school we were taught that cutting generally sounds more natural than boosting, and my experiences so far agree with that.


You need to post an example.

This could be due to low quality variable bitrate - and those "bits" are just gone. Trying to boost the missing areas will just bring forth bad artifacts.

If this is an old recording or something hard limited (by RMS), you may get lucky using a sidechained multiband updward expander: using the low frequencies as sidechain key input you tell an upward (multiband) expander to boost high areas.

As said: post an example.

  • And keep in mind that the example Michael (and I) wants isn't a visualization, but the actual audio.
    – user22688
    Sep 30 '17 at 16:30

"Audio recordings"? Maybe on tape? And you have some gating/limiting effects in the high frequencies going on?

The very first measure is to make sure that you are playing back the tape with the same kind of Dolby Noise Reduction that it has been recorded with.

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