I have some old mp3 files that were made years ago then copied from device to device as I upgraded systems. The original CD’s no longer play so can’t remake the files without buying new CD’s. Some of them have a very tinny quality to them it sounds like a cymbal being constantly played through the file. I’m using audacity v2.1.0 on a win10 system. I tried using a low pass filter set at 2khz and it helped some but not a lot. Is there a better way to remove this sound?
Do you know what the bit-rate (kbps) is for these MP3s? (If not, this site can tell you: https://mediaarea.net/MediaInfoOnline but watch out for misleading adverts on that site).
Assuming these are MP3 compression artifacts, they can’t be removed although you might be able to make some improvement with equalization. Equalization is little more “surgical” than a low-pass filter. A 2kHz low-pass filter is drastic!!!
When experimenting with the equalizer, the Graphic EQ mode is easier than the draw curves mode, and I’d suggest “pulling down” one slider at a time in Preview to see what (if anything) makes an improvement.
Ideally, it would be best to avoid another generation of MP3 compression so if you can use FLAC, export your edited/improved files as FLAC. If you must have MP3, choose a high-quality setting (maybe 240kbps or higher) or V0 to V3 (V0 is the highest-quality VBR setting).
If you don’t want to buy new CDs, you might want to consider looking for used CDs. Or if there are a few “important songs”, consider downloading the MP3s from Amazon.
…And for future reference when ripping CDs, consider making a FLAC archive even if you want to listen to MP3s. A good-quality MP3 can often sound identical to the uncompressed original, but it is lossy and if you edit it and the re-export to MP3 (or other lossy format) you are going through another generation of lossy compression and the “damage” does accumulate. If you have a lossless archive you are “future proof”.