edited files sounded great and then very bad

I’m a novice at this and any ideas or suggestions would be greatly appreciated. I have Windows 10 and I’m using Audacity 2.4.1, I imported a 16/44.1 wav file and applied several effects with Audacity at 32 bit float/44.1 and then exported it as a 16/44.1 wav file. I didn’t save the project, just exported the file with effects. I did this with several songs and there was a great improvement.
Then, a few days later and a few plays later the sound was suddenly very bad. Wavy and erratic and weak. Sometimes starting well and then going down hill.
I tried three music players and another device. No good. Then I tried editing other songs.This time I could tell they were not doing well just by listening to the preview feature. Audacity didn’t like the files that had previously been edited and the new ones that I imported sounded bad right from the first application of effects.
As I said, I’m new to this. Could editing cause the files to become unstable? Is it something about the settings in Audacity or my computer settings? A loudness meter showed files with -14 to -15 LUFS and an expected dynamic range, but there is low volume and bad sound quality on playback. Many thanks for any help you can give.

Three music players on the same computer?

What was the “other device”?

Thank you very much for the quick reply. Yes, the music players were on the same computer and I had also made mp3s that I listened to on my Android phone. All sounded weak with fluctuating sound. Could it be that my old desktop computer and Audacity don’t work well together. The original files play ok, just too much hiss and bass. Audacity took care of that until things somehow deteriorated.

Are you saying that the project sounded good in Audacity prior to exporting?
Did you listen to the exported MP3 file at that time?

Unfortunately I doubt that we can fix those exported files, but we can perhaps try to work out what went wrong.
See if you can reproduce the problem, and keep a careful note of exactly what steps are required to reproduce the problem.

Yes, I imported a wav file and applied noise reduction, EQ, compression, normalization and the results were a great improvement. It sounded good in Audacity and it sounded good initially as an exported wav file on a music player. I edited several songs with good results for the first few plays. Then something happened. The sound became weaker and wavy on several players, including Audacity. I made the mp3 after things had gone bad, so that might not have been a good test.
I will edit a few songs again and see what happens. I’ll try to make sure the problem is not just the music players on my computer. Thanks very much for your help.

Check that your computer sound system isn’t applying any effects.
Audio files don’t just change on their own.

“Disable all sound effects” under Enhancements was already checked. Will use Audacity on some songs later today. Right, I don’t think even a new guy like me could do something where files sound good and then not good. I’m hoping there’s a fairly easy explanation that I’m just not seeing, because I love Audacity and the way it improved the sound in a big way. Thanks again.

I tried again and things have gone from bad to worse. The problems used to happen after exporting a file. Now it happens during the editing. It’s very disappointing because of the great results I had earlier with Audacity. I have the latest version of Windows 10 with all updates and I’m using Audacity 2.4.1.
Here’s the latest development: I import a wav file to Audacity and it sounds just as I would expect, the same as on a media player. Too much hiss and bass and it needs to be louder. So I try effects such as noise reduction and filter curve. Using the preview feature, I find something that improves the sound and hit OK to apply the effect. The resulting sound is not the same as the preview. Not even close. How can that be? I tried it with different effects and different wav files and the same thing happened. I reinstalled Audacity and the same thing happened.
Is this a clue to something I can do or a sign that these wav files are somehow not compatible with Audacity? It’s just some acoustic instruments and vocals with some friends, but it’s very important to me. Any ideas or suggestions are greatly appreciated. Thanks.

The way that you describe the problem doesn’t sound possible.

If you could provide a short test file (just a few seconds) and precise steps to reproduce the issue, then we may be able to spot what is going wrong.

Too much hiss and bass and it needs to be louder. So I try effects such as noise reduction and filter curve.

Whenever you boost anything you can end-up pushing the levels into [u]clipping[/u] (distortion). And, there are other effects that can push-up the levels.

Audacity itself won’t clip so if you are not playing at full volume (and clipping your digital-to-analog converter) you may not hear the distortion until after you export. Many formats, including “regular” WAV files are hard-limited to 0dB so the file can be clipped when you export.

I believe [u]Show Clipping[/u] is enabled by default but you should check your configuration. Then if you “see red” you can use the Amplify or Normalize effect to bring the peaks safely down to 0dB. (Audacity is showing potential clipping.)

Mixing (combining a guitar and vocals, etc.) also brings-up the levels and cause clipping. But, Audacity shows the tracks separately and since you don’t see the mixed waveform you won’t see the clipping. If you are mixing, you can export as 32-bit floating-point, which will not clip. Then open the floating-point file and run Amplify or Normalize the bring the levels safely-down before exporting to your final-desired format. Or, if you happen to have headroom after mixing, you can bring-up the volume.

Maybe you can reproduce what happens with me. The difference between the preview and applied effect is only slightly noticeable in a short clip, but quite dramatic over the length of the song.

I imported the file and clicked on the normalize effect. I found that a preview of -0.5 with all boxes checked sounded good. Loud without clipping or distortion. I previewed the entire length of the song. The sound was good. When I clicked OK and applied the effect the result was much softer than the preview and there were some wavy parts. When I’ve done noise reduction or EQ, etc, the same thing happens. The preview is not matching the applied effect. Something messed up with the files? They do play. They just get weird when they are edited Something about the OS? I would try a different computer, but one is not available at this time.
One other note about editing the files. There’s a very small sweet spot where they sound good. For example, a compression ratio of 1.4:1 sounds good, but 1.3 or 1.5 does not. That happens with other effects as well.

I think all my Audacity settings are good. I’m not having any sound problems on my computer.

Thank you very much for your help.

I don’t know why there’s a difference with preview. But like I said, you can get clipping when you export. Or you can damage the sound if you export as low-quality MP3. (High-quality/high-bitrate MP3s are also lossy but usually the sound quality is fine.)

The Normalize effect is simply a volume change. It can’t hurt anything. Generally you should normalize as the last step, but it doesn’t hurt if you want to normalize more than once. If normalizing ends-up boosting the volume, of course it will also boost any background noise making the noise more noticeable. But, that’s no different from turning-up the volume control. (RMS Normalize is different as it can push the peaks into clipping.)

For example, a compression ratio of 1.4:1 sounds good, but 1.3 or 1.5 does not. That happens with other effects as well.

These are tools… It’s a lot easier to break something with a hammer than to build something with a hammer. :wink:

I’d say compression is particularly difficult to set-up because there are several settings (and different compressors behave differently), and it depends on the recording you start with and what you’re trying to accomplish. Limiting is a special kind of fast-compression and there are fewer settings so you might want to start with limiting… depending on why you are compressing and what you are trying to accomplish.

Noise Reduction can also have undesirable side-effects. If the noise is bad (and/or if you use a lot of noise reduction) “the cure can be worse than the disease.”

Generally, these are corrective effects. A very-good recording doesn’t need EQ, or anything else! But, they can also be used as “special effects” if you just want to alter the sound in some particular way.

I imported a song from a band into Audacity. A commercial release. I tried to change the loudness a bit with normalization. The same thing happened. Just like my own files, the preview and the applied effect did not match at all. But this was not really the original problem.

When I first edited the songs a week or so ago they sounded very good. Then the sound quality of the files somehow changed after a few days and a few plays! Probably not possible, right? Digital files don’t just change on their own. And subsequent attempts at editing files failed badly Why does my computer not work well with Audacity when there are no other problems? Is there something about my machine or my OS that makes it not get along with Audacity? I love Audacity and everything about it, but my computer apparently doesn’t. I uninstalled and reinstalled Audacity. This is important to me, so it’s pretty frustrating. Maybe I’ll just have to work on the files with a different machine, but one is not available to me now. Thank you very much for any ideas.

I’m far from an expert, but I know the basics of Audacity. In the past I used noise reduction and EQ and compression and limiter and normalization in different combinations as needed and I had good results. I have no idea why things have gone bad between my computer and Audacity.