Noise

Audacity Help Forum Windows
1

I am getting an annoying background noise I would call digital artifacts. I’m not sure if this term is correct. Regardless, It is there and shouldn’t be. I am using an analog Yamaha MG32 mixer run through a Scarlett 2i2 audio interface into a Sony Vaio laptop dual core with 4 GB ram running Windows 7 for recording. I am using Audacity version 2.0.3. Windows Media Player is sometimes open in the background but not actually playing anything. Can you possibly tell me what this is and how to get rid of it? Thanks in advance for the help. Here is a link to our site you hear hear the noise on the first item that loads: http://kelloggsvillenazarene.org/?page_id=175

2

There are two things that frequently cause that type of noise:

  1. Excessive use of noise removal effects.
  2. MP3 compression.

I suspect that it is a combination of both.

The solution is:

  • Start with a better recording so that less noise removal is needed.
  • Use the least amount of noise reduction that you can get away with
  • Encode to MP3 format only at the very end of the production process. Use high quality WAV format for any intermediary steps (and back-up copies).
  • Record in mono, or convert to mono before encoding as MP3.
  • Use as high a bit rate (kbps) as is viable (considering that this is a long file for the Internet and you don’t want the file size to be too massive)

Unfortunately this type of sound quality damage is not repairable.

3

I’m not using any kind of noise removal unless there is something turned on by default in Audacity. Upon finishing recording I save as an Audacity project and then immediately export to MP3 to upload to our podcast site. So, I know the MP3 could cause some noise but this seems excessive. It may not be repairable but I do have it in the original Audacity project format still.

4

There are no effects applied to recordings by Audacity. Effects are only applied if you specifically apply them.
There may be settings in Windows that are automatically applying effects.

Have a look in the Windows Sound Control Panel and ensure that all “enhancements” are turned off.

Oh good, so there is a chance that we may be able to do something :slight_smile:
What is the voice quality like in the original recording? Could you post a short sample (just 5 or 6 seconds) to the forum in WAV format. See here for how to do that: https://forum.audacityteam.org/t/how-to-post-an-audio-sample/29851/1

As you are on Windows I’ll move this topic to the Windows forum.

5

OK, so I took some more time to actually look into the problem a little deeper. My original recording sounds ok in Audacity. I then checked the recording that was exported to MP3 on the computer with WMP and it still didn’t have the “noise”. So I went to the site that the recordings are uploaded to and found that they were transcoding them to 32 bitrate. I believe this may be the cause of the problem. I’m checking to see if they allow a higher transcoding setting. This is not high quality music so I believe that 128 should help eliminate the noise and still save some file space. If so I will try this on my next upload tonight and see if it helps. If anything else to consider please let me know. Thanks for your help so far.

6

32 is the absolute, rock-bottom, minimum bitrate for a mono show. And that’s assuming the show up until that point was perfect with no distortion or damage at all. Many people give up on 32 because it’s so brittle and even if everything goes OK, some listeners can tell there’s something wrong with the sound quality — worse if you have something to compare it to. A podcast of a popular radio show used to jam a promo voice on the front before the show started. It was pretty obvious they skimped on the vocal quality because the announcement sounded like a cellphone compared to the show. They don’t do that now.

Companies used to do this in the early days when everybody was fascinated with the ability to hear internet radio shows and presentations. Not any more, so yes, that’s a good place to start.

Koz

7

As Koz implied, also check what format they allow you to upload. The better the quality that you upload, the better the quality of their re-encoded version is likely to be.
If they only allow you to upload a low bit-rate version, see if you can find out what happens if you upload in the same format that they use. In other words, if they only allow 32 kbps as the final format, then can you bypass the re-encoding by exporting from Audacity as 32 kbps, or do they still “transcode” it.