Dubbing material recorded on a 56k phone line

Hi…am currently trying to digitize old radio shows that I recorded online via a 56k phone line MANY years ago. Can the sound quality be improved as I digitize the recordings? Cannot remember exactly what Windows program I was using back then (either 98 or XP) , but I am currently running Windows 7 along with Audacity 2.1.3.

Any help/advice will be greatly appreciated.

Thanks!

What format are these recordings? Are they cassettes? MP3? WAV files? Wax cylinders?

Cassettes with Dolby. I know that if had Broadband at that time, the original quality would be better than the 56K I was using then.

Thanks in advance for any help/advice.

Cassettes (regular bias) with Dolby.

Thanks in advance for any help/advice.

We need to start with the diagnosis… What’s wrong with the sound?

There are 4 things I’d be concerned with -

  1. Noise. That could be noise from the cassette or from the original tape/record/broadcast.

Noise Reduction may work but if the noise is bad you can get artifacts and “The cure can be worse than the disease”

  1. High frequency roll-off. Again, that could be a limitation somewhere in the analog chain, or depending on the digital format/sample rate, the highest-highs could be brickwall filtered-out. You can correct some of that with equalization but you can’t boost what’s not there and boosting the highs will boost the tape hiss.

  2. Digital compression artifacts. If MP3 or some other lossy compression was used you may have compression artifacts that cannot be removed.

  3. Digital or tape drop-outs. Again, there’s no fix for that.


You’ll also need a [u]line input[/u] on your computer, so if you have a laptop you’ll probably need an external USB audio interface with line-inputs.


P.S.

I know that if had Broadband at that time, the original quality would be better than the 56K I was using then.

That is really low (for music). It would have had to be some kind of lossy compression. A good quality MP3 is typically 192kbps or higher. I think most of the original Napster files were 128kbps. (Those Napster files were downloaded, not streamed, so it just takes longer with a slow connection.)

So… If it’s the music you’re trying to save and you want good quality you are better-off replacing it (assuming it’s available digitally).

Let me clarify a bit :slight_smile:

I was recording material direct from radio stations that were streaming. I had a 56K phone line internet connection at the time. No mp3. I’m in the process of converting my tapes to CD and I was wondering it the sound quality can be improved with Audacity. Thanks :slight_smile:

As far as I know, no publicly available software currently exists which can enhance low-fi audio. However, it will become a reality soon enough since people have used neural networks to do it.

https://kuleshov.github.io/audio-super-res/

Short answer: Not with Audacity.

Longer answer:
Audacity provides editing / processing of audio from audio files or from audio recordings.
Audacity does not provide real-time processing while recording. You have to record first, and then you can edit / process the recording.

As to whether or not Audacity can improve your recording, it depends on what’s wrong with the recordings. If the problem is “low quality due to low bandwidth”, then neither Audacity or any other application can fix that (though note jh90s’s comment re. experimental work with neural networks). If the problem is something else (such as low volume or low level background noise, or hum), then it may be possible to make some improvement with Audacity.

If you post a short sample of the recording, then we may be able to be more specific. (See here for how to post an audio sample: https://forum.audacityteam.org/t/how-to-post-an-audio-sample/29851/1)