hum on recording

I have bought a USB cassette player to transfer tapes to MP3 format. This is my first use of Audacity and I get a dreadful hum after transferring to CD. Can anyone offer any suggestions on my setup please? The USB cable is only about 15 inches long and I am assuming that the cable is suitably earthed. I am using Windows 7 64bit. Audacity is 2.0.6. On my control panel, I have wound up the input to around -6 DB. Is this too much input?

I get a dreadful hum after transferring to CD.

How about before that? After you capture the music and the show is still in Audacity?

I have wound up the input to around -6 DB. Is this too much input?

While it’s a reassuring idea to have one place to put all the controls and leave them there forever, sound doesn’t work like that.

What you are intended to do is set the volume controls wherever they need to be so the blue waves peak around .5 or so and the sound meter peaks bounce around -6 (those are actually the same sound value measured different ways).

Yours will be a little more erratic than this. I did this just to make a good picture. I also make my meters a lot bigger by grabbing the right-hand edge and pulling sideways.

The bad news is given the cassette machine is USB, the system is unlikely to add hum after the cable. So the player itself may be in trouble. That’s why I want to know if the shows hum before you make the CD.

It’s also possible your CD player is humming, but that’s less likely.

Which USB cassette player? In detail.


HI there, sorry about the delay in replying, have been off my computer for a few days now. The USB cassette recorder was bought in a UK supermarket under its own brand name and is a “Maginon Portable Cassette Converter”. The software and instructions supplied are not very clear for someone who has never done this kind of thing before. In fact I had to get the MP3 software from another site (Lame) and modify my systems .cfg files to allow it to pick up this library file to convert the audio to mp3 format. I shall try and re-record one of the tapes again with those levels that you suggest and try and put it on to a CD again. Will report back when I have had a go to see if it works by reducing the input level.
Thanks again for your response.

I shall try and re-record one of the tapes again with those levels that you suggest and try and put it on to a CD again.

Actually, you should do another capture and listen to it in the computer by playing it in Audacity. If it’s humming there, then making a CD will do no good.

There’s another part of this that’s not quite right. You don’t need lame software because you shouldn’t be using MP3. MP3 is for posting work on-line or for your personal music player. It causes sound damage and is to be avoided if you can help it. Audacity high quality WAV exports are the same quality as that of Audio CDs.

There’s another trick. Set playthrough on and you will be able to hear the work as you transfer it.

Audacity > Edit > Preferences > Recording > Playthrough.

This also lets you hear the quality of the transfer before you press record. Right Click anywhere in the red recording meters and select Start Monitoring. Play the tape. Is it humming?


That is something else I did not know, so I need to save it as a .wav file to go onto the CD. Hopefully I will get a chance tomorrow afternoon (UK time) to try it out and I will report back. By lowering the input level like you said, and listening afterwards there did not appear to be any hum, but that is not to say that when the volume has been raised to listen to it on a CD player, there will still be no hum
Thanks again for your help and education :slight_smile:

Audio CDs always have the same very high quality. Their capacity is measured in minutes, not compression quality.

Audacity default audio sound quality is 44100 (lower left Audacity window) and if you choose the default export, it will give you a 16-bit WAV music file. Audio CD format is 44100/16-bit/Stereo.

There is a disclaimer in here. You can also make a Data CD, essentially a 120mm shiny hard drive. You can put anything you want on those including hours of MP3 files, but they probably won’t play in your mum’s Buick and anybody else that has a pure Audio CD player.


Regarding the hum…my 2-cents…

I record books on tape on my laptop, using Audacity and a Samson usb mic. I found that, regardless of usb cable length, if I have the mic closer than about 1.5-feet to my laptop, a hum is induced. It took some trial and error to find this and then determine a minimum distance between my laptop and the mic.
This was a bit of a test to begin with because the books I read are typically RTF text files that I read from my laptop’s screen… so what I had to do was make the font a little larger on these docs so I could keep the laptop and mic separated while still being able to reach the laptop to scroll down as I read.

…just a thought…get a longer usb cable. The cable that came with my mic is 6 feet long.