2 LH channels or 2 RH channels

Windows 10. Recording from vinyl on a Numark turntable onto my PC.
The Audacity trace on LH and RH channels is identical. In other words; instead of recording a LH and a RH channel, it appears to be recording either 2 LH channels or 2 RH channels and it doesn’t sound right. Have I clicked on something I shouldn’t?

How is the Numark turntable connected to your computer?

It’s connected via a usb cable (btw Audacity Version 2.3.3) USB at the PC but I don’t know what the type of plug called is at the turntable end.

Right-click on the Windows Volume/Speaker icon and select Open Sound Settings.
Select the USB device* as your Input Device.
Then select Manage Sound Devices and navigate through the settings to make sure it’s set for 2-channel stereo. (Sorry, I’ve forgotten the exact steps.)


As a “sanity check”, run the Vocal Remover effect. It works by subtracting left from right to remove the phantom center so if left and right are identical you’ll get total silence. That’s what I expect…

If you have a mono record but you’re recording in stereo, most (but not all) of the audio will be removed but any record noise will not be reduced so you’ll end-up with a quiet, noisy, recording.

If you run the traditional Vocal Remover set it to Simple (Entire Spectrum).

If you run Vocal Reduction and Isolation, select Remove Vocals and set the Low Cut slider to minimum and the High Cut slider to Maximum (for maximum center removal with no filtering).


  • It probably won’t say “Numark USB turntable” because Windows doesn’t always know what you’ve plugged-in, but it should say “USB… something”, and presumably you’ll only have one USB audio device. (And, you should see the same device name in Audacity.)

Sorry Doug, I fell at the first hurdle. Where is the Windows Volume/Speaker icon. My excuse is 82 year old computer illiterate.

Bottom right of your screen - in the toolbar
Speaker icon.jpg

This Manual page may be useful to you: https://manual.audacityteam.org/man/windows_accessing_the_windows_sound_controls.html


Thanks for that Doug. See attached. The record being copied is an Orchestra and Chorus so there is a big difference in the LH and RH tracks but the waveforms on the screen are identical.
Also, is there any other way of adjusting the recording level other than by the Gain knob on the Turntable?
screen shot 1.jpg

Sorry Waxcylinder, I should have addressed the previous post to you.
Barry Y

See also: Windows: accessing the Windows Sound controls - Audacity Manual

If the recording device is set to “1 channel (mono)” in the Windows Sound settings, then Audacity will only receive a mono signal regardless of the settings in Audacity.

Hi Steve,
It doesn’t seem to matter what changes I make to the Windows Sound settings, Audacity records 2 identical channels. As it is recording the same thing on both channels it is in effect “Mono”. The only thing I’ve found that looks a bit iffy is the attached. What do you think?
Windows sound settings.jpg

Your turntable is listed as “Microphone, USB Codec”.
Click on it to select it, then click the “Properties” button. A window will pop up, and somewhere in there it says the number of channels. I’m betting that it says “1 channel (mono)”, but you need to set it to “2 channels (stereo)”.

Sorry Steve,
I thought we were getting somewhere there but I followed your instructions but couldn’t find any reference to number of channels. :frowning:

  • Click on the “Microphone, USB Codec” icon to select it
  • Click the “Properties” button.
    You should now see a pop-up window with 4 tabs.
  • Click on the “Advanced” tab.
    You should now see in the “Default Format” section, the number of channels.

I found it and it was set to one channel so I changed it to " 2 channels CD Quality". Unfortunately Audacity has not changed. When recording from the Turntable it still shows identical L and R channels.

It’s normal for both channels of a stereo track to look very similar. This track is stereo - I can hear the stereo.

Second Track002.png

Yes! on studying the traces very carefully they appear to be very similar but they are not the same.
I think my problem is solved.
Thanks to Steve and everyone who helped to guide me. :smiley:

And there’s the proof… Orchestra and Chorus.
Stereo trace.jpg