Left and Right Channels are identical

Audacity Help Forum Windows
1

Hi
I am recording from vinyl some of which is 40 years old, I am using a turntable which is part of an intergrated system involving CD player and stereo radio. in between the laptop and the music system I have linked a Behringer USB audio Interface UFO020. The channels on the Audacity screen are showing identical waveforms. The same had happened when I have recorded from a music DVD - using a DVD player and the Behringer.

Thanks
Garethmorgan

2

Hopefully, you’re using a UFO-202?

Is Audacity in stereo?

Audacity > Edit > Preferences > Devices > Recording.

The device may say something like “USB Audio Codec” or something like that.

The UFO-202 can be used as a raw turntable preamplifier as well as a straight Stereo interface. There’s a switch on the device.

See how far you get with that. There’s another signal test you can do. Plug a straight RCA to RCA cable into the UFO-202 instead of the entertainment system and touch one tip at a time while you’re recording. You are intentionally creating sound buzz as a test, and it should appear on one side or the other.

You should be plugged into the connectors labeled “Input.”

http://kozco.com/tech/audacity/pix/touch.jpg

This test is a little fuzzy because it depends on how electrically noisy your environment is, but it’s really simple and quick.

Koz

3

Sometimes Windows thinks a USB audio device is a mono USB microphone. See [u]this page[/u].

Another simple test is to unplug the left & right channels one at a time to see what happens when only-left or only-right is connected.

The channels on the Audacity screen are showing identical waveforms.

I wouldn’t go by how the waveforms look… Usually there is lots of similarity between the left & right channels. If you want to “prove” the left & right channels are identical, you can use the Vocal Remover effect with the frequency range set to 0 20,000. That will subtract the left & right channels giving you dead silence when the channels are identical.

I am recording from vinyl some of which is 40 years old…

…The same had happened when I have recorded from a music DVD -

Most 40-year old records (1974) are stereo. But if you go back to the 1960s, there were still quite a few mono records. If you do the “subtraction trick” of a mono record (with a stereo recording) you won’t get dead silence… You’ll get record noise and any analog differences in the channels.

And, I have older movies on DVD that are mono. I even have a concert video from 1992 that’s mono, but that’s unusual.

4

It’s worth finding yourself an LP that has distinctly different left & right channels to test - my gold-standard for this is the opening track of Sgt Pepper (stereo release of course not the mono version).

WC

5

I think Windows Vista and later will by default always set to mono a plug and play USB audio device that has no manufacturer-supplied drivers.


Gale

6

Thanks Koz

it is a UF0 202 and the recording was set to stereo, I have tried both the phono and the line but after making the change identified in the last post I have a better signal from the line as opposed to the phono. I have not yet had time to try the RCA to RCA approach (I will have to see if I Can get one).

Gareth

7

Hi Doug

Thanks - I have tried the “Vocal Remover” - there was no noise and the waveforms were horizontal. By removing the plugs one at a time there was no effect when the “left” was removed and when the "right was removed it seemed to stop the recording.

Gareth

8

Thanks WC

I have tried 2 LPs with a wider range of sounds and there is no difference to what is happening

Gareth

9

Thanks Gale It was set to mono and I have changed to the settings stated in the page you made reference to. There has been no difference in the channels being identical.

Gareth

10

Hi

Many thanks for the advice. I have made comments to each of them highlighting what the effects were.

Gareth

11

What output on the integrated music system are you connecting the Behringer to? Are you sure there is no mono switch on the music system you may have overlooked?

Gale

12

Hi Gale

I am not aware of a mono switch, I am not sure of your first question I have linked the Left and Right sockets on the back of the system with input left and right sockets on the Behringer. I have used the earphones socket on the system this morning and it did come out in stereo.

Many thanks
Gareth

13

Do you get stereo if you put headphones in the Behringer and set the monitor switch on the Behringer to the source that includes the input (that is, the music system)?


Gale

14

Hi Gale

I tried again this afternoon and had a different result. There was a difference between the 2 channels some of the time and the size of the waves forms was different. There is another problem - there is a buzz/hum throughout the recording. Do you think this is a situation where “earthing” is needed - if so the RCA cables I am using to connect the system and Behringer has an earth at both ends, I can see where it attaches to the Latter but where would I attach it to the back of the system?

Again many thanks
Gareth

15

Have a look at the Manual for the stereo system. There may be an exposed ring (where the outputs and inputs are) for that purpose.


Gale