Am I recording in Stereo?? [SOLVED]

Audacity Help Forum Windows
1

(Windows 10, Audacity v. 2.1.2)

I am recording a stereo LP. I have stereo preamp, cartridge, etc. Audacity says “2 (Stereo) Channels” on the top toolbar. It also says “Stereo” in the gray area to the side of the area that shows the waveforms. When I replay the recording it SOUNDS like stereo, however:

Why do the two waveforms (L and R channels) always look identical–during recording and playback? Why are the peaks for both channels always identical and always marching exactly in lock-step? I have never seen this with either cassete recorders (e.g., my Nakamichi CR7-A, now long dead), or my Pioneer CD-Recorder. Can anyone explain what is going on here?

Thanks!

2

You missed an important step. How did you get the turntable into the computer? “Everybody Knows” you should get an adapter to fit into the single socket on the side of your Windows laptop. That socket is for a combo stereo headphone and mono microphone, a “headset.” If you did that, your recorded show is very probably two copies of Left. The Right signal isn’t connected to anything.

So how did you get there? If your cables allow it, you can touch first one tip and then the other while you’re recording. Make sure your other hand is only touching rubber or plastic parts of the cable.

You are intentionally creating buzzy interference just as a test. I bet only one of the two cables wakes up. Depending on your adapter, it’s also possible both left and right light up no matter which cable you touch.

Koz

3

You can also unplug one channel at a time from the preamp while recording to confirm that the unplugged channel goes silent.

You can also try the Vocal Remover effect. If the vocals and other center channel information gets removed, you’ve got stereo. If you get “dead-digital silence”, both channels are identical. If it gets very-quiet, but with loud clicks & pops, you’ve got a mono record. (Lots of older records were mono.)

4

Hi,

Thanks for your replies. I am supplying sound to the laptop via USB cable from an ART Phono Plus ADC. This is hooked to my preamp and to my non-USB table (Oracle Delphi Mk. III table/SME V arm/ Sumiko Blue Point 2 cartridge). Something somewhere is not stereo–I played the FLACs back last night on Foobar2000, and indeed the peaks are in lockstep… I will examine everything again today.

5

What we’re all doing although it may not seem like it, is divide the system in half and test that. Then figure out which half is broken and test again.

Did you wire up the phono cartridge and is it one with actual wires instead of plug-in? I did that wrong once and got some very seriously damaged sound.

Audacity doesn’t get sound from your USB devices. It gets it from Windows. I know you can force Windows setups to be mono—sometimes by accident. Right-click the speaker icon and check how Windows feels about your USB connection.

Koz

6

ART Phono Plus ADC. This is hooked to my preamp and to my non-USB table (Oracle Delphi Mk. III table/SME V arm/ Sumiko Blue Point 2 cartridge).

Everything but the preamp.

What is it?

The ART Phono Plus ADC has a perfectly delightful RIAA phono preamplfier built in. Why are you using a second phono preamp? You are connected to the ART Phono Plus ADC Line-In, right? Not the Phono In. Start a recording and disconnect those cables one at a time to see what happens.

Koz

7

Problem solved–It was indeed a Windows issue. I right clicked the Windows speaker icon (bottom right of screen), selected my USB recording device, then Properties, Advanced, and saw that “One Channel, 16 bit” was selected. I proceeded to select “2 Channel, 16 bit, 48000 Hz, DVD quality”, and, sure enough, the waveforms for the two channels are indeed different, and the peaks are different as well. I know this is not CD audio sampling rate, but I thought I would check the highest quality option. I am interested in recording at 48 kHz. Audacity still lists the sampling freq as 44.1, so I assume I will have to change that to actually get 48.

As for the preamp–long story. My own preamp is an Audible Illusions Modulus 2B vacuum tube preamp with phono stage. It is currently at my audio dealer for troubleshooting, and likely new tubes. It was extensively modified by Brooks Berdan–eight pairs of Cardas jacks, Cardas wire, etc, etc. A really great sounding preamp. In the meantime, they lent me a McIntosh solid-state phono preamp, which is feeding into my Sumiko Project Preamp, then into the ART (yes, line level input).

When I get the Audible Illusions back, I will have one less box to deal with, and will connect it to the ART via the Tape out output. I have a hard time believing that the ART phono pre will sound as good as my Audible Illusions, hence the setup I described.

However, I am curious to just see what it all sounds like with just the ART directly from turntable. The Sumiko is a high output moving coil at 2.5 mV output. We’ll see.

(BTW, my high end audio dealer suggested that Ayre makes a $4K ADC–but I am not willing to pay even an eighth of that right now, hence the ART purchace. I am happy with it so far!!)

Thanks for your help.

8

Yes, 48000 is the video sample rate. Most music software can deal with both that and 44100 with no trouble and most video editors “know” how to convert. Your a/d converter has to be able to handle whatever sample rate you choose and there’s even something about certain conditions where Windows will limit the sample rate. That might be good to investigate.

There’s a reason studio recordings are done at 96000/24-bit. That’s so post production has no limits—there is no series of filters, tools, effects or corrections which will ever run out of bits.

44100 isn’t like that. Strict Nyquist limit is not 2.0, it’s 2.6 and 44100 is not perfect and surgically accurate much past about 17KHz audio. 48000 is better. It runs out of steam around 18.5KHz.

Koz