Clipping observed under 0dB, and recording levels

I am a newbe at converting audio my private cassette stereo recordings to digital using Audacity. My 30 year old JVC Receiver (with JVC cassette player - no preamp) is connected to my Dell Laptop using a Behringer UFO202. The Behringer is plugged into the headset port of the Receiver because I have no other tape output port that is amplified.

I have observed that certain combinations of recording/Receiver volumes result in clipping at from -3 dB to -6 dB. Audacity’s “Find Clipping” does not find any clipping but I certainly do observe major clipping in the waveforms.

Now, I have read elsewhere in this forum that Audacity clips at ONLY 0 dB. Can I therefore assume that my Receiver is actually doing the clipping BEFORE it gets to Audacity? Can there be any other plausible explanation?

Obviously I want the best possible digital conversion when I go on to master the stereo tracks. I am thinking of setting the volume combination (recording/Receiver) to observe no clipping AND record at a level of about -12 dB to -18 dB recording level, will that get me what I am aiming for?

Yes, actually, Audacity doesn’t do clipping at all - it just records whatever is sent over on the USB cable. The Behringer will clip at 0 if you have your headphone output too high. That is the only thing in your setup that would give you a hard clip at 0 dB. It is also possible that the tape recording is already clipped.

Try turning down your headphone volume.

Yes, it’s possible that the headphone output is clipped. For example, you can get analog clipping if you crank-up the volume and try to get 110W out of a 100W amplifier.

So I’m not surprised that you can clip the headphone output but I am surprised that the Behringer doesn’t clip first (at 0dB).

…This is not your problem but the microphone input on some soundcards clips (in the analog circuitry) below 0dB .

That should work, but run the Amplify effect so you can take an “apples to apples” comparison of the waveforms to see if it’s really making a difference. (You’ll want to Amplify anyway).

And yes, the tape itself could be clipped. Analog tape tends to “soft clip” and if different tapes are clipped at different levels it could be different tape formulations. And you wanted a hot signal to overcome tape noise so it was common to occasionally go “into the red”.

And when you turn-up the volume (to the headphone output) you can’t go over -3 or -6dB?

Audacity is just checking the levels so you can get false positives and false negatives. Its showing potential clipping.

If you are recording, usually it’s the analog-to-digital converter that’s clipping at exactly 0dB so for most people it’s a good indicator if they check immediately after recording. “Regular” WAV files are also hard limited to 0dB so if you import a WAV file and it shows clipping it’s probably true. If you have a clipped waveform and you lower the volume in Audacity (a negative Amplify value) it will “hide” the clipping without fixing the distortion.

But if you have a non-clipped waveform and you boost the bass (or something like that) it can go over 0dB in Audacity and and it will show red even though it’s not actually clipped (yet). If you lower the level before exporting (or before playing) you can avoid clipping.

MP3 files can go a little over 0dB without clipping so sometimes an MP3 “shows red” even though it’s not actually clipped. (But your digital-to-analog converter can clip if you play it at “full digital volume”.)

And there’s another quirk with MP3s… The lossy compression changes the wave shape making some peaks higher and some lower. So the MP3 can go over 0dB even when the original file wasn’t clipped.

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