How Audacity determines clipping?

I have a huge archiving project from analogue media, where setting audacity recording level must be re adjusted at next run after first recording has been finished. Is there a visual clipping display option (without zooming in and scrolling through 45 minutes recording), displaying recording location or region where clipping has been occurred?
I see there is in menu setting “show clipping” - how it’s expected to work?
For testing purpose I recorded extra over saturated track but no visual red effect on screen like in user manual.
Please see attached image - I’d name cut off peaks as clipping but these aren’t displayed red by Audacity.`
Any ideas, what Audacity determines as clipping?

Please notice attached screenshot.

I already answered that [u]here[/u] in a reply to your other post. It’s just looking at the digital amplitude and showing POTENTIAL clipping.

It doesn’t know if your preamp (or other analog circuitry) clipped while recording or if clipping occurred somewhere else. You can import a clipped digital recording and it won’t show clipping if it’s clipped below 0dB. Or you can import an MP3 or floating-point WAV that goes over 0dB without clipping and Audacity will show red.

It LOOKS like there’s something wrong with your hardware* but you may be able to prevent the clipping by lowering the level. That’s just something you’ll have to try (if you can adjust the analog level). It looks like peaks at -3dB or less would be OK. You never told us anything about your hardware setup.

And again, there’s no problem with leaving headroom and amplifying digitally after recording… That’s the normal process with digital recording.

***** It’s a very-minor problem if you know about it and if you can prevent it by lowering the volume. If the analog-output from your cassette player is clipping and it doesn’t have a volume control then you can’t fix it (unless you get a different cassette player).

The same is true if you have a cassette player with USB built-in. With those things you can’t adjust the analog signal into the built-in ADC so that can’t be fixed either.

That option shows a red vertical line wherever a sample touches or exceeds 0 dB. If the audio is clipped below 0 dB, it will not be marked by “show clipping” (see:

“Analyze menu > Find Clipping”

I excavated out my 40 years old oscilloscope, signal generator and created a 1kHz 0dB test tape.
For use with Akai GX-65 cassette deck connected to desktop computer motherboard line in socket.

You are right, there is indeed something wrong with motherboard Realtek ALC892 chipset hardware setup.
Clipping occurs already in motherboard sound card “Line In” preliminary stage, difficult to notice instantly because old cassettes playback level is quite low.

  1. Is there any audio diagnostics software, which could help to set up audio settings?
  2. Any suggestion of new hardware - perhaps USB audio input device providing easier to see through and set up recording with Audacity?


I excavated out my old oscilloscope, signal generator and created a 1kHz 0dB test tape.

I assume you know there is no there’s no automatic calibration between 0dB on the tape and 0dBFS (digital).

But if the soundcard doesn’t go all the way to 0dBFS, then it has a defect. An ADC should clip at exactly 0dB. But it’s not so terrible if you remember to keep it below -1dB, or so. :wink:

And the tape machine’s output isn’t clipped, right? That would be unusual.

  1. Any suggestion of new hardware - perhaps USB audio input device providing easier to see through and set up recording with Audacity?

The [u]Behringer UCA202[/u] is popular and inexpensive but it doesn’t have a recording-level control. Or, there are lots if higher-end [u]USB audio interfaces[/u] with switchable mic-line inputs. These always have recording-level knobs. Most audio interfaces have combo XLR/TS/TRS connections so you’ll need [u]adapters[/u] or adapter cables.

Don’t buy a regular “SUB soundcard”. They are like laptops with only mic-in and headphone-out.

Direct cassette deck line out 1kHz 0dB sine wave direct RCA output isn’t clipped on oscilloscope screen but is significantly clipped in output from computer line out.
With music from old 40 cassettes, which signal level is remarkably lower because of ageing, it isn’t always instantly visible on output waveform.

Now I may attempt to understand mobo’s integrated sound chip behavior and perhaps it’s possible even to fix but as next step I’d take my time to check other possible hardware options.

Thanks for inspiring support.