"Unofficial", seemingly arbitrary clipping occurring

Hi, thank you for reading. I am new to Audacity and digitizing vinyl in general, so please bear with me. I am aware of the hard clipping that will occur if the volume level reaches 0 dB. That’s why I reduced the recording level to 75% (though it is 85% in the screenshot as I was testing a higher volume level for reasons explained below) when using my Audio Technica AT-LP120 with Audacity 2.3.3 for Windows 10. I am connecting the AT-LP120 to my computer using the included USB cord.

I recently noticed that for some of my songs, the audio seems to get clipped well below the 0 dB threshold, and does not show up with red lines when using the view clipping setting. For example, if I am watching the meter tool bars while the song is recording, it looks like they arbitrarily decide that they will not move right of a certain threshold (in the attached picture, around 2.5 dB or so). And you can see on the waveform that the sound appears to be harshly clipped during a loud part of the song, even though it’s not near 0 dB. The audio also sounds distorted, although I have an untrained ear. I would be happy to share the WAV file with anyone.

Also–I tried increasing my recording volume to see if this seemingly arbitrary threshold moves as I change the recording volume. And, lo and behold, the threshold moved accordingly. So it doesn’t appear to be some kind of set decibel level where the clipping is occurring.

I am trying to digitize my late grandfather’s music as a quarantine project and I’ve been investing a lot of time in this, so you can imagine it’s quite frustrating to be having this seemingly inexplicable problem. In case anyone is curious, my grandfather was Gar Bacon and did most of his work in the late 50s. Here’s one of his songs: https://www.youtube.com/watch?v=1kkEs1wMIus

Thanks so much for taking the time to read.
Arbitrary Clipping.PNG

Did you turn off all the Windows Enhancements?

This poster was transferring tapes, but he’s having similar problems.

Step one might be making sure all the sound processing and tools in the Windows machine are turned off. Windows comes out of the shrink wrap all set for business conferencing and communications. All the tools are running: Noise Reduction, Auto Level Set, Echo Cancellation, Processing etc. etc.

Turn all that off.

I’m not a Windows elf. Google or Right click the speaker icon lower right and drill down to the Windows recording settings. Get rid of Windows Enhancements.

If you use Skype, Zoom or any of those, you need to turn all that off, too. Make sure all the apps are shut down and then clean start: Shift+Shutdown > OK. Wait a bit. Start. Do Not let anything else start when the machine comes up. If you can keep it off the internet, so much the better.

Connect your player.

Audacity > Edit > Settings >Recording > [X] Playthrough. That should run the playback service at the same time and let you hear what’s going on. Note, it may be out of step with the bouncing sound meters. That’s normal.

Play the test tape. Click in the recording meters > Start Monitoring. Both Record and Play meters should bounce with the music and you should hear without actually making a recording.

does not show up with red lines when using the view clipping setting.

Show Clipping doesn’t do what you think. It can’t measure sound over 0dB, so it guesses what’s likely to be overload damage based on how close to 0dB the sound is and the attack and release of the waveforms. Because of that, you can have terrifically bad overload damage at, say 70% and Show Clipping won’t know.

I’m guessing getting rid of Windows Processing should solve a lot of these problems.

One other note. File > Export the work as perfect quality WAV (Microsoft) 16-bit. That’s the same uncompressed format as Audio CD.

That’s your Capture Master and you can make that into anything else. If you go straight for the MP3, you can’t ever change it without causing compression damage and distortion
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Home USB turntables have some interesting problems of their own. You’re probably not going to leave it to your grandkids, right? You’re going to get to the last record and throw it out. Turntable makers know this and they make it juuuust good enough to get to the last record.

If you have a good analog turntable, it’s sometimes a terrific idea to adapt that to your computer and record that way. It’s likely to be much better quality.

Koz

That’s weird but it does look like clipping. If it’s not a [u]Windows “enhancement”[/u] it would be analog clipping in the turntable’s analog electronics.

The weird thing is - Any kind of USB device like is usually designed so the analog-to-digital converter will clip before anything in the analog section, and ADCs always clip at exactly 0dB.

I’ve also read that the LP120 normally has a low output, so is that an unusually-loud record?

If the electronics inside the turntable are clipping, the solution would be an external preamp and interface. (I believe your turntable has analog outputs and a switch to bypass the internal preamp.) If you have a desktop/tower computer with a regular soundcard you can get a phono preamp and use line-in on your soundcard. Or if you have an older stereo with phono-in and “tape out”, you can use the phono preamp built into it.

Otherwise, the [u]ART USB Phono Plus[/u] is an audio interface with a built-in phono preamp. The Berhinger UFO202 is another option but it doesn’t have a recording level control so you might run into the same clipping issue with “hot” records.

Thank you KOZ and DVDdoug for your insightful replies. Per your suggestion, Koz, I tried disabling all Windows enhancements, though I was only able to find enhancements to disable on the speaker side and on the internal mic, but not on the Codec line input. That said, after disabling everything, I still had the problem.

I am starting to think this may be a problem with the LP120 as DVDdoug suggested. I am reaching out to Audio Technica and also ordering a cord so I can connect to my Macbook Pro to see if using a Mac eliminates the problem.

Depending on what AT says, I might end up having to order an external preamp and interface, which is frustrating given that I spend $270 after taxes on this LP120.

DVDdoug, thanks again. I think I need to buy an external preamp–are you saying that the ART USB Phono Plus is a good option for an external preamp? I wanted to make sure because you said “otherwise” after discussing using an external preamp.

The Dynasty ProAudio DA-UA2D seems to have strong reviews and is less expensive than other USB preamp options–does anyone have an opinion on this product? Thanks!