I use windows 10 and have upgraded to Audacity 2.3.1.
If I record from the internet lust as a laptop, everything is fine. If however I plug an external screen into my laptop via HDMI, the level peaks at about -10db which I think is low. My settings when the screen is plugged in are:
Windows WASAPI
Mic = Screen (Loopback)
2 (Stereo)Recording Channels
How do I raise the signal?
When you record via loopback, the machine has to run the playback system (for the internet) and the record system (for Audacity) at the same time and arrange a place for the signal to “turn around.” When you introduce an additional digital pathway, apparently, that turn around place gets distorted.
There is more than one way to arrange loopback.
https://manual.audacityteam.org/man/tutorial_recording_audio_playing_on_the_computer.html
You have a different device list now than you had before.
Koz
OK, I have made sure that playthrough is off. I am still monitoring about -10db peak though which is a bit low. The mixer controls are both on full.
I’m not sure what you mean by a different device list
High Definition Multimedia Interface is a new digital connection to your computer that wasn’t there before.
The computer might think it has to send the YouTube music all the way out to the HDMI monitor before it turns around and comes back for recording. That could mean your HDMI monitor volume control is now a part of the recording pathway.
Try reducing the HDMI volume control to a very low value and see if the Audacity recording volume also drops. If it does, then that’s what’s wrong. The HDMI connection may be incompatible with internet recording.
If it doesn’t, then I have no idea.
Koz
OK I tried that, it makes no difference
it makes no difference
This is a forum. Users helping each other, not a help desk.
So this is where we wait for a different forum elf who may have a better idea on what’s happening, or wait for someone who has the same problem you do.
Koz
OK, no probs, thanks for trying. I unplug my HDMI then have to set my ‘microphone’ to the internal speakers and it goes really loud. Maybe the answer is don’t do it with the HDMI connected 
If I record from the internet lust as a laptop, everything is fine.
Have you actually tried it back-to-back with the same exact program and the same source? A lot of websites (Apple Music, Spotify, YouTube, etc.) are now using loudness normalizing which usually reduces the volume overall and most audio will peak below 0dB.
How do I raise the signal?
You can use the amplify after recording. “Technically” you loose resolution when you reduce the recording volume but it should be no worse than what you’re hearing through the HDMI connection.
I will try recording from the same source without the HDMI connected just to make sure. I did see that you can amplify after. I did also wonder if there is another programme that will make mp3s all the same volume
OK yes, there is a massive difference in volume when I play the mp3. The recording without HDMI though sounded as if it had a bit of reverb or something. It was peaking at 0db. I have now lowered the mic on the mixer to .90 and it is peaking at about -2db.
OK, I may have found a workaround. I recorded with the HDMI connected then used the volume slider on the track to adjust to about -2db peak and then exported that as an mp3. A bit of a faff but that seems to work
I did also wonder if there is another programme that will make mp3s all the same volume
[u]MP3Gain[/u]. If you don’t know this already, peak levels don’t correlate well with perceived loudness. MP3Gain (and ReplayGain) try to match the perceived loudness.
There are lots of quiet-sounding songs with 0dB peaks so some quiet songs can’t be increased in loudness without clipping. Therefore, MP3Gain and ReplayGain (or any volume-matching technique) will tend to reduce the volume of most of your music. If you have enough gain on the analog side that’s not a problem as you can just turn-up the volume control, but some people are disappointed by the reduced volume.
Also… This is usually not a big deal, but as you also may know MP3 is lossy compression. The wave shape changes making some peaks higher and some peaks lower. The end result is that the highest peaks in the MP3 are usually higher than the highest peaks in the uncompressed original (by 1dB or so).
OK thanks