Sample rate: 44.1 KHz
Edit → Preferences → Quality
Sample format: 16 bit
You can ignore that. MP3 doesn’t have a fixed bit-depth. Your headset probably records at 16-bits, and Audacity uses 32-bit floating point internally.
MP3: Constant bit rate, 128 kbps
After installing the optional LAME recorder, you can adjust the MP3 settings when you save (export).
Volume: approx. 88-90 dB
That’s an acoustic (SPL) loudness reference. i.e. It’s the loudness of the sound hitting your ears and it depends on your speakers, your volume control, etc. You may be able to ignore it, or you may need it when setting your LUFS/RMS dB level.
approx. -20 LUFS/RMS
You may need a 3rd-party tool or plug-in to measure that.
Noise floor: If possible around -70 dB or better.
That’s not an easy spec to meet with a home recording. It depends on the noise in your microphone/headset electronics and the acoustic noise level in your “studio”. You may be able to improve it with Noise Reduction or a Noisegate, but these tools can sometimes have side effects, so you have to experiment.
Of course, if you adjust the volume up or down the background noise also goes up and down by the same amount, so you need a good signal for a strong signal-to-noise ratio.
No matter what I do I am unable to record loud enough - I’m at least 10 dB too quite whatever I try to do.
How are you measuring that? (You can easily check the peak level by running the Amplify effect, but that doesn’t correlate well with average “loudness” or RMS.)
You can adjust the volume after recording with the Amplify effect. But,if you amplify too much to the point where the peaks go above 0dBFS, you’ll get clipping (distorted flat-top waves).
The ratio (difference*) between the peak and average/RMS is constant (if you amplify linearly without clipping). So, if you boost the peaks by +3dB, the average will also be boosted by +3dB. So… If your peaks are hitting 0dBFS and your RMS level is too low, you’ve also hit the maximum RMS limit for your particular recording.
If you need to boost the RMS level without boosting/clipping the peaks, you can use dynamic compression (Compressor effect). There are various settings to experiment with, and there are various compressor plug-ins so this may take some practice and experimentation. (Almost all commercial recordings have compression for a consistently strong-loud sound.)
…recording through a Logitech 340 with USB connector.
You may not get “broadcast quality” from a gaming/communications microphone. You’ll get better results with a “studio style” USB condenser microphone (AKA a “podcast” mic). For example, the [u]Blue Yetti[/u] is very popular and has some nice features. (I don’t own one.)
- Decibels are logarithmic so subtraction gives you a ratio.