It doesn't have the loudness button so to speak, but if you set audio settings to stereo mode with only main left and right channels, set sound to large speakers, subwoofer to none, LFE to main, adjust the 5 band equalizer to +6db on 300hz and +3db on 50 hz, the sound will change and pretty much sound like the loudness button, you can even add more bass with the control button and increase bass to your liking from 0db to 10db until it sounds extremely thick and creamy, albeit colored.

No need to adjust treble as this receiver already produces extremely crisp highs.

Better late than never....