The ability to use an iPhone or iPad to power and stream music to the nano is amazing. However since it’s a class compliant device it disables the volume controls on those devices and iOS tends to play music peaking at 0db. There’s always a balancing act of cranking the volume in your presets to match the volume from the device. The only volume controls adjust both up and down at the same time.
The QC has the ability to adjust this and solves this issue.