Got myself a pair of Forty Sixty, mainly for music listening and playing instruments. Paired them with a Focusrite Scarlett 8i6 for optimal performance and signal quality.
I can't tell that Forty Sixty are suitable for mixing or music production, I cannot confirm they can be considered flat-sounding. IMHO, they lack clarity and openness, the highs are backed out, lower mids are somehow boomy. Bass is strong but not detailed or fast enough. Instead they are simply pleasant to listen to (in a blind test you wouldn't tell these are studio monitors, well you wouldn't tell these are HiFi either), but In near field listening the stereo scene is blurred and lacks accuracy. Please note I'm here comparing to a pair of Adam T5V which I had for a while and which I loved to listen to, their clarity and the stereo scene were astonishing, I would say I was just immersed in sound. Regretfully, I had decided to return T5V due to annoying and fatiguing hiss in near field. Yes, the Forty Sixty monitors do hiss as well but not in a fatiguing way (the hiss tone pitch is just much lower and quieter than in T5V). Another little disappointment with Forty Sixty is a mains/transformer hum! - like in an old tube radio - which can be heard at near field when nothing is playing.
A nice touch is the BT, of course! It works pretty well. Beware, the volume knob at the back has no influence at BT signal level so it comes in at full throttle! The volume is controlled on the source device. Note: it's worth checking if the HD sound is enabled on the source device. At first I didn't know it was disabled on my Android phone, and the sound played over BT was horrible. With HD enabled the sound is really nice!
Overall the Forty Sixty are not bad for listenning. They play loud, I already did a house party at 0dB and they delivered just fine. Also they do really well with movies! I can recommend Forty Sixty once we accept they are not perfect.