I have a R4 PRO head and it makes a difference to stroll with two pairs of static style U87 on a bar, a good Li-Ion battery and a small 12v HD20 headphones on the ears. It's quite amazing with the R4 PRO. I even made an installation with a satellite dish equipped with a Schoeps Colette for "capturing the sound" and a Schoeps stereo pair for the atmosphere in three channels and then mix to harmonize the two sources, it's an animal making sounds "House" and "not academic", but the thunder! preamps and hold up dynamically. Jeep