I don't understand the point of this looper having a MIDI In port. It's meant to keep up with external gear and synchronise with the 'clock in' signal from other sources. In my case, I've tried multiple devices as MIDI clock sources but the Boss RC 500 does not play along as a slave device. The unit mangles the loop I've just made, making it sound unusable. Boss's advice is to disable Tempo Sync feature, which defeats the purpose of having a MIDI In, Clock Sync port. The unit cannot adjust to slight clock variations and therefore constantly time-stretches the recorded loop, making it sound like it's skipping frames, all jumbled up. Also, if Tempo Sync is disabled, the recorded loop plays at random intervals, when the unit feels like it. I can't make any sense of it.
The unit does work as a Master Clock, however, so not all is lost.
I think what Boss needs to do in a software update is to make it ignore the slight BPM changes of an incoming clock, average across time and disable the time-stretching algorithm for decimal point clock variation, or at least make it an option to disable time-stretching without disabling the Tempo Sync.
I've sold my unit after not seeing any significant updates from Boss. Unfortunately the unit did not fulfill my needs. I've moved onto a Pigtronix Infinity looper and it syncs to a clock without issues.
