Greetings,
Best practice states to connect MB directly to a computer, not to USB hub. And the same holds true for Beatstep Pro. I've been eyeing the Keystep Pro but am now concerned that it too will required a dedicated USB port. That would not normally be an issue but my iMac only has a finite number of ports and am not left with available open ports to host other devices.
Is all that really necessary, I mean are these devices so sensitive to timing or generate so much traffic that they require a dedicated port? The speed of USB 2.0 is around 480 Mbits/s. That's a lot of bandwidth for a single device.
I've read that the USB 2.0 standard does not allow for "low speed" or "full speed" devices to be polled more than 1,000 times/second; "high speed" devices may be polled up to 8,000 times/second, but require fancier electronics. A MIDI interface takes 320 microseconds (0.32 milliseconds) to send each byte of data; if multiple notes are pressed simultaneously, two bytes will have to be sent for each note after the first, so simultaneous notes will be played at least 0.64 milliseconds apart.
Having MIDI timings rounded off to the nearest millisecond would represent a loss of timing precision, but it's only slightly worse than the loss of timing precision imposed by the MIDI standard itself. An interface which communicated as a "high speed" device could have a 1/8 millisecond polling interval, which would cause only minimal loss of timing accuracy; I don't know how many interfaces do so, however.
One would hope that in this era of technology that Arturia devices use high speed USB technology and all this dedicated USB business is just to rule out timing issues when hubbing MB along with with say "noisy" devices. Of course the other aspect is that not all USB hubs perform the same and some pollute the USB channel with EMI that impares sound quality.
If this requirement is based on the poor hub quality (and the market is flooded with cheap units) then that makes sense. And I would like to understand if others have been successful using their MB with hubs, which units have worked and which to avoid. I would have to speculate that "AC powered" hubs is a requirement.
