 If an event is sent on two channels at once, the event on the second channel cannot transmit until the first one is finished, and so is delayed by 1 ms.If an event is sent on all channels at the same time, the last channel's transmission is delayed by as much as 16 ms.This contributed to the rise of MIDI interfaces with multiple in- and out-ports, because timing improves when events are spread between multiple ports as opposed to multiple channels on the same port.