Philip Rees 2M
Midi Merge Unit

Philip Rees 2M

Philip Rees 2M
Philip Rees 2M

2M has the power!

As the 2M has a built-in mains power supply it has the power available to drive several outputs! There are thru outputs for each of the two MIDI inputs. The merged data is available simultaneously on two MIDI outputs, so you can drive two MIDI slave devices at the same time. Another benefit of the mains powered unit is that a fast processor with large ROM and RAM memory is able to be used.

The 2M has multiple large data buffers to minimise data loss. To mitigate undesirable delays, it could become necessary to reject some data. The 2M does this gracefully and automatically according to a priority discard system; redundant data is thrown away first.

Clock interlock system
System Real Time messages (that includes the normal tempo-relative MIDI clocks) and time sensitive System Common messages (including Time Code quarter frame messages, Song Select and Song Position Pointer) are kept in the right sequence and retransmitted at the first opportunity. System Real Time messages are managed by an intelligent interlock system, which prevents clock stream conflicts - see the state diagram above.

Time Code compatible
MIDI Time Code (MTC - that's not the same as MIDI clocks!) and the Universal Real Time System Exclusive messages are only accepted on MIDI IN A. The merging of two MTC streams would be pointless, and indeed two simultaneous sources of Time Code would be bizarre. You just connect a source of Time Code to input A if you want the code to be retransmitted, and to input B if you want the code to be discarded.
Very reasonably, the presence of MTC on input A automatically inhibits the retransmission of System Exclusive messages received on input B, in order to assure the integrity and punctuality of the Time Code.

System Exclusive
The 2M is especially capable of making the most of interleaving System Exclusive transfers, and minimising the disruption of concurrent performance data. System Exclusive messages less than 140 bytes long (the majority) are inserted into a performance datastream. Appropriate action is taken, if necessary, to prevent stuck notes and pitch bend values when longer SysEx messages are to be retransmitted.

Pitch Bend summing
Pitch bend values, relating to the same MIDI channel but coming from opposite inputs, are arithmetically combined. This is far better that allowing them to clash, which can give horrible results.
The 2M understands and sends 'running status', so you get the benefits of more efficient communication and faster response. As it automatically inserts status bytes when it has the opportunity, problems with receiving devices that tend to lose current status are avoided.

Neat package
The 2M MIDI Merge Unit is exceptionally compact (109mm x 109mm x 41mm). It has a built-in mains (ac) power supply and the integral mains lead (ac power cord) comes with a plug. Versions can be supplied for both international ac voltage ranges.

  Philip Rees 2M