Can recommend MidiTemp (Multiplayer/Multistation) as well. Discontinued, but you may be able to find some used at a decent price. Although, they are old units with quite an non-informative display (in a remote) in regard to what is possible with them (potentially very complex stuff).
I´ve got an Multiplayer MP88W (1u rack), which got:
8 MIDI input ports
8 MIDI output ports
My unit came with no HDD, but I´ve installed an CF-SCSI adapter PCB inside instead of an HDD. Which seems to function properly so far.
It can function as an patchbay, filter/processor, router, song sequencer etc. An very neat feature is that you´re able to have 8 “matrix structure” banks active at the same time, and one song bank (plus one wave bank, if you´re using normal wav-files in it too).
8 matrix banks at once, means that you´re able to setup specific functions that overlays each others. Each bank that lies in a higher numbered group has a higher priority than the lower numbered.
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[li]So you could setup bank one to be a specific port/channel router which you don´t switch normally (the main IN/OUT routing structure).[/li]
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[li]A second bank could then be an bank where you have specific filters (NN, CC# and PC# etc) setup for each and every port/channel. As well as having specific program change transmissions for other gears (on each port * 16 channels). This bank and its possible 128 presets, could then itself be controlled via program changes.[/li]
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[li]Then you would still have 6 matrix banks more to go, for whatever more you may need. You can have them controlling each other if you want to as well (= very complex net structure).[/li]
[li]The song bank can also be controlled via program changes, and each song can even be paired with an specific matrix preset if you want. Or be setup so it will automatically select different ones within the song itself (i e as the abovementioned second bank).[/li]
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Given that you have an HDD installed, it will ALWAYS record everything incoming at ALL INPUTs (that you´ve set as armed). Which you may or may not choose to save for later use as an specific MID-file (which you then choose to reside at the song preset number you want). You will have to press a few buttons everytime you want to keep anything. If not and you press play again, it will dis-regard whatever you did prior to pressing play. But you can record many minutes or even hours perhaps (depending on HDD size), tweaking and playing away, and you don´t even have to worry about remembering pressing record each time. Downside, as said, is that you´ll have to decide after each time (you´ve pressed stop) if it worth saving.
I´ve barely scratched the surface of the surface here. But I guess you could think of it as being an 1u computer loaded with Midi-OX (except for its hex code monitor feature). Where its only task is dealing with MIDI with minimum risk of any (computer) OS malfunction in the heat of action.