I think this is a good topic. I was going to start the same thought on another forum, but will share here instead. At first I thought this was limited to currently available gear, but I see older stuff has been listed. YAMAHA FS1R - 4 part / 32 voice - my absolute favorite FM box (until another comes along). TG33 - 4 part / 32 voice - should be a cheap unit today, vector synth. CLAVIA Nord Modular Rack - 4 part / voices depend on complexity - lots o' fun. E-MU anything by E-MU will most likely be 16 part with lots of voices, they have a boatload of 1U romplers and 2U or 4U samplers, some with up to 128 voices. An E-MU rompler and an ARP is all one would need to do entire sets. TASTY CHIPS GR-1 - 4 part / variable voice - I actually would NOT recommend this one as the only synth companion for the ARP. It's a great synth, I love it, but doing typical synth sounds for most incarnations of arpeggiation is not its forte. Then again, perhaps I should think outside the box more. SYNTHSTROM AUDIBLE deluge - 16 part / variable voice - a deluge and the ARP is my portable system that I take when I'm on the road, way fun, hours of satisfaction. I'm glad to see the Roland SH-4D was already listed. I've been impressed by this synth of late. I tell myself I will never buy it, but I really like its architecture and range of sounds. I wish it would have been available when I was buying grooveboxes.

I've been monitoring this thought since it was first posted. I'm very interested. Being a musical neophyte, I could use all the help I can get. I'm such a newb, that I don't think I fully grasp the concept, but I think I like it. But questions come to my mind about how this would work. If, for example, you are currently playing an F Maj chord, it would seem to me that the particular key and mode you are playing in would dictate, or limit, the possible chords to consider for common chords. Just knowing the current chord doesn't seem like enough information to suggest what to play next. Then again, perhaps I'm limiting myself by rigidly adhering to modes. Also, it would seem that appropriate chords to suggest would also be influenced by the overall theme targeted. A "happy and bouncy" song would probably have different suggested chords than a "dark and ominous" one. But, I don't know. Still, I'm somehow intrigued by this idea. This has also prompted me to check out phone apps to suggest chords. Thanks for that idea!

This may be an opportunity to introduce the idea of Ports to the ARP. For example, each of the four arps could be assigned to a port individually, in addition to a channel. Instead of arp 1 (and 2, 3, 4) having MIDI Channel of 1-16 in 'midi out' in 'set' mode, a second push of the 'midi out' button could select a port. Port would be USB-A, USB-B, 5-pin DIN, or all. This could be interesting, but I'm not sure how much value such flexibility would present to the user. I can only imagine it would help if someone were to use an ancient 5-pin DIN device that could only listen in OMNI mode, in addition to a modern USB MIDI device on another port. Might be helpful in a minimalist setup. Then again, might not.

Thank you for the reply and clarification. Seems it works as intended. Unfortunately, I cannot disable MIDI Thru on the external controller. Alas it appears that my plan of daisy chaining will not work. Something else will have to give up a place on the limited and coveted MIDI IN slots on my router. At any rate, as a request, could a future software version supply a switch for enabling/disabling MIDI Out data on the USB-A host connector? Perhaps on the Menu button of the Set Mode. I do see the benefit of putting MIDI Out data on the USB-A, for this allows, say, a portable setup to consist of just the ARP and an external synth.