I thought about a LAN protocol since the end of '90s, with audio and MIDI, but I never built/developed a real working thing. Too busy with work, gigs and other hobbies. So I’m not so updated with audio-MIDI over Ethernet (like MADI) and all those high speed "standards). Too bad, it’s a very fascinating world.
Like you, I’d like a wired solution. A black box with bidirectional multichannel audio, USB, MIDI, video, etc. would be perfect (in my dreams). 
TBH, my ambitions aren’t that high - I’m quite happy to have everything digital audio safely around my Cantabile rack. I only need to connect my keyboards and touchscreen (and maybe a mouse to be safe) to that rack and to get a HDMI signal to my touchscreen. That’s pretty much it at a minimum.
Getting more ambitious, it would be nice to have a MIDI back-channel from the rack to my LivePrompter tablet, but currently, that’s connected happily via WiFi. Since we run our mixing via WiFi, we have a WiFi hub on stage, anyhow.
Should we ever get to the stage where that’s not possible (festival organizer not allowing individual WiFi), I’d probably have to find a solution for that back-channel using MIDI via Ethernet (iConnectivity mio interfaces) - could be made to work as well. In that case, I’d probably run all MIDI through that route back and forth, and use the KVM extender just for the touchscreen and mouse.
Getting a bit more complicated now… 
Well, a dream is a dream. 
So you are planning that KVM extender and iConnect. Using the 5-pole MIDI, avoiding the USB?
I have doubts about sending USB-MIDI controllers over that extender. You know, reliability? Latency? My gut says no.
Well, I’ll see about that KVM extender - will get it soon, so will be able to test it. I’ll definitely report back on my experience.
Worst case, I’ll just run the touch screen and mouse over it - not timing-critical.
re MIDI connection: no, I won’t send that over long DIN cables, although that would probably work, since we don’t play huge stages. But the iConnectivity interfaces are fully networked, so the alternative scenario is to run a second Cat6 cable along with the KVM one and use it to connect the mio interface (underneath my keyboards) to the router / WiFi access point that sits on top of my rack. So the mio would be
- USB connected to my LivePrompter tablet on stage
- DIN or USB connected (both should work) to my two keyboards
- ethernet connected to the Cantabile PC
MIDI latency over wired ethernet should be below 0.5 ms, so should be neglegible
So I’d have a manageable cable run to the backstage rack:
- Cat6 for KVM
- Cat6 for MIDI
- XLR for vocals
- (buffered) line for guitar
- [XLR back for in-ear —> probably not for the typical festival set-up]
Wrapping these together with tape into a quasi-multicore, and set-up and tear-down should be manageable…
Cheers,
Torsten
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Looking forward to the results.
That’s OK. MIDI is electrically not bad (current loop) but it lacks any error correction protocol, so long cables are not at all a good idea.
Not quite a simple setup
OK, KVM extender just came in - and I have to say, I’m impressed! Works plug&play - just inserted it in the HDMI and USB connections, and everything simply worked.
First, I only ran the touchscreen over it, then I got courageous and also connected my MIDI keyboard via USB - and there’s really no noticeable latency or jitter! Feels rock-solid.
I’ll definitely keep everything set up like this for the next couple of weeks and give it a thorough shake, but it looks like I may be on to something. One single Cat6 connection between my on-stage keyboard rig and the Cantabile rack - that’s all it needs to function! Of course, I’d probably keep the USB and HDMI cabling for the “standard” solution with me, but this promises a much more flexible on-stage setup, where I don’t need to keep my Cantabile PC directly around my feet, but can set it up safely at the back of the stage.
Now just a bit more fiddling with the rest of the setup (mic, guitar, in-ear) - I think I’ll wrap that into a nice multi-core and be done with it - two leads from my place to backstage, that’s pretty clean 
Will keep you posted!
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Sounds interesting. How long is the KVM-PC cable?
I have tested this with a 5 m and a 10 m Cat6 cable between the PC and the keyboard rig. Works nicely with both…
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Thanks, Torsten. G.A.S. strikes back, I’m buying one.
MOTU AVB could do this using ethernet, although their units are expensive. Basically you’d have a small interface on stage such as the MOTU ultralight then connect that via ethernet to another MOTU AVB interface (such as the MOTU 8M), which would be connected to your computer on a rack offstage. You could run audio through this as well.
They can do audio & MIDI, but no USB or video. I thought about MOTU or iConnectivity, but it didn’t really address my requirements.
With a Cantabile PC backstage, you’ll want sone kind of remote display…
The one I linked to above:
https://foxun.com/product/50mhdmi_extender_with_kvm_support1080p
Bought it from a German online shop kvm-switch.de
Supposed to be able to run my connection (USB+HDMI) over 50 meters - I guess, I’ll never go beyond 10 m, but never hurts to have reserves 
Cheers,
Torsten
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Ok, as they say “Duh”.
I haven’t seen the Foxun one here in the US. I’m still looking around.
Thanks
I have a question regarding battery backup power for the off-stage PC.
When I first started using VSTs (I think it was when NI-B4 was first released) I used a small form factor PC with an PCI soundcard. It worked great - except for occasional power fluctuations, which would cause the PC to crash. It was especially problematic when we played some outdoor gigs where power was supplied thru a generator. For awhile I started carrying a battery backed up PSU, which of course added significantly to the weight ad size of the rig. I was quite happy when I was able to find/afford a powerful enough laptop with an external soundcard and since then I’ve not experienced any power issues, which I assume is due to the internal battery.
For those of you using PCs (not laptops), have you experienced crashes due to power fluctuations? If so, what do you do to prevent them?
Thank you - David
Yeah, I can relate: on one of our gigs, someone from the house kept messing with the power supply during our setup, cutting off power without any warning multiple times - I nearly killed the guy…
Usually, we have pretty decent power here in Germany, and I’m reeeeeally suspicious of the kind of gig where you get generator power. In that case, I’d probably carry a UPS device plus a power conditioner - and still worry 
I can relate to that experience!! Many times I’ve wanted to strangle a sound guy or a venue employee. 
I always use a UPS now. Primarily because my Kronos has a 3 minute boot type whilst pre-loading samples from SSD, and that was one recommendation I picked up from Korg forums: if you gig with a Kronos, a UPS is a must. Of course now I have an NUC PC in my gig rack, not a laptop, for Cantabile then it is protecting that now as well.
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I’ve used a UPS since a gig some 15 years ago. There was power brownout, and it fried my Allen & Heath mixer along with my Roland Keyboard Amp.
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I remember one gig we did in Pure Floyd (the one where I lost my Cantabile 2 setup due to plugging a USB 2 device in a USB 3 port and only got it back 5 mins before we started!) where the power was really dodgy and tripping all over place, but at least the keyboards just kept running thanks to my APC UPS, which was a blessed relief given all the other problems I had!
That was the gig where I learnt the hard way to
- Label all ports and cables if one device is really fussy about being in a USB2 port (my Focusite Diamond interface) - in all the panic I failed to notice that, and starting Cantabile 2 in that config caused a sh*t load of problems
- Do not start Cantabile 2 unless all connections are correct, as per #1 (Cantabile 3 is much more tolerant in this respect!
) - Backups are fantastic, but useless if you do not have them with you, and they are 120 miles round trip away from you, and you have an hour before the gig starts…!!!
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