I'm assembling my rig, and I can't seem to find a suitable solution.
My band wants to share a rack-mounted synth module stack between all three members on stage. BomeBox and MIDI Translator are invaluable for this purpose, as they serve to 1) Span the distance between our rack and the stage with a single cable, and 2) dynamically re-route the MIDI signal flow as needed between players and synths.
Thus far, I have a BOME box at the rack, and a BOME box on stage, connected through a rack-side POE switch.
My question: how do I (robustly and professionally) distribute the stage-side BOME box to my bandmates? It seems my options are:
- Wire all stage-side MIDI devices to a MIDI Hub at the stage snake.
- Separate-but-visually-identical input and output cables are extremely error-prone during setup and cause stage clutter
- No support for USB MIDI devices at the players' locations
- Build a ruggedized USB hub at the snake location and use it to distribute the BOME box's USB port to three separate DIY USB midi interfaces (which will include their own USB ports)
- Ground Loops
- If I build a passive USB hub, there will be insufficient power for USB midi devices
- If I build an active USB hub, there will be ground loops between instrument cables and USB power
- Buy BOME boxes for the other two band members and connect them through a second POE switch at the snake location. Build a USB/MIDI interface for each band member.
- Exorbitant cost of BOME Boxes ($400 CAD each)
- How many BOME boxes can interconnect via Bome Network Protocol in an Ethernet 'star ' configuration?
Can anyone help me wade through this?
Hi, are all of the MIDI devices on stage USB capable? If so, I would go the USB route to reduce cables. If you are afraid of ground loops, you could instead use a heavy duty portable phone battery as a power source. I’ve often powered my BomeBox from one of these. Take care that it provides consistent power, though and is not set up for fast charging (cycling power output depending on target device charge).
I use on similar to this:
You may want to get 2 for long gigs or as a backup. I’ve never drained mine in 4-5 hours of use on my rig.
If they are all MIDI DIN devices, I would just use the output side from each device (unless you want incoming control of the device as well) to reduce the amount of cables. Of course you could get some MIDI to USB converters ( Roland UM-1 or iConnectivity MIO-1) to convert to USB.
For 3 devices you may or may not need a powered hub depending on their current draw. BomeBox should be able to provide up to 1A of power if you are using POE. Although the USB 2.0 spec says up to 500ma per device, I find that most of my my devices are drawing less than 50ma since they have their own power source. I tested using this USB monitor.
That said, the DIN to USB converters I mentioned DO require USB power however I have not measured their current draw.
If they do indeed require power from the BomeBox, you may have to use a powered USB hub. Again I would measure as in many times I find it not necessary.
As you say the individual BomeBoxes would probably be the cleanest but also most expensive solution. You may want to ask Florian for a volume discount. The worst he could say is no but I usually find him pretty reasonable able these things depending on your current circumstance. (I can’t speak for him on this so no guarantees).
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I received a good answer from Bome via email thread and wanted to add it to Steve’s excellent advice above.
The Bome box was developed to address the challenge I am trying to solve: to distribute midi across distances using a single cable and without causing ground loops. Yes, it is a bit pricey when used for this purpose alone. However, it is one of a kind. (With the possible exception on rtp-midi… but I don’t know enough to speak to this.)
I’ve ordered two more Bome boxes and may order one more if the (anticipated) need materializes.
I do have one further question though. It is oft-repeated that POE power is the most robust way to power the bbox. Does POE power not introduce ground potential differences if, say, a powered USB hub is plugged in to the bbox? Perhaps this is because I am only considering POE power as “remotely-powered?” Should I stop buying POE switches and simply power each bbox from a local POE injector while the POE “out” port remains connected to the central (non-Poe) Ethernet switch? Thoughts are welcome.
(Note that local battery power, though valid, is not the solution I’m looking for. I can’t afford to depend on my own presence of mind to charge the thing before each gig.)
Hi, I recommend POE for 2 reasons.
1) 48 volts is less susceptible to slight power variations than the micro USB which I believe is 5 volts.
2) The POE connectors are latching so less likelihood to pull them loose during a performance.
Finally, I would daisy chain them to provide POE over them all. That way they are all on the same power source and less susceptible to ground loops. And if you are using the MIDI DIN connections to band members rigs, the MIDI connectors are further opto isolated.
48v vs. 5v : Makes sense. Good answer. Thanks!
RJ45 more secure than USB : I’m with you. Although the right-angle USB connections on the cables supplied with the Bome box were a welcome sight. They are far better than the standard connector in this regard.
Daisy Chaining : This is where I get confused. The answer doesn’t line up with what I think I understand about ground loops.
To understand, first keep in mind that I will inevitably use ALL the available connections. Both USB and DIN will be connected, often to multiple devices via hubs. Some of these devices and hubs will inevitably require additional power from a local power supply.
Stop right there… I now have one power source (the first Bome box in the POE chain) providing one grounding reference from the rack, and another power source (the transformer of a local USB hub) providing a second grounding reference from a power strip at the player’s feet. Does this not create the potential for ground loops? And does not a daisy chain add further to the problem by connecting additional grounding references at each player’s locally powered USB hub?
I would think that a star-networked, standard-non-powered-ethernet connection** to the stage rack for each Bome box would eliminate this concern, and that a local POE injector for each player’s bome box and USB hub would ensure that each USB hub / Bome Box pair would reference the same ground voltage.
I’m happy to be proven either right or wrong on this… just want to understand fully either way.
** It is my understanding that, while the ethernet (or rather TIA) specification prescribes transformer-balanced and isolated (ground loop-proofed) differential pairs as a component of the Ethernet standard, the POE standard necessarily breaks that convention. I’m looking into this now, as I might not understand this fully.
There will always be BOTH USB and DIN style connections at every Bome box.
Daisy chaining the BomeBoxes via POE will ensure there is a common ground. Only one ground reference for all BomeBoxes through the ground cable between them originating at the POE to the first BomeBox.
I’ve never experienced MIDI ground loop problems with USB (MIDI) only USB (audio).
With that said, if you have only 2 USB devices attached to a given BomeBox, you will not likely need a powered hub so you can just use the same ground reference from the BomeBox as you get through POE.
Granted, your attached devices may have their own power source which might create ground loops. Something like the below could probably help in isolating any problematic USB connections as they are billed as “isolators”.
I bought one but never had to use it. I suspect that you could get this cheaper than the one I bought $17.49 USD.
Again, the only ground loop related issues I ever seen are more audio (digital or analog) related and I’ve never encountered a MIDI ground loop issue. I thought I did, which is why I bought the isolator but the problem ended up being something different.
Thanks for your continued responses, Steve. They are helping. Sorry that I keep batting them back, it’s how I learn.
- Daisy Chaining the Bome Boxes will indeed ensure a common ground… but hooking them up in a star configuration to a shared POE switch would do the same, I believe. Thoughts?
- You said “if you have only 2 USB devices”… I am designing this system to grow with the purchase of midi gear over many years to come. Any limits I place on the number of USB devices attached to each Bome box will be exceeded eventually… if not immediately. That’s why I’m so keen on building it correctly.
- I had previously looked into USB isolators and had not found such a reasonably-priced solution as yours. I think that is my answer! I’ll just build with impunity and add one of these to the USB connection if and when a USB peripheral or hub requires its own power. If the device does its job, it should address my concern about multiple power distributions with conflicting ground references. Thanks!!
Steve offered usb isolators as a solution in one of his comments. That, I believe, should work just fine.