A Plea for PoE

At risk of sounding like I'm gatekeeping, I think that ever since music festivals became the primary medium for electronic music, live performance has become more about the giant spectacle of screens, lights, and fire. The musician becomes a mere speck on the stage, only there to make the audience feel like they're not just paying for a pre-programmed lightshow and a playlist¹. CDJs and laptops lock the performer to one position, and limits the dynamism and physicality of their performances. Heck, it's called Electronic *Dance* Music, but I've never seen a DJ do much more than bob their head, pump their arms, and clap their hands (TODO: write an article about how throwing a cake should be considered a dance move). It's great that electronic music has given lighting and effects operators the freedom to unleash their craft on the world, but I can't help but compare these shows to rock concerts and drum circles, and wonder: what could it look like if today's instruments were better at expressing today's music?

To emphasize: it is not the music, the musician, or the stage that is in need of reform. There is plenty of musicianship and creativity in electronic music today; arguably more than there was for rock and classical. It's just that the limitations and hassle of the hardware restrict how that music can be performed. Perhaps a laptop is effective and convenient enough for the *production* of music, but I don't see a future in laptops as a tool for *performance*.

Anecdote of a musical stage perforance

I recently helped out with a few showcases for a local multimedia festival. One such showcase was run by a record label, and they brought in a bunch of musicians of various genres, and they had to go on one after another. Some bands had 5+ members and drum kits, while one had just a laptop and a microphone². Now, between the two, you would think that the laptop would be a lot easier, right? Well, technical difficulties with the laptop put the whole schedule back almost an hour. A dongle was lost at some point, cables had to be switched out, devices had to be restarted; a culmination of Murphy's Law. And this was on top of the already cumbersome setup process of taking each device out of a suitcase and plugging in the various power and USB cables.

I can't guarantee that the following proposal will solve all of this, but if there's anything I've learned from those last few days of stage work, it's that electronic music performance is in dire need of simplification. In its current state, using a laptop on stage with its tangle of cables going to MIDI controllers, audio interfaces, and power supplies is a complicated problem, solutions for which are very fragile (compared to setups for other types of music performance). My goal with this manifesto is to improve technology in order to simplify the experience for electronic musicians performing their music.

Crash course on PoE

Power over Ethernet (PoE) is a set of networking standards designed to allow for power delivery over (you guessed it) an Ethernet connection. Similar to USB-PD, the devices use the protocol to negotiate power, and both sides have to be compatible with the standard.

PoE vs USB-PD

	Ethernet	USB 3.0
Use cases	Limited to internet networking, and a small handful of other niches (one of which we will come back to later)	Very flexible, and near-universal (which seems to have been the goal, based on the name).
Speed	Cat 5e only allows for speeds up to 1 gigabit per second (but Cat 8 allows for up to 80 gigabits!)	At time of writing, can go up to 20 gigabits per second with compatible devices and cables.

	PoE	USB-PD
Availability	Power usually comes from a switch, and PoE switches aren't abundantly common outside of IT and commercial networking solutions (though PoE switches seem to be more common than USB-PD hubs)	Most laptops come with USB-PD chargers at time of writing, and if a battery bank has a USB type C output, chances are, it supports USB-PD.
Power	802.3af (Base-level PoE) nominally supports 15.4 watts, while 812.3bt (PoE++) supports up to 90 watts [1][2]. Usually runs at 48 volts [3].	Boasts over 180 watts at 36 volts.
Impl*	Requires IC for rerouting the connections depending on whether PoE is negotiated	Doesn't necessarily require a dedicated chip, only that your microcontroller has peripherals for USB-PD negotiation.

*: It's a bit tough to say authoritatively which is easier to implement from a hardware development perspective (focusing on the receiving end), as I've never implemented either. My understanding is that in USB-PD, the power arrives through dedicated conductors, while with PoE, the power comes in on the same twisted pairs that data could come in on. No citations for anything said in this row; it's all guessing and speculation. I will hopefully be able to update it soon after trying some stuff out and doing more research.

So why PoE?

Despite USB being a better standard for 90% of applications, there is still a reason that Ethernet dominates the networking industry. The two main benefits that I can see are: cables are extremely cheap (and easy to crimp yourself), and can get extremely long. With USB 3.0 (using 26 AWG wire), you get approximately 3 meters maximum [4]. On the other hand, Ethernet cables (of any Category) are generally rated for 100 meters. The extra length is *absolutely vital* for making digital music controllers more portable. With USB, the musician is tethered to a circular area with a radius of 3 meters, but with Ethernet, the laptop doesn't even have to be on the stage. It could be setup somewhere out of the way and left alone between performances, which would have almost certainly prevented the issue with the laptop in the anecdote from earlier. Or you could go as far as to have a rack-mount desktop, connect it to a PoE switch, and run a single ethernet cable to each musician and move around with the same freedom that an electric guitarist might have. Just one cable between the musician and the sound system.

While I don't know of any hardware that uses PoE specifically, there are plenty of open standards for audio over an Ethernet connection, often used to send many channels of audio over a "digital snake" from a stage to its sound booth and back. It isn't strange to see a roll or two of Cat 5(e) cable in a live venue's arsenal.

Some Pioneer CDJs and mixers are equipped with Ethernet for a feature that they call Pro DJ Link. Among other things, it connects any attached filesystems to other devices on the network, and can send the audio to a laptop (also on the network) with the appropriate software. I only know about this because during the aforementioned showcase, anytime there was a DJ accompanying the vocalist, the CDJs and mixer would be brought on stage in their flight case, (along with a Wi-Fi router and power strip), and setup was as easy as just plugging in the power and letting the booth take it from there. It went without a hitch every time.

The current state of DJ hardware connectivity is the future that I see for all music hardware: controllers, audio interfaces, rack-mount synthesizers, effects processors, eurorack, and anything other electronic device that can be used to make or perform music, all connected to one PoE switch offstage and nothing else.

Enter: Open Sound Control

By reading this far, you have just activated my trap card. For the past 3 years or so, I have slowly been coming to the conclusion that Open Sound Control (OSC) is the solution to almost all of my musical problems. Voice synthesizer plugin needs some way to receive phoneme info? OSC has character and string types. Want more semantically useful numeric types in a tracker-based DAW? OSC has single and double precision floats, 32 and 64 bit integers, booleans, infinity, timetags, and nil (if you count that as a numerical value). Need a file format that can express sample-accurate timing and namespacing? It's not standardized, but oscdump has a pretty reasonable output, and if that's not to your liking, you can just store the raw bytes, since time information is encoded in the packet (along with the message and its namespace, of course). Of course, OSC has its own drawbacks, so if you can do something entirely with MIDI, it's probably best to do it with MIDI. But if you need the length of an Ethernet connection anyway, you might as well use OSC as the transport layer for your MIDI data.

One of the notable things about OSC is that its designed to run on top of a network. Most OSC-compatible software asks for things like IP addresses and ports, and can communicate with OSC endpoints over the internet. OSC was made for Ethernet, and with the locking clip feature of RJ45 connectors (or optionally Ethercon), longer maximum cable length, and industry adoption of audio over Ethernet, I predict that PoE music hardware will be the "killer app" of OSC.

Closing thoughts

Please let me connect the music half of my 19" rack to the networking half.

Footnotes

References

[1] https://www.netgear.com/business/solutions/poe/overview/

[2] https://www.tp-link.com/us/solution/poe/

[3] https://superuser.com/questions/1105242/how-many-volts-there-are-in-poe

[4] http://janaxelson.com/usb3faq.htm#ca_maximum