The promise of the decoupled architecture—the “Open Air” philosophy—is an engineer’s dream. You separate the physical control surface from the processing engine, granting yourself the ultimate agility. A fader isn’t just a volume slider anymore; it’s a universal, assignable control vector.

But as you start wiring the system together, Anthony, a dark reality quickly rears its head. You push the motorized fader up. The software volume goes up. Then, the fader violently twitches, fights your finger, and shoots back down, sending the software volume spiraling into a chaotic blur before crashing the network with a flood of packets.

You haven’t just built a control system. You’ve built an infinite feedback loop.

Here is the story of the hardest obstacles in decoupling hardware from software, and the technical gauntlet the Splinker must run to maintain order.

Obstacle 1: The “Ghost Touch” and the Infinite Echo

The Analogy: Imagine two people standing in an infinitely reflective hall of mirrors, trying to communicate with walkie-talkies that have their buttons permanently taped down. Every word one person says is immediately echoed back by the walls, and that echo is picked up by the other radio, which transmits it back again.

The Technical Reality: In a bi-directional system, devices are incredibly literal.

1. The human finger moves a motorized fader to 0.7.

2. The fader’s sensor detects this and fires an MQTT message: SET VOLUME 0.7.

3. The software engine receives it, updates its internal state, and faithfully broadcasts the new state to the network: VOLUME IS NOW 0.7.

4. The physical fader receives this state update. Its motor physically drives the fader to the 0.7 position.

5. The Fatal Flaw: The fader’s sensor feels the motor moving it, assumes a human just pushed it, and fires a new control message: SET VOLUME 0.701.

The Overcome: This is why the origin_source and msg_guid are strictly necessary. The Splinker acts as the bouncer at the door, forcing every device to wear a nametag. When the hardware receives a state update, it must check the origin. If it sees its own ID, it applies a digital mute to its sensors: “I started this action, so I will update my motor to match the state, but I will ignore the resulting sensor twitch.”

Obstacle 2: The Physics of Meat and Metal (Inertia)

The Analogy: You are driving a massive cargo ship, but your steering wheel is connected to a laser pointer. The laser moves instantly to wherever you point it (digital software), but the ship takes five agonizing seconds to actually turn (physical motors). If you keep aggressively turning the wheel back and forth before the ship catches up, you snap the rudder.

The Technical Reality: Software updates in microseconds. Motors, gears, and belts take milliseconds or even tenths of a second to physically arrive at their destination. Furthermore, human hands are jittery. When you slide a fader, you aren’t sending one command; you are sending hundreds of granular micro-adjustments (0.61, 0.63, 0.68).

If the Splinker tries to force the motorized fader to physically track every single micro-bounce of a feedback loop while the human is still holding it, the motor will burn out or the fader will aggressively stutter against the user’s finger.

The Overcome: This requires a sophisticated Debounce and Settling protocol. The Splinker must recognize an active “Splice” stream. While a flood of commands is coming from a single source, the Splinker flags them as is_settled: false. It instructs the receiving hardware: “Do not fight the human. Let them move.” Only when the stream goes quiet for a predefined window (e.g., 50ms) does the Splinker send the is_settled: true command, signaling the physical motors to cleanly snap to their final resting position.

Obstacle 3: The Time-Warp of the Network

The Analogy: You are mailing a series of letters to a friend with instructions for a recipe. You mail Step 1 on Monday, Step 2 on Tuesday, and Step 3 on Wednesday. But because of chaos at the post office, your friend receives Step 3 on Thursday, Step 1 on Friday, and Step 2 on Saturday. If they follow them in the order they arrive, the cake explodes.

The Technical Reality: Networks are unpredictable. In an IP-based MQTT system, packets can take different routes. This causes network jitter. A user might quickly slide a fader from 0 to 10. The system generates:

• Packet A: Value 2

• Packet B: Value 7

• Packet C: Value 10

If a micro-bottleneck occurs, the software might receive them in the order: A, C, B. The volume goes to 2, jumps correctly to 10, and then disastrously jerks back down to 7, where it stays.

The Overcome: Relying on the network to sort out the echo is a losing battle. The solution requires an Interaction Lock (The “Do Not Disturb” Protocol) built directly into the hardware and UI widgets.

When a human finger touches a motorized fader, the controller engages a strict hardware-level lock (is_locked = True). While the human is touching it, the fader violently deafens itself to the network. It drops all incoming LINK_FEEDBACK messages into the void, refusing to update its visual position or fire its motor, while simultaneously blasting its own SPLICE_ACTION commands out to the software.
The infinite loop is severed because the hardware is physically incapable of reacting to its own network echo. Only when the human lets go does the lock disengage, allowing the fader to listen to the network once again.

By: Anthony Kuzub. A Confused Broadcast Engineer

I’ve spent the last twenty years in OB vans and broadcast control rooms. In my world, “latency” is a dirty word. (production offsets is what I like to call them) If a signal is one frame out of sync, we panic. If a host hears their own voice in their IFB (earpiece) with even a 10ms delay, they stop talking and start shouting at us. You can judge an in ear mix by how far they throw the beltpack.

So can you imagine my confusion when I recently stepped into the commercial AV world to help commission a high-end boardroom.

I opened a clients DSP file—a standard configuration for a room with ceiling mics and local voice lift—and I saw something that made me think I was reading the schematic wrong.

There were Acoustic Echo Cancellation (AEC) blocks on everything.

Not just on the lines going to the Zoom call (where they belong), but on the microphones being routed to the local in-room speakers. I turned to the lead AV integrator and asked a genuine question:
“Why are we running the podium mic through an echo canceller just to send it to the ceiling speakers five feet away?”
His answer was, “To stop the echo.”
And that is when my brain broke.

The Chicken, The Egg, and The Latency

In broadcast, we follow a simple rule: Signal flow follows physics.

If I am standing in an empty room and I speak, there is no electronic echo. If I turn on a microphone and send it to a speaker with zero processing, there is still no echo—there might be feedback (squealing) if I push the gain too high, but there is no distinct, slap-back echo.

So, I looked closer at the AEC block in the software.

• Processing Time: ~20ms to 50ms (depending on the buffer and tail length).
Suddenly, the math hit me. By inserting this “safety” tool into the chain, we were effectively delaying the audio by nearly two video frames before it even hit the amplifier.

Here is the loop I saw:

1. The presenter speaks.
2. The DSP holds that audio for 50ms to “process” it.
3. The audio comes out of the ceiling speakers 50ms late.
4. The microphones at the back of the room hear that delayed sound.
5. Because 50ms is well beyond the Haas Effect integration zone, the system (and the
human ear) perceives this as a distinct second arrival. A slap-back. An echo.

Creating the Problem to Fix the Problem

I realized that in this room design, the AEC wasn’t curing the echo; it was the source of it.
Because the system was generating a delayed acoustic signal, the other microphones in the room were picking up that delay. The integrator’s solution? “Oh, just put AEC on those back mics too.”
It felt like watching a doctor break a patient’s leg just so they could bill them for a cast.
In the broadcast world, we use “Mix-Minus” (or N-1). If a signal doesn’t need to go to a destination, you don’t send it. If a signal doesn’t need processing, you bypass it. You strip the signal path down to the copper.

The “Empty Room” Test

I proposed a crazy idea to the team. I asked them to imagine the room completely empty. No Zoom call. No Microsoft Teams. Just a guy standing at a podium speaking to people in chairs.
• Is there a remote caller? No.
• Is there a far-end reference signal? No.
• Is there a need to cancel anything? No

If we simply bypassed the AEC block for the local reinforcement, the latency dropped from 50ms down to about 2ms. At 2ms, the sound from the speakers arrives at the listener’s ear almost simultaneously with the actual voice of the presenter. The “echo” vanishes.

The system became stable not because we added more processing, but because we stopped fighting physics.

A Plea from the Control Room
I’m still learning the ropes of AV, and I know that VTC calls are complex. But I can’t help but feel that we are over-engineering our way into failure.
If you have to use an Echo Canceller to remove an echo that you created by using an Echo Canceller… maybe it’s time to just turn the Echo Canceller off.