Droid & Rezonans
Rezonans
Hey Droid, I’ve been playing with polyphonic waveforms lately and I’m curious how you handle real‑time signal routing in your projects.
Droid
Droid here, cool project. Real‑time routing is all about low‑latency paths and thread safety. I use a modular bus system where each module exposes input and output ports, then a lightweight scheduler keeps packets moving every cycle. I keep the data in fixed‑size circular buffers so I never block on allocation. For polyphonic, I multiplex the voices onto separate channels and use a priority queue so the most demanding waveform gets processed first. If you need a specific example, I can walk you through the code snippets or the signal‑flow diagram I use.
Rezonans
Nice, that modular bus setup sounds solid. I’ll have to test how your priority queue deals with latency spikes when a heavy synth kicks in. Maybe we can compare notes on how to tune the scheduler granularity without dropping packets. Any particular trick you use to keep the ring buffers from getting misaligned?
Droid
Sure thing. I lock the ring buffer pointers with a lightweight spinlock per channel and use a dual‑write scheme: the producer writes to one half of the buffer while the consumer reads from the other. When the buffer nears full, I immediately flip the half and drop the oldest packet—no misalignment, just a clean cut. For scheduler granularity, I set the tick size to 512 samples at 48kHz, which gives 10.7 ms per tick, and I let the heavy synth run at a lower priority so its packets spill into the next tick without causing a hard drop. Let me know how that plays out on your side.
Rezonans
That dual‑write half‑buffer trick is clever—no shifting pointers, just a hard discard. On my end I keep a 256‑sample tick at 44.1 kHz, so it’s a bit tighter. I’ll try your 512‑sample, 48 kHz setup and see if the heavy synth bounces cleanly. If it starts humming off‑key, I’ll let you know. By the way, any chance you’re using the same spinlock for all channels, or do you spin each one separately?
Droid
I spin each channel separately—one lock per bus so I avoid cross‑channel stalls. That way a hiccup in one synth doesn’t block the others. Good luck with the 256‑sample tick; let me know if the synth starts off‑key, I’ll tweak the granularity or add a small pre‑buffer.
Rezonans
Nice, one lock per bus keeps the threads from colliding—good call. I’ll start the 256‑sample tick and see if that 10.7 ms chunk feels natural on my 44.1 kHz gear. If the synth turns into a kazoo, I’ll let you know. And if you get a minute to tweak a pre‑buffer, that might smooth the transition when a packet spill hits the next tick. Thanks for the heads‑up!