Circuit & Mikrofonik

Mikrofonik

Hey Circuit, I was just tweaking a 360‑degree mic array for a robot project, and I’m wondering how you’d handle the signal routing and impedance matching. What’s your take on making the audio feed clean enough for real‑time AI processing?

Circuit

Hey, for a 360‑degree mic array you want a low‑noise, matched‑impedance front‑end. Use a differential TIA per mic with a 50‑ohm source impedance, then buffer each with a low‑noise op‑amp into a 100‑ohm load. Keep the traces short and shielded, use star‑grounding, and pull the bias with a high‑value resistor so the signal stays clean. For real‑time AI, digitize at 48 kHz, apply a 24‑bit ADC, and send the stream over a high‑speed bus like SPI‑DMA or I²S to your DSP. Keep the PCB layout symmetrical so the phase isn’t skewed – that’s the key to a clean, usable audio feed.

Mikrofonik

Thanks for the rundown – I’ll stick the 50‑ohm source to the differential TIA, but I’m still debating whether a 100‑ohm load is too high for my 48 kHz ADC. Any thoughts on the bias resistor value? Also, my PCB is a bit cramped; maybe a ground plane would help more than star‑grounding? Let me know if you think the phase symmetry is really that critical for the AI to “hear” the world evenly.