A new FW test file has been sent to me by Sabaj and is currently being tested. (SABAJ_A30a MCU_FW 220928)
Changes from the last FW
1. It became a natural change by reviewing the characteristic curve of the volume control.
2. The SW setting has been changed so that low-pass and high-pass are now combined.
SUB Cut Off Frequency: OFF, 70, 80, 90, 100, 110, 120, 140, 160 (Hz)
When SUB is set to OFF, the SW output stops and the speaker output outputs the entire band.
When the SUB frequency is set to 70 to 160Hz, the speaker output will be in high-pass mode linked to the SUB setting frequency and will be low-cut. It feels like the SUB setting frequency is the crossover point.
I've tested it and haven't found any problems so far, so I think Sabaj will issue a new FW soon.