I am experiencing a persistent, audible hiss (high noise floor) when using the HiBy R1 in USB DAC mode. This hiss is present even at the absolute lowest volume settings and continues even when no music is actively playing, which isolates the issue to the DAC mode itself rather than the audio source.
Steps to Reproduce:
Boot the HiBy R1 with the custom firmware.
Connect the HiBy R1 to a host device (smartphone or tablet) to use as a USB DAC.
Plug in IEMs/headphones.
Observe the audible hiss immediately, before any music is played and at the lowest volume.
Expected Behavior:
The background should be completely silent (black background) when no music is playing and at low volumes in USB DAC mode, similar to the stock firmware behavior.
Hardware & Environment Tested:
DAC: HiBy R1 (running this custom firmware)
Host Devices: Poco X6 Pro, Redmi Pad Pro 5G
Cables Tested:
Stock HiBy R1 USB cable (with USB-A to USB-C converter)
Original Samsung USB-C to USB-C cable
Troubleshooting Steps Already Taken:
I have thoroughly tested this to rule out host-side processing or cable issues:
Host OS Settings: Set to "Original" sound mode on both Xiaomi devices. Dolby Atmos and Xiaomi Sound features were completely disabled.
HiBy Music Player App Settings (on phone):
Activated "Exclusive HQ USB audio access".
Tested "USB Audio Performance Mode" (both activated and deactivated - hiss remains).
Tested DSD Mode on: PCM, Native, and DoP (hiss remains on all).
Source Material: Issue is not caused by track noise, as the hiss is present even when the player is stopped/paused.
Cables: Swapping between the stock cable and a high-quality Samsung C-to-C cable yielded the exact same result.
!!!
Limit current also does nothing
I am experiencing a persistent, audible hiss (high noise floor) when using the HiBy R1 in USB DAC mode. This hiss is present even at the absolute lowest volume settings and continues even when no music is actively playing, which isolates the issue to the DAC mode itself rather than the audio source.
Steps to Reproduce:
Boot the HiBy R1 with the custom firmware.
Connect the HiBy R1 to a host device (smartphone or tablet) to use as a USB DAC.
Plug in IEMs/headphones.
Observe the audible hiss immediately, before any music is played and at the lowest volume.
Expected Behavior:
The background should be completely silent (black background) when no music is playing and at low volumes in USB DAC mode, similar to the stock firmware behavior.
Hardware & Environment Tested:
DAC: HiBy R1 (running this custom firmware)
Host Devices: Poco X6 Pro, Redmi Pad Pro 5G
Cables Tested:
Stock HiBy R1 USB cable (with USB-A to USB-C converter)
Original Samsung USB-C to USB-C cable
Troubleshooting Steps Already Taken:
I have thoroughly tested this to rule out host-side processing or cable issues:
Host OS Settings: Set to "Original" sound mode on both Xiaomi devices. Dolby Atmos and Xiaomi Sound features were completely disabled.
HiBy Music Player App Settings (on phone):
Activated "Exclusive HQ USB audio access".
Tested "USB Audio Performance Mode" (both activated and deactivated - hiss remains).
Tested DSD Mode on: PCM, Native, and DoP (hiss remains on all).
Source Material: Issue is not caused by track noise, as the hiss is present even when the player is stopped/paused.
Cables: Swapping between the stock cable and a high-quality Samsung C-to-C cable yielded the exact same result.
!!!
Limit current also does nothing