Non-Bose system. Upgraded Alpine Component speakers in the front only.* 2018 Mazda 3, but most Mazda's have been using this TAU (Tuner Amplifier Unit) for over a decade now.
Even with the car off, in accessory mode, once the infotainment system boots up, a high frequency (10kHz) hiss appears. It is very faint, however after adding an external amp to the system the hiss is more pronounced and noticeable, even when driving and all sound muted. Using a phone spectrum analyzer, the hiss is a 20db spike above background noise at exactly 10kHz, and only 10kHz.* Without the amp connected it is only a 6db spike, so it is clear the hiss is from the TAU and not the amp.* Note that the hiss is there even when the audio is paused, volume at zero or muted.* Unfortunately, you can't turn off the Mazda audio system.
I wanted confirmation if others have this condition (this way, the system is just poorly designed, I will just live with it).
Does anyone have an idea to solve it?
It is unlikely anyone will hear or notice this with the stock tweets, for they are near useless and do not even reproduce 10kHz frequency.* The issue would be noticeable with upgraded speakers and/or secondary amp.
Even with the car off, in accessory mode, once the infotainment system boots up, a high frequency (10kHz) hiss appears. It is very faint, however after adding an external amp to the system the hiss is more pronounced and noticeable, even when driving and all sound muted. Using a phone spectrum analyzer, the hiss is a 20db spike above background noise at exactly 10kHz, and only 10kHz.* Without the amp connected it is only a 6db spike, so it is clear the hiss is from the TAU and not the amp.* Note that the hiss is there even when the audio is paused, volume at zero or muted.* Unfortunately, you can't turn off the Mazda audio system.
I wanted confirmation if others have this condition (this way, the system is just poorly designed, I will just live with it).
Does anyone have an idea to solve it?
It is unlikely anyone will hear or notice this with the stock tweets, for they are near useless and do not even reproduce 10kHz frequency.* The issue would be noticeable with upgraded speakers and/or secondary amp.
