POP sound at boot DUDU6

hey @DUDU-HUANG @YAOXILONG how about this case

I, too, can report having the same unpleasant pop sound upon booting the system. I have to mention that my car has an OEM stock external amplifier so that I had an issue with constant humming noise already on the m6 3D firmware by Mekede. Therefore I use a special hardware equalizer to decrease the gain for each of the four channels to minimize the noise.
Still, the pop sound very rarely appeared before switching to DuduOS 6.

HondaCivicDriver
What hardware equalizer are you using and how effective is it? Same issue here and I'm trying to figure out the best way to eliminate such noises. The noise reduction setting on the unit works ok, but I'd say about 30% of the humming/hissing noises are still there.
I'd like to try something to convert from the SPDIF out to the line level input of the car's amp, but not sure if there are such device that won't cost the same or more than the Android unit itself.
There are also High to Low level converters but good ones are not cheap and I'm convinced that taking advantage of the digital output of the unit would be a much better opiton.

What's everyone approach on these cases when there is an OEM or aftermarket external amp in the car?

What I use is this one:
https://incartec.co.uk/product/ISO-to-ISO-amplifier-integration-interface-cars-with-original-amplifier-20-273
Price: £33.33 (£40.00 inc VAT)4 channel adjustable ISO to ISO amplifier interface.
Use to install a new radio in a car that has an original fit amplifier that takes a pre amplified audio feed.
This interface converts the high level audio output of a new head unit to a low level pre amplified signal which will work with an amplifier.
4 adjustable channels for optimum audio quality, it has a built in ground loop isolator and filters to get the best sound from the amplifier.

It is pretty much effective, I used a screwdriver to minimize the gain per channel and even if reduced as much as possible, I could still hear a very small noise from the left front speaker. You can only hear it in a standing car, and only with good ears , so most persons did not even notice it.

HondaCivicDriver Thanks a lot for your detailed answer.
If you still ear some noise, it might not solve my issue because what I ear in my system is also not noticable to everyone and only when the music is at low volume and soft, which with my blues/rock/metal playlists is not usually the case The POPs however are quite loud and noticeable by even my deaf grandmother.

But your tip reminded me that I have a similar adapter from a previous instalation in another car. Something from Connects2 which should be of good quality. However connectors are not compatible. I'll give a look at the schematics and maybe I can make it work. But I would still like to find something that would allow me to use the digital output (spdif or coaxial) and convert it to analog low level signal that can feed the Bose amp. That's a nice feature of these Mekede M6s. I just need to find how to use it.

suicidalguitar

Just as an update, I did manage to use the Connects2 harness I had in storage for 7 or 8 years. Bought it for tablet + Sony old school 1Din radio install on another Audi TT I had before, so I was up for a good start.
Tested it for the sound quality and straight away what a difference. I was not expecting a Hi to Lo converter that did not cost me an harm and a leg (although I must admit I can't rememeber how much it was) to give me better sound quality than using the low level RCA output. The 30% of the humming/hissing noise that was still there is now gone. The sound quality has dramatically improved. I was kind of happy with it before (apart from the noises at low volume), but now I am truly amazed. Much closer to the CD quality of the original headunit.

Unfortunately the CANbus was not compatible with the FYT unit. Connectors were totally off. But I was so amazed with the sound quality improvement that I had to find a solution. So after what felt like an eternity staring at both harnesses (FYT and Connects2), and both CANbus boxes, I decided to try a transplant. In my mind it was making sense so I took the risk. It felt like an open-heart surgery. Guess what?! It worked the first time.

This headunit never ceases to amaze me. Huge improvements after installing DUDU, followed now by a huge sound quality improvement.

Ich habe ein Störgeräusch im Subwoofer, wenn der Lüfter vom Radio angeht.

Es wäre besser den Lüfter und die Steuerleitung vom Verstärker zu trennen.

Wenn ich den Lüfter abstelle, ist das Geräusch weg.

HondaCivicDriver you did help. That's also what these forums are for after all.
This mess behind our head units is the worst nightmare of an Hi-Fi enthusiast
It's a never ending job for us head units enthusiasts though. For now I'll leave it alone as I'm in the process of moving job, city and house (and the 2 little girls also need attention), but I'm aware there are many useless cables that can be removed/cut off. Starting by the RCA that is now useless. SIM card reader is in the same connector otherwise it would already be out. A good idea would be to remove those pins from the connector.....Damn!!! Now I want to do it