Hello, I know it's a repetitive topic but I want to build another amplifier and I'm confused about the speakers. I've seen videos on YouTube that say I have to take the speakers from the original amplifier wiring. Post Data assembles the Chinese radio with the wiring that is plug and play. I would like if someone has done it to tell me if it is in the factory amplifier wiring. I have already installed music in other cars, it is my first time with something like this. Thank you so much.

 

Your hesitation is totally valid. There are uniqueness to audio system in Lexus. You can find details in threads when you search Aux-in ... do limit it to RX300.

I will just list few.

1. Display shares audio and AC controls.
2. Non standard slot for head unit [special after market double din adapter is needed.
3. Accessories and audio sources use a serial protocol to communicate amongst them.
4. RX300 has two different audio systems from factory and they are not pin compatible.
5. To prevent noise pickup the audio level and technique is non standard. Generally the pre-audio level is 1Vrms into 330Kohm (or 1k ohm load). Lexus uses dual differential l+,l-, r+,r- signals with their own level and load.

Most of the effort here has been upgrade/replace speakers and adding an alternate audio source.
Some have alternate (independent) headunit and amp and use the existing or additional speakers.

I am not sure what your ultimate objective is ... tinker/explore or improved audio or updated audio. The overall acoustics of the RX (open hatch) will prevent you from reaching high quality sound.

My personal conclusion was to add a Aux-in and call it a day. Mostly my source has has been NPR radio which does not have a demand on the music reproduction and higher volume levels.

Salim