It gets wierd:
The sound of audio devices is influenced by many factors, to a greater or lesser extent. The main ones are the choice of the circuit, the correct layout of the printed circuit board, the selection of parts. After fulfilling these basic conditions, you can proceed to the following: choosing the material of the printed circuit board, its coating, the material and coating of the tracks, choosing the type of internal wiring and working with internal resonances of materials, etc.
It is not difficult for a manufacturer to check the influence of different factors, since several identical devices are made at the same time, and in one of them the factors are gradually changing, and then all this is listened to. It is difficult for the average consumer to do this. It can change external factors such as audio wires, vibration decoupling, stands, etc.
In my devices I do this:
-- When soldering, only Cardas solder is used. In other words, the entire device is soldered with such solder. There were a lot of experiments with solders, I settled on this one, but not because it is the best in the world, but it most of all approached my concept in terms of sound.
- The PCB is handmade from vintage getinaks, not industrially made from fiberglass. I did numerous experiments and settled on this material. It would be easier and cheaper for me to order boards in China, but if I set the bar to maximize the sound quality, then, in my opinion, it should be done that way. The material of the printed circuit board, oddly enough, also brings its influence to the final sound.
- The printed circuit board is not covered with a protective mask and other inorganic dyes.
- PCB tracks are polished with special inactive polishes (3 grain sizes), manually.
- The printed circuit board has minimal dimensions and combined mounting is used for the shortest possible signal passage: output, surface, hinged, point to point. Such installation is not technologically advanced, and requires a lot of time and a special sequence of actions.
- High-quality, branded, matched by ear details. Here, too, a large number of experiments were carried out. In my opinion, there are no better parts, and they need to be selected for each device separately. They, so to speak, set the "character of the sound".
- The choice of connectors is determined, again, by the concept - high-quality material, the minimum amount of metal in them, the shortest possible signal path.
- Programming the bluetooth microcircuit according to the given technical specification - unnecessary functions are turned off, etc.
It is not profitable to do all this in mass-produced products, but with manual production, for sound quality, this can and should be done.