Audio Systems: Alpine type-s system, poor ventilation, power amplifier

Question
The six cabin speakers unpredictably drop out seemingly when the volume level exceeds 19, the system is tuned at volume level 20. The rear subwoofer doesn't drop out when
the 6 cabin speakers drop out. The sound techs that installed this system have no idea, we've spoken to Alpine and they suggest it may be a short and the sound techs are going to rip the system out and start again, this is going to take an entire day. Nobody I talk to seems to have much idea. The entire system is as is displayed on the alpine type-s system package except the amps were upgraded. I have component model numbers for all system parts if necessary but the package is advertised on the alpine sites.

Answer
A short somewhere in the speaker wiring is first choice for cause of this type of symptom but there are others such as a defective speaker that has an impaired voice coil, poor ventilation of the power amplifier, internal protection circuit in the amp set wrong from the factory, wiring from battery to the power amp too small and so forth.  

If it is something less than obvious I do recommend you let the installation team look through it carefully and let them look for the things mentioned above.

Hope this helps.
C