Each person can decide what they want to do with their own car and its sound system, so I don't want to take sides about how loud someone should play their audio system. However, there are some basic facts about audio systems that people may want to be aware of:
1. Some are saying they play their audio system loud or very loud. The OP said he played his at maximum volume, which is probably not the same thing.
2. Audio systems, especially high quality ones, attempt to reproduce a live musical experience to the best of their ability. One of the characteristics of live music is that it has significant dynamic range, which is the difference between the softest passages and the loudest (in terms of decibels or db) in the music. Typically, the peaks in decibel rating of folk, jazz and pop music music are relatively short lived transient peaks of 10db (and sometimes more) compared to the average sound pressure level. Recorded hard rock or electronic music may be somewhat more compressed, and have peaks of 6db over the average sound pressure level. The more compressed the music source is, the louder the average sound pressure level is when the volume is turned up.
3. To handle transient peaks of 10 db over the average sound pressure level, an amplifier has to put out 10 times the number of watts of power compared to the average sound pressure level. If the system volume is turned up all the way, then there probably is no reserve amplifier power for the peaks without "clipping" of the amp output signal, which means it is driving the amp past its design limits and causing massive distortion (harmonic and intermodulation distortion, among others) to the speakers. This can cause the amplifier output transistors to fail, and can cause speakers (especially tweeters) to literally have the voice coils melt. Even woofers can be substantially damaged.
4. If a sound system is turned up to maximum volume so that the average sound pressure level was using all 900 watts (or whatever is available on the Genesis) of amplifier power, then 9000 watts would be needed to cleanly reproduce music with transients of 10 db over the average sound pressure level.
5. Fortunately, most car systems have limiters and/or compression in attempt to keep the peak power of music transients from causing damage to the system. The use of such limiters and compression will degrade the quality of the sound (compared to a live musical experience), but at least might prevent damage to the system. Some systems may completely shut themselves down when encountering dangerous power output conditions. These limiters were largely unavailable in audio systems of any kind before the inclusion of microprocessors in sound systems, and before that audio system protection consisted mainly of fast blow fuses in amps and speakers.
6. A sound system designed for buyers of certain kinds of cars "may" tune their sound systems (via compression, etc) to severely limit the transient peaks in order to allow the music to play at extremely high sound pressure levels without damage to their systems, while other cars may use little or no compression in order to more faithfully reproduce the music that is typically played at more moderate levels (but still loud). These are design decisions that have to be made, and compromises that have to be made. My "impression" (in reading comments on this forum from owners of both models) is that the G2 Genesis has more compression than the G1 due to the number of sound system failures that were encountered on the G1. But even with more compression, I don't really know if the G2 sound system can be safely played at maximum volume all the time.
Hopefully, the OP only caused the protection circuits to engage, and the system can be reset or restarted to work normally, and was not permanently damaged.
