For loud, noisy:
* Boisterous
* Raucous
* Turbulent
* Uproarious
* Vociferous
* Din (noun)
* Cacophony (noun)
For insistent, demanding:
* Urgent
* Insistent
* Strident
* Vehement
For excited, agitated:
* Excited
* Frenzied
* Agitated
* Hysterical (extreme)
More specific:
* Belligerent (for a hostile clamor)
* Tumultuous (for a chaotic clamor)
* Thunderous (for a very loud clamor)
* Earsplitting (for a very loud clamor)
The best synonym for "clamorous" will depend on the specific context and the nuance you want to convey.