Here is a history
Main Monitors
Horn systems have also improved and modern Westlake's with TAD drivers are amazingly good too as are JBL's or Meyers. My comments here are not to bash horns at all! Just mentioning alternatives - that is all. Although I would add that you can do far far better than an Altec 604 these days. Altec 604 is no longer competitive IMHO.
Main Monitors
Horn systems have also improved and modern Westlake's with TAD drivers are amazingly good too as are JBL's or Meyers. My comments here are not to bash horns at all! Just mentioning alternatives - that is all. Although I would add that you can do far far better than an Altec 604 these days. Altec 604 is no longer competitive IMHO.