Bob, that is correct. The performers and recording venue are not part of the sound system. They are part of the recording process. While I definitely agree that these things are important to the overall result of the sound we hear, they are defined well before we ever get a chance to play them. Therefore, from our playback standpoint, our source is the recorded material, however good or bad it may be, and the unit that we play it on. From there the signal travels through the electronic equipment, and to the speakers. Once it leaves the speakers, it is in the acoustic realm again, and is not part of this discussion, as it was "speaker or source" that was the question asked.
Asa, to answer your question, yes there are neural synapse responses, electrical nerve impulses, muscular contractions, etc, in the creation of music. While this may constitute the absolute source of the music, as I responded to Bob above, it is not in the realm of the playback equipment to change that, other than to degrade it. Therefore, I still contend that the playback system consists of the source material and player, electronics, and speaker. I make no claim that these other things have no effect on the sound. I only claim that the reproduction system has a limited, defined scope as I described above. Things that have been recorded are beyond the source player's ability to change, except to degrade, and things that happen in the room and the listener's ear and brain are also beyond the speaker's ability to change. So again, I define the playback system as the parts between, and including, source player and speaker.
I would also like to mention that I disagree with the notion that is commonly promoted that the room is the most important part of the system. It is not. The room is simply the last item of influence on the sound before it reaches the ear. If the sound is not produced by the playback system correctly, the room has no ability to improve upon what has been played. However, if the room is good, then a well played-back recording will have a better chance of sounding the best that it can sound. This is the same idea that I espouse regarding the entire chain. Anything that is lost or degraded in a previous item in the chain, cannot be recovered or improved upon down the line. It can only cause additional loss or degradation. Carnegie Hall will not make a "close and play" sound good.
I state all these things in a context, because I do not mean to imply that speakers, or rooms, or amps are of little importance. They are vitally important. However, they are totally incapable of making up for any losses or degradation that happens to the signal prior to the signal arriving at their input jacks. At best, they can only perfectly pass the signal that they were given by the previous item in the chain. The only item that can actually bring more information into the system is the source equipment, because its job is to extract the information from the recorded media. The more information extracted, and the more accurately it is extracted, BY THE SOURCE PLAYER, is the only way that the system can actually improve the sound that the system puts out. The rest of the system components can only try to do their jobs of amplification and speaker output without corrupting the signal any further. The idea that a speaker can actually improve the signal is fallacious. All it can do is attempt to tranduce what it is fed, with minimum degradation. The entire argument around electronics and speakers improving the sound, is based upon the quality with which these items pass the signal to the next item in the chain. A good amp, or a good speaker will pass that signal with minimum loss and degradation, and therefore is a better component than one which does not do this. None of them improves the signal. They only pass it better. This is the key point. The word PASS. In contrast, a source component does more than just pass the signal. It extracts the signal from the media. When this process is improved, more musical information enters the system, and the system gets a better signal to work with. Then the rest of the chain can do its best to pass it well.
All components are important. But the source component is the only component that can bring more information into the signal. This is why it is the most important component in the playback system.
