How close to the real thing?

What percentage of the real think does the microphone capture? What percentage is lost in the cable from the microphone to the microphone preamp? What percentage is lost in the mic preamp? What percentage is lost in the cable from the preamp to the mixing console? What percentage is lost in the mixing console? What percentage is lost in the cable from the console to the recording device? What percentage is lost in the recording device? What percentage is lost in the cable back to the mixing console? What percentage is lost in the mixing console as EQ and level are adjusted? What percentage is lost in the cable going back to the recording device? What percentage is lost in the cable going to the A/D converter? What percentage is lost in the A/D conversion? What percentage is lost by downsampling to 44.1KHz and reducing the word length to 16bits?

The above is a very simplified version of the recording process and I haven't even got to the playback process. The biggest drop in quality is at the very first stage -- the microphone. There are some marvelous mics out there, but I don't know of any experienced person suggesting that the mic captures more than 50% of the original sound. Being that the losses in quality are additive I suspect that 5% is about right.

Depends on the music, setting and venue. I was in a very upscale hotel recently that had a jazz trio, bass, sax & piano. They were playing music that I was very familiar with and I was feeling quite good about how well my systems sounds compared to the live artist. Instrument placement, tonal balance is very good, I would rate literally 90%. When I go to a live orchestra. My system cannot convey, the real depth and stage presence that a live orchestra conveys over the large stage. Maybe I don't have good enough recordings on classical, I must admit, I am weak in classical recording and my jazz selection is quite good but my number drops profoundly.

If memory serves, the late Peter Walker (Quad) answered to such a question- about 15%.

I disagree with the previous answers.
From the starting point of recorded music.. The wax cylinder.. the sound THEN was perhaps at least at 30% in reality. (consider it an exponential curve)
By the 50's we were at least up to 80% or better.
Now i would say state of the art os up near 90% to 95% minimum.
Of course with an exponential curve, the closer we get to 'real' the harder it is to get better!
And with a curve going to infinity (true in every way to perfect reproduction) we probably will NEVER get to !00%.. but we are a Hell of a lot closer than 5%!
IMO that sort of answer is just to elicite consternation/controversy, and has no merit, or is taken out of context.
And of course as we get better, the gaps in what is left to achieve become more apparent, and perhaps the desire to get those last little itty bitty bits might make one say we are so very far away from 'perfect sound forever" LOL.