I would like to throw one thing into the discussion: There is a huge perceptional difference between actual live performance and listening to a recording in a room through loudspeaker or headphones.
During a live performance we are engaged with all our senses and our brain (or whatever it is) can compensate for a huge dynamical span. In a good concert venue we hear sounds at the edge of audibility and still can manage very loud sounds, too.
In the usual listening situation in a living room, very quiet passages are drowned in the noise around us and loud passages are really often too loud (I'm not even starting what happens with the sound quality of typical stereo sets in a small to medium room when things get really loud
). So probably everybody has the experience of 'riding the level', meaning running to the volume control of the amplifier and turning it up when things get too quiet and turning it down when things get too loud.
This is the first compressor ever invented, bevor the compressor was invented...
So if the musical performance was good (that's the starting point, because otherwise not tweaking will help) and the recording was done with some understanding what kind of usage of microphones and preamps and recorders makes sense, sometimes some tweaking beyond simple level matching and converting to the required digital format could make a huge difference.
One needs to bear in mind that there are of course processor plug ins of very different level of quality and sofistication. One barely can expect to get the job done in a satisfactory way with some free plugs running under a free DAW. Quite unlikely.
So now concerning the three major processes used in mastering beyond level matching: compression
, EQ and reverb (prblems with left-right balanced must also be dealt with, and format conversion will also require some dithering)
I think a subtle compression
with well chosen parameters (threshold, attack, release) can actually help to match the rift between live performance and home audio. The key point is to compress in away that is barely audible. If you start to hear the compressor working in any obvious way, then disaster is on the way.
The same is with EQ, though that is much much more difficult to use in a good way. But even nice sounding spaces have their deficiencies, and good microphones have them too. So a very carefully done correction of some more blatant problems can save a musically good performance that has sonical flaws.
Also reverb can be useful when recorded in very dry rooms. Big care has to be taken not to create conflicting reverberation patterns giving the listener the impression to be sitting in two different spaces at the same time. (This happens BTW also with recordings in reverberant spaces like churches when the recording engineer uses a near or middle field pair and a far field pair for ambience. I have hear otherwise very nicely made recordings that make you feel sitting on two different chairs quite far apart.
So from my point of view one can only give a salomonic answer: USING PROCESSING? IT DEPENDS...
What counts most IMHO is a pleasant result and not the way how you arrived there. The truth of the actual performance is totally meaningless to anybody who wasn't there.
Music is a big continent with different landscapes and corners. Some of them I do visit frequently, some from time to time and some I know from hearsay only ...
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