I'm going to be truthful here. I've been recording classical/natural acoustic recordings for quite a few years and the quality of your recording is high (and frankly the mp3 vs wav differences are not really as important as many believe) - but the thing that has happened is that it does not sound like you'd hear if you were there. If you listen carefully - you can hear left/right shifts in both the piano and the cello as the pianist goes up and down the keyboard and the cellist moves. The performers are often the clients, yet they have never, ever heard what they sound like to others. The worst case is that of a person playing the trumpet or trombone. They are precluded from hearing what their instrument sounds like - they physically cannot do it, so when they hear a close perspective recording it sounds to them, right. To me, it sounds wrong. In this recording, the cello is HUGE - it is as wide as my speakers are apart, as is the piano, but shifted a little from centre. Pianos have width, even from a distance, but a cello has much less width. Indeed, from more than around 12 feet away, cellos are a mono sound source. A violin even closer - almost mono by 9 feet or so. If you record them with an X/Y, M/S or any of the subtle variants - ORTF etc, then your cello is virtually mono, and the space is stereo - having a really clear width and depth. It's a brain thing - delay, shift, reflections etc - they all set the scale. If you have a pianist on stage, then the extra distance means it too will have hardly any real width. If you mic it in stereo, how do you blend the two channels to fit in with what a distant stereo pair capture? It's hard, sometimes impossible. Spot mics in an orchestra are the same trickiness - setting left to right and front to back to make the fader just do volume rather than spacial shifts is really hard. I still have trouble time aligning them.
In this recording I hear oodles of instrument quality and player ability, but the soundstage is mega confused, and checking on headphones with eyes closed produces many sudden soundscape shifts in the cello, and the pianist sounds like he is playing a 20ft wide piano sometimes. If you look on Spotify for Camille Saint Saen's carnival of the animals - the swan, you will find a huge collection of recording of the same piece - many are very old and his like the devil, some feature the performers breathing and some are close, others distant. The cellos all sound vastly different in perspective. I used these on my old students as they were VERY obvious differences. Much is preference, but out of all of them, yours is at one end. It's lovely and clean, precise and tight. I'm just not sure it should be? With the mp3 thing - my pianist colleague hears every little detail of mistakes he made - things I cannot hear, but he cannot tell the difference between an mp3 and a wav?