Would you put your head inside a piano? No? Then why place a microphone there? [with video]
The sound in this clip has several issues, but for me the main problem is the piano. This is classical music, and when it was written there was no such thing as 'sound', in the commonly-used sense of amplification, recording or broadcast. In the days before sound engineering, singers sang, pianists played, and the audience listened - from a distance.
This gives us a very good guide to what the performance should sound like. It would seem logical to amplify, record or broadcast the performance with as natural a sound as possible.
The obvious chain of thought starts by placing a stereo pair of microphones in a natural listening position. This won't work because the microphones don't have the human ears' and brain's ability to focus their attention on the sound coming directly from the performers, and ignore much of the ambience and reverberation from the room. So in nearly all cases, the microphones must be placed closer to the performers than a natural listening position.
It would be possible to find exactly the best location for a stereo pair of microphones by experiment, such that it captured an ideal balance of direct sound and reverberation. However, this takes time, and isn't controllable from the mixing console once the performance has started. It is more flexible to use a separate microphone for each performer (perhaps two for the piano, to record it in stereo) and also have two spaced microphones out in the room to pick up the reverberation. With a set up like this, the engineer can control the balance between singer and piano, and the balance of direct versus reverberant sound. The result, with care, can be very natural and lifelike.
The question arises of how close the vocal mic and piano mics should be to their respective sound sources. The closer they are, the less spill they pick up from the other source, but the less natural their sound quality becomes. Here the vocal mic (it looks like a Schoeps) is at an acceptable distance, but the piano mic is VERY close - actually inside the instrument. There is no way the natural sound of the piano is going to be captured.
If problem No. 1 is the piano, problem No. 2 is the reverb. The reverb is hideous.
Clearly this is a TV studio, not a concert hall. It is therefore more practical to use digital reverb than it is to use ambience mics. But when digital reverb is used, it is vital to make it sound as natural as possible. It needs to sound like a believable acoustic space, an appropriate acoustic space, and it needs to integrate seamlessly with the direct sound.
Here, the reverb is wrong on all three counts. I don't know what kind of acoustic space this is meant to be, but I have difficulty in imagining any performance venue where the reverb would sound like this. Secondly, the reverb doesn't sound like what the studio looks like. This disconnect gets the brain's 'that's all wrong' signals buzzing. Thirdly, the direct sound and the reverberation don't come across as integrated at all. Ideally one should be able to focus on the direct sound, or on the reverb, but not quite know where the dividing line is between them. Here, the direct sound and the reverb are as different and isolated as the proverbial chalk and cheese.
There is one factor however that makes all of the above understandable, and allowable to a certain extent. This is, or at least was, live TV. Live broadcasts always have an uncontrollable element and there's a desire to minimize whatever can go wrong. What can go wrong here is that the studio guests can't be relied on 100% not to talk during the performance. So placing the microphones as close as possible is the way to get around that. Close miking will also avoid the studio background noise, which you can hear being faded at the beginning of the clip.
Placing the mics so close will inevitably create a huge contrast between the direct sound and the reverb. So although the reverb still does sound completely wrong, its lack of integration is understandable.
In conclusion, this is an interesting example of audio that really isn't very good. But it is useful to examine the reasons why, and also to speculate how it might have been done better under live TV conditions.
P.S. Although the vocal mic seems to be a Schoeps, the sound has a rather harsh and rasping quality. This isn't what I would normally expect from Schoeps and, unless the clip mic Julia Lezhneva is wearing was accidentally left on, I would have to speculate inappropriate EQ or other processing.