This is interesting. Sample 2 works much better as far as hearing the differences.
I think I am detecting differences in distance from mic as each sample is produced. Are you moving from mic to mic? 1 and 3 seem like there is more variation in what I think is proximity effect. Not so much an increase of lows but on a sample or two a thinner sound as if the vocal is from slightly farther away from the mic, or moving while enunciating.
We don't know which position the S1 is in. Although the differences are subtle, it can be difficult to distinguish the S1 from the Compact without the reverb on the S1. Can we assume that all eq is flat on each unit?
Again, I would not choose which one I liked best, I would ask which one the singer liked best.
Visualizing the sound suggests to me that 1 is the S1, and 2 is the Model II and 3 is the Compact. However, I know from comparing some 15" JBL speakers I have on a stereo system to a pair of Bose 501 stereo speakers, that trying to guess based on visual impact does not always work well with Bose speakers. When I listen to presence it becomes confusing as the tone I think is Model II seems to have the least presence, however, it should fill the room better than either of the other two. EDIT; I wonder if the recording mic is out of line with this system's best dispersion resulting in less definition / presence?
Because this exercise began with some of my thoughts on the S1 maybe we need to ask, What do we want the system to do with our voice? How much other musical content is in the mix? and, Where do we want the vocal to sit?
If the vocal sound of 2 was in a mix with a bassy acoustic guitar, the vocal would lose some of it's impact to the blend of low tones between vocal and guitar. However if the same bassy guitar was mixed with sound of 1, the vocal might retain it's clarity, and stand out.
If I was using the system that produced the vocal sound of 2, I would probably clean it up a bit by reducing the low tones and boosting the presence a little. Just to make sure the vocal stands alone. Considering the three systems, the lack of presence in the vocal is a little surprising in this system.
System 1, I might reduce the highs just a tad, but overall I like this.
System 3, there is something missing in this sound on some of the samples, some of the time. Others sound just fine. The only thing that makes sense to me is head movement while singing. Over all I like this one too.
I think if I was in front of any one of these mics, and could not make eq changes, I could use proximity effect to make the system work for me. Find the sweet spot and hang in there.
There are times and rooms where one might choose one sound over the other, and in a different room change to something else.
I wonder a bit about how much just the use of three different words might affect the natural SPL of the voice and the response of the systems? Hold your palm in front of your mouth at the same distance as you would be from a mic and sing the same words that ST did. Notice the difference in the amount and pressure of the breath on your hand.
Sometimes instead of an answer, the question gets more questions.
I would like more detail on the room setup and method. Vocal mic placement vs. speaker placement, configuration of Compact and S1 etc.