Science has come up with a theory called string theory which in very short means that the world is really made of vibrations. But in Judaism, we already knew that, as it says in the verse in tehilim בדבר השם שמים נעשו. This world is made from Gods word vibrating out.

When we want to express an idea to others we vibrate it out with our words, if we want to express something deeper like feelings we can express them in a song .If we want to express our deepest feeling of longing it can sometimes come out as a cry but to express it to others we can only tell a story of how it would feel but we have no way of truly expressing the actual deep feeling.We can say verses like
עַל מִשְׁכָּבִי בַּלֵּילוֹת בִּקַּשְׁתִּי אֵת שֶׁאָהֲבָה נַפְשִׁי בִּקַּשְׁתִּיו וְלֹא מְצָאתִיו
but there is no way to truly express that because its something that is from deep in our true essence.

Shir hashirim is our deepest longings which we can not express in any way .We can only say a story how it would feel and that is why Reb Akiva said שיר השירים קודש קודשים .The holy of holies in the Bais hamikdash is a place where no one can enter except for the purest man on the purest day .The gemara says that the holy of holies was built in the place of the אבן שתיה
The point from where the whole world was created .that singular point is an analogy of God's essence as the Gemara says מקום הארון אינו מן המידה the space of the ark does not take up any physical space because that space is the point pointing to his essence before the world expanded.Before the vibrations came out .

When we touch on our deepest essence we are touching God's true essence which is the reason why we say shir hashirum on Pesach .As the tzemach tzedek says in דרך מצותיך ,Mazo is about belief in god not about understanding or feeling God .When we feel or understand God we are touching on his vibrations not on his essence.We have no way of truly touching his essence except for hearing a story about it and that's what the simple Mazo and Shir hashirum are truly about