Believing is unnecessary, but it matters because it may skew how you interpret results… The same way superstitious beliefs are tied to false associations, you might attribute an actual result from the field to something more logical and rational. Believing is also tied to expectations. A lot of people only “believe” something works if their exact expectations are met.
Rates at which results happen are affected by a lot of things, belief is not directly one of them… At times, results might be happening, but for one reason or another, they are too weak or slow to be perceptible.
There is a also a need to address what you stated about subconscious limits removal. The Audio is not working on your conscious beliefs, it’s working on your subconscious programming, while the two overlap, the second does not qualify as a belief in the traditional sense of the word.
The main law that governs it all is balance. Balance needs to be maintained… this is why a lot of people lose results or stop having them working after a while of use. Being grateful that something worked in a miraculous way is good, but avarice and uncontrolled glee, belief in omnipotence, will get the law of balance to put you back in your place in the pecking order.
You are an ego, an aspect, a small part, not the totality of the divine, the universe or reality in which it and you are one, are the same reality or universe in which none of what you want matters, because everything meshes into a single consciousness, no desire, only totality and oneness.
Going back to results and belief. Your beliefs CAN affect results if they cause you to subject yourself to one form of subconscious control or another. A lot of what is in this world below is based on the world above, and contracts are something very real, as are life scripts (movie projections in our world). Approval or acceptance is the equivalent of signing a contract in certain contexts, which is why mindfulness and being present is very important. Always make sure you are not an character in a script or that you have accepted to do something against the terms you approve of.
You can use beliefs to your detriment or advantage, but understand that the belief itself is not what makes the difference, belief is a catalyst, an intermediary for some other type of causal relationship… it’s part of your conscious filter, or your user interface so to speak (to make it a bit more relatable), you need beliefs to interact with the world as a human, otherwise, you are either pure animal or pure spirit… It can exert an effect on speed or intensity, but not actual results. Results are inevitable, because they are being processed impartially…
Does the sun (energy) care if you believe in it or not to shine its life giving rays? Does your belief affect whether your body produces Vitamin D upon exposure? No. It’s a program that is coded into this operating system. On the same token, being dark skinned and fair skinned does affect how long it takes for you to get the minimal effective dose after exposure, and that’s where lineages come in… because we live in a world where gene pools have been heavily diluted, you will notice a lot of difference in the potency of certain fields between multiple individuals. Your hardware matters… or as it is called in Alchemy, your Athanor… but as shown in the given example, irrespective of what it is, ultimately, the RESULTS ARE INEVITABLE, one way or another.
Another example I like to give is using names or words of power. Following proper technique makes the results more refined and controlled, but no matter which angel, demon, entity name or word of power you use, by virtue of how the system works, they will hear and respond to it, how, depends on you, but it has been given us the ability to command all hierarchies of being/consciousness by name… this is why the names of the elements and minerals are universal, changing only slightly in phonetic pronunciation … we use this to command mineral consciousness… albeit unsatisfactorily nowadays, because the essence of the art has been lost.
So, back to giving you a final answer: No.