Hello.
I have seen similar questions already but I still haven’t conceptually wrapped my head around it.
I’m thinking about kamma, realities, and conditions.
Kamma Vipaka from past lives condition the realities now right…? The experience of eye consciousness and so on. Kamma determines/conditions whether it will be, say a beautiful view or not.
What determines the Kamma Vipaka? Is it accumulated… Where or how 
I think I have caught myself in a thought loop.
Present moment, each and every moment, we create new kammas.
Kamma does not affect utu weather.
It is difficult to contemplate the kamma on its whole totality and intertwining entangled nature. I think it is called an imponderable.
Generally, the causes of past lives are what affect you in this life.
What you do in this life, can affect you but it is weak. But it still can come your way.
You have no control over past kamma’s results.
You do have control over the kamma you make in this life. Try to focus on that. But it is good to focus on past lives and see how it can affect you today as a thought experiment.
Generally…
If something is pleasant, it is the result of good kamma.
If something is unpleasant , it is the result of bad kamma.
4.077. 77. acinteyyasutta - 77. unthinkable8. apaṇṇakavagga - 8. guaranteed
“cattārimāni, bhikkhave, acinteyyāni, na cintetabbāni; yāni cintento ummādassa vighātassa bhāgī assa.
“mendicants, these four things are unthinkable. they should not be thought about, and anyone who tries to think about them will go mad or get frustrated.katamāni cattāri?
what four?buddhānaṃ, bhikkhave, buddhavisayo acinteyyo, na cintetabbo;
the scope of the buddhas …yaṃ cintento ummādassa vighātassa bhāgī assa.
jhāyissa, bhikkhave, jhānavisayo acinteyyo, na cintetabbo;
the scope of one in absorption …yaṃ cintento ummādassa vighātassa bhāgī assa.
kammavipāko, bhikkhave, acinteyyo, na cintetabbo;
the results of deeds …yaṃ cintento ummādassa vighātassa bhāgī assa.
lokacintā, bhikkhave, acinteyyā, na cintetabbā;
speculation about the world …yaṃ cintento ummādassa vighātassa bhāgī assa.
imāni kho, bhikkhave, cattāri acinteyyāni, na cintetabbāni; yāni cintento ummādassa vighātassa bhāgī assā”ti.
these are the four unthinkable things. they should not be thought about, and anyone who tries to think about them will go mad or get frustrated.”
Dear Roxy
good to see you posting again.
To understand this we need to look at the processes detailed in the Abhidhamma and Commentaries. Or the wonderful summary of the Abhidhamma in the Abhidhammatthasangaha.
Nina Van Gorkom’s books are also helpful as they are written in a clear way that is easy to digest- and are highly accurate as she took pains to keep strictly to the orthodox.
Nevertheless I will give a shorter reply than reading an entire book.
My first comment is that your question pertains to what is occurring repeatedly at every moment and so it is highly pertinent to our lives. It relates to causes and effects.
vis. XVI 85
As long as a man is vague about the world,
About its origin, about its ceasing,
About the means that lead to its cessation,
So long he cannot recognize the truths
In fact all life is a continual round of defilements leading to kamma which produce results (vipaka) now and in future lives.
There is the round of defilements (kilesa-vaṭṭa),
the round of kamma(kamma-vaṭṭa),
and the round of results(vipāka-vaṭṭa).
Let us consider the senses now.
Take a moment of hearing (sota-vinnana). For the hearing to arise it needs sound (a rupa) which is conditioned by many factors. It also needs ear base - a rupa (matter) which is conditioned by past kamma .
(Note that as venerable Subhuti mentioned we can`t know what the kamma (the deed) was from the past ) .
The sound that is experienced by the sota-vinnana is either the result of past good kamma or past bad kamma: if the sound is anittha (unpleasing undesirable) this is due to past bad kamma and vice versa if ithha ( desirable, pleasing). This experience is the round of results(vipāka-vaṭṭa) that I mentioned earlier.
Often we are not sure whether the experience was result of past good or bad kamma. My daughters like to play Taylor Swift songs sometimes- to me that is unwelcome sound. But is hearing it the result of past bad kamma or…?
After the sound there are processes which either attach to it or are averse to it or are ignorant about it (or possibly understand it) and this is the round of defilements (kilesa-vaṭṭa), Concepts are formed up at this time based on the sound(s).
If there is very strong disliking of the sound perhaps it can condition even kamma-vatta : some fathers might break the sound device that plays Taylor Swift 
It should also be noted that while past kamma is the main reason that desirable or undesirable sound is experienced there are also supporting conditions that are needed.
And the ear base is produced by a different kamma than the past kamma which conditioned the hearing.
Now as far as accumulations: as well as the kilesa conditioning kamma, they also accumulate tendencies that are beneficial or not…
So we see it is complex and yet this can be understood. It can begin to be seen to be happening now. And thus understanding can gradually replace ignorance. This is not mere theory, it really is the way things are.
There is much more to be said but maybe first see if this post helps.
The sensations, feelings just are. They are neither pleasant nor unpleasant, nor neutral for that matter. The judgement ‘unpleasant’ ( or otherwise ) is the sankhara ( kamma resultant ). The unwholesome habitual re-action ( sankhara > kamma ( > sankhara etc ad infinitum ) is to judge phenomena to be pleasant or unpleasant or to ignore.
Is this always the case? Is every sound we hear the result of past kamma? So if we hear an unpleasant sound, is it the result of bad kamma? What about when devas and brahmas come to the human realm? If they hear bad sounds in the human realm, is it also due to past bad kamma? I thought devas and brahmas only experience the result of past good kamma not bad kamma.
Yes even devas can experience anittha ( undesirable) objects through the senses.
It is good you are asking about this as there are many confusing ideas around.
See this topic for more about this.
And also this
Here is a related essay.
Another important fact. The words ittha and anittha are used for describing the objects at the sense doors.
Anittha can be translated as undesirable or not pleasing. And ittha as desirable or pleasing.
But only at the body door is there actual unpleasant feeling or pleasant feeling.
Even a nasty smell, although anittha, comes with neutral feeling.
So complex and yet these truths are showing themselves all the time.
I feel It’s an utterly profound matter. We may travel on the same mountain path, but you may never notice the rotting snake carcass or step on even a single you know what…
Kamma Vipaka from past lives condition the realities now right…? The experience of eye consciousness and so on. Kamma determines/conditions whether it will be, say a beautiful view or not.
According to Atthakatha, beautifulness etc. of an onbject is conditioned not by the kamma itself (as if a kamma CREATES this or that object, as if everything is happening only inside the mind), but only helps to reveal an object, alredy determinated as to “beatifulness” etc. by its own nature, and if it’s “coarse” and “upleasant”, the vipaka citta is going to be from an unprofitable kamma, and vice versa (excrements, for example, would give akusala vipaka for tongue, eye and nose consciousness, but kusala vipaka for body one, since its tangible datum is kind of pleasant, like soft etc.). The stage of javanas, on the other hand, might be various accroding to the inclination of this or that individual, hence we have masochists (upon experiencing some coarse tanglible datum like from knives etc., their body-consciousness vipakas are invariably akusala from some akusala kamma, but following javanas are with greed, and not with hate as you would expect), and insight-workers (upon seeing some really plesant object according to its own nature, or tasting some really good food, their according vipakas are invariably kusala from some kusala kamma, but following javanas are kusala with paññā, and not akusala with greed as one would expect), etc.
“The sensations, feelings just are. They are neither pleasant nor unpleasant, nor neutral for that matter. The judgement ‘unpleasant’ ( or otherwise ) is the sankhara ( kamma resultant ). The unwholesome habitual re-action ( sankhara > kamma ( > sankhara etc ad infinitum ) is to judge phenomena to be pleasant or unpleasant or to ignore.“
Mistake: I mean sense objects of all six senses “just are”. Immediately feelings arise. The habitual (re)action is determined by kamma resultants (sankharas). This re action is then a kamma. If instead the feeling is seen as it really is and met with neither aversion, greed or ignorance but with equanimity no new kammas are made hence no future sankharas.
I think this requires a different way of thinking. Rather than looking for a philosophical explanation, put you self in the shoes of a powerful yogi and think about this from that perspective. I think deeper we get into pariyatti(Thera/Theris have done an amazing thing for us), better idea we can get, leading to stronger faith…
I think this is what has me in a thought loop.
If you can… you can try to read
The Workings Of Kamma By Ven Pa-Auk Sayadaw. This will explain quite a lot. It is strongly based on Classical Theravāda. It is a profound book on kamma. I think it is good to also read the jātaka and the Buddhist Legends. These often show how cause and effect works, especially the Buddhist Legend stories that have “Story of the Past” sections. Jātaka often explain the habitual nature from life to life that exist today. Start with Buddhist Legends before reading Jataka.
see these posts for more about accumulations
Is Samsara an Automation of Random Cause and Effect Stream? - General Theravada topics - Classical Theravāda (classicaltheravada.org)
I am not sure what I wish to express comes through but there is deeper way to look at this, that goes beyond such questions like where is the kamma accumulated (where is Nibbana-dhatu) etc. That is to say from a paccayākāra(causality) perspective.
From the Dhammasangani
atītā dhammā
anāgatā dhammā
paccuppannā dhammā.
nibbānaṃ ṭhapetvā sabbe dhammā siyā atītā, siyā anāgatā, siyā paccuppannā. nibbānaṃ na vattabbaṃ atītantipi, anāgatantipi, paccuppannantipi.
‘atītā dhammā’ are not ‘anāgatā dhammā’ or ‘paccuppannā dhammā’
‘anāgatā dhammā’ are not ‘atītā dhammā’ or ‘paccuppannā dhammā’
‘paccuppannā dhammā’ are not ‘anāgatā dhammā’ or ‘atītā dhammā’
But for example
Certain ‘atītā dhammā’ can condition certain ‘paccuppannā dhammā’ as arammana, kamma, pakatūpanissaya etc
PS: I feel, for the Theravada faithful, getting at least a basic exposure to the Patthana is highly beneficial.
We are studying that now at IIT