Learn English – “..to hearing from you and getting inspired..”

1. Are you hearing that noise?
2. That cake is tasting delicious.
3. You are smelling like a rose.
4. He is seeing the blue sky.

All of the above sentences would be considered as being either ungrammatical or nonstandard English by most prescriptive grammar books. And I would avoid saying these type of phrases myself. Furthermore, it is true that verbs of senses are not normally used in the present progressive but I've never read a grammar book which strictly prohibited their use. Sentences 1 to 4 will sound more natural and "native-like" if the present simple tense is employed.

1. Can you hear that noise?
2. That cake tastes delicious.
3. You smell like a rose.
4. He can see the blue sky.

The verb hear often means we perceive or detect a sound with our ears. It is not a dynamic action but an involuntary one, hence it is classed as being a stative verb. On the other hand, the verb listen expresses intention and is a dynamic verb. Consider:

A: What are you listening to?
B: This great album by [group], I'm always listening to their music.

You couldn't replace listen with hear in that particular context.

To express the concept that a noise is audible with your ears, we often use the modal verb, can in the present tense.

(Three friends on Skype)
A: Can you hear me, now?
B: Yes, I can hear you loud and clear.
C: No, sorry. I can't. It's very difficult to make out what you're saying. The audio's not very good I'm afraid.

Wikipedia confirms and adds

Verbs of mental state, sense perception and similar (know, believe, want, think, see, hear, need, etc.) are generally used without progressive aspect, although some of them can be used in the progressive to imply an ongoing, often temporary situation (I am feeling lonely), or an activity (I am thinking about a problem). (...) In colloquial English it is common to use can see, can hear for the present tense of see, hear, etc.

However, the verb hear also means to receive information by the ear, as Ws2's answer illustrates, and in this case the progressive form can be used e.g.,

• I'm constantly hearing stories about those awful people who've recently moved in the neighbourhood. They say, the son is an ex-convict.
• I am constantly hearing about sugar and how it is truly evil (...).
• This is the first time I'm hearing this.

and in the phrase quoted by the OP

"Are you hearing enough complaints?" = Have you been receiving information recently?

^{Feel in my opinion, does not fit very well in the category of stative verbs. Feel when it is a sense can be used in the progressive form as much as the present simple tense. 1) I'm feeling lazy today (I feel lazy today) 2) How are you feeling? (How do you feel?) 3) He's not feeling too well. (He doesn't feel too well.) BUT 4) What are you doing? I'm feeling this textile (I feel this textile.).}

I can use the continuous tense in the following without any fear of sounding odd: "I'm smelling this milk to see if it's any good", "What are you tasting?"; "The sniffer-dog is smelling all the suitcases for explosives" (as suggested by Ws2); and "I'm seeing Anthony later tonight."

Michael Swan in Practical English Usage gives a list and definition of these stative verbs.

There are many verbs that are not usually used in the progressive tenses and others that are not used in the progressive tenses in certain of their meanings. The most important of these [stative] verbs are:

1. dislike, hate, like, love, prefer, want, wish
2. astonish, impress, please, satisfy, surprise
3. believe, doubt, feel (=have an opinion), guess, imagine, know, mean, realize, recognize, remember, suppose, think (=have an opinion), understand
4. hear, see, measure (=have length etc), taste (=have a flavour), smell (=give out a smell), sound, weigh (= have weight)
5. belong to, concern, consist of, contain, depend on, deserve, fit, include, involve, lack, matter, need, owe, own, possess
6. appear, resemble, seem

So to summarise, it is not true that the verbs, hear, see, taste, etc. are not used in the continuous forms, it depends on context and meaning.

In your examples, 1.a is correct because it is referring to what the subject, or person, is current hearing. it is still in progress. 1.b would mean the same thing as " I can't believe what I am able to hear from here". It does not refer to what you have heard, instead it refers to what is possible to hear.

2.b is more natural and you are correct in that scenario. What you should consider is that since it is a movie, they may have only shown the character witness the dark entity once but still could have seen it after as well.

In example 3, both are correct but differ in meaning. 3.a means that the subject is still seeing it. Also, it could be referring to something specific. With 3.b, it is more open ended so the question could be general, as in nothing specific.

example 4 seemed to have been well answered in the other forums. I hope this was a little helpful.