DN 21 hearing sounds in jhāna, samādhi, and paṭisallīnā

Links about jhāna from DN 21

        DN 21⁰ - (Sakka doesn’t want to disturb Buddha’s jhāna)

            DN 21^0.1 - (fire burning is also called ‘jhāna’)

            DN 21^0.2 - (Sakka convinces musician to pull Buddha out of jhāna retreat with poem)

            DN 21^2.0.1 - (Sakka visits Buddha but sees him in ‘samādhi’)

            DN 21^2.0.2 - (Lady requests vistors including Sakka to not disturb Buddha’s meditation)

            DN 21^2.0.3 - (sound of Sakka’s chariot pulls Buddha out of ‘samādhi’)

            DN 21^2.2.2 - (pīti and pamojja are the mental joy, 2nd jhāna is better than 1st jhāna)

            DN 21^2.2.4 - (could be referring to asubha here, 2nd jhāna is better than 1st jhāna)

            DN 21^2.2.6 - (upekkha of 2nd jhāna and higher is better than 1st jhāna)

Can you really see someone becoming stream enterer without at least a finger snap’s time worth of first jhāna?

            DN 21^2.5.2 - (Sakka gave musician promotion, and 80,000 devas become stream enterers)

Analysis

This is the part that most people see, in reference to hearing sounds in jhāna.

            DN 21^2.0.1 - (Sakka visits Buddha but sees him in ‘samādhi’

            DN 21^2.0.2 - (Lady requests vistors including Sakka to not disturb Buddha’s meditation)

            DN 21^2.0.3 - (sound of Sakka’s chariot pulls Buddha out of ‘samādhi’)

Exactly which samādhi is not specified. The the sound of the chariot pulling the Buddha out of samādhi, is reminiscent of the loud chariot noises that force scores of monks to escape into the forest in AN 10.72, to escape the loud sound 'thorns'. 

I decided to read through DN 21 carefully, to see if there were any other details that could uncovered in regard to hearing in jhāna. Right at the beginning of the sutta, we have:

            DN 21⁰ - (Sakka doesn’t want to disturb Buddha’s jhāna)

            DN 21^0.2 - (Sakka convinces musician to pull Buddha out of jhāna retreat with poem)

Sakka, the lord of the heaven of 33, knows that Buddha is on jhāna meditation retreat (paṭisallīnā).

Here, the term 'jhāna' is used, not samādhi. If you do a search for paṭisallīnā in the suttas, you find that there are many passages where it's used almost as an equivalent for jhāna and samādhi. So whatever the meditator is doing in the secluded private retreat, the Buddha seems to expect they're going to be doing it with jhāna quality of samādhi.

The VRJ (visuddhimagga redefinition of jhāna) would say that the 4 jhānas are disembodied frozen states of stupor, with 5 senses disconnected from the mind, it's not possible to hear sounds.

Yet, DN 21 says Sakka doesn't want to disturb the Buddha doing jhāna. So Sakka convinces his deva musician friend to play music and sing an epic poem to charm the Buddha and induce him to leave jhāna. Does that sound like VRJ? If Buddha was in a disembodied frozen stupor, Sakka would not feel concerned about making loud noises, or distracting the Buddha, let alone using music to lure the Buddha to take a break from his jhāna retreat. In fact, Sakka could invite 1000 of his loudest musician friends, have an epic party that rocks the planet, and the Buddha wouldn't hear a thing.

The next occasion Sakka wants to visit the Buddha, this time he is in an unspecified 'samādhi', but a lady is there watching over him, to discourage visitors from disturbing the Buddha. 

Why would an attendant need to even be there if the Buddha was in a state where he couldn't hear anything for several hours? Visitors could come as they please and the Buddha wouldn't hear or notice at all. 

When Sakka is turned away by the lady attendant, he rides off in the chariot and the Buddha informs him later the loud sound of that pulled him out of the 'samādhi'. Does that sound like VRJ (vism. redefined jhāna) to you? 

And Finally, One very important detail that I just realized:

Sakka is the lord of the heaven of thirty three. They can manifest their body in a form (rūpa) that ordinary humans can see, but usually, they're invisible to humans except those with psychic powers, which require imperturbable version of 4th jhāna. That state of 4th jhāna can be done in any posture, wide awake, walking around, eyes open.

So for the Buddha to hear the deva musician's poem during his jhāna retreat, to hear Sakka and his chariot on the later occcasion in a samādhi, the Buddha would have to be in the imperturbable version of 4th jhāna, where you can hear sounds, read minds, see divine forms (rūpa) hear both human and divine sounds. 

Conclusion

Loud Sound is a thorn in all 4 jhānas, including imperturbable version of 4th jhāna.

Loud Divine sounds can be divine thorns also, as Sakka's chariot shows.

VRJ (visuddhimagga redefinition of jhāna) is a completely different system of meditation than what the Buddha talks about in the 4 jhānas from the suttas.

DN 21 Tv commentary on what kind of samādhi Buddha was in when sound Sakka's chariot caused him to emerge from it

♦ salaḷāgāraketi salaḷamayagandhakuṭiyaṃ. 

aññatarena samādhināti tadā kira bhagavā sakkasseva aparipākagataṃ ñāṇaṃ viditvā okāsaṃ akāretukāmo phalasamāpattivihārena nisīdi. taṃ esa ajānanto “aññatarena samādhinā”ti āha. 

bhūjati ca nāmāti bhūjatīti tassā nāmaṃ. 

paricārikāti pādaparicārikā devadhītā. sā kira dve phalāni pattā, tenassā devaloke abhiratiyeva natthi. niccaṃ bhagavato upaṭṭhānaṃ āgantvā añjaliṃ sirasi ṭhapetvā bhagavantaṃ namassamānā tiṭṭhati. 

nemisaddena tamhā samādhimhā vuṭṭhitoti “samāpanno saddaṃ suṇātī”ti no vata re vattabbe, nanu bhagavā sakkassa devānamindassa “apicāhaṃ āyasmato cakkanemisaddena tamhā samādhimhā vuṭṭhito”ti bhaṇatīti. tiṭṭhatu nemisaddo, samāpanno nāma antosamāpattiyaṃ kaṇṇamūle dhamamānassa saṅkhayugaḷassāpi asanisannipātassāpi saddaṃ na suṇāti. bhagavā pana “ettakaṃ kālaṃ sakkassa okāsaṃ na karissāmī”ti paricchinditvā kālavasena phalasamāpattiṃ samāpanno. sakko “na dāni me satthā okāsaṃ karotī”ti gandhakuṭiṃ padakkhiṇaṃ katvā rathaṃ nivattetvā devalokābhimukhaṃ pesesi. gandhakuṭipariveṇaṃ rathasaddena samohitaṃ pañcaṅgikatūriyaṃ viya ahosi. bhagavato yathāparicchinnakālavasena samāpattito vuṭṭhitassa rathasaddeneva paṭhamāvajjanaṃ uppajji, tasmā evamāha.