On Unstressed Vowels
The vowels may be pronounced as in Italian: ē and ō (long) having the 'close' values as in nero, nome; ĕ and ŏ short, when stressed have the open values as the first syllables of netto, notte; when unstressed the 'close' values as in the final syllables.
Here Tolkien describes both stressed long vowels and unstressed short vowels as 'close' in Italian:
Although Italian contrasts close-mid (/e, o/) and open-mid (/ɛ, ɔ/) vowels in stressed syllables, the distinction is neutralised in unstressed position in which only the close-mid vowels occur. The height of such vowels in unstressed position is context-sensitive; they are somewhat lowered ([e̞, o̞]) in the vicinity of more open vowels.
That does coincide with his own pronunciation in the recordings, but clearly contradicts his description of ɛ — e and ɔ — o mergers. Here we follow this note saying that unstressed short vowels had the same quality as long ones, but keep their mid-quality as stated in other materials.
Help
Is OP2 note sufficient for such amalgamation? Perhaps may is indication that Italian is also meant to be an approximation, and mid-quality is correct. + [ ] should Tolkien's pronunciation be adopted despite OP2?