Hugh Robjohns wrote:... I never judge sound quality from YT clips as there are too many unknowns...
Youtube now provides information as to whether it has reduced gain (loudness normalised) on uploaded files. Right click on the video being watched and "Stats for nerds" appears. YT does not increase level on "quiet" uploads but does lower ones considered to have too high average loudness - for a less unpleasant listening experience when listening to a random series of uploads of (previously) varying average loudness. If loudness normalisation has been used, that is gain reduction, the words "content loudness" appear along with the amount in db that the file has been gain reduced.
Unsurprisingly, the TIOBE file which I referenced has not been loudness normalised by YT, for its average level is very low, much lower than we would expect. I dont know what is its highest peak because I cant easily check it ( I would need to rerecord the entire movie in real time) but there's no reason to believe the upload is lower in average level than intended by the production company. So ... that an uploaded file from a major distributor is any lower in gain than was uploaded and intended seems highly unlikely.
When you said elsewhere the upload is "stupidly low' (in average level) it is indeed, but it's not the fault of YT who dont increase the average level of any uploads. It's "stupidly low" because most likely that was the file uploaded to YT!
And as we know, given that audio data compression as used on YT first throws away very quiet high frequencies, uploading to YT a file with much reduced high frequencies is the very last thing a good engineer would do. Again skilled mastering for the lower resolution destination format.
Unsurprisingly, compared to a loudness normalised DVD the audio on the DVD of the same remaster (2016) is also stupidly low .
But as already mentioned more than once, it's more than that. Within the file itself, the balance of speech frequencies is cockeyed. The vowel sounds are far too loud compared to the consonants. In technical terms, the frequencies below roughly 2 kHz are too high compared to those between 2kHz and 4 kHz, the latter carrying the important consonant sounds. It sounds muffled and indistinct. Turning the volume up helps somewhat but then the vowel sounds can become unpleasantly loud for many listeners.
It's interesting to compare the production company's promo sample to another older transfer YT upload. YT has loudness normalised the older transfer (second file) down by 8.6 db (see "stats for nerds") but it's still subjectively louder - and speech much clearer - than the official sample.The reason is that - again - the speech frequencies in the older transfer are much better balanced. More like normal speech. It doesnt have an excess of lower frequencies. YT does not change spectral balance.
And again, in the older transfer, the frequencies in the critical speech intelligibility band are relatively higher, so they are less likely to be reduced by the YT audio codec...compared to the official latest upload which risks those same highs, already too low, being reduced even lower by the YT codec.
https://youtu.be/9GsrDe96HUE Official sample 2016 remaster
https://youtu.be/IPLBAYvZVY8 Older transfer, same section at 1:05:19