Newsgroup: it.hobby.hi-fi
Titolo: 44.1/16 vs 24/96 (in inglese)

Penso sia interessante per molti (scusate l'inglese)- da rec.audio.high-end
More evidence supporting the idea that 44.1 KHz sampling is good enough for everbody
Audio Engineering Society Convention Paper 5876: Perceptual Discrimination
between Musical Sounds with and without Very High Frequency Components Given
at the 115th AES Convention in New York about a month ago. This paper can be
ordered from the AES web site: 
www.aes.org
 .
This paper describes the test methodology and the results of a series of
listening tests performed by researchers at  NHK Science & Technical
Research Laboratories, Tokyo, Japan. These tests compared the playback of
recordings with and without audio signals above 21 KHz.
19 different musical selections and one synthetic sound were used:
1 "Satsuma-Biwa" "Satsuma-Biwa"
2 Litha Drums, Bass, Pf (Jazz Piano Trio)
3 Meditation Vn, Pf
4 Romanian Folk Dances Vn, Pf
5 Intermezzo de "Carmen" Fl, Pf
6 Beethoven: Sym. No.9 4th Mov. Picc
7 Bach: Suite for Vc No.2 - Prelude Sax
8 Bach: Suite for Vc No.6 - Prelude Sax
9 Piece en forme de Habanera Sax, Pf
10 Partie Sax, Pf, Perc
11 Sednalo Bulgarian Chorus (SACD ARHS-1002)
12 TihViatar Bulgarian Chorus (SACD ARHS-1002)
13 Meditation+White Noise Vn, Pf, High frequency band consists of only white
noise.
14 Airs Valagues Fl, Pf
15 Tchaikovski: Sym. No.6 3rd Mov. Full Orchestra
16 Doralice Vo, Gt (Bossa Nova)
17 Chega de Sauadade Vo, Gt, Pf, Perc (Bossa Nova)
18 tiny rose Vo, Pf, Gt, Fl, Perc ("the birds")
19 butterfly Vo, Pf, Gt, Perc ("the birds")
20 Autumn Leaves Drums, Bass, Pf (Jazz Piano Trio)
"First, 36 subjects evaluated 20 kinds of stimulus, and each stimulus was
evaluated 40 times in total. The results showed no significant difference
among the sound stimuli, but that the correct response rate for three sound
stimuli was close to the significance probability (5% level). It is
concluded that one subject attained a 75% correct response rate which
constituted a significant difference. In order to make a strict statistical
test, we conducted a supplementary test with this subject who had attained
the best correct answer rate in the first test. This subject evaluated six
kinds of sound stimulus, and then evaluated each sound stimulus 20 times. As
a result, no significant difference was found among the sound stimuli, and
so this subject could not discriminate between these sound stimuli with and
without very high frequency components."
In other words, of 36 listeners, only one listener scored substantially
better than random guessing, and when retested, he could not duplicate his
earlier results. This indicates that they were due to luck. In fact a study
of statisitics and actual experience suggests that with a group of 36
listeners, it is pretty certain that one or more listeners will get good
scores due to luck, that they won't be able to duplicate when re-tested.
So, you can flip pennies or compare 24/44 to 24/96 and get pretty much the
same results, provided you hold all other relevant variables equal.

 More evidence supporting the idea that 44.1 KHz sampling is good enough
for everbody
Tutto questo dibattito sui limiti uditivi umani in concomitanza con
l'esordio degli standard ad alta densità mi sembra derivato esclusivamente
da strategie di marketing abbastanza idiote.
Anche io che sono tutt'altro che un tecnico ho finalmente capito che i nuovi
standard non servono a riprodurre segnali a frequenze che forse gradirebbe
il mio cane o un pipistrello di passaggio ma ad immagazzinare più
informazioni spostando fuori della banda audio rumore e distorsione (detto
così alla carlona) oltre che a garantire una migliore dinamica teorica.
La cosa veramente buffa è che lessi da qualche parte (non ricordo se se ne
discusse anche qui o in un altro ennegi) di un test che aveva pretese di
scientificità, sempre condotto da giapponesi, e che sosteneva esattamente il
contrario. In quel caso i simpatici folli in camice bianco andavano a vedere
direttamente come i segnali ad alta frequenza "stuzzicavano" la corteccia
cerebrale.
Altrettanto ridicola mi sembra la proliferazione di supertweeter con
esplicito riferimento a SACD e DVD-A.
Ciao
Fernando

 same results, provided you hold all other relevant variables equal.
l'oggetto del thread e' pero' sbagliato: se non e' ancora chiaro quante 
siano le effettive migliorie tra 44.1 e 88.2, differenze tra 16, 20 e 24 
bit sono parecchie.
ciao
spi