dekkersj
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Verwijzing naar een jAES artikel: het cd-formaat in een ABX
Audibility of a CD-Standard A/D/A Loop Inserted into High-Resolution Audio Playback.
Conventional wisdom asserts that the wider bandwidth and dynamic range of SACD and DVD-A make them of audibly higher quality than the CD format. A
carefully controlled double-blind test with many experienced listeners showed no ability to hear any differences between formats. High-resolution
audio discs were still judged to be of superior quality because sound engineers have more freedom to make them that way. There is no evidence that
perceived quality has anything to do with additional resolution or bandwidth.
Abstract:
Claims both published and anecdotal are regularly made for audibly superior sound quality
for two-channel audio encoded with longer word lengths and/or at higher sampling rates than
the 16-bit/44.1-kHz CD standard. The authors report on a series of double-blind tests comparing
the analog output of high-resolution players playing high-resolution recordings with
the same signal passed through a 16-bit/44.1-kHz “bottleneck.” The tests were conducted for
over a year using different systems and a variety of subjects. The systems included expensive
professional monitors and one high-end system with electrostatic loudspeakers and expensive
components and cables. The subjects included professional recording engineers, students in
a university recording program, and dedicated audiophiles. The test results show that the
CD-quality A/D/A loop was undetectable at normal-to-loud listening levels, by any of the
subjects, on any of the playback systems. The noise of the CD-quality loop was audible only
at very elevated levels.
Bron: Journal of the AES, September 2007.
En een aanvulling: http://www.bostonaudiosociety.org/explanation.htm
Groet,
Jacco
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dekkersj
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Bij deze het antwoord met daarin opheldering over de gebruikte apparatuur:
| Quote: |
Mr. Dekkers: I have not really addressed your question about the loading of the SACD/DVD Audio player. We have reason to believe that there were
no adverse loading effects, but even if there were the experimental design removes any possible consequence.
The player we used for most of the tests was a Yamaha DVD-S1500. Neither the owner's manual nor the Yamaha web site seems to have specifications for
analog output impedance but I assume it is around 100 ohms. The CD recorder is an HHB CDR-850, has a line-level input impedance of 10k ohms. There
should be no adverse effects from this combination.
Beyond that, however, is the more basic fact that the experimental design compensates for any such effect. The CD recorder is always connected to
the output of the player no matter what the switch condition. Even if the CD recorder were to induce some small loading effect in the player's
output, that effect would be present in both sources.
The analog output of the player in the experimental setup is the target -- the ideal audio source to which the comparisons are being made. As we
stated in the article, the combination of player and the recordings sounded exceptionally good, and, it turned out, so did the same signal passed
through the CD-quality loop.
I hope this answers your question.
Sincerely, E. Brad Meyer
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Ik denk dat hij het niet erg zal vinden dat ik hem quote. Bovendien is het informatie dat mi thuishoort in het artikel zelf. Ik had hem ook de vraag
voorgelegd hoe men dacht over het loading effect dat de cd-recorder heeft op de uitgang van de sacd/dvd-a speler.
Groet,
Jacco
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dekkersj
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Ook bij de vrienden van Hydrogenaudio is het onderwerp niet onopgemerkt voorbij gegaan: http://www.hydrogenaudio.org/forums/index.php?showtopic=5740...
En ook een van de auteurs heeft zich gemeld in de draad aldaar: http://www.hydrogenaudio.org/forums/index.php?showtopic=5740...
Groet,
Jacco
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dekkersj
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Inmiddels heb ik de service doc zelf besteld van die yammie, en ben aan het rekenen geslagen. Dit is het resultaat voor de spanningsoverdracht van DAC
naar uitgangstulpje:
-3dB bandbreedte: 49,5kHz
Ingezoomd rond de 20kHz:
En voor de groepslooptijd:
Ofwel: geen fasevervorming in het hoorbare gebied.
Lijkt me dus duidelijk: 20kHz komt er met gemak uit.
Groet,
Jacco
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dekkersj
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Geopperde tegenargumenten in AES Convention paper 9174.
Met discussie nav AES convention paper 9174. En dan hier een pdf print-out van de discussie tot 9 mei 2015.
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