Hallo Eric,
Kabel.
Es hat sich auch bei mir bestätigt, daß auf der digitalen bzw. netzwerkigen Seite Jitter als hörbare Störkomponente praktisch nicht existent ist.
Julian Dunn, der das "Jitter"-Phänomen jahrelang untersucht hat, schreibt dazu:
Quelle: Audio Precision Note #5: Measurement Techniques for Digital Audio by Julian Dunn
Ich habe dazu auch eine Grafik gefunden, die das nochmal unterstreicht.
Quelle
Hiernach tritt Jitter als Einflußelement auf das Audiosignal nur bei Wandlung AD oder DA auf.
Gruß
Thomas
Zitat von Ohrwurm
Beitrag anzeigen
Es hat sich auch bei mir bestätigt, daß auf der digitalen bzw. netzwerkigen Seite Jitter als hörbare Störkomponente praktisch nicht existent ist.
Julian Dunn, der das "Jitter"-Phänomen jahrelang untersucht hat, schreibt dazu:
Audibility considerations It is one thing to be able to identify and measure sampling jitter.
But how can we tell if there is too much?
A recent paper by Eric Benjamin and Benjamin Gannon describes practical research that found the lowest jitter level at which the jitter made a noticeable difference was about 10 ns rms.
This was with a high level test sine tone at 17 kHz.
With music, none of the subjects found jitter below 20 ns rms to be audible.
This author has developed a model for jitter audibility based on worst case audio single tone signals including the effects of masking.
This concluded: “Masking theory suggests that the maximum amount of jitter that will not produce an audible effect is dependent on the jitter spectrum.
At low frequencies this level is greater than 100 ns, with a sharp cut-off above 100 Hz to a lower limit of approximately 1 ns (peak) at 500 Hz, falling above this frequency at 6 dB per octave to approximately 10 ps (peak) at 24 kHz, for systems where the audio signal is 120 dB above the threshold of hearing.”
In the view of the more recent research, this may be considered to be overcautious.
However, the consideration that sampling jitter below 100 Hz will probably be less audible by a factor of more than 40 dB when compared with jitter above 500 Hz is useful when determining the likely relative significance of low- and high-frequency sampling jitter.
But how can we tell if there is too much?
A recent paper by Eric Benjamin and Benjamin Gannon describes practical research that found the lowest jitter level at which the jitter made a noticeable difference was about 10 ns rms.
This was with a high level test sine tone at 17 kHz.
With music, none of the subjects found jitter below 20 ns rms to be audible.
This author has developed a model for jitter audibility based on worst case audio single tone signals including the effects of masking.
This concluded: “Masking theory suggests that the maximum amount of jitter that will not produce an audible effect is dependent on the jitter spectrum.
At low frequencies this level is greater than 100 ns, with a sharp cut-off above 100 Hz to a lower limit of approximately 1 ns (peak) at 500 Hz, falling above this frequency at 6 dB per octave to approximately 10 ps (peak) at 24 kHz, for systems where the audio signal is 120 dB above the threshold of hearing.”
In the view of the more recent research, this may be considered to be overcautious.
However, the consideration that sampling jitter below 100 Hz will probably be less audible by a factor of more than 40 dB when compared with jitter above 500 Hz is useful when determining the likely relative significance of low- and high-frequency sampling jitter.
Ich habe dazu auch eine Grafik gefunden, die das nochmal unterstreicht.
Quelle
Hiernach tritt Jitter als Einflußelement auf das Audiosignal nur bei Wandlung AD oder DA auf.
Gruß
Thomas
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