downbeat

"NOW jitter is audible to way more low levels." this will be my last post on this, otherwise we could go round in circles, and i'm not at all sure how your previous post relates to listening to music. i know at what level jitter is audible, the independent test i linked to above tells me, as does every other independent test i have been able to find. my own listening tests to tracks with jitter injected back up the results from the other tests i have seen.

i have lifted this from another forum. Thank you for the e-mail. I suppose that you read our paper titled 'Detection threshold for distortions due to jitter on digital audio(http://www.jstage.jst.go.jp/article/ast/26/1/50/_pdf).'. Before this paper was published in the Acoustical Science and Technology, we had published another paper 'The maximum permissible size and detection threshold of time jitter on digital audio.' Unfortunately, it was written in Japanese. In our first experiment, which was reported in the Japanese paper, we used a fixed listening condition and fixed materials. All of 14 participants were university students without any special training. The audio system that we used consisted of the following equipment. D/A converter --- SEK'D ADDA2496S preAmp. --- Luxman C-7 main Amp. --- Luxman M-7 loudspeakers --- DIATONE DS-205 They costed about $10,000. I don't know if they belong to high-end or not. All participants could distinguish between sounds with and without time jitter when the jitter size was 9216 ns. A few could when it was 1152 ns. No one could when it was as small as 576 ns. There was a question, however, if the result would depend on the listening environments and the skill of the listeners. That is why we carried on the second experiment. This second experiment is reported in the paper, the one that you probably read. Listeners in the second experiment were all professionals, audio engineers, recording/mixing engineers, musicians, etc... Sound materials were selected by the listeners so that each listener could use his (her) familiar materials. The experimenter (we) visited the listeners' studios or listening rooms so that we could use listeners' own DAC, amplifiers, loudspeakers and headphones. The system configurations, therefore, varied among listeners. They were mostly mid-end or above, I suppose. As you can find in the paper, some listeners could distinguish the sounds when time jitter was 500 ns. It could not be detected, however, when the jitter was as small as 250 ns. In both experiments, there was considerable difference in listeners' performance. I don't know, however, if it was because of their audio experience. We had expected much better performance in the second experiment because the listeners were professionals and they could use their favorite environments and materials. Our conclusion up to now is that the normal hearing listeners' detection threshold for time jitter in program materials is several hundred ns. I appreciate that you are interested in our paper. Thank you for asking questions. Best wish -- ASHIHARA Kaoru

there are more then enough tests that prove people can't hear jitter until it reaches levels of 50ns or more. way higher then is present in modern cdplayers and dacs. my system is very resolving and i've done a few 'jitter audibility' tests. i am happy that expectation bias accounts for the differences. http://downloads.bbc.co.uk/rd/pubs/reports/1974-11.pdf the above is a jitter audibility test done by the b.b.c. :-)

i don't think they do sound different. i've tried amarra and pure music against itunes, they sound the same. i would guess that expectation bias accounts for the perceived differences.

i just connect my mac mini or macbook via optical with max buffer.

first off, i think you would be better served by ripping your cd's to flac, rather then playing the cd in the laptops drive. something like dbpoweramp or eac will be fine for ripping. other kit depends on whether you want to listen with your headphones or get some speakers.

he says some of that in last months hifi choice magazine, iirc. some of the things i've read that man write, have led me to dismiss anything he says regarding computer audio. and given he writes such rubbish about c.a., i have to question anything he writes about hifi in general. all the above is strictly imo, and all that.

Thanks a lot barrows, you've saved me a lot of reading! I was pretty sceptical that this software would sound different to itunes if it was bit perfect, so I may as well test my scepticism to the full and install more ram too.;-) Cheers!

Hi, I just installed the demo on to my mac mini. Big difference in sound from itunes. Is it setup to be 'bit perfect', as is? I just want to make sure there isn't any EQ or anything going on. If something needs changing in the preferences, could someone let me know? I think my mac has 1GB of ram and i want to be able to use the remote app on my ipod, so not sure about less is more, hog, memory play, etc.

Hi, in response to your question about the DAC-X, I tried a DAC-XP with my mac mini, it did not sound good. It sounded very good with the Cyrus cdxt-se transport, but almost broken on my mac. I had a dacmagic at the time, and even fed by the cdxt-se transport I didn't think it was 'night and day' better. My chord qbd76 however...

i haven't heard the natalie merchant one, but the ray lamontagne album is excellent.