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Charles

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  1. and found it to be bit-correct. zero crossing bug gone ! Very good, Charles
  2. I tested the OS10.6 and 10.4 versions of the actual drivers, and still got the same bug. Every positive sample is off one bit while all negative samples are correct. I think there may be 2 ways to correct it. 1) find the piece of code where the wrong calculation is happening (that would be desirable). or 2) just fix it afterwards somehow like: if sample > 0 then sample = sample + 1 I am positive that we will get a bit-perfect MAC driver real soon, which would make the hiface a full recommendation, as it already is for Windows users. Charles
  3. ... where the bug actually is happening. This OS-X is a complex thing. However, my Mac mini's Toslink output does give correct data, so I just don't know whether this is a system issue ... I do not think that additional software (like Amarra) will be needed to give bit-perfect output. I am confident that the m2tech team will get it all working real soon, let's send them some good vibes, Charles
  4. The detail and the aggressiveness that you have perceived (hiface-mac), are not separable, in this case, they go together. What you perceived as detail, was a function of the distortion caused by the data error causing the zero-crossing distortion. The third harmonics caused by the uneven zero-crossing give you the sensation of detail, however it is not detail which is on the recording as you cannot create detail by modifying the data of the original. On the other hand, the more analog sounding representation from the hiface connected to your PC, was just correct data. Because it sounds softer (compared to the bugged mac playback) you can listen deeper in the long run, much deeper. And full detail can only be revealed in a setup that sounds so good, that it enables you to go deeper and deeper into the music. If its really good, there seems to be no end to this, LOL Charles
  5. Yes, they are working on new Mac drivers since then. Although I got no click and pops under Leopard, I had this 1LSB crossover distortion, which does not happen with the hiface on a Windows machine. It's only on the Mac, and it gives a nasty sound. Marco emailed me, that they identified the crossover bug to be caused by a piece of software that was recommended by apple itself as part of the software development kit. They are now using a different routine, and if I understand Marco's last email correctly, they are still struggling with clicks and pops ... As soon as the next mac update is available, I will test the bits over again, and post results. We have put so much effort in ripping our CDs, so that they are bit-correct representations of the original, and many are putting a lot of energy in making great hi-rez vinyl recordings. So what we really do need is a 100% bit-correct playback, else all our efforts will be in vain. I consider the M2tech hiface a really great product, and I'm eager to get the new driver, to have correct playback. If some hiface user here has a mac & XP computer, he may be tempted to listen to the sonic difference between the bit-correct XP output (driver 1.02) and the mac output with the LSB crossover bug (driver 1.03.3) Charles
  6. Hi there, there's a bug in the hiface's data stream when playing from a mac. Don't panic, I think this can be corrected very easily. For your reference I have just copied the email I sent to Marco of M2tech. ------- Hey Marco,, I've being bit-hunting the whole sunday, I finally found the Hiface bug, LOL Apart from the clicks, I knew after about 5 seconds of listening to the Hiface through my Attraction DAC that something very basically was wrong ... I have tested on OSX 10.4.11 and on OSX Snow Leopard. Clicks are gone in Leopard using the latest driver (1.03.3) from your website, but the sound issue was still there. The sound was overly analytical with exaggeration of third harmonics. Some kind of a high-frequency disturbance and annoyance. Looking at the clock-precision of the hiface's S/PDIF stream, and considering the Attraction DAC's jitter immunity, I thought that this would definitely not be a jitter issue, but would have to do with the actual data being sent. So I captured the data, sent from the hiface with a ESI Juli@ card and compared the ESI Juli@ recording with the original wav file. (I should notice that the ESI Juli@ is 100% bit correct, maybe something for your test rig too ...) Analyzing the data, I first appreceated that the samples were in their correct spots, so there is no asynchronouse sample-rate conversion happening, very good When looking at the sample values, it took a while until I realized that the negative half-waves were represented 100% correctly, while on every positive half-wave, all samples are -1 bit (one bit subtracted). For example, the hiface would send 25978 but the original value would be 25979. With all negative samples being sent correctly, this means that the hiface is generating a zero crossing distortion (very simliar to that of a transistor amplifier), as every zero crossing of the signal will create an offset of one single LSB. Now you can call me crazy, but I felt that there was an issue with the data right from the start, just by listening to the Hiface for a couple of seconds through my Attraction. But to be honest, I did not think that it was just one single LSB, the very Atom of the digital sprectrum. The good news, I also tested bit-accuracy on a Windows XP machine (the 2nd part of my sunday) and voila, your Hiface sends all samples 100% correct :-) But on the Mac, you got this 1-bit zero-crossing bug. However, XP sending correctly means, that it is only a tiny driver issue and you can correct it very easily, so that all your hiface-fans running apple can also benefit from 100% bit-correct playback. Marco, congratulations, you are 99.99% there, now it is very easy to make it 100% Charles -- ALTMANN MICRO MACHINES http://www.jitter.de http://www.altmann.haan.de http://www.mother-of-tone.com
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