And?
What does it sound like?
J the signal itself is somehow convolved into the output waveform as frequency response error.
Jitter?
I wouldn't recommend having the output set at 24/96; going from 44.1KHz to 96KHz isn't an integer upsample (unlike 48 to 96).
I find non integer up-sampling kills the music.
I keep mine set to 16/44 because that's what the original source was (CD).
When on this setting the output is bit perfect.
I wouldn't recommend having the output set at 24/96; going from 44.1KHz to 96KHz isn't an integer upsample (unlike 48 to 96).
I find non integer up-sampling kills the music.
I keep mine set to 16/44 because that's what the original source was (CD).
When on this setting the output is bit perfect.
Bit perfect playback was tested by playing back Dolby Digital and DTS audio tracks (ALAC encoded) through iTunes into a Meridian 568 (via optical). If the sample rate or bit depth is altered the music turns into hiss.
Have a read of the wiki pages benchmark media have written about how to set up a MAC or PC for itunes and computer audio settings. It's very informative and states why leaving the MIDI output settings as high as possible has no issues. The MIDI driver doesn't up sample IIRC.
Have a read of the wiki pages benchmark media have written about how to set up a MAC or PC for itunes and computer audio settings. It's very informative and states why leaving the MIDI output settings as high as possible has no issues. The MIDI driver doesn't up sample IIRC.
This would be my first guess as to what is wrong too. The whole point of having a good DAC is that it does the upsampling in an intelligent way. If you let your Mac upsample the 44.1 source data to a 24/196 data stream you may as well not have bothered with the fancy DAC because any contribution its logic stage might make is well beyond the audible spectrum.
So try setting the Mac's TOSLink output to 44.1kHz/16bit using "/Applications/Utilities/Audio Midi Setup". Then if your DAC's any good it will clock and upsample the data stream to a higher rez in an ear-friendly way. That's what it's for.
P.S. don't use USB, and don't bother with all those Terminal tweaks and hi-fi hocus pocus: your hard drive does not suffer from acoustic feedback, and 44.1/16 data output will not tax any recent Mac.
I find optical the least satisfactory of the Macs outputs , async firewire or Async USB transfer protocols are technically the best way of transferring timed data.
Keith.
Have a read of the wiki pages benchmark media have written about how to set up a MAC or PC for itunes and computer audio settings. It's very informative and states why leaving the MIDI output settings as high as possible has no issues. The MIDI driver doesn't up sample IIRC.
'Lo.. Could you please kindly point me in the right direction for this article?
I can't find it
Cheers.
Hi Spacey, nice to hear from you again, even though you have abandoned the One True Path that is ATC
You are slightly wrong on this one. First of all it has nothing to do with "midi" or "midi drivers", it's just that the mac dialog box happens to have two tabs, one of which is "audio" and one of which is "midi". We're talking audio here even though people across the internet who don't quite know what they are talking about like to refer to it as "audio midi" (/rant).
Secondly, as the wiki correctly states, by setting the audio in OSX up for the highest sample rate that your DAC will support (eg 96k) rather than the actual sample rate of the digital audio you are playing, you are telling OSX to resample everything that isn't actually at 96k (or whatever you've set there). This was, as the wiki states, disastrous in older versions of itunes. The wiki now says that the resampling abilities of iTunes have greatly improved from version 7, so that it is not harmful or rather "will not add significant distortion to the audio". Not exactly a ringing endorsement...
I expect that iTunes is better than the ancient Creative Audio resampling on my PC so perhaps the effect is less marked but it is still a sub-optimal way of going about things. I will have a listen to see how it sounds when I get a moment. You should also try a compare and contrast exercise when you get a chance.
The fact is that changing the sample rate in this way to force a conversion will guarantee that you do NOT have bit perfect digital information flow from your source media to your DAC. Doesn't sound like a great idea. Others would agree with me, eg the manufacturers of the DACport:
http://www.centrance.com/products/dacmini/blog/2010/09/28/resampling-exposed/
I've also just found this interesting guide to computer audio published by DCS (the co that makes very very high end CD players and DACs).
http://www.dcsltd.co.uk/assets/dCS_Guide_to_Computer_Audio.pdf
It was updated last month and recommends (on page 20) that when using iTunes and Mac OS the sample rate is set in that Audio dialog box to match the exact sample rate of the tracks to be played. There are also similar instructions for the PC world - all with the goal of maintaining bit perfect audio...
Andrew
Isn't it funny when someone proclaims with huge confidence something so obviously wrong?Can I be so bold as to try and explain what jitter is, seeing as virtually no-one on here seems to understand it?
Digital signals are just voltages. They are actually stepped, not continuous as in an analogue signal. When the data demands a voltage that falls between two voltages next to each other, the actual voltage oscillates between the two. THIS IS JITTER.
I saw it simplified as the "digital equivalent of W&F". I think that still works.I think he's quite an expert in the field.
I am just reading up on it again now. I am sure you are never wrong about anything, you aren't the type.Isn't it funny when someone proclaims with huge confidence something so obviously wrong?