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In Reply to: RE: Lossless Compression vs. .WAV audio quality ? posted by AbeCollins on October 13, 2008 at 07:51:23
I have once or twice compare the same selection direct from CD, from WAV, from ALAC, and from FLAC. I haven't heard any significant differences. OK, maybe I have indifferent equipment and bad ears.Dropouts have always been my biggest issue with computer playback regardless of file format. However recently, (on good advise from Dawnrazor, I think), I set Foobar2000's 'full file input buffering' to 200000kb. So far this seems to have almost eliminated dropouts.
Something else that has made an objective difference is selecting my M-Audio Revolution 7.1's ASIO driver in Foobar. Using this driver with either ALAC or FLAC, the HDCD indicator on my DAC lights up; this isn't the case using Direct Sound, nor with iTunes playback of ALAC. However truthfully I can's say I hear a difference on account of it.
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Feanor's Classical Survey: 250 Exemplary Compositions
Edits: 10/16/08 10/16/08Follow Ups:
Fean,
Glad things are improving.
YOu might want to try adjusting the ASIO buffer in either Foobar or with the Maudio card.
Unless you have them at the highest now, I bet that helps a lot.
nt
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Feanor's Classical Survey: 250 Exemplary Compositions
In general, you are likely to get better sound quality (between glitches) when you use fewer buffers and fewer glitches when you use additional buffers. You should use as few buffers as possible. It is best to experiment with your system and find out what software is causing glitches. You can kill off all unnecessary processes and system services. (It may not be so easy to find out which are "necessary". If you kill a necessary one you will have to reboot your system.) I say "in general" because the effects on sound quality are system dependent. For example, if your DAC has very good jitter rejection then software timing changes in the PC may have little or no effect on sound quality. Similarly, if your DAC has a huge amount of its internal jitter, then any extra from the PC won't matter. So if you don't hear differences, it may be a good thing or a bad thing, technically. (Musically, it's good if you don't have to obsess over subtle differences in sound quality!)
I used the task manager to look at running processes and observed their cpu usage, disk accesses, and page faults as a way of finding ones that I should kill off. This isn't a perfect way, since the task manager uses sufficient resources so that it disrupts the system, e.g. causes audio glitches itself.
I would start by disabling your network adapter or physically disconnecting the network cable. Then uninstall your anti-virus software. (With Norton, simply disabling the various features did not prevent the computer from going on holiday for extended periods.) There may be anti-virus programs that can be temporarily disabled without leaving a significant effect on audio performance, but I am not familiar with them. I don't use any anti-virus software on my audio workstation, but then it is behind a hardware firewall from the Internet and only connected to my LAN intermittently. I don't web surf or do email on this machine.
Running an ultra lightweight audio application such as cPlay helps as well. This does most of the work before the music playback starts, including FLAC decoding. If you have the RAM, then this is the way to go. Even upsampling is very efficient with this software. Of course, without the overhead comes the lack of fancy features.
Tony Lauck
"Perception, inference and authority are the valid sources of knowledge" - P.R. Sarkar
I have kept my dedicated music PC pretty lean. I like to stream internet radio hence I'm a bit reluctant to disable the anti-virus, albeit the risk is probably small if I restrict Internet use in general.In Task Manager I set Foobar to 'Above Normal' priority. This made no difference in sound quality I could detect though it might have reduced dropouts ("glitches") a bit. What really got ride of the dropouts, as I mentioned, was specifying as generous input buffer in Foobar, on the other hand I keep the output buffer small when using ASIO.
I can't really judge the jitter tolerance of my DAC. My older Assemblage DAC has no special jitter provisions that I'm aware of. The only comparison I've had is to my CD player which is entry-level Sony; the Assembage is slightly better, being a tad airier and perhaps very slightly better resolved.
As I mentioned also, using ASIO apparently sends the DAC a better bit stream than does Direct Sound since with the former the DAC recognizes an HDCD signal. However I guess this doesn't say anything about jitter.
Fortunately I'm not obsessive about tiny differences. If differences such as there might be aren't pretty apparent to me, I don't go looking for them.
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Feanor's Classical Survey: 250 Exemplary Compositions
Edits: 10/21/08
Tony Lauck
"Perception, inference and authority are the valid sources of knowledge" - P.R. Sarkar
nt
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Feanor's Classical Survey: 250 Exemplary Compositions
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