To Doug Schneider,
I very much enjoyed your article, “If You’re Not Getting Into Computer-Based Audio Now, You’re Crazy.”
In many of your other articles, you talk about the importance of measurements and I wondered if you made any for this article. You made a statement that “iTunes runs on Windows, but most audiophiles agree that it sounds like crap.” Was that crap, meaning not as good as other software players, or crap, worse than CD playback? And did you personally listen to iTunes on a Windows machine and find that it sounds like crap? I'm not trying to pick a fight, just trying to understand how iTunes would be good on a Mac, but “sound like crap” on a Windows unit. I would appreciate your insight.
I have quite a bit of experience with iTunes on Windows. Most of the experience comes as a result of my wife using it on her computer to manage her library consisting of thousands of low-resolution MP3 and similar files that she syncs to her iPod and iPad. I’m constantly helping her out with it. It works well for that.
At the beginning, I tried iTunes on Windows on my own computer, but I quickly dismissed it as a credible audiophile playback system for a variety of reasons. One of the reasons has to do with its lack of support for certain file types, particularly FLAC. There are ways to get around that, but there are other issues too.
The main issue is that, from what I can tell, iTunes relies on passing the music data entirely through the Windows sound subsystem, which, in my experience, can degrade the output depending on the version of the Windows operating system and the settings there. I could get into great detail about what can happen to the signal, but this response will get too long. However, I will say that one of the main problems is that Windows is usually set up to resample the signal from the playback software to whatever bit depth and sampling rate that has been set under Sound in the Control Panel area. For example, on the Sony laptop I use, the Sound properties were set by default to convert music signals to 24-bit/48kHz. That means if a 16-bit/44.1kHz CD-quality signal were passed through it, the bit depth and sample rate would automatically be changed to the higher rate. While some people may think that resampling a 16/44 signal to a higher-resolution signal is a good thing, my experience shows that it’s often not. There are problems with non-integer sample-rate conversions, plus Windows upsampling algorithm is hardly state of the art. You can go in and fiddle with these settings, but you shouldn't have to; instead, you want to bypass them. iTunes’ inability to bypass this processing completely and talk to the hardware directly is a major shortcoming of that program. For that reason among others, iTunes in not an audiophile-grade player, at least not right now -- maybe that will change in a future version. If someone from Apple disagrees with me and tells me how I can configure it to overcome the limitations I mentioned so that it performs equally well as what I'm going to mention next, I'm all for it.
J. River’s Media Center is the program I use and recommend for Windows. I’ve used Media Center 15 on Vista and 7 with no trouble whatsoever, and I know people who also use it on XP and have had no problems. Media Center features a 64-bit data path and has a DSP engine that includes upsampling, but it can also be configured to leave the music signal completely alone. Media Center supports all relevant file formats and can be set up to bypass a large part of the Windows sound subsystem (how much of it I’m still trying to figure out) and talk directly to the USB port and connected hardware using WASAPI, ASIO or Kernel Streaming output methods. I happen to use WASAPI. For audiophiles, this is a huge benefit because you can be assured of outputting your files to an external DAC perfectly, without any Windows processing done in between the player and the port.
That it’s controlling the DAC correctly is actually quite easy to test if your DAC has a sample-rate readout (many of the newer ones do). I use a setup trick that Chris Connaker wrote about some time ago on ComputerAudiophile.com. The key is to set your Windows Sound properties to a bit depth and sample rate that’s not often used for high-quality music playback -- 16-bit/32kHz and 16-bit/48kHz are settings I like to use. When you first boot up your computer, the DAC should be indicating one of those settings, indicating the Windows sound subsystem is in full control of the DAC. Providing you have Media Center configured correctly, when it starts playing back a song, the readout changes to the resolution that Media Center is delivering, indicating that the playback software has now wrested control of the DAC, which is what you want. If you start experimenting with Media Center’s upsampling options, you’ll see the readout change depending on what you select. However, my experience has shown that the native sampling rate is usually best. In other words, if a file is 16-bit/44.1kHz, leave it at that.
Understanding how and why these programs can sound different requires understanding that the they don’t operate in isolation -- “underneath” the programs are various layers of the operating system that do things that users often don’t know about. . . . Doug Schneider