In Issue 202 I concluded my review of the Amarra software program with, “If you want to hear how good a quality Mac-based system can really sound, you have to use Amarra. In the end, it’s that simple.” Time and the latest version of Channel D’s Pure Music software may make me eat those words. Priced at only $129, Pure Music promises to improve not only iTunes’ sonics, but also adds high-resolution capabilities along with a host of other advanced sonic and ergonomic features.
Pure Music is such a powerful program that reading its “User Guide” is a must. I daresay that you will be reading this informative tome more than once. I recommend keeping Pure Music’s User Guide PDF open on your desktop for the first week or so of operation, especially during initial setup. While nothing in Pure Music’s preference panels is completely inscrutable, without the User Guide anyone not familiar with Pure Music’s many options could screw up its settings in a myriad of ways. Don’t say I didn’t warn you.
Like Amarra, Pure Music’s principal function is to bypass iTunes’ signal processing and substitute a more direct and powerful 64-bit processing program. In addition Pure Music offers automatic rate-switching from 44.1/16 all the way up to 192/24, gapless playback of files that have been designated as gapless files, memory play, real-time high-resolution upsampling of CD tracks, a 64-bit internal signal path, dithered volume control, phase inversion, a subwoofer crossover, multichannel support, support for audio processing plug-ins, Core Audio HOG mode playback, high-resolution audio streaming, precision signal metering, reverse play, and more. Some of these features, such as HOG mode and memory play may sound like gibberish to the uninitiated, but these two features alone make Pure Music capable of elevating even a lowly Mac Mini into a formable music delivery device.
I could easily fill many pages with a detailed description of individual preference panes and the various options these panes offer, but you can download the User Guide along with a demo version from Channel D’s Web site.The free demo offers fifteen days of full-featured usage, and I daresay that once you’ve used Pure Music going back to ordinary ol’ iTunes will be tough, unless you’re listening through a Dixie cup and a string.
Although a novice user, the sort of person who feels intimidated by anything labeled “preferences,” can simply download and run Pure Music, to hear its full potential does require optimizing it for your particular system’s capabilities. But even when it is used “plain vanilla” without any system optimization, I could hear differences between iTunes and Pure Music.
Among Pure Music’s “must use” features is memory play. This loads your music file’s stream into an adjustable RAM buffer before it’s sent to your rendering device or DAC. It usually takes a few seconds for the buffer to fill and music to begin playing, but you can select a “Hybrid buffer” setting which will play the first couple of seconds of a track without buffering while the data is loaded into the buffer and then automatically switches to buffered mode once the buffer is filled.
Pure Music’s upsampling capabilities allow it to turn a 44.1/16-bit file into a higher-res file. Among the options are “power of two” upsampling. According to Pure Music’s User Guide, “this operation is more efficient than factored upsampling, and in the case of Red Book CD, 88.2kHz is, all things considered, a better target than 96kHz.” If your DAC will support it, a Red Book CD can be upsampled all the way to 192kHz. With the Weiss DAC 202 I was able to set up Pure Music so it upsampled 44.1/16 files to 192/24 before sending them to the DAC.
Another unique feature of Pure Music is the HOG mode. According to the user guide, “this option reserves the audio device for Pure Music’s exclusive use while Pure Music is running. To use this feature, the audio device selected in Audio MIDI Setup should be set to a different device than the one used by Pure Music, to allow iTunes to fully access an audio device if necessary. Accordingly, by default, HOG Mode cannot be used for the audio device selected in Audio MIDI Setup.” This feature is best used on a dedicated music system. On a full-service computer it means that any time you want to use any program that requires an audio stream it will have to go to an alternative audio device, such as your internal speakers or a second DAC.
My final preferred HOG setup was pretty clever, if I do say so myself: I used the Weiss DAC 202 in FireWire mode for my Pure Music feed and the Empirical Audio Off-Ramp 3 for all other audio tasks. To change from Pure Music to other audio sources I only needed to select the DAC 202’s RCA/SPDIF input.