- Written by Chris Groppi
- Published on 27 September 2011
Channel D Pure Music High Resolution Music Server Software In Use
First, let me say that even if Pure Music sounded identical to iTunes, the software would be a no-brainer $129 purchase for the features like automatic sample rate control, software sample rate conversion, high quality digital volume control, memory play, hog mode etc. It adds a huge number of features to iTunes useful for audio enthusiasts, while retaining the superior iTunes music library interface. That the software genuinely improves sound quality is a huge bonus. I was not really expecting an improvement in sound quality. The Halide Bridge's asynchronous USB output and the re-clocking of the BDA-1 should pretty much eliminate any issues with jitter from the computer source. The player software in theory just converts the audio file into something playable (a PCM stream) and hoses it out. Of course exactly how this is done matters. Playing files with Pure Music resulted in clearly better sound for every file I played. As you might expect, the difference wasn't gigantic, but it was certainly there. The primary improvement was in clarity and resolution. With normal iTunes, I had to struggle to hear detail as compared to Pure Music, like there was some sort of inaudible background noise present that was covering up small details. With Pure Music as the player, those details popped out, just like you'd get from a better DAC or a quieter preamp. Another improvement was a reduction in "digital glare", for lack of a better phrase. When listening to lower quality digital sources, I eventually get a bit of a headache, or a feeling of pressure on my ears that isn't there with better sources. I regularly get this when listening to music on my portable system (iPod Classic, Headroom Total Bithead, Etymotic ER-4S). If I listen to a high bit rate MP3 or AAC, the pressure is there and is annoying after listening for a while. The same iPod also has Apple lossless files on it. With them, the pressure present with the compressed music is relieved. Switching between iTunes and Pure Music on my home stereo had a similar effect, although not as pronounced as going from a compressed to uncompressed media. With Pure Music, I didn't notice any big difference when turning features on and off. Memory play didn't actively sound better than normal, but I left it on anyway. It certainly didn't sound worse. Hog Mode also didn't seem to improve the sound across the board, but did prevent annoying system sounds (like your "you have mail" bong from playing while you listen). The only thing the OSX mixer will do is make the sound quality worse, so bypassing it is a good idea no matter what. I did not check the upsampling carefully because of my system configuration, and I did not use the dithered volume control. Both these features could be particularly useful if you have a high bit depth and sample rate connection to your DAC, or if you want to try configuring your system with no preamp (DAC connected directly to your power amp). FLAC playback worked fine for me. I couldn't tell the difference between the FLAC and Apple Lossless versions of the same music.