One of my small pleasures I sometimes have the opportunity to engage in is a Saturday visit to the local library. I really like the Tuckahoe library near us, it's not the closest one in my county, but it's 2 stories. On the first (higher) floor, they have a great magazine area, and I grabbed a copy of Stereophile. I usually stay long enough to completely read 1-2 magazines. Many times I also grab food magazines. I've been known to make a "photocopy" of something of interest, like a recipe, with my iPhone while reading. And this time around, I read something about some "iTunes bypass software." Hmm. I'd seen pictures of Amarra before... but what is this software, and why might I need it? One of the players on the Mac is Pure Music. Like their webpage advertises, I'm trying the software for free (I've got 8 days left, I think). I had problems with it running on my MacMini music server with 1GB RAM using all of the program's features, but I also installed it on my main work computer in my home office, a MacPro with 8GB of RAM. I can't find a really good explanation of what this software does on the surface. Technically, it lets me choose songs from my iTunes library, but then instead of letting iTunes "play" the music and make the audio, it does that. I currently am running it in the following configuration: * no Gapless support * Memory play * upsample to 96kHz with MaxFidelity * audio hog (blocks all other audio on system) Memory play purportedly loads tracks into RAM and plays them from there. I am not sure what technically prevents something in memory from being written to disk with virtual memory. But supposedly since the we're reading RAM, the music is more "pure." Upsampling takes music presented at one frequency rate, say 41.1KHz and changes this rate to something like 96kHz. More samples is more precise, but since the music wasn't recorded with those samples, some math is involved in filling the gaps. Some folks say upsampling makes stuff sound better. I am not sure what audio hog does really, except avoids the pesky web pages from interfering with my sound while listening. In theory, it means the pipe to the audio output (in this case, I'm using the built-in digital audio out) is alone reserved for my music. Isolation sounds like a good thing. Then I read something called "bit perfect" music... this in effect is a measure of what the music says on the computer is what is reaching the DAC sitting above my computer. Is the stuff on one device equal to the stuff on the second? If iTunes was bit perfect, then there'd be no real reason to have something like Pure Music on my computer! The software can do more, too. But specifically I am interesting in their "playback algorithms" and the "playback engine." How is this different from what iTunes do? And which one(s) are bit-perfect? Computer audio is a fascinating topic. There are a lot of issues at play for audiophiles using computers today: * how did you rip or acquire your music? * what formats is it saved in (Apple Lossless, FLAC, MP3, AAC, etc.)? * how are you outputting your music to a digital to analog converter (DAC)? * which DAC are you using? * how do you connect the DAC to an amplifier or pre-amplifier? The equipment to squeeze more "quality" into the listening experience can be wallet-rattling. I've been happy with my current set-up on this computer for awhile, and I'd categorize it as a "midrange" setup. It's hifi to some, not to others. I'm not using tubes, silver cables, or clean power. I am, however, using a digital TOSlink cable from my Mac to a DAC. I've set my Mac to output all digital signals at 24 bits, 96 kHz (the maximum for this DAC and optical out). I can enjoy this native resolution with some music I've purchased online, but most content is ripped lossless at 16 bits, 41.1 kHz. It gets upsampled. I use fairly good headphones into a integrated amplifier. When not using headphones, I use the same amp to drive some bookshelf speakers. Both the speakers and the Rotel RA-970BX were a gift from my parents when I graduated college in 1996. They still are serving me well. So, when a $130 piece of software comes along and might improve the sound quality profoundly, I'm listening. It's great the company is offering a 15-day trial, and they're quick to answer questions via e-mail. The first time around, I couldn't tell a difference. Then the more I thought about it, I did hear differences, but I wondered if they were psychological. You read what other people say "certainly better than iTunes!", but what's the difference? Then I had some problems. It skipped. It skipped a lot on the music server downstairs. So I went back to an earlier version of the software that seems more stable. I turned off the gapless support. Good times. I picked some favorite tracks, including ones I've used each time I've gone into a hifi store when auditioning equipment. The music certainly sounds good. It's filling my ears, it's rich, it's beautiful. But it wasn't until I forgot and stopped listening to the music - doing other things on my computer like Web surfing - that I realized there was in fact a change to the sound. My ears were less fatigued. I could also turn up the volume more - and it was louder sure - but it was less... sharp. I suddenly thought I understood what people were saying about "air" to sound... the music had some buffer around it... it was less confrontational, perhaps a tad more smooth sounding. But then I began asking the questions... * why was it this way? * was this better? * am I sure? If you haven't invested any money into a sound system, then... you might not care. Your equipment might not be able to pick up the subtle differences - and I should note that with my equipment - the differences are subtle. But as you invest in more sensitive and more capable equipment (speakers, cables, DAC, etc.), you might be looking for something that profoundly improves your listening experience. I still need time to figure this out... but for now... I can safely say that Pure Music makes listening with headphones less fatiguing to my ears. I listened for several hours at one sitting, and when I got up, there wasn't the relief I hadn't realized I enjoyed when the cans came off... Or... either I'm only listening more intently because I've installed a new gizmo.