I just purchased exactly the same song from iTunes and Google Play Music to compare them. If you are interested, here are the differences.
iTunes uses AAC, while Google Play Music uses mp3. Google Play uses a slightly higher bitrate, but that probably compensates for AAC being a better algorithm. I can’t hear any audible difference. Read on to see the actual specifications of each music format.
Google Play Music
MPEG Layer 3 (mp3) Stereo 44.1Khz
320 kbits/sec
9.34MB
iTunes
AAC Stereo (L R) 44.1Khz
275.5 kbits/sec (I assume it’s variable bitrate)
8.06MB
Many moons ago I imported my CDs into iTunes. At the time, 20, 30, 40 and then 80GB iPods were the playback device of choice. At first, I used MP3 with VBR, then AAC with “best rate”.
This resulted in mediocre quality music, but it all fit onto a 40GB iPod 4th gen.
Listening the the music using PC speaker was kind of ok, too if you can tolerate the quality.
A year ago, I got bored one afternoon, so I dug up my old iPods, 4th Gen monochrome and 5.5th Gen Video and upgraded the later with a new battery and 512GB SD card space instead of the 80GB internal 1.8” spinning rust. Now, that I have more space than my CD library in the older, low quality files hold, I decided to re-import all the CDs once more in Apple Lossless encoding. I believe that this is full CD quality.
I can’t hear the difference between Apple Lossless and actually playing the CD on a stereo, regardless if I play them through speakers or a headset (Sennheiser HD 414 or Sennheiser PX-100 IIi, both excellent sets).
The bit rate of Apple Lossless varies between pretty low (even down to 400 kbit/sec for very early (low 1980s CDs, AAA recordings) all the way up to 1300 kbit/sec for DDD recordings.
Most music you can get online is either 256 or 320 kbit/sec and that’s unfortunate, since so much quality just gets cut and you listen to a high amount of distortion. Therefore I rather spend the extra money to buy the physical CD and import it myself. Most times you can get CDs way cheaper at eBay than if you purchase the tracks from Apple or Google or the like.
Thanks for reading.
Chris