Why rip CDs or download music at high bitrates (eg beyond 192 Kbps)?

Question

Here are the facts as I have read them:

1. Most humans cannot hear the difference beyond ~192Kbps (a full, scientific study would be great)
2. CD audio is encoded at 1378.125Kbps

Okay, so the latter makes it sound like there is plenty of data available, so you can rip at 256Kbps or 320Kbps without interpolating (let alone downloading a song from an e-store which has access to the original sources at even higher than CD fidelity).

However, if most people cannot detect any difference between something sampled at 192Kbps and the same thing sampled at 224Kbps, then why do I keep seeing so many people ripping things at 256Kbps and 320Kbps? (I’m not talking about “audiophiles” who say that they can hear dog-whistles and can detect the difference between 320Kbps and 321Kbps; I mean most, normal people.) Yes, 128Kbps is noticeably different than 192Kbps, but I find that beyond 192Kbps, the speakers/earphones play a much bigger role in the sound than the bitrate.

Whenever I rip one of my CDs, I usually just rip it at 192Kbps (CBR). (Personally speaking, I consider downloading on the other hand to be different. I would download the highest bitrate that the music store offers since it would be my “master” copy, the next closest thing to the CD, and then down-sample it to 192Kbps if I need to save space—or maybe even regardless.)

Is there any tangible reason to bother going higher?

Answer 1

Is there a reason? No, not really.

However, I've had a few CDs with a few songs in the industrial genre (a remix by Nine Inch Nails) which have very rapid, rhythmic sounds overlaid by very chaotic sounds like an electric guitar. There is one particular section of a song which features this type of music. Unless the encoder is set to a very high bitrate the music will skip beats or stretch them out, both of which are jarring to the listener. This may be due more to the sample rate being to low rather than the encoding bitrate, but I found that it would only work well on very high lossy or lossless encoding. That said, this particular song is fairly unusual, and most people would probably consider the song indistinguishable from noise.

The outro to this song beginning shortly after 5:10 is a good indication of the type of sound which codecs seem to handle poorly. It's not exactly what I'm thinking of, but I can't remember the name of the other song. Even this YouTube video seems off to my ears, though, and it's a copy of the studio album.

Answer 2

Yes. The issue is not so much for a first-generation copy such as listening to the ripped file, as much as the potential quality loss when re-compressing later.

For example, imagine a file that's been compressed using a lossy algorithm such as MP3. You then use this file to, say, record a DJ mix, which is then compressed again to MP3. You email this mix file to a friend of yours who wants to transmit it over satellite or internet radio.

You're now looking at three compression-decompression steps. Each time you're going to lose different data. Even if they're all, say, 192kbps, it's going to sound a LOT worse than an original 192kbps compression.

Disks are cheap and your music collection will, in theory, last you your lifetime. Who knows if one day you'll want to use your 192kbps files (which sound fine today) as the background music for a DVD or Blu-ray Disc sometime down the road? (These compress their audio using lossy codecs as well.)

Huge hard disks are incredibly cheap these days, so storage isn't really a concern. You should archive your audio in the highest possible quality so that it's viable for uses other than direct listening in the future, by you or others.

You also point out that when purchasing music online you download the highest quality, and that you transcode accordingly for mobile use, but only rip your CDs as 192kbps. This presumes that you still keep your CDs around as the "master" copy, should you need the original data. For many people, getting rid of the CDs is the whole idea - optical media is slow and bulky compared to modern storage systems like 2.5" hard drives or flash. The representation on the disk becomes the master -- and it sounds like you already recognize the value of having the highest quality master available (versus a lower quality "working" copy).

PS: You are misusing the term "sampled" when you say "sampled at 192kbps". The sampling rate and the data rate of the compression algorithm are entirely different things. The sampling rate (the number of audio samples per second) does not change regardless of how the data is compressed.

Answer 3

MP3 doesn't encode all data the same, so even at 192kbps some artifacts can be introduced given specific audio input. Encoding at a higher rate mitigates this.