I was surprised how apparent the differences in the 4 tracks were on my middling system at home. I could easily tell the difference once I knew what to listen for.

I’ve stored all my music in FLAC for sometime. It’s pretty trivial to convert flac to 192 Kbs VBR MP3 if I need it to be portable, and storage is so cheap now there’s no reason not to.

I hate to even admit this but I’m still buying physical media (CDs). I was buying 192kb/s mp3 off of amazon for a while but have since gone back to physical disc. I buy the disc, rip it twice, once in 192kb/s and once in FLAC. FLAC goes to a 64gb USB drive for my denon 4308 and the 192’s go on my iphone and 80gb ipod classic. Original disc goes back into the jewel case and into a box in the closet.

Great podcast Tom… I’ve sent a handful of people over to listen as well as cross posted on my FB.

Excellent podcast! I really enjoy hearing from these “specialists”. It’s a shame we only get guests when Dina goes away though. I really believe that Dina would be interested by many of these guest hosts and I think she would likely raise some interesting questions of her own!

For the poll:

I have a few 128kbps and a fair number of 256kbps AAC tracks – all of which were iTunes purchases (thus, I was at the mercy of what was available for sale at the time).

My CD collection is ripped at 320kbps AAC and I use those files for transfer to my iPhone or casual listening. For any serious listening, I just use the actual discs.

I did my own, subjective listening tests a couple of years back when I was trying to decide what compression I should use. I ripped a few familiar tracks to various compression rates and formats. I would compare two tracks at a time and simply try to judge which was better. I did these comparisons at random and without knowing the rates to which I was listening. To my surprise, I put the tracks in perfect ascending order with 128kbps at the bottom, followed by 192, 256 and so on. Just listening by ear, I couldn’t distinguish the 320kbps versions from the original disc or the lossless format. So that convinced me that 320kbps AAC was “good enough” for my portable and casual listening needs 🙂

So, thanks to Austin’s great work, I know that I am losing something, but I still feel confident that I made the right choice. For a portable player, lossless compression just isn’t enough if you have a large library. 320 gets the job done. And, like I said, subjectively, I could hear the difference myself 🙂

Leif,

Don’t fill bad, I still buy physical media too. I can’t stomach paying the same price or more for a download and not getting the best quality and a physical copy of the data.

Austin here. I too buy physical media. I steadfastly refuse to purchase any music that doesn’t come to me at lossless quality. Also, even though I’m part of a younger generation (I’m 25) I’m a total collector and can’t bear not having a physical copy of something I bought. I’ve just recently come to accept the whole digital download phenomenon with my purchase of a PS3 and the purchase of games on the PSN.

One additional point of the several that a failed to get into the show was that upon analyzing the level information of the tracks, we noticed that the while the original had peaks at -0.3 dB, the 128k mp3 had peak information reaching as high as 1.7 dB, probably due to intersample peaks. Anything over 0 dB full scale equals distortion. We then instructed our batch converter to drop the level of the original 2 dB before converting; the resulting 128k file was significantly more pleasing to the ear, as there weren’t nearly as many distortion artifacts from clipping. The peak level now sat at something like -0.2 dB.

An application of this would be in the conversion of most current music, particularly pop music, of which most is subjected to high levels of compression and brick-wall limiting. The peak levels are often pushed as close to 0 dB as they can be, occasionally even being allowed to clip by sloppy limiting. Using this technique of level reduction before conversion, it would appear that slightly better sounding mp3s of lower bitrates can be attained.

“…several that *I* failed…”

Great episode of the podcast. I love stuff like this! Last summer I got an HP MediaSmartServer for home back up. One of the things I did is begin to rip most of my cds onto it, so I could stream them over the network to my PS3 (and listen on my newly purchased Salk SongTowers!!! – Thanks for the speaker shootout!) I used 320kbps mp3, thinking that would be sufficient. Well, after listening to both the streaming and the cd, it isn’t sufficient. Great for on my Zune, but not for my living room. Now I’m toying with re-ripping or not.

Thanks again for topics like this. I love the technical topics that I can apply myself, like the room treatments, etc. Could I suggest getting a guest to discuss DIY calibration using a “cheap” sensor such as the EyeOne?

Jon

Fascinating podcast. I maintain two iTunes libraries, thanks to Smart Playlists. One is the Apple Lossless library and the other is the AAC library where everything is 128 kbps. I first rip the disc losslessly and then re-encode that into AAC. The lossless library is the one I listen to on my stereo system and the lossy version goes on my iPods or cell phone. I find it’s convenient that way.

And yes, hard drives are so cheap now that space is no longer a factor. I would recommend buying two hard drives though and use one as a back up. I’m sure people don’t want to waste all that time re-encoding an entire library again.