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A short rant about low bitrate transcoded mp3s

January 14, 2015

NOTE: I’m not going to get into a ‘format wars’ debate about this and I’m assuming that we all know the difference between ‘lossy’ audio files (eg: mp3s) and ‘lossless’ ones (eg: FLAC). And, for the purposes of this rant, I’m using ‘transcode’ as a shorthand for a file converted from one format (and bitrate) to another, and in the process losing a significant amount of the audio information encoded therein.

GrumpyCatWhen I’m sent an album in digital format to review, I listen to it closely, and in depth, several times on a variety of systems (eg: portable mp3 player, computer and (if the PR people deign to provide me with a CD) on my hi-fi). I read whatever I can find about it and the musician/band online. I like to know who played what as well as the background to the recording. I read the lyrics – on the increasingly rare occasions that anyone bothers to provide them.

But before I do any of that, I check the spectral analysis. This tells me what bitrate the file is and provides a quick and easy visual confirmation of whether or not it’s a transcode. And it’s a source of considerable vexation when it turns out that, not only is the music at a low bitrate, but it’s a transcode and is therefore missing most of the frequencies above 14-16kHz.

The standard excuse of record company execs and PR droids is that they’ve sent me the ‘airplay’ copy – radio stations typically compress their broadcast streams very, very heavily to ‘optimise’ their bandwidth usage, which means a hefty reduction in the frequency range transmitted. I don’t buy into this excuse in the slightest – why would radio stations bother to have CD players and studio reference quality speakers, if they’re only playing 128kbps mp3 transcodes?

Which leads me to wonder why it is that these record company execs and PR droids think it’s OK to send out such poor quality audio files to reviewers. I mean, they’re happy enough to skim my reviews for key phrases and comments to use, free of charge and without even mentioning the reviewer’s name, for their own promotional purposes – yet they persist in sending out the equivalent of a faxed B&W photocopy of a photo of a painting for review. Don’t get me wrong, if I was an art reviewer, I wouldn’t expect to be sent (for example) the original Mona Lisa to review, but I sure as hell wouldn’t try to review it from a picture postcard.

And before anyone starts telling me that I can’t tell the difference between a 128kbps transcoded mp3 and a FLAC file, let me turn it around and ask them if they’re seriously trying to tell me that they couldn’t hear any qualitative difference in the sound between these two files, as per the spectral analysis screengrabs below:

Spectral01-192tc

 

Spectral02-eac_rip

/end rant

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