FLAC is a well-known lossless audio codec that is widely supported. It’s a lossless scheme that is able to compress a standard PCM soundfile and then uncompress it back to its original form…exactly. FLAC also supports metadata tags that make it better then other uncompressed file formats like WAVs that contain only the audio. But it is still a compressed format…or so I thought until it was pointed out to me that the latest version of dBPowerAmp 14.4 (a popular software application that is able to convert an uncompressed PCM file into a FLAC file) has an option to produce a FLAC file that without any compression. Why did the programmers and software designers at illustrate (the company behind dBPowerAmp) choose to include “uncompressed” as a choice? The quick choice is because some audiophiles feel that compressing a file (even losslessly) changes the sound of the file. There’s a whole article in The Absolute Sound about this very issue. In fact, a while back I wrote about it too.
Here’s the deal. First, let’s talk about compatibility of the FLAC codec across the players and platforms that you’re likely to run into in the “music server” world. The vast majority PC software players and media servers support FLAC files. This includes Sonos, Meridian Sooloos, JRiver, Linn hardware, Squeezebox (discontinued) and Transporter from Logitech, PS Audio “Perfect Wave” DAC and even the latest universal players from Oppo Digital (the BDP-103 and 105). The bad news is that any of the “i” devices from Apple do not play FLAC files. It turns out that Apple has their own lossless codec called ALAC (Apple Lossless Audio Codec) and they support compressed AAC files.
The dBPowerAmp FLAC converter is capable of compressing digital audio files by 2:1 or even 4:1 depending on the material being converted AND the “Lossless Level” setting used during the conversion. Or you can choose to use the “lossless uncompressed” setting to simply take advantage of the better ID tagging that FLAC offers.
It’s the “Lossless Levels” that have caused some controversy among audiophiles. If the FLAC codec is lossless then why would there be different levels of lossless. There aren’t. But there are different levels of processing that can be applied to the compression of a file. If you want to encode a file quickly, then you could choose Level 0. Level 0 applies the least processing to the source file. While it does result in a valid FLAC file, that file is only slightly smaller than the original. Level 5 is the default setting and Level 8 will take the most time AND result in the smallest file. It’s pretty obvious that the more time the processor takes the more it will be able to find redundancies that can shrink the overall file size. The output of ALL of the levels results in a file that when reconstituted is identical to the original PCM file.
But some listeners and writers claim that they can tell a difference between the levels. In fact, a guy posted the following on a forum, “[I could] easily hear differences between different levels of FLAC compression and uncompressed wav [files]”. And the article in The Absolute Sound magazine claimed the same thing. The only possible explanation for any perceptible difference has to be the processing that is applied in real time during the decoding of a FLAC file.
Imagine a very tightly compacted file that was subjected to a lot of fancy processing done using Level 8 of the dBPowerAmp converter. If an underpowered PC was tasked with “unwrapping” the file in real time and then delivering it to your DAC, it might…just might…fall behind on a few bits and bytes resulting in a change in the sound. However, if you took files that were compressed using any of the “Levels” and decoded them out of real time, they would be bit for bit identical to the original and would output the exact same sound. No one would be able to tell the difference!
So it is conceivable that a FLAC file could sound different from one that is less compacted or was made using the new “uncompressed setting”. It’s a great file format because of the robust tagging features but it is not without its detractors.