MQA – Master Quality Authenticated or Missing Questions/Answers

 
I was going to call this article MQA Misrepresented because that’s what I am really writing about here, but I felt the title I chose also represented not the “what”, but the “why”.

By now no doubt, you may have heard about the new thing called MQA (Master Quality Authenticated). It was invented and launched back in 2014 by Meridian Audio, it is now licensed and owned by MQA Ltd.
Put simply, MQA is the brain-child of Meridian Audio. It is a codec that allows for better lossless streaming by reducing the bandwidth required to stream lossless audio, a good thing indeed! It is basically an enhanced version of FLAC, if you will. It is lossless audio that takes up less space than FLAC and certainly less than wav files. This is how it was presented from the start and at a demo I attended some two years ago. The issue is that lossless formats are big and sending them over the internet is problematic at best. For example, when you try to send say, a needle drop (recording from analog tape or indeed vinyl) or even redbook CD over the internet, you have to reduce the size of the file packet, which means compression of the data. That means there will be loss of dynamics and other things that affect sound quality. This is especially troublesome with streaming more than downloads. One can download a large file, but you can not stream a large file, the buffering process alone would take hours. A song would sound broken up note by note. Never mind what Tidal claimed before, they are on-board with MQA from the beginning citing this very reason, so you have to compress the file into a smaller packet. The problem is that once compressed you can’t return it to its original lossless state. So if you sent an analog or even CD sourced song for streaming after compressing it to MP3, which is what is mostly used, it will not sound the same at the end of the line in playback.  Even other lossless formats that are smaller such as FLAC don’t get properly unpacked at the end. The DACs we use simply can’t do the job in the case of streaming. MQA claims to solve this problem, which is the very reason why it was invented from the start.

I’m no expert on streaming and such, but as was explained to me by Meridian/MQA, put plainly, MQA encoding is ‘lossy’; it hierarchically compresses the relatively little energy in the higher frequency bands into data streams that are embedded in the lower frequency bands using proprietary dithering techniques. After a series of such manipulations, resulting 44 kHz data and a final “touch-up” stream (compressed difference between the lossy signal from unpacking all layers and the original) are provided to the playback device. After that, the compressed difference between original 96/24 and 48/16 are together distributed as a 48/24 stream, of which 48/16 bit-decimated part can be played by normal 48/16 playback equipment. One more difference to standard formats is the sampling process. The audio stream is sampled and “convolved” (their word, not mine), with a triangle function thing, and interpolated later during playback.
In other words, it makes it so that “lossless” data can be sent down the internet pipe for streaming, which results in better sound quality and that is where some confusion gets in. MQA-encoded content can be carried via any lossless file format such as FLAC or ALAC; hence, it can be played back on systems either with or without an MQA decoder. In the latter case. MQA claims that nevertheless the quality is higher than “normal” 48/16, because of the novel sampling and convolution processes. In my opinion that is a little misleading. MQA is not a native sound quality enhancer in the plain sense, but improves sound quality for streaming by preventing degradation of the original recording at the end of the line, so to speak.

In that demo 2 years ago, did I hear a difference between the normal lossless file and the MQA file? At the beginning of the demo it was explained that one may not hear a difference because of what MQA is all about, but some folks might hear a difference. The problem with this demo was two-fold. 1) Sadly, the equipment being used was faulty and introduced extraneous noise, so I felt it was not a fair demo and 2) they turned up the volume on the comparison (MQA) files, thereby further skewing the demo. (Continue next page)