MQA (Master Quality Authenticated) file coding and decoding (codec) has been with us since late 2014 and to this date questions linger about its performance, benefits and weaknesses. There’s been a lot of discussion about MQA regarding everything from its superiority (or lack thereof depending on which side of the argument you are on) to whether its proprietary nature is generally bad for the music business. We get a considerable amount of requests for information regarding LS50W and MQA, so without wading into the subjective swamp regarding the non-technical aspects of MQA, here are some answers to the most frequent asked questions regarding the platform.

 

 

MQA Is Not A File Format

MQA is a codec that is carried by ALAC and FLAC containers allowing playback of MQA-encoded music on non-MQA licensed hardware players.

 

MQA is a lossy compression codec which means file sizes are smaller, allowing users to store more songs per storage device. But of course, smaller file sizes come with a price – the loss of certain musical and spatial data that makes our music come alive. MQA’s codec solves this problem by storing the “lost” data from the under-utilized areas of the high frequency area of the musical spectrum “folded” within the data from the denser lower frequency range.

 

 

Long-But-Not-Painful Explanation    

Using a proprietary dithering technique, the low-density data in the upper frequency range (e.g above 11kHz or so) is compressed into data streams that are embedded in the lower frequency bands, therefore preserving the original source data.

 

The layered 44kHz data streams and a “touch-up” stream (that compares the original 96kHz/24-bit stream to the dithered 48kHz/16-bit stream for accuracy) are then sent to a dedicated hardware decoder for full resolution playback or to a non-MQA device for standard resolution playback.

 

Since MQA-encoded music can be carried within lossless file formats it can be played back on systems without a dedicated MQA decoder. However, the decoded audio has noticeable high-frequency noise occupying the 3 LSB (least significant bits), so MQA playback on non-MQA hardware is effectively limited to 13 bits, not 16. MQA counters this limitation by claiming that because of their proprietary sampling and coding methods the resulting audio stream is still higher than standard 48kHz/16-bit.

 

 

MQA uses a proprietary dithering process, what is dithering?

Dithering is a complex process that injects white noise into a frequency band to prevent quantization errors and limit cycle errors during digital processing. The white noise is then filtered out upon decoding.

 

 

What is the quality of MQA playback without an MQA hardware or software decoder?

Although the MQA file streams as a 48/24-bit file, normal 48/16-bit (or 44/16) playback equipment will only process and decode the 48/16-bit data (and then only the 13 LSB). This means an MQA file – regardless of source resolution – will only be 48kHz/16-bit (or standard resolution) when played back on standard (non-MQA) equipment.

 

 

What is the quality of MQA playback with an MQA software decoder but not an MQA hardware decoder or MQA-enabled DAC?

There are several music platforms and streaming services that offer the partial decode of MQA files (Tidal HiFi, Audirvana, Roon). However, if you want to use one of these services to fully decode MQA you will need an MQA-enabled DAC otherwise the resolution will be 96kHz/24-bit even from a 192kHz/24-bit source file. Software decoders are unable to unfold the HF data that was inserted into the LF data stream which results in the lower resolution, although the resolution is still considered high. Again, this is only an issue when playing back 192kHz/24-bit source files that were recorded, mastered and processed at that resolution. If the resolution is lowered at any point in the process prior to the file reaching you, the resolution will remain at the lowered resolution, regardless of the resolution of the final file. To ease confusion think of it this way – you can't put data back in that you took out as some prior point. This is an important consideration when purchasing high-resolution music – where did the file come from and at what resolution was it recorded, mixed and mastered. This is the basic philosophy behind Master Quality Authenticated – but most of the music we purchase was not recorded and mastered at high resolution. Caveat emptor.   

 

 

What is the quality of MQA playback with an MQA software decoder and an MQA hardware decoder?

If you are using an MQA-enabled DAC the resulting resolution can be 192kHz/24-bit assuming the source is of equal resolution. If you are using an MQA-enabled DAC and one of the software platforms as mentioned above the resulting resolution will be 192kHz/24-bit.

 

Therefore, any combination of playback devices other than an MQA-enabled DAC and an MQA-enabled software decoder results in a resolution of 48kHz/16-bit. This means you may very well be listening to an MQA-encoded file but only hearing it at standard resolution.

 

 

Why doesn’t the LS50W directly support MQA-encoding?

Bear in mind that research and development on new products begins years before release. MQA was announced in December 2014 and not fully available for several months after. MQA is also a relatively new technology with a small penetration in the overall market. The cost of including MQA in the LS50W would have dramatically raised the price of the product and simply put, the sonic benefits haven’t yet outweighed the consumer cost. With an MQA software encoder you can take advantage of 96kHz/24-bit resolution with the LS50W and for resolutions higher than that, you can still enjoy full high-resolution audio, just not with MQA-encoded files.