Please see the answer below from Aurender Customer Suppor RE: Aurender MQA handling explained:
"MQA decoding is hardware dependent on the DAC being used and so while the file is encoded in MQA, it is in a standard PCM "wrapper" or container file. The file can be either 16 bit or 24 bit (depending on the provenance of the original master file) and is either a 44.1kHz or 48kHz sampling rate, dependent on the A/D conversion and mastering sampling rate of the the original file.
In order for an MQA file to be properly decoded, it needs to be used with appropriate DAC hardware that carries an MQA certification. Otherwise it will just play back as a standard PCM file (capable of supporting either of the specs mentioned above). A user with a non-MQA DAC will still receive some of the benefits of MQA encoding, namely reduction of temporal blur, but the MQA decoding process is tailored for the DAC architecture and is only supported by MQA certified DACs. Since your Ayre Codex does not have an MQA hardware decoder, it does NOT see the MQA encoder flags and therefore just plays back the file at whatever the native sampling rate is (44.1kHz or 48kHz).
Further, it is a common assumption that an MQA file with a base sample rate of 44.1kHz or 48kHz will always result in a higher sampling rate after MQA’s “unfolding”, or decoding process. However, a fully decoded, unfolded MQA file on an MQA certified DAC can and often is still at a max sampling rate of 44.1kHz/48kHz. The decoding process is actually (more importantly) correcting for how the DAC is converting the signal to analog, by correcting for errors in the time domain. The sampling rate is based on the provenance or source of the original file.
To illustrate this a bit, a source file from a recording using MQA encoding may have a master sampling rate of 352.8kHz (8x 44.1kHz), which would be contained in a 24-bit, 44.1kHz sampling rate “wrapper” so that it can be used with non-MQA DAC hardware. When the file is delivered to MQA DAC hardware, the DAC will detect the appropriate flags that the file is encoded in MQA, and “unfold” the file using MQA’s decoding process to the original maximum sampling rate of 352.8kHz.
On the other hand, a recording that has a source provenance of 24-bit, 44.1kHz will still be contained in the same 24-bit, 44.1kHz “wrapper”, and when MQA DAC hardware detects the MQA encoder flags, will still decode the file to the original max sampling rate of 44.1kHz.
In short, MQA is less about the sampling rate of the file, and more about having provenance for the original recording, and removing errors in the time domain in the DAC hardware. Unfortunately, when Tidal introduced Masters (MQA encoded files), some of this information has been made a bit murky by some of MQA’s own marketing lingo about “Core” decoding (an initial software decoding required for an MQA Renderer, or a non-MQA DAC, currently only available in Tidal’s App, and Audirvana music player software), which everyone thinks must result in a 2x unfold before the DAC.
In other words, people want to see a higher sampling rate. However, this is simply not the case in practice and even a Core decoded file may only have a sampling rate of 44.1kHz or 48kHz if that’s what the original master file’s maximum sampling rate is.
Actually you can find out more about Aurender and MQA playback at the link here:
http://support.aurender.com/mqa-playback.html "
A special thanks to Aurender Customer Support for the above explanation answering our MQA related questions.
