Question

Connect, Meridian and MQA

  • 27 January 2017
  • 56 replies
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56 replies

Look back at this post. Anything arriving in 24-bit MQA would evidently be truncated to 16-bit, removing the ultrasonics 'origami', and leaving 13-15 bits of resolution above the noise.

As for the idea of 16/44 'Red Book' MQA as described in that Stereophile article, forgive my scepticism but it all sounds rather reminiscent of HDCD. To be compatible with regular 16/44 PCM any extra information must be buried in the least significant bits, raising the noise floor on a standard decoder. Any real benefit must surely lie in more careful mastering, which might as well be delivered in plain old 16/44 PCM.

And
An MQA CD is a Red Book CD and is 100% compatible with any existing CD player.... if the bitstream is passed to an MQA decoder, it is unfolded to 176kHz (in this case) and rendered to the DAC at 24-bit.
really does stretch credulity. 24/176 content in an uncompressed 16/44 carrier which retains Red Book PCM compatibility?!


I've seen engineering specs for perpetual motion machines with more credibility.
Badge +1

...
Speculation: increasing the negative waveform by 1 bit could lead to minor clipping. Could this be why a limiter is needed?


That doesn't appear to be the case. In addition to truncating to 16-bits and the filling the bottom byte of the S/PDIF 24-bit sample with "junk", the limiter appears to be clamping the digital output amplitude to -1.4 dBFS (16-bit sample level ~27880 out 32768) for levels above this.

Using a 24/44.1 test track that sweeps every pos/neg sample value from 0 to FS at 24-bit, results in a 22050 Hz tone that increases in amplitude over time, per:


When the track is played on the Connect, with the digital output captured, when compared to the original, the following visualization shows the limiter in action at the higher amplitude level, getting more aggressive at the higher levels. One possibility for this behavior is to minimize inter-sample peak clipping, but considering current mastering practices of normalizing to 0dBFS, and that this "clamping" is only occurring for higher levels, this will result in a non transparent reproduction of most current album releases.

I've seen engineering specs for perpetual motion machines with more credibility.
It doesn't look like Archimago buys it either. Scroll down to "MQA-encoded CD".
Rather than as a move worthy of celebration by MQA proponents, I think this is more a sign of MQA's "last stand".
A thoughtful piece from Linn (who presumably are no friends of Meridian): https://www.linn.co.uk/blog/mqa-is-bad-for-music
A thoughtful piece from Linn (who presumably are no friends of Meridian)
LOL. They wouldn't be, because this also encroaches on their music downloads business, from which website:
"Linn makes download files available in three quality levels: MP3 (good), CD Quality (better) and Studio Master (best)."
Studio master is 192khz;)
A thoughtful piece from Linn (who presumably are no friends of Meridian)
LOL. They wouldn't be, because this also encroaches on their music downloads business, from which website:
"Linn makes download files available in three quality levels: MP3 (good), CD Quality (better) and Studio Master (best)."
Studio master is 192khz;)


The battle of the snake oil masters.