Truncating MQA files to 16 bits and the blue light still shines

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The technical basis of MQA rests on two concepts:

 

1. There is very little music information above 50 kHz.

 

2. High-res sounds good because of time domain performance.

 

In Stuart's and Carver's view, almost all of the music data is present within a sample rate of 96 kHz, and information above that is just noise. MQA seeks to maintain the music data, eliminate the bandwidth dedicated to noise, while improving time domain performance.

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Just now, mansr said:

That much I agree with.

 

This is patently false.

 

All that can be done using standard FLAC.

 

That's bollox.

 

Stuart and Carver made their cases for time domain. Has someone rebutted it?

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Doesn't the 8 LSB just contain the ultrasonic unfold data?

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So, we know that the least 8 bits are ignored by the MQA security algorithm. There seems to be no reason why it couldn't do checks against those bits, so I assume the omission is on purpose. Why? Well, the last 8 bits contain the ultrasonic unfold data, so I assume this was a choice MQA developers made in order not to break DAC hardware that can't accept more than 16 bit input. 

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1 hour ago, miguelito said:

What do you mean "checks against those bits"? The only way to encode a signature is to use some of the data bandwidth.

 

It uses data from the control stream and the upper 16 bits, right? There’s no reason why it couldn’t also use the bottom 8 bits. We know that the lower 8 bits is the ultrasonic fold data which means the developers wanted to allow the lower 8 bits to be truncated/discarded for some reason, probably compatibility.

 

BTW, I tried playing the "mqashill.wav" directly over a Plex server from my Technics SU-30G, and while the file is seen by the unit it fails to play it back. If using Roon playing back via a USB link the file will play back and it does show "MQA Studio" on the display.