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+--- Thread: Does Devialet Decimate DSD? (/Thread-Does-Devialet-Decimate-DSD)
RE: Does Devialet Decimate DSD? - David A - 08-Feb-2019
Is the Lumin info screen showing input or output? That's an important part to understanding how this all works.
RE: Does Devialet Decimate DSD? - alandbush - 08-Feb-2019
I thought USB comm protocol was similar to HDMI, I.e. that a handshake is performed between two devices to determine their capabilities. In this case, the USB device (Devialet) reports it’s capabilities to the USB host (Lumin) which modifies its output accordingly, I.e. the Lumin downsamples to conform to the Devialet capability.
Generally, I’ve noted that most, if not all digital devices, display the incoming sample/bit rates rather than the outgoing rates.
RE: Does Devialet Decimate DSD? - mmorrison55 - 08-Feb-2019
Yeah, the screen likely is the incoming signal. Almost sure of it...
But I did double check my settings on the Lumin and everything related to sampling is set to “native”. If the usb protocol is as you say, then that likely is what is happening and would explain the pcm signal but unsure why it didn’t do the same for dsd > 64.
RE: Does Devialet Decimate DSD? - thumb5 - 08-Feb-2019
@alandbush is right: a USB device has a set of descriptors that advertise its capabilities. For an audio device this includes combinations of sample rates and bit depths it is able to support. The connected USB "host" (the Lumin in this instance) reads these descriptors when the USB connection is established and can then select which sample rate/bit depth combination to work with.