iFi's Pro iDSD (official) - NEW Firmware - MQA and more.

[simonklp]

On Monday, January 15, 2018 at 12:48 AM, AMR/iFi audio said:

The iDSD PRO offers the following choices of digital processing:

 

I. Direct - Bitperfect 

• Both PCM and DSD signals are not processed in any way.
• For PCM this is effectively what is sometimes called "non-oversampling" or "zero-oversampling", for DSD it means DSD is retained in the original DSD format and directly converted to analogue without any digital processing.

II. PCM - upsampling 

 

• In this case PCM is up-converted to 16 X PCM (705.6/768kHz) using a choice of digital filters (Minimum Phase, Apodising, Transient Aligned) that offer different tradeoffs of time-domain and frequency-domain performance.
• DSD remains completely unprocessed.

III. DSD - Remastering

• In this case all incoming audio (except DSD512) is converted to either DSD512 or DSD1024 as selected, using the filter selected (including Bitperfect, meaning no digital filtering is applied).
• All the above mentioned digital processing options apply to all sources, including the network audio bridge and AES/EBU & S/PDIF inputs.
• Inputs other than USB are currently limited to maximum sample rates of 192kHz PCM and DSD(64) via DoP.

 

In a nutshell, when:

• DSD512 Remaster is selected, then all audio (except DSD512) is upconverted to DSD512.
• DSD1024 Remaster is selected, then all audio (yes, DSD512 as well) is upconverted to DSD1024.

The upconversion process allows different digital filters, including Bitperfect (no filter), to be selected.

 

 

For example, this image shows the screen in DSD Remaster DSD1024 mode with a 44kHz input signal being upconverted to DSD1024 (45.158MHz) using the Bitperfect filter.

 

Why the terms of "DSD-Remastering" and sometimes "converted" are used in case of DSD, while the terms of "PCM-upsampling" and "up-converted" are used in the description of PCM?

 

Is there any difference between the terms?