Add auto maximium up-sampling capability when playing back MQA

At the moment, MQA core decoder is limited to 88.2/96k without rendering. The added feature will automatically up-sample (both 88.2/96k multiples) to the maximum capability of DAC, say 352.8/384k. This simplify of using DSP where different multiple frequencies are involved.

@MusicFidelity personally I think this is something that should be under user settings and not automated or defaulted…not everyone will want to upsample to the max…nor will everyones hardware be capable either to do so just because the DAC might be able to support it. Plus it might not always produce the most listenable preferred results.

This is essentially already there. What’s the difference between this and just switching upsampling on to the max for that zone in the main upsampling settings?

Actually, this feature has one important advantage; by up-sampling to the maximum capability of your DAC, which Roon can detect the maximum sampling rate supported, your DAC will be running without any form of over-sampling digital filters, say if your DAC max out at 352.8/384k, inside the DAC digital filter is bypassed. Roon can applied a custom design ‘optimised impulse filter’, this helps to improve impulse response. This will work like a ‘renderer’

In the area, using an NOS DAC, like Holo Spring, then it is okay not to up-sample as MQA core is always running at 88.2/96k. Roon can then apply a custom design ‘optimised impulse filter’, this helps to improve impulse response.

I think I get what you’re saying. Let’s use an example DAC.

The Pro-Ject Pre Box Digital S2 DAC is both an MQA and MQB DAC (decoder and renderer). It is also officially Roon Tested.

Since the DAC itself can fully decode Tidal MQA 353kHz files (like the attached album), then I think @MusicFidelity is asking for Roon to do the MQA decoding and MQA up-sampling to 353kHz using that DAC’s MQA filter.

Again, in this case it is both a Roon Tested and MQA approved DAC. In this use case, you’re not bringing any new MQA functionality to the DAC itself that wasn’t already there. You’d just be taking all MQA decoding & MQA up-sampling out of the DAC and doing it in Roon fully. It would need Roon to work even closer with the Roon Tested and Roon Ready partners and be approved by MQA Ltd of course.

You have manually do it in the DSP SRC, does it take care of different multiple sampling frequencies? MQA core output 88.2k or 96k

I believe so. Just like it would upsampling any other material.

The issue is with DSP involved… (not to mention the load of MQA unfolding which has yet to be determined here as to the CPU resources needed) how much capability is available in the CPU for such maximum upsampling to work effectively plus the myriad of other filters and whatnot that might also be employed. If the processing speed drops to below about 1.4X then things will fail…at what point to you determine what to back down to?

I still say its best left to the user ultimately for this setting to be managed.