I noticed the phenomenon I want to describe when I was playing Pink Floyd’s The Dark Side Of The Moon MQA192 from TIDAL.
As you know, on TDSOTM the tracks flow smoothly without any breaks. Loud pops and/or sound distortion occurred in the transitions of the tracks. The phenomenon is not accidental, it always appears on other albums, noticeable and annoying, and unacceptable on albums where the tracks are played without breaks and flow smoothly. Applies to all higher than MQA96 (at least MQA192 and MQA352). If the file is not “gapless”, the effect is simply inaudible at the moment of “silence”.
During the experiments with Device settings (volume, buffer, MQA) I noticed that when you turn on “DSP volume” and set it to even -1 dB, the problem of crackling disappears completely (of course, the MQA LED also disappears, which of course results from the fact that on (e.g. in the signal path after Roon plays the MQA signaling and sends it after RAAT, there is a DSP-1dB regulation interfering with the MQA data).
Later I discovered (due to my DAC Topping EX5 displaying the current bitrate) that for a gapless MQA192 file, when switching between tracks, 192 disappears for a fraction of a second, 96 bitrate appears, and immediately returns to 192.
In the signal path in the Authentication position, the signal parameters disappear, which I managed to capture in the attached screenshots.
I also turned off all elements interfering with the signal path - headroom, up-sampling, EQ, etc… Adverse effects disappear.
To summarize the results of my “investigation”:
when playing “gapless” MQA albums with a bitrate higher than 96k, e.g. MQA196, in the transitions between tracks there is a short break in MQA authentication and the bitrate changes to 96k, which causes crackling in the played sound.
This phenomenon only occurs when there are DSP corrections in the signal path.
With DSP corrections turned on, the phenomenon disappears when after the MQA Restore step we insert the DSP volume control.
I ran the tests on the Roon Server installed alternately on macOS and Windows 10. With MQA196 there was a large CPU reserve (Processing speed about 16 on macOS and about 8 on Win10).
Have you tried same files with another app playing them as MQA decoded? Sounds like the dacs the issue as Roon will be sending it 96/24 as it’s performing the first decode stage the rendering stage to 192/24 is the dacs side of things and it’s having issues at the transitions maintains lock. Adding the dsp volume is breaking MQA so you won’t be getting it rendered as such on the DAC. Sounds like MQA on this DAC is suspect.
Do you have Roons MQA settings for the zone as Renders Only? As if using any DSP your using Roons decoder therefore the DAC is purely a renderer.
I also tested playback in Audirvana System (latest version) - the phenomenon does not occur at all!!!
So it’s not a DAC problem.
All the more so, what I tried to describe, the problem appears at the very beginning of the signal path, i.e. at the MQA Authentication stage, before decoding and rendering. As I described, the problem disappears when all DSP operations on the signal are removed. Which also doesn’t seem to indicate any cause on the DAC side.
As described in the above linked case that was closed without a solution, I am experiencing pop sounds between tracks, when pausing/unpausing a track, skipping ahead in a track, adjusting parametric eq, etc. only on MQA 24/192 files. I too have determined the pop occurs during the above changes because your software changes the resolution from 192 to 96, which my DAC picks up and causes the popping sound. I can see the readout on my DAC changing from 192 to 96 to 192 as the pop occurs.
Why can’t you keep the resolution at 192 prior to the EQ stage instead of changing it to 96?
Other than removing the EQ, what settings changes can I make to eliminate the pop sound?
As an example, refer to the Van Halen I album on Tidal. Under versions, there is a MQA 24/192 version and a MQA 24/96 version. I can play the 24/96 version with no pops; no resolution changes are sent to my DAC. But the pops occur when I play the 24/192 version.
Please see @Carl’s helpful comments above concerning MQA decoding.
Concerning any pops or digital distortion, please equip our team with either an approximate timestamp of an example event or the name of the track(s) playing when this last occurred.
We can activate diagnostics for your RoonServer instance to send system logs to our servers - these will have captured any failure events in transcoding if they occurred.
