Upsampling MQA with Roon DSP, strange effects! [Sabreberry Sample Rates]

Support
1

Hi
As one of my endpoints i use a Raspberry 2B, wired, with a Sabreberry HAT.
It works beautifully in all aspects and sounds really nice at resolutions up to 24/384Khz (with the latest DietPi build, 149). However, this morning i discovered a very strange behaviour!
I have been having issues with my Mojo when upsampling causing it to loose sync on PCM streams (pink noise in one or both channels) or dropouts on DSD. These Mojo issues seem to be more frequent on “hot” material, i.e. mixed close to maximum output and that generally means loudness wars casualites.

I recently added Gorillaz new album Humanz (DeLuxe) in MQA to my favorites. A few of these song are so freakin’ loud they will turn your speaker membranes inside out! :wink:

Anyhow, i have not yet discovered any bad effects from upsampling in Roon and most music sounds great. However when listening to Gorillaz and their song Saturnz Barz this morning i was baffled? This is not what it sounds like!
I turned off the upsampling to eliminate any clipping and the sound returned to normal! I tried with headroom management but to no avail. Have a listen to the short clip that more than enough lets you understand the differences!
Standard playback of the MQA stream - 00:00-00:37 (Here i activate upsampling)
Upsampled Gorillaz - Saturnz Barz (MGA 24/48) into 24/384 - 00:39-01:08

Something obviously goes very wrong, dont you think? :slight_smile:

The soundpaths:

IMG_0708.PNG2048×1536 1.32 MB

IMG_0707.PNG2048×1536 1.15 MB

Any ideas? I cant see/hear this on other DACs though…

2

In a response to my own question i conclude that that the Sabreberry does NOT do more than 352.8Khz samplerates! I have a similar behaviour with local content!
So, nevermind this flummox and Carry On! :smiley:

1 Like
3

Hi Mikael,

Roon shouldn’t show sample rates that the hardware can’t handle. Sounds like the Sabreberry could be bluffing. One for @brian I think.

4

Hi @Mikael_Ollars ----- Thank you for your report and sharing your feedback with us. Both are appreciated!

We discussed this yesterday. When Roon communicates with a DAC we are told by the device what samples rates and formats it can handle. In this case, it sounds like the DAC may be telling us it can support a sample rate outside of its actual capabilities. Keep that in mind when configuring the device, particularly when using upsampling settings like “Max PCM”.

Thanks!
-Eric

5

Thanks for the feedback Eric, actually the Sabreberry did not report more than 192Khz capabilities before the newer kernel that enabled 384khz for the HAT brigade.
Perhaps @Dan_Knight will know why it can do 352.8 but NOT 384khz?
If am not mistaken it is used with the “Hifiberry DAC” option from the list of available HAT’s.

6

Hi Mike,

Not sure if i’am honest as although this is using the HiFiBerry DAC overlay (pcm5102a), its a completely different chip (ES9023).

For 384KHz, we apply two patches to the DietPi RPi kernel:

  1. ALSA defines for 384KHz. Allowing ALSA to support 384KHz.

  2. 384KHz support for pcm5102a codec:

linux/sound/soc/codecs/pcm5102a.c
@@ -26,7 +26,7 @@
 	.playback = {
 		.channels_min = 2,
 		.channels_max = 2,
-		.rates = SNDRV_PCM_RATE_8000_192000,
+		.rates = SNDRV_PCM_RATE_8000_384000,
 		.formats = SNDRV_PCM_FMTBIT_S16_LE |
 			   SNDRV_PCM_FMTBIT_S24_LE |
 			   SNDRV_PCM_FMTBIT_S32_LE

The pcm5102a claims it supports 384KHz:
http://www.ti.com/product/PCM5102A

Cant seem to find max frequency on ES9023:
http://www.esstech.com/index.php/en/products/sabre-digital-analog-converters/sabre-hifi-mobile-dacs/sabre-hifi-stereo-integrated-dacs/es9023/

1 Like