Support for 176.4 kHz max PCM rate?

Hi!

First and foremost, thank you for the great piece of software. I haven’t yet gone through the trial period, but I’m constantly findings new things to enjoy about Audirvana and its sound quality. :heart:

I’m using UPnP+RPi3+Hifiberry digi to send SPDIF to Xindak DAC-8 via coax. The latter is already a bit older DAC, but its my treasure because IMHO its sublime sound quality :slight_smile:

I recently noticed that while officially the Xindak is listed in marketing material only to accept 96/24 input stream, I was able to successfully (and may I say, very enjoyably) upsample Redbook 44,1/16 material to 176,4/24 on Audirvana and send it to the device. However upsampling to 192/24 results as a really crappy playback. Xindak has some internal upsampling thingies going on (and two very vaguely named operation modes for that), so it might be the reason why the 192/24 does not work. But well, who knows what’s going on there.

Unfortunately the maximum PCM rate dropdown in the audio device settings does not include an option to limit the maximum rate to 176,4 kHz. I know this is not a common situation, but do you think it could be possible to add that there? Currently if I want to take advantage of it, I have to change back and forth with 96 kHz and 192 kHz manually.

Thank you so much for your help in advance!

In the custom upsampling settings you can define the limit.
For example
44.1 to 176.4
88.2 to 176.4
176.4 to 176.4
48 to 96
96 to 96
… of course you can up sample to integer multiple only

1 Like

Well thank you @stefano_mbp! That’s a really nice find indeed! Let’s just say that this continues the theme of finding new things about Audinirvana every day…

Indeed, I’m able to do what I want with that.

I just feel that perhaps this is still a reasonable feature request, because the 176.4 kHz is a direct multiplier of the Redbook sample rate, so omitting it from the dropdown feels a bit arbitrary design decision. Or is there some clear drawbacks that I can not think of at the moment :smiley:

1 Like

OK, I found a problem with the suggested workaround: The upsampling target frequencies are global settings, unlike the max PCM rate, which is a device specific setting.

When I switch from Xindak to another DAC, I need to manually switch to different upsampling settings. So I’m back in changing settings manually :confused:

I still think that 176.4 kHz as an option in the max PCM rate dropdown would make sense feature-wise.

Wondering, how does up sampling help improves the audio quality?

Up sampling improve the quality of the antialiasing filter, some of CD player have a similar function.
And if you use plugin in, like an EQ, it is better to use a high sample rate.

Have the same sample rate could be fine with sequence of files with differents sample rate, the DAC don’t have to switch.

But re sampling could increase the value of crest so be careful.