Sample rate changes in spite of preferences setting

Discuss Decibel, a high quality audio player.
Post Reply
kemoly
Posts: 10
Joined: Tue Jul 24, 2012 1:10 am
Location: Perú
Contact:

Sample rate changes in spite of preferences setting

Post by kemoly » Sun Feb 03, 2013 7:31 pm

I'm seeing that Decibel changes the sample rate in spite of having set the preference for no sample rate adjustment. I'm attaching a log file that shows the issue. This happens with M4A, FLAC, etc. The Musical Fidelity is an upsampling DAC so I'd prefer to have the upsampling happen in the DAC.
Attachments
Decibel.zip
Decibel log file
(1009 Bytes) Downloaded 214 times

User avatar
sbooth
Site Admin
Posts: 2450
Joined: Fri Dec 23, 2005 7:45 am
Location: USA
Contact:

Re: Sample rate changes in spite of preferences setting

Post by sbooth » Sun Feb 03, 2013 8:11 pm

I didn't see any device sample rate changes in the log you posted. From that log it appears the DAC is set to 96 KHz but the file is 44.1 so there was sample rate conversion from the file's rate to the device's rate. Is that not the behavior you'd like?

kemoly
Posts: 10
Joined: Tue Jul 24, 2012 1:10 am
Location: Perú
Contact:

Re: Sample rate changes in spite of preferences setting

Post by kemoly » Sun Feb 03, 2013 10:40 pm

What I expected was that Decibel would transmit the file to the DAC at 44.1 and the DAC would do the upsampling to 24/192. I thought that when I set the "adjust sample rate" preference to "off", the music would not be upsampled or downsampled by Decibel before sending it to the DAC, but instead the data transfer rate to the DAC would be adjusted to fit the music's sample rate.

User avatar
sbooth
Site Admin
Posts: 2450
Joined: Fri Dec 23, 2005 7:45 am
Location: USA
Contact:

Re: Sample rate changes in spite of preferences setting

Post by sbooth » Mon Feb 04, 2013 12:51 am

It actually works the other way around- "adjust sample rate" will set the DAC's rate to that of the file.

kemoly
Posts: 10
Joined: Tue Jul 24, 2012 1:10 am
Location: Perú
Contact:

Re: Sample rate changes in spite of preferences setting

Post by kemoly » Mon Feb 04, 2013 1:21 am

Thanks, yes, I realized that as I was typing my reply. Having the setting in the "Output Device Options" should have clued me in ... what a knucklehead!

mullet
Posts: 8
Joined: Sun May 14, 2006 1:47 pm

Re: Sample rate changes in spite of preferences setting

Post by mullet » Wed May 15, 2013 7:34 pm

I was curious about this as well... So with the setting unchecked what exactly happens?

This is what I do know... I have a Gamma-2 DAC that automatically takes every audio signal and upsamples it to 24/96 via an ASRC chip. The actually DAC chip is capable of 24/192, but I'm not sure if I'm playing 24/192 material if it's actually playing back at that rate. I'm also under the impression that my Mac laptop can only output up to 32/96 via the optical out (via the Audio MIDI settings), which is what my DAC is taking in. I'd typically set it to 24/96 because of the DACs capabilities.

So if I have the adjust sample rate box unchecked what is being played back if I'm playing a 16/44 FLAC? If I'm using exclusive access mode then I can't change the settings in Audio MIDI app. If I turn off hog mode then I can change the settings to 32/96.

I'm just trying to figure out how this all works.

kemoly
Posts: 10
Joined: Tue Jul 24, 2012 1:10 am
Location: Perú
Contact:

Re: Sample rate changes in spite of preferences setting

Post by kemoly » Fri May 17, 2013 12:54 am

As I understand it this is what happens:

1. If you check the option, Decibel will adjust the DAC's transfer rate to send the file in the best quality possible (in most cases, the exact file resolution, in some edge cases, as close as possible with software resampling)
2. If you uncheck the option, Decibel will do up-sampling or down-sampling in software to send the file to the DAC in the sample rate that the DAC is originally set to.

Hope this helps.

Post Reply