Dummy to dummy multichannel DSP on the ultra cheap instructions

[MCH]

Hey @AbacusLX , I am very curious about the X3. Would you mind posting what you get from:
amixer -c nameofyourcard contents
Thanks!

 

[AbacusLX]

Hey @AbacusLX , I am very curious about the X3. Would you mind posting what you get from:
amixer -c nameofyourcard contents
Thanks!

here is the result :

I hope this speaks to you, I don't really.

If you know how to access the line input (which apparently has an ADC), that would be great.
Thanks!

My apologies for my English, it's an online translator that does the work.

 

[MCH]

Yes, it does have an aux in.
I am far from being an expert (remember the title of this thread) I recommend you to ask the guys in madsimon2 thread. But from my experience with other sound blaster cards, you might need to switch manually in alsamixer to mic input and then save the changes or even, depending on the card, use SoundBlaster software in a pc to switch the source and the card remembers the setting.
But remember, this was with different SoundBlaster cards.

 

[TabCam]

...

Now let's say you reduce the volume by -20 dB digitally. CamillaDSP is using 64 bit floats so it can do this operation with essentially no loss, the original -96 dBFS noise floor from your 16 bit file shifts down to -116 dBFS, so clearly the DAC noise floor is higher than this and will govern the resolution.

Because we have dropped our level by -20 dB our max output voltage is now 1.14 x 10^(-20/20) = 0.114 V. At 24 bit our effective dynamic range is now 20 x log (0.114 x 10^6 / 5.7) = 86 dB, so 10 dB off 16 bit resolution. At 16 bit our effective dynamic range is now 20 x log (0.114 x 10^6 / 18.1) = 76 dB, now 20 dB off 16 bit resolution.

All of this only get's worse once you multiply the DAC residual noise with an amplifier.

Michael

Wouldn't you only drop it by 6 dB as to stay at the same level an equal dac that can go to 2V? It seems to me the U7 cannot play louder than at 1V and the X3 (playing at 16 bit) can play 6 dB louder but has the same 96 dB dynamic range. It also depends on how Asus has implemented their DAC but I would expect that if 1V is the maximum, the Least Significant Bit is 96 dB below 1V.

As I see it, it only is a limitation if you use headroom (need to correct dips) in camillaDSP. You cannot use those dB/bits for volume anymore and are limiting the dynamic range.

 

[mdsimon2]

Wouldn't you only drop it by 6 dB as to stay at the same level an equal dac that can go to 2V? It seems to me the U7 cannot play louder than at 1V and the X3 (playing at 16 bit) can play 6 dB louder but has the same 96 dB dynamic range. It also depends on how Asus has implemented their DAC but I would expect that if 1V is the maximum, the Least Significant Bit is 96 dB below 1V.

As I see it, it only is a limitation if you use headroom (need to correct dips) in camillaDSP. You cannot use those dB/bits for volume anymore and are limiting the dynamic range.

This was a hypothetical example showing the impact of digital volume control on the U7 with 16 bit and 24 bit playback formats in CamillaDSP, not a comparison between the U7 and X3. The main takeaway was to not unnecessarily truncate to 16 bit in CamillaDSP as you will end up with much worse system SNR, even if you are starting with 16 bit data.

Certainly the max output level of the DAC will have an impact on how much attenuation you need to achieve a reasonable listening level, the lower the output level the less digital attenuation you need. I do not understand your comment about 6 dB attenuation to stay at the same level as a DAC that can go to 2 V.

Regardless it was a simple enough fix, just set the playback format to S24LE3 and reclaim 10 dB of dynamic range .

Michael

 

[TabCam]

This was a hypothetical example showing the impact of digital volume control on the U7 with 16 bit and 24 bit playback formats in CamillaDSP, not a comparison between the U7 and X3. The main takeaway was to not unnecessarily truncate to 16 bit in CamillaDSP as you will end up with much worse system SNR, even if you are starting with 16 bit data.

Certainly the max output level of the DAC will have an impact on how much attenuation you need to achieve a reasonable listening level, the lower the output level the less digital attenuation you need. I do not understand your comment about 6 dB attenuation to stay at the same level as a DAC that can go to 2 V.

Regardless it was a simple enough fix, just set the playback format to S24LE3 and reclaim 10 dB of dynamic range .

Michael

The comment was that if you play at a -20 dB for a dac that can output 2V, that would probably mean that the U7 needs to play at -14 dB in order to reach the same loudness level.

And of course, enable as much bits as you can to minimize the detrimental effect of digital attenuation.

 

[Hainnes]

Is this build also capable of working with ac3 audio from toslink ? I'm trying to build a fairly cheap roomcorection dsp for my home theater.

 

[MCH]

Is this build also capable of working with ac3 audio from toslink ? I'm trying to build a fairly cheap roomcorection dsp for my home theater.

hi Hainnes. I am afraid it wont, for two reasons. The xonar does not have any toslink input. and this tutorial is based on moodeaudio, that doesnt make it any easy to input audio from soundcards.
I would recommend you to visit the camilladsp tutorial thread, maybe they can help you there:

RPi4 + CamillaDSP Tutorial

Intent of this thread is to provide a tutorial for setting up CamillaDSP on a RPi4. There is a lot of good information scattered through ASR, DIYAudio and the CamillaDSP GitHub but there also appears to be a lot of apprehension. My goal is to give concrete examples of how to use CamillaDSP with...

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