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Problem: Pi 4 with Boss DAC 1.2. New user
#1
Hi all
Only had my Pi 4 for a couple of weeks and everything is new to me.
In this time, I started using another well known software and have been trying Moode for the last week or so.
Have also just changed from a Dragonfly Red to Allo Boss DAC.
So apologies for these questions which I am sure are “old hat” for many, but not for a new user;
1) re EQ. in basic terms, how does “off” differ to “flat” curve?
2) when EQ off, my output rate stays same as decoded rate i.e. 16bit. When EQ on, output rate jumps to 32 bit and I have no idea why. 
3) Allo Boss uses Burr Brown chip. I am given 4 options under ‘chip/device”options and have no idea what any of these mean. “FIR interpolation with de-emphasis” is chosen by default. Are these options related to Moode operation or should I be looking elsewhere for answers?
Thanks to all. Very much enjoying using Moode so far, although am struggling a bit with the Library/playlist functions.
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#2
1) re EQ. in basic terms, how does “off” differ to “flat” curve?
- Off removes the EQ plugin from the DSP chain.
- On/Flat inserts it in the chain and even if the Flat curve results in no amplitude change in the frequency bands the plugin IIRC always zero-pads the bit depth to 32 bit word length. You will also see the bit-depth being automatically zero-padded to 32-bit for any audio device that only accepts 32-bit word length. Its most common in USB DAC's with high speed USB chip sets.

2) when EQ off, my output rate stays same as decoded rate i.e. 16bit. When EQ on, output rate jumps to 32 bit and I have no idea why.
- See #1

3) Allo Boss uses Burr Brown chip. I am given 4 options under ‘chip/device”options and have no idea what any of these mean.
- Chip options are described in the data sheet for the chip. They are only available in moOde if the device driver for the chip exposes them to ALSA and it makes sense to code for them. This is the case for Burr Brown PCM and TAS 5xxx chips.
- The Oversampling filters also called Interpolation filters perform necessary noise removal in the Nyquist band. Each filter does it differently. For listeners with super hearing they each might result in very subtle differences on sound characteristics.
If you are interested, these links can help you learn about the PCM5122 chip options and interpolation/filtering.
https://www.ti.com/lit/ds/symlink/pcm512...52FPCM5122
https://dspguru.com/dsp/faqs/multirate/interpolation/
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#3
(07-19-2020, 09:38 AM)Leviathan Wrote: Hi all
Only had my Pi 4 for a couple of weeks and everything is new to me.
In this time, I started using another well known software and have been trying Moode for the last week or so.
Have also just changed from a Dragonfly Red to Allo Boss DAC.
So apologies for these questions which I am sure are “old hat” for many, but not for a new user;
1) re EQ. in basic terms, how does “off” differ to “flat” curve?
2) when EQ off, my output rate stays same as decoded rate i.e. 16bit. When EQ on, output rate jumps to 32 bit and I have no idea why. 
3) Allo Boss uses Burr Brown chip. I am given 4 options under ‘chip/device”options and have no idea what any of these mean. “FIR interpolation with de-emphasis” is chosen by default. Are these options related to Moode operation or should I be looking elsewhere for answers?
Thanks to all. Very much enjoying using Moode so far, although am struggling a bit with the Library/playlist functions.

Try each of the filters in turn and listen to the difference, if any.

Also try Sox 32 bit / 384 kbps (at the various quality levels) and determine which sounds best to your ears with your amp and speakers.  A 384kbps input signal to the TI 5122 DAC on the Allo Boss will bypass the on-chip interpolation. Many report that it sounds better than the on-chip filters.

And report back with your results.

Phil
Pi 4B 1GB / SMSL Sanskrit 10th MK II USB  DAC / Pro-ject Elemental / Marantz CD6004 / Marantz PM6004 / Monitor Audio Bronze 2
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#4
(07-19-2020, 02:03 PM)Tim Curtis Wrote: 1) re EQ. in basic terms, how does “off” differ to “flat” curve?
- Off removes the EQ plugin from the DSP chain.
- On/Flat inserts it in the chain and even if the Flat curve results in no amplitude change in the frequency bands the plugin IIRC always zero-pads the bit depth to 32 bit word length. You will also see the bit-depth being automatically zero-padded to 32-bit for any audio device that only accepts 32-bit word length. Its most common in USB DAC's with high speed USB chip sets.

2) when EQ off, my output rate stays same as decoded rate i.e. 16bit. When EQ on, output rate jumps to 32 bit and I have no idea why.
- See #1

3) Allo Boss uses Burr Brown chip. I am given 4 options under ‘chip/device”options and have no idea what any of these mean.
- Chip options are described in the data sheet for the chip. They are only available in moOde if the device driver for the chip exposes them to ALSA and it makes sense to code for them. This is the case for Burr Brown PCM and TAS 5xxx chips.
- The Oversampling filters also called Interpolation filters perform necessary noise removal in the Nyquist band. Each filter does it differently. For listeners with super hearing they each might result in very subtle differences on sound characteristics.
If you are interested, these links can help you learn about the PCM5122 chip options and interpolation/filtering.
https://www.ti.com/lit/ds/symlink/pcm512...52FPCM5122
https://dspguru.com/dsp/faqs/multirate/interpolation/
Very grateful for the comprehensive reply. Thank you.
re the Burr Brown filters - I will have a look at the info from the link you kindly gave. I have to say, though, that my initial listening tests for each of the 4 filters produced no discernible differences - at least none that I could hear.
Thanks again. I’ll continue playing and report back any findings.
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#5
(07-19-2020, 03:28 PM)philrandal Wrote:
(07-19-2020, 09:38 AM)Leviathan Wrote: Hi all
Only had my Pi 4 for a couple of weeks and everything is new to me.
In this time, I started using another well known software and have been trying Moode for the last week or so.
Have also just changed from a Dragonfly Red to Allo Boss DAC.
So apologies for these questions which I am sure are “old hat” for many, but not for a new user;
1) re EQ. in basic terms, how does “off” differ to “flat” curve?
2) when EQ off, my output rate stays same as decoded rate i.e. 16bit. When EQ on, output rate jumps to 32 bit and I have no idea why. 
3) Allo Boss uses Burr Brown chip. I am given 4 options under ‘chip/device”options and have no idea what any of these mean. “FIR interpolation with de-emphasis” is chosen by default. Are these options related to Moode operation or should I be looking elsewhere for answers?
Thanks to all. Very much enjoying using Moode so far, although am struggling a bit with the Library/playlist functions.

Try each of the filters in turn and listen to the difference, if any.

Also try Sox 32 bit / 384 kbps (at the various quality levels) and determine which sounds best to your ears with your amp and speakers.  A 384kbps input signal to the TI 5122 DAC on the Allo Boss will bypass the on-chip interpolation. Many report that it sounds better than the on-chip filters.

And report back with your results.

Phil
Thanks for taking the time to reply. Please see above reply re initial thoughts after trying the 4 Burr Brown chip filters.
Re SOX, I have tried the suggested 32 bit/384 but am struggling to hear any significant difference between this and leaving SOX disabled.
I need to do two things though. First, some serious listening with music more suited to revealing differences. 
Second, do a bit more reading on the subject of digital filters, up sampling, etc. From all that I have heard/read over the years, I am still struggling with the concept that anything can/should improve the sound of (say) a redbook CD at 16 bit/44.1 KHz. I have for so long subscribed to the belief that you cannot improve/replace what isn’t there in the first place, that it’s going to take some serious persuasion for me to change my mindset. I am always open to new ideas though!
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#6
@Leviathan

I noticed you said

Quote:but am struggling to hear any significant difference between this and leaving SOX disabled.

That's the problem with audiophilia. You can get so wrapped up in chasing the optimizations you forget to "enjoy the music." This isn't a test you somehow have to pass. 

Quote: I am still struggling with the concept that anything can/should improve the sound of (say) a redbook CD at 16 bit/44.1 KHz. 

Ay, there's the rub! You don't get to listen to the sound of a Redbook CD. What's on the CD is a string of bits.

You listen to 1) what the recording engineer decided was the right mix of microphones, signal preprocessing, and digitization techniques followed by 2) what the DAC engineer decided was the right mix of conversion techniques and filtering followed by 3) the effect of the rest of your audio chain. (The basic process of reliably extracting the bits from a line of craters "dug" in a layer under the surface of a rapidly rotating circular disc is itself an art.)

At every step, engineering choices have to be made trying to balance the demands of conflicting requirements. It's possible for a DIY'er to change the resulting balance. So, naturally, folks do.

Be happy making these changes costs nothing and undoing a change is easy. Imagine if each change cost the same as the magic speaker cables some feel compelled to buy.

Regards,
Kent
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#7
(07-20-2020, 11:15 AM)TheOldPresbyope Wrote: Imagine if each change cost the same as the magic speaker cables some feel compelled to buy.

Oh drat, I knew I'd forgotten something!

Off to purchase some now Tongue
Pi 4B 1GB / SMSL Sanskrit 10th MK II USB  DAC / Pro-ject Elemental / Marantz CD6004 / Marantz PM6004 / Monitor Audio Bronze 2
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#8
On a more serious note, I did find an audible difference between the different filter settings for the TI DAC.

Personally, in my setup (see my sig), SoX 32/384 very high quality sounds best to my ears.

Some of these tweaks might well reveal limitations further down the audio chain, so people's experience might differ with other audio cables, amps, and speakers.

Find what's easiest and best to your ears in your environment and go with it.

It would be great to find one set of settings which everyone agrees sounds better, bit I think there's a very slim chance of that happening.

Cheers,

Phil
Pi 4B 1GB / SMSL Sanskrit 10th MK II USB  DAC / Pro-ject Elemental / Marantz CD6004 / Marantz PM6004 / Monitor Audio Bronze 2
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#9
The filter option "Ringing-less low latency FIR" will not produce "pre-ringing". The filter's characteristic is similar to the analog filters. I prefers this one. This corresponds to S.M.S.L Sanskrit 10th MK II's filter number FL3. Sanskrit 10th MK II uses AK4493. https://www.audiosciencereview.com/forum...png.57282/
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#10
(07-20-2020, 08:48 PM)efung Wrote: The filter option "Ringing-less low latency FIR" will not produce "pre-ringing". The filter's characteristic is similar to the analog filters. I prefers this one. This corresponds to S.M.S.L Sanskrit 10th MK II's filter number FL3. Sanskrit 10th MK II uses AK4493. https://www.audiosciencereview.com/forum...png.57282/

That's the one I preferred too on the 5122 without using SoX.  Along with -6dB gain in the 5122 options.

Phil
Pi 4B 1GB / SMSL Sanskrit 10th MK II USB  DAC / Pro-ject Elemental / Marantz CD6004 / Marantz PM6004 / Monitor Audio Bronze 2
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