'Analog Dinosaur' succumbs to the joys of FBA : enter Raspberry Pi 2/IQ-Audio DAC+!!

[tubehunter]

The dac's PCM volume is set too low, your signal to noise is reduced.

Set the PCM to 86 = 0Db anything less is reducing your signal to noise.
Set both Playbacks to 100 = 2volt or 0 = 1volt if you set this to 0 = 1volt you can increase your PCM in Volumio and increase your signal to noise and reduce the clicks

[Marco]

I thought 86 (PCM) was 0db, Dunc?

Marco.

[Ashmore]

Thanks Duncan. PCM is at 85 - my alsamixer (picore) doesn't have an 86 (85 then 87). Playbacks are both up as you suggest. Clicks still there intermittently and the more I listen the less I am able to attribute them precisely to definable differences in track quality or suchlike. Anyway, I'll take this issue away for a few days while I experiment some more as I don't wish to become a 'click bore'.... though any further thoughts or suggestions are of course very welcome.

Simon

[Marco]

Hi Simon,

You can also set the PCM level out with of Alsamixer, simply by moving the (volume) dial up and down, in the Playback section of Volumio. That can easily be adjusted in increments of one, from 0-100. Therefore, if you want, set it to 86, using that process.

Simply keep the Hardware opinion enabled, and adjust the dial to 86, and leave it there. You can then disable Hardware, if you wish, and the system will always default to the 86 position, until you change it again

In terms of eradicating your 'clicks', make sure that the 'Buffer before play' option, in the Playback section of Volumio, is enabled (and thus set at 10%). If it is, try increasing it to 20%, and see what happens then

Marco.

[Krisbee]

Rather than use alsmaixer, you can set the IQAUDIO DAC+ volume level to +0db with this command:

amixer -c X sset PCM 86% -M

Where X is the "card" number, which may be, 0 or 1, depending on your setup. To decide the number, use this command:

aplay -l

If the results is this:

card 0: sndrpihifiberry [snd_rpi_hifiberry_dac], device 0: HifiBerry DAC HiFi pcm5102a-hifi-0 []

Then X is 0. Otherwise just use the card number returned by the command.

[Busybee330]

For those like me who are new to this , here is another interesting review , quite positive indeed :

http://parttimeaudiophile.com/2015/0...usic-streamer/

[guyb]

OK, so I have been trying the PI DAC+ for a few days or so and like it.

However, as my external DAC setup handles DSD and sounds just as good, if not better according to my wife, I am going to stick with that.

So I am going to stick the PI DAC+ and the clear smoked case for IQaudIO for sale if anyone is interested.

Guy

[WAD62]

piCorePlayer doesn't seem to upsample by default but there are an array of settings for squeelite to set it up. However, for some reason, its quirky and the settings don't always 'stick'. With a lot of mucking about I've managed to force it into submission.

Here's what I did:
In Upsample Settings I put in mI then saved it.
Reload the page and add X to the Upsample Settings so: mIX
Save it then reboot.

With the IQAudio DAC+ this forces it to upsample to 192KHz

If you want to keep up sampling to an Integer value for 44.1 material go back to the settings page for squeezelite and type -u (minus u) in the various input box
Save it, then in the max sample rate box type 176400 Save it and reboot.

To check what is actually being o/p ssh into the RPi (user: tc password: nosoup4u) and cut n paste this into the command line:
sudo cat /proc/asound/card1/pcm0p/sub0/hw_params

What ever you do do not be tempted to use 352800 in the max sample rate box, you'll need to re image your SD card

The mIX setting is interesting, the first letter defines how much SOX suppresses alias artefacts from the up sampling process, you can set v h m l or q (Very High, High, Medium, Low and Quick) I think the higher settings take more processing to achieve and may not be the best sounding, h or m seem to work well.

The second letter chooses which type of filtering you use and so far I've found this make a very noticeable change to the sound, you can choose M for minimum phase, I for Intermediate or L for Linear I prefer the intermediate filter, the X ensures the up sampling is done to the highest rate set IE 176400

Hi Neal, very useful reference post...

I've been having a play with piCorePlayer/Squeezelite's SoX upsampling capabilities using...

'vIsX:::28::'

...which the settings have taken first time, saved, and restarted with new settings...and it's working, at least I think it is

I've used the above command...

To check what is actually being o/p ssh into the RPi (user: tc password: nosoup4u) and cut n paste this into the command line:
sudo cat /proc/asound/card1/pcm0p/sub0/hw_params

...and I see

tc@piCorePlayer:~$ sudo cat /proc/asound/card1/pcm0p/sub0/hw_params
access: RW_INTERLEAVED
format: S32_LE
subformat: STD
channels: 2
rate: 192000 (192000/1)
period_size: 3840
buffer_size: 15360

...so is this the current output rate, or what the DAC is capable of? My assumption from your post is that this is a real time sample of the output

Cheers for any clarification...

Edit;

Easily proven, just reset to no upsampling, restarted, and now back to...

tc@piCorePlayer:~$ sudo cat /proc/asound/card1/pcm0p/sub0/hw_params
access: RW_INTERLEAVED
format: S32_LE
subformat: STD
channels: 2
rate: 44100 (44100/1)
period_size: 882
buffer_size: 3528

...so it's obviously working

Now to see if it sounds any better or worse, and whether there are any synchronisation issues with my other players, due to the buffer size differentials

[NRG]

Hi Will, yes thats the current sample rate being played....

[WAD62]

Hi Will, yes thats the current sample rate being played....