Sample rates, WAV depth etc

Hi Sampleboxers thanks for having me. Ill try to be a good boy 😎. Ive been using Samplerbox with a raspi3b + The old Cirrus DAC hat + Nektar gx61 to fill the space inside an old gutted Estey reed organ since 2020. I recently set about upgrading and trying to improve the sound quality so I dowloaded your feb 2022 image and booted it. Problem number 1: the cirrus hat stopped working. I had to #sudo update && sudo upgrade to fix it. I also installed mc to make navigating the filesystem easier. I'm still seeing messages saying "Alsamixer not setup so no hardware volume control" despite the fact that alsamixer starts without hesitation from the command prompt.

The main problem I'm having is that I have tried to improve the sound quality using audacity (on a different machine)to normalise the samples down (and up. The pipe organ samples in particular) to -6db. Samplerbox no longer recognises them! I cannot get my head around what the actual requirements are and how to satisfy them. The instructions say a sample rate of 16 or 24 bits is required. I think this actually means sample depth. At 44.1khz a 16 bit stereo sample depth gives a sample rate of 1.411MHz. iIn reality this is a sample depth of 32bits 2x16). Can anyone make this a bit easier to understand?

Regards
Peter
The bush
Western Australia

Hi Peter,

You're absolutely welcome here

Regarding the Cirrus logic Audio card:
I checked various forums and found the support for this card has been discontinued several years ago. Translated to PI/samplerbox terms: there is no related overlay (boot:/overlays/*.dtbo) available.
I see several threads of people writing their own kernel hacks, which is outside scope of this project.
This basically means that you are lucky when you can make it function more or less with a similar driver. The alsa mixer message is caused by samplerbox not being able to control the volume. If that's all I wouldn't worry too much as you can preconfigure a safe max volume and control the playing volume via midi - see Controlling the Volume.

Regarding the samples:
With audacity you need to use the "export to WAV" option where the sample rate is referred to as "encoding".
For samplerbox you can choose either "signed 16 bit PCM" or "signed "signed 24 bit PCM".
Mind that audacity doesn't recognize the WAV loop markers - and thus actually destroys the loops = continuing sound while pressing the key - essential for organs.
I usually use Wavosaur, simple but effective - with batch operations.
If you're succesfull in improving the samples and willing to share: - plse send me a PM so we can have a better version in the downloads.

Regards, Hans