Leedh digital volume?

[JustJones]

Doesn't the D&D DSP have a built-in volume control? That'll be the best place to apply it, because it'll be applied at the full resolution of its DSP pipeline. If it's a hassle to use whatever smartphone app they provide to control the DSP volume, maybe get an iPod Touch just to run the volume control app and leave it on your equipment rack.

I'm not sure I haven't received them yet I thought it would be easier to control with whatever streaming app I had open. I was also looking at a Gustard U16 which takes USB and outputs optical/coaxial/aes. Connect a raspberry pi4 roon bridge to it. I don't think they have a smartphone app I believe the control runs in a web browser.

 

[mansr]

This looked interesting but I'm not a mathematician or engineer.

That's what they're counting on. Anyone who is will see straight through it.

 

[bennetng]

Details here, I guess

https://www.processing-leedh.com/copie-de-presentation

@mansr that doesn't totally look like BS to me

Take a look at the input signal:

...and the output signal. Notice what? The spikes are doubled. How can this be "distortion-free"?

The fallacy is the use of non-dithered 16-bit input signal. A dithered input signal doesn't have these harmonics. Since mansr is here so let's do this with SoX. Save the text below as a .CMD file, put it in the SoX directory then double click it:

@echo off
sox -V -n -b 16 input.wav synth 22 sin 1500 gain -.0004
sox -V input.wav -b 24 output.wav gain -20 dither -p 20 stats
pause

The first line generates a 1500Hz tone in SoX's native bit-depth (32) at -0.0004dBFS, then dithers to 16-bit and saves as "input.wav".
The second line takes "input.wav" as input, reduces 20dB and dithers to 20-bit (-p 20), then saves as "output.wav". WAV file does not allow 20-bit so the 20-bit data need to be padded to 24-bit.

If there is no error, then you will see an output like this:

sox:      SoX v14.4.2
sox INFO nulfile: sample rate not specified; using 48000

Input File     : '' (null)
Channels       : 1
Sample Rate    : 48000
Precision      : 32-bit


Output File    : 'input.wav'
Channels       : 1
Sample Rate    : 48000
Precision      : 16-bit
Sample Encoding: 16-bit Signed Integer PCM
Endian Type    : little
Reverse Nibbles: no
Reverse Bits   : no
Comment        : 'Processed by SoX'

sox INFO sox: effects chain: input        48000Hz  1 channels
sox INFO sox: effects chain: synth        48000Hz  1 channels
sox INFO sox: effects chain: gain         48000Hz  1 channels
sox INFO sox: effects chain: dither       48000Hz  1 channels
sox INFO sox: effects chain: output       48000Hz  1 channels
sox:      SoX v14.4.2
sox INFO formats: detected file format type `wav'

Input File     : 'input.wav'
Channels       : 1
Sample Rate    : 48000
Precision      : 16-bit
Duration       : 00:00:22.00 = 1056000 samples ~ 1650 CDDA sectors
File Size      : 2.11M
Bit Rate       : 768k
Sample Encoding: 16-bit Signed Integer PCM
Endian Type    : little
Reverse Nibbles: no
Reverse Bits   : no


Output File    : 'output.wav'
Channels       : 1
Sample Rate    : 48000
Precision      : 24-bit
Duration       : 00:00:22.00 = 1056000 samples ~ 1650 CDDA sectors
Sample Encoding: 24-bit Signed Integer PCM
Endian Type    : little
Reverse Nibbles: no
Reverse Bits   : no
Comment        : 'Processed by SoX'

sox INFO sox: effects chain: input        48000Hz  1 channels
sox INFO sox: effects chain: gain         48000Hz  1 channels
sox INFO sox: effects chain: dither       48000Hz  1 channels
sox INFO sox: effects chain: stats        48000Hz  1 channels
sox INFO sox: effects chain: output       48000Hz  1 channels
DC offset   0.000000
Min level  -0.099998
Max level   0.099998
Pk lev dB     -20.00
RMS lev dB    -23.01
RMS Pk dB     -23.01
RMS Tr dB     -23.04
Crest factor    1.41
Flat factor     0.00
Pk count       7.96k
Bit-depth      17/20
Num samples    1.06M
Length s      22.000
Scale max   1.000000
Window s       0.050
Press any key to continue . . .

Notice near the end of the console output shows "Bit-depth 17/20", indicates the effect of 20-bit dithering, with 20dB reduction there are 17 bits of integer precision. Now put these two files in DeltaWave:

Obviously the blue one is the original file, the white one is 20dB reduced. No spikes whatsoever. Also the use of 20-bit output in that article is completely silly, why don't just use 24-bit?