surr3a1 wrote:I do get the Bit Test idea to some extend but I absolutely disagree that the digital signal is "0" and "1". That is simply not true at all.
There are no "0" nor "1" in any signal and stating otherwise is plain childish.
The signal is current with certain value which can be altered by the cable. I hope that we don't need to explain this to anyone.
Decoding the signal is done with certain tolerances and in a certain way. If the current is not transferred perfectly to the other side(which it never is) then one "0" can become "1" and vice versa, and this is a fact!
If that happens in this case and with this DAC is a different case and a different reality of course.
What everyone needs to remember is that there are no numbers jumping inside a cable so, please, stop this saying because it is annoying!
I'm sorry, but you somehow still have misconceptions about how this all ties together.
Look, this is the data format of a wav file:
http://www.ringthis.com/dev/wave_format.htm
Your audio data can be up to 32bit (see the last line there).
Such data packets are being transferred between sender (a player) and a receiver (the DAC).
Digital audio is nothing but data in a certain format. Header and payload, same like with network protocols in computer networks (header and payload, payload is the actual data being transferred in 0's and 1's, binary format).
The up to 32 bit of data are represented by bit values (0's or 1's).
https://en.wikipedia.org/wiki/Binary_file
Once the binary audio data arrives at the DAC chip, then the DAC performs a conversion from binary data (0's and 1's) to a real analog wave form.
Between sender (player) and receiver (DAC chip) you will always have the same sequence of data.
If the data would change it would mean, that your wave file has been corrupted during transfer.
This can happen due to
- transport errors which you can see as CRC error or hear as audio drop
- change of volume at the player or sending it through an audio driver which doesn't work lossless
The Bit test checks that a predefined binary file arrives in good shape. The 32bit of audio data / payload.
If this test file arrives in good shape between player and DAC chip, then also other audio data will survive the transport. That is the idea behind the bit test.
With the bit test you can validate from source to destination (player to DAC chip) that audio (binary) data in a certain format will be transferred lossless / unchanged.
And this you can validate through e.g. USB, ADAT, SPDIF, MADI ...
Whatever transport you choose .. with the Bit test you check whether the "payload" / the digitized audio (the 32bit inside of a data packet in a certain format) are still the same.
At the very end headers are stripped from a packet and the pcm audio data are being send through the DAC to make the D/A conversion. Then you have no zeroes and ones anymore, there you have again an analog waveform.
This is always the same principle of digital data transfer.
The only difference with the ADI-2 DAC/Pro is, that he has additional features that other devices do not have.
- can show you CRC errors in the driver
- you can check with Bit test for lossles audio transfer
- you can manipulate the audio data in the DSP in front of the DAC chip (B/T, PEQ, dynamic loudness) ...
And so on and so on.
BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13
- sorry, excuse me, I couldn’t hesitate -
