Sony WH-1000XM4 Wired and Bluetooth differences

[mertyyanik]

I'm not sure if I marked the right place to ask this question. When we connect our headphones with bluetooth, headphone's dac and amplifier in headphone itself doing the job for music. What happening when we listen with wired connection? Is the dac in our computer used or is it still used in the headphone's dac? My computer do not have a bluetooth and do not have a good dac. If i buy a bluetooth dungle, is my sound quality improve because of headphone's dac and amplifier?

[IamNic]

Hello @mertyyanik,

if you switch them on while connected wired, the headphones will use its DAC.

- Nic

[Joe_Dohn]

You have the option to use the built-in DAC/Amp if you turn them On as Nic mentioned, and you can also have them turned Off if you decide to use an external DAC/Amp later on.

[IamNic]

Hello @Joe_Dohn,

thanks for the constructive addition to my previous comment.

- Nic

[Joe_Dohn]

@IamNic Always a pleasure! ^^

@mertyyanik has this answered your question by the by?

[Sonyvores]

Sorry guys but that's not how it works ^^

If you go wired, the dac of the headphone will never work. It's just logic.

A DAC is a Digital to Analog Converter. Once wired, the headphone only receive analog signal.... there is nothing inside the headphone that will reverse the signal back to digital to go through the DAC inside headphone....

If you use the cable, there are 2 options:

Headphone off=> passive mode non Hi-Res (weak and limited sound)

Headphone on=>passive mode amplified (stronger and fuller)

                          =>passive mode amplified Hi-Res (max capabilities but you need to turn off the NC)

In passive mode, only the DAC from player source is working, DAC in the headphone never works

[mertyyanik]

Hello, thanks for your reply.

So, i have two question.

1) My computer's dac is not very good. So, if i buy a bluethoot dungle, my sound quality will improve, right?

2) For passive mode amplified Hi-Res, why i need to turn off NC?

[Joe_Dohn]

@Sonyvores thanks a lot for the clarification as I seem to have confused when a DAC would be used compared to the built-in Amp.

@mertyyanik

1) We can't really say the quality will "improve" since the dongle could be of lower quality if it doesn't support LDAC or AAC for example, so that depends.

2) Not quite sure, but I'd guess it has something to do with the fact that the NC feature uses a "powered" or "active" circuit.

Hope this helps!

- JD

[IamNic]

Hello @Sonyvores,

---

@Sonyvores  schrieb:

there is nothing inside the headphone that will reverse the signal back to digital to go through the DAC inside headphone....

---

can you elaborate how you come to this conclusion?

The chipset of the headphones has multiple ADCs build in as you can see in this sheet for the CS48L32 chip.

Now it is up for speculation, whether these are just used for the NC-microphones, the "call" microphones or actually the 3,5mm input when they are switched on (what I assume).

Why do I assume it - it has two "Stereo digital microphone interfaces" as you can see in the block diagram in the PDF or directly here in this graphic.

I assume these interfaces are used by the NC microphones.

This leaves the two ADCs unused and therefore open to convert the analog signal that comes in trough the 3.5mm audio jack to be converted into a digital signal and be enhanced/amplified before being pushed back to the earcups trough the DAC.

Unfortunately that neither proves mine (and @Joe_Dohn 's) nor your statement as well as not disproving either (at least yet).

If you know more, please let us know, so we can get to a definitive answer for @mertyyanik.

- Nic

[Sonyvores]

@mertyyanik 

For your 1frst question, @Joe_Dohn said it all. 

For your 2nd question, that's because once NC is on, it reduces the driver response so it can't go full range and as a consequence it's not Hi-Res. The "anti noise" for cancelling also interferes and NC circuit can also add some electric noise to the final signal.

@IamNic

It's an interresting theory but in practice nobody will ever design it that way coz it doesn't make sence for audio quality. Simply because the analog signal that arrives in the headphone is already full of noise and not pure anymore and also degraded by the poor connectors and headphone cable itself. Converting it back in Digital will just keep artefacts and noise from the 1rst convertion and can add some more before converting it again in analog. It's a non sence to do that as the result will be worst. A DAC is only used for converting from source file. The only time a ADC is required in audio sound is when you need extreme fidelity recording but it requires a dedicated chip. A multi chip one like the one in XM4 can't handle that level. And finaly the easy proof, such extra convertion  (digital=>analog=>digital=>analog) will add lag time when you watch a video.

Btw the Wh-1000Xm4 carries 4 NC mic and 3 mic for calls.

As an expert you should be able to ask confirmation and more explaination from Sony. If you don't know who to ask, Ayae should be able to help you on that question