Noise shaping and the Ultra DAC

[Musician]

Its important to , in the WiiM meny select 24 bit 96 kHz ( the default toslink output resolution is 16 bit 48 kHz ) .
Theres a bug ( or was? ) that makes the ultra used as a dac sounding worse than it should when 16bit/48 is selected.
Amirs review at ASR shows this with 16bit 48kHz selected in the WiiM meny showing much worse measurement result than a ”real” 16 bit resolution should provide.
This goes away completely when selecting 24bit 96 kHz in the WiiM meny.
According to Amirm, there are some kind of noise shaping going on .

WiiM Ultra Streamer Preamp Review

This is a review and detailed measurements of the WiiM Ultra network streamer, DAC, phono stage and preamplifier. It was sent to me by the company and costs US $329. Physical attribute are modern and attractive enough. Alas, I can't say the same thing about the graphical interface. Icons seem...

www.audiosciencereview.com

 

[Wiimer]

Its important to , in the WiiM meny select 24 bit 96 kHz ( the default toslink input resolution is 16 bit 48 kHz ) .

Are you confusing output resolution with input resolution?

 

[Musician]

Are you confusing output resolution with input resolution?

Sorry, youre right. Its the output resolution on the WiiM meny that should be set at 24bit 96Khz.
I have corrected it

 

[Wiimer]

Sorry, youre right. Its the output resolution on the WiiM meny that should be set at 24bit 96Khz.

Yes, and I believe you posted the DAC measurements. Sorry if I'm wrong.

To be honest I'm not sure either - Is Amirm talking about the sample rate of the source (48/96kHz) for this measurement?

 

[Musician]

Yes, and I believe you posted the DAC measurements. Sorry if I'm wrong.

To be honest I'm not sure either - Is Amirm talking about the sample rate of the source (48/96kHz) for this measurement?

As I understand it , the 16 bit 48kHz resolution setting is not perfect when using the toslink input and the inbuilt dac of the Ultra.
There is noise in the signal , and that noise apparently goes away by using the 24bit 96kHz setting in the WiiM app.

 

[Wiimer]

As I understand it , the 16 bit 48kHz resolution setting is not perfect when using the toslink input and the inbuilt dac of the Ultra.
There is noise in the signal , and that noise apparently goes away by using the 24bit 96kHz setting in the WiiM app.

But how can the sample rate of the Toslink input be changed?
I don't think the WiiM app can do that.

I believe there are only three things you can do with the WiiM app.

- Toslink output resolution
- Fixed Toslink output resolution
- Line in Resolution


In this case, "Toslink in > analogue out", so there is no point in changing the Toslink output resolution to 96 kHz

 

[Burnside]

Yeah, I’m confused too. Is this suggesting that no matter what input source you use, the optical output resolution should be set at 24/96 if you’re using that? Also, if you use the optical output, you wouldn’t be using the Ultra as a DAC as per the post title.

 

[Musician]

Yeah, I’m confused too. Is this suggesting that no matter what input source you use, the optical output resolution should be set at 24/96 if you’re using that? Also, if you use the optical output, you wouldn’t be using the Ultra as a DAC as per the post title.

If you are using the toslink output from a CD player into the Ultra, or a television toslink output and use the Ultra as a dac , you have some issues with the default setting 16/48 . The sinad according to Amirm is only about -85 dB if you look at the graph.

If you select 24/96 this issue goes away ( also seen in the graph .

I would guess that hdmi input on the ultra may have the same issue as toslink input.
But Amirm hasn’t tested that so no evidence of this.

 

[Mr Ee]

I'm with @Burnside here; totally confused!
How does the optical output setting affect the digital input / analog output?
We've seen some time ago in posts here that the 16 bit setting in the 'Line-In Input Resolution" for the ADC is a poor choice, and iiirc that is the default value and general concensus (with proof?) was 24 / 96 was the 'best'.

 

[Burnside]

If you are using the toslink output from a CD player into the Ultra, or a television toslink output and use the Ultra as a dac , you have some issues with the default setting 16/48 . The sinad according to Amirm is only about -85 dB if you look at the graph.

If you select 24/96 this issue goes away ( also seen in the graph .

I would guess that hdmi input on the ultra may have the same issue as toslink input.
But Amirm hasn’t tested that so no evidence of this.

What “default setting”? How do I select 24/96 for toslink input?

 

[hgo58]

What “default setting”? How do I select 24/96 for toslink input?

Of course not possible. The resolution is defined by the incoming signal. And that is what the WiiM DAC will use also.

You can set the sampling resolution for the line input (analog) and for the digital output (coax, optical).

There may or may not be some issue with a optical input of 16/48 but it cannot be changed.

I just think the OP misunderstood the setup?

 

[slartibartfast]

What “default setting”? How do I select 24/96 for toslink input?

I don't know how Amir produced that 48kHz wideband distortion graph but it seems to me that he is changing the source sampling rate, nothing to do with any settings on the Ultra.

 

[Musician]

What “default setting”? How do I select 24/96 for toslink input?

It’s the toslink output resolution setting in the WiiM app that apparently ( and strange ) also limits the performance of the inbuilt dac, - if using Ultras toslink input as a standalone dac . The default is 16/48, should be set at 24/96.

It would be nice to see more measurements of Ultras toslink input using the internal dac , with different settings 16/48, 24/96, 24/192.

 

[Burnside]

I don't know how Amir produced that 48kHz wideband distortion graph but it seems to me that he is changing the source sampling rate, nothing to do with any settings on the Ultra.

In which case, wouldn’t this suggest taking a feed from a tv which is often 16/48 and then using the WiiM DAC to output analog isn’t optimal? I don’t see how you could make this better other than not using a tv and line out

 

[Burnside]

It’s the toslink output resolution setting in the WiiM app that apparently also limits the performance of the inbuilt dac, - if using Ultras toslink input as a standalone dac . The default is 16/48, should be set at 24/96.

If you’re using toslink output, you’re not using the inbuilt DAC - or are you suggesting that changing an unrelated setting can impact the DAC’s analog output?

 

[Musician]

If you’re using toslink output, you’re not using the inbuilt DAC - or are you suggesting that changing an unrelated setting can impact the DAC’s analog output?

You can change the toslink output resolution in the Wiim app , and still select and use the internal 9038 dac line level ( with the toslink output unused and turned off )

 

[hgo58]

It’s the toslink output resolution setting in the WiiM app that apparently ( and strange ) also limits the performance of the inbuilt dac, - if using Ultras toslink input as a standalone dac . The default is 16/48, should be set at 24/96.

It would be nice to see more measurements of Ultras toslink input using the internal dac , with different settings 16/48, 24/96, 24/192.

I think the misunderstanding is in this sentence "Increasing the sample rate fixed that indicating that there is some kind of noise shaping going on".

The increase in sample rate is of the optical test input, not the WiiM digital output. This is defined by the test setup, not the WiiM.

 

[Burnside]

I think the misunderstanding is in this sentence "Increasing the sample rate fixed that indicating that there is some kind of noise shaping going on".

The increase in sample rate is of the optical test input, not the WiiM digital output. This is defined by the test setup, not the WiiM.

So back to my comment #14 which I’d think isn’t an uncommon case, should users still change the seemingly unrelated optical output resolution to mitigate this “noise shaping”? And wouldn’t this be something that WiiM can fix in firmware?

 

[slartibartfast]

I think the misunderstanding is in this sentence "Increasing the sample rate fixed that indicating that there is some kind of noise shaping going on".

The increase in sample rate is of the optical test input, not the WiiM digital output. This is defined by the test setup, not the WiiM.

That was my interpretation

 

[hgo58]

So back to my comment #14 which I’d think isn’t an uncommon case, should users still change the seemingly unrelated optical output resolution to mitigate this “noise shaping”?

I would say no but it will not harm unless you need the optical output at 16/48.

I cannot imagine why the optical output resolution should be used for the DAC input resolution.

And wouldn’t this be something that WiiM can fix in firmware?

There were a fix some time ago about sample rate conversation and the way it is used by the LinkPlay connections. Maybe that also fixed this?