Wiim Ultra - turntable input is low-passed at 20 kHz

[574stereo]

Hey Wiim users, Wiim etc

I just used my Wiim Ultra to digitise a recording off vinyl, and even when the optical output was set to 96 kHz, the recording seems to be low-passed at 20 kHz or so.


See the screenshot (a spectogram from RX audio editor)
Chain was Wiim Ultra > RME Babyface Pro > Mac
All sample rates were correctly at 96 kHz with the RME clocked to the optical input.

I would expect to see information well above 20 kHz... no?


Thanks!

 

[slartibartfast]

Hey Wiim users, Wiim etc

I just used my Wiim Ultra to digitise a recording off vinyl, and even when the optical output was set to 96 kHz, the recording seems to be low-passed at 20 kHz or so.


See the screenshot (a spectogram from RX audio editor)
Chain was Wiim Ultra > RME Babyface Pro > Mac
All sample rates were correctly at 96 kHz with the RME clocked to the optical input.

I would expect to see information well above 20 kHz... no?


Thanks!

Why would you expect to see signal much above 20kHz on vinyl? Unless it is noise of course

 

[hgo58]

Hey Wiim users, Wiim etc

I just used my Wiim Ultra to digitise a recording off vinyl, and even when the optical output was set to 96 kHz, the recording seems to be low-passed at 20 kHz or so.


See the screenshot (a spectogram from RX audio editor)
Chain was Wiim Ultra > RME Babyface Pro > Mac
All sample rates were correctly at 96 kHz with the RME clocked to the optical input.

I would expect to see information well above 20 kHz... no?


Thanks!

Of course it cut of at 20 kHz. That is normal when sampling analog audio to avoid any aliasing even when sampling rate is higher than the Nyquist frequency.

 

[574stereo]

Why would you expect to see signal much above 20kHz on vinyl? Unless it is noise of course

Absolutely, vinyl tends to have a gentle roll off starting around 15-16 kHz.

Also, pops and clicks tend to extend way up in frequency. Even the surface noise should be very visible in the spectogram.

 

[slartibartfast]

Absolutely, vinyl tends to have a gentle roll off starting around 15-16 kHz.

Also, pops and clicks tend to extend way up in frequency. Even the surface noise should be very visible in the spectogram.

This is a recording at 24/96 using a Musical Fidelity preamp and it does actually show frequencies above 20kHz I suppose.

 

[d6jg]

It very much depends on the ADC chip you are using and I don’t think that is WiiMs strong point.

@slartibartfast what are you using in that screenshot?

 

[slartibartfast]

It very much depends on the ADC chip you are using and I don’t think that is WiiMs strong point.

@slartibartfast what are you using in that screenshot?

Do you mean software? If so Audacity. If hardware it's the Focusrite Scarlett 212 interface.

 

[d6jg]

Do you mean software? If so Audacity. If hardware it's the Focusrite Scarlett 212 interface.

I meant hardware. I’d expect the Focusrite to provide that sort of range as it’s 24/192 capable isn’t it? Is the ADC in the Ultra as good? I think not

 

[slartibartfast]

I meant hardware. I’d expect the Focusrite to provide that sort of range as it’s 24/192 capable isn’t it? Is the ADC in the Ultra as good? I think not

I think you can choose 24/96 as the input for the Ultra though. You would expect it to capture up to 48kHz. The RIAA curve is applied in software though so we don't know what that does above 20kHz.