Not to Scoop

[tailspn]

So what frequency does the noise start at? I thought it was supposed to be in the ultrasonic region.

Well, here's the spectrum plot from the Grimm AD1 64fs DSD converter. Remember, the tape hiss from a good tape is about -60dB, and that's white noise throughout the audio spectrum.

Any audible noise modulation affects with 64fs DSD has to be produced within the output (audio) stages of a DAC, and the downstream components. That noise IM has to be the result of either the modulation products of the audio and noise (<-140dB) within the audio band, or rising noise modulating with acoustical audio information above say 20KHz. Not too much signal level there, IMO. In any case, any IM is non coherent, since it's the product of an audio signal and random noise, so the product is more random noise.

 

[c1ferrari]

And "normal" DSD64 doesn't?

Hi Julf,

I'm learning about direct-to-2 channel, live recording, using minimal mic technique.

Thus far, I have a preference for recording and playback @ DSD128.
Schoeps mics --> Gordon mic pre --> Korg MR2000s recording chain.

I'm hoping Tascam markets a DSD256 recorder with native DSD out

 

[mep]

View attachment 11808

Well, here's the spectrum plot from the Grimm AD1 64fs DSD converter. Remember, the tape hiss from a good tape is about -60dB, and that's white noise throughout the audio spectrum.

Any audible noise modulation affects with 64fs DSD has to be produced within the output (audio) stages of a DAC, and the downstream components. That noise IM has to be the result of either the modulation products of the audio and noise (<-140dB) within the audio band, or rising noise modulating with acoustical audio information above say 20KHz. Not too much signal level there, IMO. In any case, any IM is non coherent, since it's the product of an audio signal and random noise, so the product is more random noise.

And the level is extremely low in the audio band. If I'm reading that graph correctly, the noise is 100dB down at 28kHz. Between 10kHz and 19kHz, the noise is mostly 140dB down.