INTERACT FORUM

More => Old Versions => JRiver Media Center 19 for Windows => Topic started by: InflatableMouse on August 31, 2013, 02:01:44 pm

Title: Please help me understand noise when I output as DoP
Post by: InflatableMouse on August 31, 2013, 02:01:44 pm
I've been running some files through frequency analyzing software. I've converted some 24/96 flacs and DSD files to wave. Some have noise, some don't. Some have a wide band at 100K, some have a smaller band at 40k, and yet another had 2 very small bands at 30 and 40k (if that was noise at all).

When I play these files with MC output set to DoP, I think they follow this path:

Convert to wave -> DSP processing -> low pass filter -> convert to DoP -> ASIO output

Does the conversion to DoP introduce its own noise?
If it does, will it be the same band of noise as what was filtered out by the low pass filter?
Again, if it does, will files that didn't have noise to begin with not have noise when they are output as DoP?

Thanks!!

Title: Re: Please help me understand noise when I output as DoP
Post by: HiFiTubes on September 01, 2013, 11:08:29 am
Isn't' this ultrasonic grunge an artifact of DSD i.e. normal behavior? But you are hearing audible artifacts with DoP that are maybe unrelated (based on other posts) that could be due to the protocol itself?
Title: Re: Please help me understand noise when I output as DoP
Post by: Matt on September 01, 2013, 11:20:08 am
By its nature, 1-bit audio is super noisy.  However, since the sample rate is so high, you can use noise shaping to push all the noise up to the inaudible portion of the frequency spectrum.

The exact frequency where DSD starts to get noisy depends on the encoder's noise shaping filter, the input signal, and the DSD sample rate.

In my opinion, this is one of the big technical drawbacks of DSD compared to high sample rate PCM.
Title: Re: Please help me understand noise when I output as DoP
Post by: InflatableMouse on September 01, 2013, 11:50:53 am
But you are hearing audible artifacts with DoP that are maybe unrelated (based on other posts) that could be due to the protocol itself?

No, no artifacts. The question was theoretical.

By its nature, 1-bit audio is super noisy.  However, since the sample rate is so high, you can use noise shaping to push all the noise up to the inaudible portion of the frequency spectrum.

The exact frequency where DSD starts to get noisy depends on the encoder's noise shaping filter, the input signal, and the DSD sample rate.

In my opinion, this is one of the big technical drawbacks of DSD compared to high sample rate PCM.

So if I understand correctly, the noise is like a 'signature' based on the combination of things you mentioned?

Does that mean that the noise in MC's DoP signal is unique to MC?

I know, I need to read up more. I'm working on it  ::).
Title: Re: Please help me understand noise when I output as DoP
Post by: HiFiTubes on September 01, 2013, 11:57:11 am
By its nature, 1-bit audio is super noisy.  However, since the sample rate is so high, you can use noise shaping to push all the noise up to the inaudible portion of the frequency spectrum.

The exact frequency where DSD starts to get noisy depends on the encoder's noise shaping filter, the input signal, and the DSD sample rate.

In my opinion, this is one of the big technical drawbacks of DSD compared to high sample rate PCM.

IIIRC, it's also touted as one of it's benefits...
Title: Re: Please help me understand noise when I output as DoP
Post by: HiFiTubes on September 01, 2013, 11:59:57 am
No, no artifacts. The question was theoretical.

So if I understand correctly, the noise is like a 'signature' based on the combination of things you mentioned?

Does that mean that the noise in MC's DoP signal is unique to MC?

I know, I need to read up more. I'm working on it  ::).

Can you clarify what you are hearing, if anything? Or, are you looking at freq. response analysis and seeing this stuff visually represented. I ask, because some folks have 'audible artifacts' which would be due to bugs - at least that's what I gather from posts in the last month or so. I'm confused what you are referring to...
Title: Re: Please help me understand noise when I output as DoP
Post by: InflatableMouse on September 01, 2013, 12:11:38 pm
Can you clarify what you are hearing, if anything? Or, are you looking at freq. response analysis and seeing this stuff visually represented. I ask, because some folks have 'audible artifacts' which would be due to bugs - at least that's what I gather from posts in the last month or so. I'm confused what you are referring to...

Thanks but the question was purely theoretical, there is no problem. I just wanted to understand a bit more about the noise and whether the DoP output from MC would introduce its own noise.