Adding dither noise to simulate SACD

[boxerfan88]

For the fun of it, started an experiment to add dither noise to simulate SACD noise.

Approach: setup a DSP chain -- after resampling to 176kHz, add SmartDitherDSP with 17 bits of content + 4bits of high passed dither.

Using DeltaWave to analyze the result, we can see the noise added in the upper frequency range (similar to SACD).

• blue line is the original music track (Birds)
• white line is the modified track with dither
• I can't really hear a difference, but I can see it in the charts.

 

[boxerfan88]

When playing back music, can see the dither noise just peeking up above the floor of of the spectrum display (red box at the bottom right), so I know it's working. Theoretically, the levels are so low, it should not be audible.

Need to monitor a few days ... see of placebo effect is taking place ... and I start hallucinating that the music sounds more analog

 

[boxerfan88]

Audio Dither Example - IAM MediaWiki

imamp.colum.edu

 

[boxerfan88]

 

[boxerfan88]

Need to monitor a few days ... see of placebo effect is taking place ... and I start hallucinating that the music sounds more analog

I think I quite like the post-processing TPDF dithering to 16bits, sounds very slightly "smoother" to me.
Maybe it's placebo effect going on, I donno.
The dithering is now staying on my DSP chain

 

[boxerfan88]

Recently changed to mda dither… even more analog…

foobar2000:Components/mda Dither DSP (foo_dsp_mdadither) - Hydrogenaudio Knowledgebase

wiki.hydrogenaud.io

.

 

[boxerfan88]

Audio Myths - The Ultimate "Myth Buster" Video - Monty Montgomery, Xiph.Org

Digital Show & Tell, Monty Montgomery, Xiph.org This Video Busts the Following Myths: Myth - "Digital audio has stairsteps." - Busted! Monty feeds an analog

benchmarkmedia.com

Myth - "Analog tape has more resolution than digital audio." (9:37 - 11:34) Busted! Tape noise and gaussian dither noise are virtually identical. Cassette tape is equivalent to about 6 bits, and the best studio reel-to-reel tapes are equivalent to about 13 bits.

Myth - "Dither masks quantization noise." (11:35 - 13:50) Busted! Dither replaces quantization distortion with a noise spectrum of our choosing. Harmonic distortion (produced by quantization) is removed by dither and this can be seen on the analog test gear.

 

[boxerfan88]

Listening test - quantization noise & bit-depth 🎧

Demonstration of noise shaping and dither. Quantization noise audibility test.

www.tonestack.net