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SONAR's dithering algorithms: When to use each kind?


rasputin1963

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SONAR 8 allows you to treat an audio track with several different dithering modes, namely:

  • None

  • Rectangular

  • Triangular

  • Powr-1

  • Powr-2

  • Powr-3
Do these different types mean anything to you? In what mixing/mastering circumstances should one deploy each kind? Does it make a big rip o' difference? :confused:

 

Yes, I know what dithering is for: digital recording tends to lock a wave into square-like forms which sound bad; dithering keeps your wave more pleasantly "messed up"--- almost in a quasi "analog" style--- across your available bits. Right?

 

 

Or are you one of those folks who reckons that dithering is a legacy of cruder digital recording times, and that it is hardly needed at all anymore these days?

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Yes, I know what dithering is for: digital recording tends to lock a wave into square-like forms which sound bad; dithering keeps your wave more pleasantly "messed up"--- almost in a quasi "analog" style--- across your available bits. Right?

I never quite heard that analogy before. Dithering is simply adding noise to the wave form. Here's a more detailed explanation.

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F1

 

 

 

Dithering


Dithering--whenever an audio signal is converted from a higher-bit resolution to a lower resolution, it is necessary to apply dither to avoid introducing undesirable quantization noise or harmonic distortion into the signal. The purpose of dither is to reduce the resulting distortion by adding low-level random noise or "dither" to the audio signal. Different mathematical calculations are used to generate dither, each method has advantages and disadvantages depending on the particular operation. SONAR Producer features the Pow-r dithering process, short for Psycho-acoustically Optimized Wordlength Reduction, which can produce lower-bit files that sound indistinguishable from higher-bit source files. When this option is turned on, SONAR uses dithering when you export a higher-bit file at a lower resolution, or lower the bit depth of a project's audio files by using the
Tools-Change Audio Format
command, or when you "render" audio (bounce, freeze, or apply effects).

SONAR Producer offers five kinds of dithering:


    • Rectangular
      --essentially white noise, no noise shaping. Advantages: least CPU-intensive, lowest signal-to-noise ratio, preferable to shaped dither when successive dithering can occur (e.g. bouncing, freezing). Disadvantages: suffers from intermodulation distortion, higher perceived loudness than Pow-r dither.

    • Triangular
      --higher level than rectangular, no noise shaping. Advantages: low CPU-intensive dither, superior to Rectangular as it does not suffer from modulation noise effects. Preferable to shaped (Pow-r) dither when successive dithering can occur (e.g. bouncing, freezing). Disadvantages: higher perceived loudness than Pow-r dither.

    • Pow-r 1-
      -noise-shaped dither. Advantages: less CPU-intensive than Pow-r types 2 and 3, lower perceived loudness than Rectangular or Triangular. Disadvantages: less noise shaping than Pow-r types 2 and 3, not recommended for operations where dither will be applied successively (e.g. bounce and freeze).

    • Pow-r 2
      --noise-shaped dither. Advantages: lowest perceived loudness, highest quality settings, recommended for audio export. Disadvantages: highest CPU-intensive settings, not recommended for operations where dither will be applied successively (e.g. bounce and freeze).

    • Pow-r 3
      --same as Pow-r 2 except most CPU-intensive and transparent of all choices.
To Choose Dithering Options

  • Open the Audio Options dialog (
    Options-Audio
    command).

  • On the Advanced tab, under Playback and Recording, choose the kind of dithering you want in the Dithering field.

  • Click OK.

That's from Sonar 6 Producer. You'll want to check your own HELP SYSTEM files for updated info.

 

 

Really, you should consider checking the online help before making these information requests. And if you don't find all you need, I'd recommend our friends Wikipedia and Google.

 

I understand that newbs don't always no where to look -- but you are hardly a newb.

 

As my old man said, look it up... it's good for you.

Great advice.

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F1



That's from Sonar 6 Producer. You'll want to check your own HELP SYSTEM files for updated info.


I find myself wondering, did it occur to
you
to just look up
dithering
in the
online help
?


This kind of request for info really perplexes me when the means of informing oneself is as close as the F1 key. (And, of course, if one were looking for more info, there's always our friends, Wikipedia and Google.)

 

Sonar's helpfiles are famous for remaining mute on all kinds of important ideas.... and for often giving only cryptic, monosyllabic hints as to what all their nomenclature means.

 

Simply by force of habit (ie., being repeatedly disappointed and/or stymied by their helpfiles), not laziness as such, encouraged me to bring up this topic here.

 

Thanks for publishing this info, blue. I'll look before I bring it up here in future.:facepalm:

 

blue, by all means, go on to read the threads that interest you more... the threads more relevant to Sound/Stage/Studio. You know, like Henry Gibson's death. :p

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Do these different types mean anything to you? In what mixing/mastering circumstances should one deploy each kind? Does it make a big rip o' difference?
:confused:

 

LOL, here we go again.

 

For pop music recorded at sensible levels dither makes no difference. I'm assuming you can't hear any difference either, otherwise you wouldn't be asking. :D

 

Here's my contribution:

 

Dither Report

 

--Ethan

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blue, by all means, go on to read the threads that interest you more... the threads
more
relevant to Sound/Stage/Studio. You know, like Henry Gibson's death.
:p

 

 

Virtually everything I know about Sonar was learned from using the program and looking things up in the Help system. So, while I agree that, at times, it could be better, it's an invaluable resource and I would urge you for your own convenience to adhere to your new resolution to check it as a first-look resource. :)

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    Yes, i know this dithering algorithm.

     

    You decide by ear what type is the best for a specific situation when you change the bit rate.

     

    Yes, it makes a difference which type of dithering you are using. You can preview the sonic quality of the dithered audio by soloing the dither algorithm, but I don't know if this feature is available in Sonar.

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David

 

Dither is not explained in any digital music production software manuals, or help file.

 

When you record and produce music in 24-bit with your digital music production software, then you re-quantize the final master to 16-bit for the compact disc release.

 

Throughout the production process you may work with a greater number of bits to represent the sample, e.g. 24-bit. However, the final version of the music for CDA (compact disc audio) contains only 16 bits per sample, therefor in the end, the digital data must be reduced (truncated) to 16 bits for pressing onto a CD.

 

Dither is an intentionally applied form of masking noise, used to randomize quantization error, in other words, the quantization error get masked with random noise which is more pleasant to the ear then the quantization error.

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I don't have a problem at all with the topic being brought up here, because many programs offer similar options, and this is good general information.

 

Dither can make an audible difference with acoustic, well-recorded classical music recordings. But as Ethan pointed out, in many cases sounds happening at that low a level are masked by other sounds, or even by background noise in your environment.

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Auditioning/testing dither

 

 

WaveLab has a hidden feature for auditioning/testing dither. To perform the test in real time, you need to have some bit-reduction plug-in, such as Waves L2 Ultramaximizer software version, and tell it to decimate to 16 bits, but turn off all its dither and noise-shaping.

 

To engage the hidden test mode in WaveLab:

 

press and hold CONTROL and SHIFT

while clicking on Options/Preferences

 

You will notice that the Preferences dialog does not open. That is your clue that you have entered into dither test mode. Now be sure you have told the plug-in to reduce the bit depth to 16 bits. You may want to open WaveLab's bit meter to verify. Now play a 24-bit file and listen to the quantization distortion. You may want to reduce the level of the track even further so the distortion is audible practically all the time. In fact, you can even turn it down until it's essentially unintelligible from the distortion. Pretty nasty-souding stuff, isn't it?

 

Now, if you're using Waves L2, engage Type 1 dither. Hear the noise? But do you also hear how the signal is now intelligible right through the noise! Now try noise-shaping and hear what that does. Basically it filters the dither, and pushes more of the energy up into the harder to hear higher frequencies. Waves Type 1/Ultra is very effective at removing quantization error, without being audible at normal listening levels.

 

It is this capacity of the human ear/brain to distinguish signal from noise, even when the signal is lower in level than the noise, that makes dither work.

 

A common misconception about dither is that it only modulates the least significant bit. Actually it modulates all bits! As a result, quantization error at higher bit levels is also largely eliminated, and microdynamic signal fluctuations smaller than actual adjacent bitscale values can be preserved, resulting in a greater clarity and detail at all levels, not just the lowest.

 

Since noise-shaping is basically filtering, 9th-order noise-shaping is simply dither that has been filtered with a 9th-order (very steep) filter. That allows the dither energy to be kept well away from the frequencies at which human hearing is most sensitive. Weiss designed Pow-r dither Type 3 that way, and Waves Type 1 Ultra is that way. Nobody's really sure how Apogee's UV22HR (both available in WaveLab) works (except Apogee, and they're not talking), but I rather like it on a lot of things.

 

That brings me to the final point. To get out of the test mode in WaveLab, just press and hold CONTROL and SHIFT while clicking Options/Preferences again. Again you will see that the dialog does not open. You should be in normal playback mode now. With this test you have been looking at your sound picture through a magnifying glass. But now you know what's happening at the lower levels, and can understand that a similar enhancement is taking place at all levels.

 

I would suggest that when you do conversions between 24-bit sources and 16-bit output files, always audition a couple of dither options to see if you or your assistants can hear a difference between various dithers. I personally alternate between Waves Type 1/Normal, Waves Type 1/Ultra, and UV22HR.

 

 

 

 

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Auditioning/testing dither

 

 

WaveLab has a hidden feature for auditioning/testing dither. To perform the test in real time, you need to have some bit-reduction plug-in, such as Waves L2 Ultramaximizer software version, and tell it to decimate to 16 bits, but turn off all its dither and noise-shaping.

 

To engage the hidden test mode in WaveLab:

 

press and hold CONTROL and SHIFT

while clicking on Options/Preferences

 

You will notice that the Preferences dialog does not open. That is your clue that you have entered into dither test mode. Now be sure you have told the plug-in to reduce the bit depth to 16 bits. You may want to open WaveLab's bit meter to verify. Now play a 24-bit file and listen to the quantization distortion. You may want to reduce the level of the track even further so the distortion is audible practically all the time. In fact, you can even turn it down until it's essentially unintelligible from the distortion. Pretty nasty-souding stuff, isn't it?

 

Now, if you're using Waves L2, engage Type 1 dither. Hear the noise? But do you also hear how the signal is now intelligible right through the noise! Now try noise-shaping and hear what that does. Basically it filters the dither, and pushes more of the energy up into the harder to hear higher frequencies. Waves Type 1/Ultra is very effective at removing quantization error, without being audible at normal listening levels.

 

It is this capacity of the human ear/brain to distinguish signal from noise, even when the signal is lower in level than the noise, that makes dither work.

 

A common misconception about dither is that it only modulates the least significant bit. Actually it modulates all bits! As a result, quantization error at higher bit levels is also largely eliminated, and microdynamic signal fluctuations smaller than actual adjacent bitscale values can be preserved, resulting in a greater clarity and detail at all levels, not just the lowest.

 

Since noise-shaping is basically filtering, 9th-order noise-shaping is simply dither that has been filtered with a 9th-order (very steep) filter. That allows the dither energy to be kept well away from the frequencies at which human hearing is most sensitive. Weiss designed Pow-r dither Type 3 that way, and Waves Type 1 Ultra is that way. Nobody's really sure how Apogee's UV22HR (both available in WaveLab) works (except Apogee, and they're not talking), but I rather like it on a lot of things.

 

That brings me to the final point. To get out of the test mode in WaveLab, just press and hold CONTROL and SHIFT while clicking Options/Preferences again. Again you will see that the dialog does not open. You should be in normal playback mode now. With this test you have been looking at your sound picture through a magnifying glass. But now you know what's happening at the lower levels, and can understand that a similar enhancement is taking place at all levels.

 

I would suggest that when you do conversions between 24-bit sources and 16-bit output files, always audition a couple of dither options to see if you or your assistants can hear a difference between various dithers. I personally alternate between Waves Type 1/Normal, Waves Type 1/Ultra, and UV22HR.

 

 

 

 

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Auditioning/testing dither

 

 

WaveLab has a hidden feature for auditioning/testing dither. To perform the test in real time, you need to have some bit-reduction plug-in, such as Waves L2 Ultramaximizer software version, and tell it to decimate to 16 bits, but turn off all its dither and noise-shaping.

 

To engage the hidden test mode in WaveLab:

 

press and hold CONTROL and SHIFT

while clicking on Options/Preferences

 

You will notice that the Preferences dialog does not open. That is your clue that you have entered into dither test mode. Now be sure you have told the plug-in to reduce the bit depth to 16 bits. You may want to open WaveLab's bit meter to verify. Now play a 24-bit file and listen to the quantization distortion. You may want to reduce the level of the track even further so the distortion is audible practically all the time. In fact, you can even turn it down until it's essentially unintelligible from the distortion. Pretty nasty-souding stuff, isn't it?

 

Now, if you're using Waves L2, engage Type 1 dither. Hear the noise? But do you also hear how the signal is now intelligible right through the noise! Now try noise-shaping and hear what that does. Basically it filters the dither, and pushes more of the energy up into the harder to hear higher frequencies. Waves Type 1/Ultra is very effective at removing quantization error, without being audible at normal listening levels.

 

It is this capacity of the human ear/brain to distinguish signal from noise, even when the signal is lower in level than the noise, that makes dither work.

 

A common misconception about dither is that it only modulates the least significant bit. Actually it modulates all bits! As a result, quantization error at higher bit levels is also largely eliminated, and microdynamic signal fluctuations smaller than actual adjacent bitscale values can be preserved, resulting in a greater clarity and detail at all levels, not just the lowest.

 

Since noise-shaping is basically filtering, 9th-order noise-shaping is simply dither that has been filtered with a 9th-order (very steep) filter. That allows the dither energy to be kept well away from the frequencies at which human hearing is most sensitive. Weiss designed Pow-r dither Type 3 that way, and Waves Type 1 Ultra is that way. Nobody's really sure how Apogee's UV22HR (both available in WaveLab) works (except Apogee, and they're not talking), but I rather like it on a lot of things.

 

That brings me to the final point. To get out of the test mode in WaveLab, just press and hold CONTROL and SHIFT while clicking Options/Preferences again. Again you will see that the dialog does not open. You should be in normal playback mode now. With this test you have been looking at your sound picture through a magnifying glass. But now you know what's happening at the lower levels, and can understand that a similar enhancement is taking place at all levels.

 

I would suggest that when you do conversions between 24-bit sources and 16-bit output files, always audition a couple of dither options to see if you or your assistants can hear a difference between various dithers. I personally alternate between Waves Type 1/Normal, Waves Type 1/Ultra, and UV22HR.

 

 

 

 

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Something said earlier in this thread has confused me a little - Alndln2 said

 

"Anyway, I couldn't tell you the difference between the noise algorithms that Sonar offers, only that PowR-3 seems to work best for me when dithering from 64 bits down to anything else(24/16 etc.). "

 

Sonar has a 64 bit mix engine, if I understand correctly. But I thought that was just like a 32 bit float - it only makes a difference if you have samples going over 0dbfs, giving you extra headroom rather than just hard clipping when you're mixing. That lead me to believe that since my master buss always has headroom to spare, I'm effectively working at 24 bits so when I bounce to a 24 bit stereo file there'd be no need to use dither. Am I confused and wrong? :confused:

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