Dither question for PROS using ProTools

[Taurean]

Ah I didn't know that ProTools was different. I'm fairly certain in Sonar everything is run at 32, and, when you have the double precision engine engaged, 64 if the plugins can take it. You can have a track in the red as much as you like, as long as it's routed tot he master and you pull the master fader down, there's no clipping on the output.

Is that aspect the same in ProTools?



Well, there's nothing "harmonically off" about dither. It's noise that's added to prevent harmonic distortions.
Furthermore, you might get an idea of "what to listen for" for something that wasn't dithered by using a lo-fi plugin that lowers bit depth. Just lower the bit depth a lot and you'll hear all sorts of stuff.

In any fixed system such as Pro Tools HD, it's always good practice to properly "gain stage". Watch the red at the tracks and at the master. In general it's just good to not "run red" any time. You know some of those original practices are just fundamentally sound.

At the heart of it, dither is noise. Just remember it doesn't "prevent" distortions. It uses a masking principle to essentially mask distortion created by truncation.

 

[gabriel g.]

YOU CAN HEAR the effect dithering does!!!!

Take a piano note with a long sustain. record this note, and wait about 1-2 minutes before stopping record.
(record in 24bit)

Now make a bounce with dithering and without dithering down to 16bit.

Turn your monitors up as loud as you can when the piano hit is fading out to compensate the volume difference.

And then judge for your own. Dithered audio is sounding more natural at this point, because the extra noise fits better with the natural noise of the monitors, Hifi, amplifier......

cheers

 

[Melodeath]

In any fixed system such as Pro Tools HD, it's always good practice to properly "gain stage". Watch the red at the tracks and at the master. In general it's just good to not "run red" any time. You know some of those original practices are just fundamentally sound.

At the heart of it, dither is noise. Just remember it doesn't "prevent" distortions. It uses a masking principle to essentially mask distortion created by truncation.

I'm not sure exactly what "fixed system" means.

Gain staging makes a lot of sense in a lot of situations (mostly hardware). I'm just saying I don't think it always applies, especially in a DAW like Sonar.

 

[Taurean]

I'm not sure exactly what "fixed system" means.

Gain staging makes a lot of sense in a lot of situations (mostly hardware). I'm just saying I don't think it always applies, especially in a DAW like Sonar.

Fixed, meaning fixed versus floating point.

Gain staging is important to always have in mind. The fundamentals of actual audio engineering include gain staging and it's not a bad habit to have. And in the post modern "engineering" world, where that term can be used very loosely, gain staging can still be useful for in the box elements that still need to be carefully staged to prevent clipping, for example plugins that do not use internal floating point resolution or digital hardware and also useful for hybrid setups incorporating analog hardware, as you even mentioned. Any factor at the heart of the craft of audio engineering applies.

 

[Melodeath]

True. I was talking about stuff that's entirely ITB and 32 or 64 bit internal processing. Perhaps I didn't make that clear.

 

[Fox Mulder]

Dither really comes in handy when there are few moments of silence here and there in any given song. It becomes apparent with fade-outs as well. Dither is least needed with metal mixes which are usually very cluttered, but we need them anyways. Hope this helps: http://www.izotope.com/products/audio/ozone/OzoneDitheringGuide.pdf

 

[chonchball]

YOU CAN HEAR the effect dithering does!!!!

Take a piano note with a long sustain. record this note, and wait about 1-2 minutes before stopping record.
(record in 24bit)

Now make a bounce with dithering and without dithering down to 16bit.

Turn your monitors up as loud as you can when the piano hit is fading out to compensate the volume difference.

And then judge for your own. Dithered audio is sounding more natural at this point, because the extra noise fits better with the natural noise of the monitors, Hifi, amplifier......

cheers

This is a great tip, thank you I'm going to try this!
I always learn better with a practical application, rather than a lot of talk on the subject anyhow!

 

[Melodeath]

I just wanted to reiterate something. Dithering is to be used whenever you lower the bitdepth. Dithering only once is not a rule like dithering when you reduce wordlength is.

It makes sense to dither as few times as possible, I think, since the noise would add up over time, but you should dither any time you lower the bitdepth. That's the point of dithering.

 

[chonchball]

so only bit depth, not bitrate?

 

[Melodeath]

What do you mean by bitrate?

Bit depth as in 24 bit, 16 bit, etc.

 

[Metaltastic]

Yup, 44.1/48/88.2 etc. is sample rate, AKA the amount of times the analog waveform is "sampled" per second, whereas the bit depth is simply how long the binary word can be, which determines amplitude/volume and thus dynamic range (cuz with a longer word, there can be a shitload more detail)

 

[Caustica]

Alright, I spoke to a colleague today who used to work for digidesign. Both protools HD and LE systems record in 24-bit fixed point. So all the audio files have this bit-depth. This is then converted to 32-bit or 48-bit for internal processing. So any kind of processing you use on it converts the file to and from these bit-depths.

Now what I meant when I said dither only once was in the signal chain. Every time you convert something you definitely should dither it. But if you have multiple plug-ins with dithering on a master buss only one of them should have dither switched on.

 

[Melodeath]

Alright, I spoke to a colleague today who used to work for digidesign. Both protools HD and LE systems record in 24-bit fixed point. So all the audio files have this bit-depth. This is then converted to 32-bit or 48-bit for internal processing. So any kind of processing you use on it converts the file to and from these bit-depths.

Now what I meant when I said dither only once was in the signal chain. Every time you convert something you definitely should dither it. But if you have multiple plug-ins with dithering on a master buss only one of them should have dither switched on.

Yes.

Oh and if you dither on your last plugin, I would turn dithering off in the PT options (I assume ti has dithering options for export), unless you're fader after the last plugin is not at 0, or adding some other signal.

 

[chonchball]

all of this has been extremely helpful and i appreciate the information! thank you for helping me understand more fully.

I now need to research fixed and floating points... with every answer comes another question