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 Post subject: sample depth 32 bit, really worth it? What's the purpose?
PostPosted: Wed Oct 20, 2010 6:01 pm 

Joined: Thu Sep 30, 2010 3:26 am
Posts: 64
Hey guys

this discussion is endless I know and I've read tons of boards about sample depth, sample rate, etc & etc. My question is purely about the sample depth though, as I understand pretty much well the sample rate thing. Does it REALLY worth it to export 32 bit audio? I mean, I always thought 24 was way enough but the 32 is so tempting haha! Seriously, what's the purpose at the end of having 32 bit audio / samples? Is it for better sound manipulation with plugins and VI's? Or better general sound quality (that, honestly, I can't hear the difference!) Just curious to know if it's worth the space on my hard drive and what's the goal of having such high depth possibilities.

Your cue, your opinion and hints! Cheers guys.


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 Post subject: Re: sample depth 32 bit, really worth it? What's the purpose?
PostPosted: Wed Oct 20, 2010 7:58 pm 

Joined: Fri Jan 18, 2008 11:31 am
Posts: 70
Location: Montpellier, France
In Ableton Live (and in many others DAWs), it's worth using 32 bit format instead of 24 bit not really because of the 8 more bits you get (24 is largely enough to make good sound), but because of the floatting point aspect.

In 16/24 bit formats, numbers are stored in memory as integer values. For musicians, it means that sound can't be greater than the highest value these sample depths provide (65535 with 16 bits, 16777215 with 24 bits). This limit is called "0 dBFS" (FS means "Full Scale"). Then, if you export a part of music that exceeds this limit (for example, if you set a level fader too high), your audio file will definitely contain saturated regions!

In 32 bit format, numbers are stored in memory as floatting point values. In this format, Live's audio engine can encode very small as well as very large number values. By convention, 0 dBFS corresponds to 1.0 and -1.0 values and normally your sound shouldn't exceed this limit in order to avoid your level meters to enter the "red zone". But in fact it can, without the risk of damaging the audio signal!

Do an experiment:

- put a well recorded audio file in an audio track
- set its level fader anormally high in order to make the level meter go red
- export the result using a 32 bit format
- import the new file in a new audio track
- have a look at the waveform: it looks saturated, doesn't it?
- now in the sample window, set the clip gain a bit down
- what do you notice? The audio file is not saturated! Magic! 8O

It's because 32 bit format can encode values that are really greater than 1.0, and Live can deal with that! :mrgreen:

Do the same experiment using a 16 or 24 bit integer format and you will notice that the exported audio file is physically and definitely saturated! :x

Note: there are at least 2 cases where you won't be allowed to exceed 0 dbFS even with a 32 bit format:

- when you record audio from an physical input of your soundcard
- when you listen audio thru a physical output of your soundcard

It's just because at these stages there are electronic components called "audio converters" that always work in integer formats. So be carefull not to saturate audio signals at these 2 critical points. Inside Ableton Live, you can do virtually what you want with your levels! 8)


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 Post subject: Re: sample depth 32 bit, really worth it? What's the purpose?
PostPosted: Wed Oct 20, 2010 8:35 pm 

Joined: Thu Sep 30, 2010 3:26 am
Posts: 64
Awesome inputs with clear point, thanks! :D


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