Record 16bit, Export 16bit - needs dithering??

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batman144144
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Record 16bit, Export 16bit - needs dithering??

Post by batman144144 » Wed Jan 13, 2016 7:23 pm

I'm recording from an analogue line source into a Focusrite 2i2. I set up my Preferences in Ableton Live 9 Lite for 44.1khz/16bit. When I export in wave, I keep it at 16bit, but Ableton is telling me it's dithering. Why?? I'm exporting at the same bit depth as I recorded at, so why the dithering? The only editing I'm doing to the original recorded signal is splitting the clip into segments with the Split command. Split is supposed to be a neutral operation. If I switch to 32bit at export, even though I recorded at 16, Ableton will not dither. Doesn't this mean it actually captured the signal at 32bit even though I selected 16? I'd like to avoid dithering altogether, but the source material does not need anything higher than 16. Anyone have any idea what's going on??
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Re: Record 16bit, Export 16bit - needs dithering??

Post by Tarekith » Wed Jan 13, 2016 7:49 pm

Ableton does everything internally at 32bit, so even though your source and end result is 16bit, all the calculations inbetween were done at a greater bit depth.
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batman144144
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Re: Record 16bit, Export 16bit - needs dithering??

Post by batman144144 » Wed Jan 13, 2016 8:10 pm

Tarekith wrote:Ableton does everything internally at 32bit, so even though your source and end result is 16bit, all the calculations inbetween were done at a greater bit depth.
So, the one and only way to not dither my output is to record and export at 32bit. Actually, it sounds like it doesn't matter what bit depth I tell it; Ableton is going to record at 32bit no matter what. Is this correct? What's the point of offering bit depth choices in Preferences? I'm not saying you're incorrect; I just don't understand. Okay, so, my only choice with Ableton Live is exporting at 32bit, or being forced to accept dithered output of some lower bit rate?

Actually, now that I think about this, it may be worse than I thought. There may be even more unnecessary processing going on. If I set my preferences in Ableton to 16bit, my Focusrite 2i2 will feed Ableton a 16bit signal, I assume. Ableton, however, only handles things in 32bit. Therefore, it processes the input signal from the very start to bring it up to 32bit from 16. Then, if I tell it to export to 16bit, it further processes and potentially mangles the data yet again to bring it back to 16bit. Wouldn't you be better off just feeding Ableton a 32bit stream to avoid it doing an upconvert to 32? You would avoid further unnecessary processing of the data, right?
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Re: Record 16bit, Export 16bit - needs dithering??

Post by Tarekith » Wed Jan 13, 2016 9:35 pm

Slow down batman. :) Live will record at whatever bit depth you specify, but it does all of it's processing at 32bit though, sometimes in case of the mixer functions as 64bit even. This is a very GOOD thing, lower noise floor, cleaner processing. Dithering in the situation you're talking about is not a concern at all, it's your final render, and dither from a higher to lower bit depth is almost always the best way to approach things.

I can guarantee you Live wouldn't do it if it was harming the integrity of your audio :)
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Re: Record 16bit, Export 16bit - needs dithering??

Post by batman144144 » Wed Jan 13, 2016 10:38 pm

Tarekith wrote:Slow down batman. :) Live will record at whatever bit depth you specify, but it does all of it's processing at 32bit though, sometimes in case of the mixer functions as 64bit even. This is a very GOOD thing, lower noise floor, cleaner processing. Dithering in the situation you're talking about is not a concern at all, it's your final render, and dither from a higher to lower bit depth is almost always the best way to approach things.

I can guarantee you Live wouldn't do it if it was harming the integrity of your audio :)
Okay, I'll try to slow down. I'll give it a shot.

If Live will record at whatever bit depth I tell it, and I then attempt to export at that same depth (and the only editing I've done is the Split command --in some cases, no editing whatsoever), why does Live dither the output :?: :?:
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Re: Record 16bit, Export 16bit - needs dithering??

Post by Angstrom » Thu Jan 14, 2016 12:12 am

It seems like you arent understanding what dithering is.

It's applied to the lowest db of the signal, to stop a truncation from (for example) -96db to -inf

Without dithering any wave crossing that boundary would be as grainy as fuck. This process smooths that boundary. More accurately : From just above -96 to 96. Nothing much more than that is happening. All the "noise shaping" terms relate to psychoacoustics and are really niceties as linear boundary smoothing is adequate.

Do you need it if you are recording at 16bit and destined for 16 bit? Yes. Very much. You do.
At some points Abletons mixer is mixing signals at 64 bit resolution, in other areas the mix processing is at 32bit

If you take 2 16 bit signals and lower the volume of one of them by -12 db then compress the master Do you really really want that processing done with 16bit word length. You answer should be FUCK NO. You'd just truncate the lower half of the dynamic range and then make that truncation audible. You need 32 bit mixing.

Consequently Live maintains a very healthy dynamic range while in the realm of floating point calculation and summing. When its time to render the sums it ensures the quitest signals dont sound like hail on a tin roof by dithering them to the intended wordlength. This is good.

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Re: Record 16bit, Export 16bit - needs dithering??

Post by Stromkraft » Thu Jan 14, 2016 12:52 am

batman144144 wrote:I'm recording from an analogue line source into a Focusrite 2i2. I set up my Preferences in Ableton Live 9 Lite for 44.1khz/16bit.
Why are you recording at 16bits anyway?
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Re: Record 16bit, Export 16bit - needs dithering??

Post by batman144144 » Thu Jan 14, 2016 3:54 am

Angstrom wrote:It seems like you arent understanding what dithering is.
Probably not. I don't work in the pro audio industry. I'm just an audio enthusiast doing some digital recording. My understanding was that dithering was only needed when going from higher bit length to lower.
Do you need it if you are recording at 16bit and destined for 16 bit? Yes. Very much. You do.
At some points Abletons mixer is mixing signals at 64 bit resolution, in other areas the mix processing is at 32bit
Maybe I don't understand what is meant by "mixing." I only have one track. I only have one clip. I'm not mixing different tracks together. My entire Live project consists of a single stereo track. That's it. That's all. I'm not doing anything more than digitizing an analogue signal and then exporting it to a file. What additional manipulation is required? Please understand, I'm not arguing with you. I'm just trying to understand. I guess there's some processing going on I don't know about.
If you take 2 16 bit signals and lower the volume of one of them by -12 db then compress the master Do you really really want that processing done with 16bit word length.
You're talking about non-neutral operations that fundamentally alter the original waveform. I'm just trying to export the original signal.

Let me put it this way: You record a conversation in Live. Maybe you trim off the dead air at the beginning and the end just to make it nice. Then you export it at the same sample rate and bit depth as the original recording. Why do you need dithering? (Again, not arguing, just trying to understand.)
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Re: Record 16bit, Export 16bit - needs dithering??

Post by batman144144 » Thu Jan 14, 2016 3:59 am

Stromkraft wrote: Why are you recording at 16bits anyway?
Because the material I'm dubbing is already mixed and mastered.
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Re: Record 16bit, Export 16bit - needs dithering??

Post by Stromkraft » Thu Jan 14, 2016 10:15 am

batman144144 wrote:
Stromkraft wrote: Why are you recording at 16bits anyway?
Because the material I'm dubbing is already mixed and mastered.
That is in my ears not a valid explanation at all. It's an analogue signal you say. This means you want to capture as much of that as possible. To retain great fidelity with recording in 16 bits you need to record hot, with 24bit you don't have to. That's a big part of the 24bit revolution. I assume you don't only have a 16bit audio interface here, and that it's a 24bit interface.

No matter what tool you use you ought do yourself a service and record in 24bits. Yes, if you want to have a final product in 16bits you need to dither and there is no problem with that. Unless you intend to reprocess your recording, in which case you need to record with something else than Live and keep the 24bit recording not dithered if possible. However, dithering is on such low volume levels that one could likely reprocess a dithered product and re-dither at the final stage and no-one would be any wiser on the fact that this re-processing had happened.

I have DJ friends that record their vinyl, always at 24bits, because they prefer the freedom of digital. 24bit gives them the headroom to make the best possible final file without risking digital clipping at the recording stage. It also gives a greater possibility to improve these recordings should they wish.
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Re: Record 16bit, Export 16bit - needs dithering??

Post by batman144144 » Thu Jan 14, 2016 6:36 pm

Stromkraft wrote:That is in my ears not a valid explanation at all. It's an analogue signal you say...
Thank you for taking the time to respond. However, rather than answer your post directly, if I may, I'd like to stay focused on the issue at hand. Why does Live dither an unaltered waveform? Does it just automatically upconvert every signal to 32bit and that's why it needs to dither down to the other bit depths?
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Re: Record 16bit, Export 16bit - needs dithering??

Post by batman144144 » Thu Jan 14, 2016 6:52 pm

Tarekith wrote:Live will record at whatever bit depth you specify, but it does all of it's processing at 32bit though, sometimes in case of the mixer functions as 64bit even.
Okay, then, two questions: 1) What if the only "processing" needed is to export the waveform? 2) If Live is going to manufacture a 32bit version no matter what for processing, would it not be better to just record in 32bit in the first place?
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Re: Record 16bit, Export 16bit - needs dithering??

Post by Tarekith » Thu Jan 14, 2016 8:55 pm

Seriously man, you're way overthinking this and worrying about things in the realm of mathematics, and not music or even sound quality. I say that as someone who makes a living making things sound as good as they can. Live will use higher bit rate processing when appropriate, it will also add dither when appropriate. Neither of these things has any possible negative impact on the sound quality of your music, in fact they only ensure the highest sound quality. This is standard behavior for most DAWs and most DSP processing, it's just not briefly shown to you in a pop up like Live does sometimes.

The fact that we as musicians even know these terms only points to manufacturers trying to push this stuff on us as having a real impact on what we make. Dither is, hands down, the very last thing anything any musician should have to give any thought to. It's sonic impact is statistically and sonically irrelevant. If people weren't trying to sell mastering plug ins to supposed golden ear know it alls, this stuff would all be happening behind the scenes the way it should.

I'm not trying to be dismissive of your curiousity to learn more, but at the scale you're stressing over there is NO, NONE, ZERO, impact to what you or anyone can hear except to make it better. Higher bit depths in certain stages of the process lower the noise floor of digital processing, dither is the same for all intents and purposes.

Recording at 32bit realistically doesn't buy you anything versus recording at 24bit and just making sure you're not clipping (mathematically on paper maybe, audibly no). If you want the simplest option and can't check if you're clipping, then recording at 32bit is the easy way to that end. It's dumb to not follow basic audio engineering principles though, namely don't clip. Anywhere, really not that hard to do in use. Do that, and 24bit is perfect, no need for the 8 extra bits. LSB, MSB, etc.

Just my $0.02.
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Re: Record 16bit, Export 16bit - needs dithering??

Post by batman144144 » Thu Jan 14, 2016 10:48 pm

Tarekith wrote:I'm not trying to be dismissive of your curiousity to learn more, but at the scale you're stressing over...
I don't know; I guess my persistence makes it look as though I'm "stressed?" I'd just like to know why Live behaves the way it does. I'd like to understand the software I'm using, particularly when it behaves in a way I didn't expect.

Everyone seems to be saying, "Hey, just trust the software. It's doing what's best." Okay. I do trust the software. I'd still like to understand what's going on. If all I'm doing is recording and then exporting -- no processing, no mixing, no folding down, no non-neutral operations whatsoever on a single, simple stereo track -- why does Live say, "Converting bit depth with Dithering"? Well, I have no intentions of converting bit depth, so that makes me stop and say, "Hey, wait a minute. Why does bit depth conversion and dithering even enter the picture?"
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Re: Record 16bit, Export 16bit - needs dithering??

Post by H20nly » Thu Jan 14, 2016 11:31 pm

Live is acting the way it does... to do the best job possible of preserving the integrity of your audio.

dithering enters the picture because the Bizzaro-alterwold-you demands dithering. Ableton is doing the best they can with his audio too.

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