September 25, 2007

Dither this...

by Chris Randall
 



Has anyone here tried the Crane Song analog dither CD, and if so, does it work as advertised? I realize that statements like "warmer, fuller, nicer" are subjective, but for the sort of people that would order and use something like this in the first place, I would expect the ability to make a statement to the effect of "it's better than UV22HR because..." or something like that.


I suppose at thirty bucks, it's kind of a no-brainer, and I guess I'll just order it and try it out for myself, but I'm curious as to whether it adds Magic Smoke or not.

 
 
 

20 comments:

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Sep.25.2007 @ 10:55 PM
Dale
Ooops. What I was trying to type was... If you create a 24bit sine wave at +23db then downconvert to a 16bit sine wave without dither, you will hear the new sounds of distortion. The randomness of the dither noise helps 'smear' the distortion so it's warmer to ear.
 
 

 
Sep.25.2007 @ 11:19 PM
Chris Randall
I imagine the readers of this blog fall in to two categories: a minority, consisting of those who know what dither is for and why it is necessary, and a majority, consisting largely of those who don't give a fuck.

Anyone that has read the manual for their square-wave-creator... err... I mean "mastering limiter" of choice should have a fairly good idea of the what and why of dither. I will agree with the earlier comment that the artifacts created by bit reduction will largely fall under the noise floor when lossy compression is applied, but that said, your master should at least begin life as a CD-ready 44.1/16 WAV/AIFF, and that should have at least been recorded and mixed at 44.1/24, if not 48/24.

That being the case, well, it's just another part of the toolkit. An interesting point comes up, though. When you render straight from your DAW to 44.1/16, when you recorded at 44.1/24 or whatever, did you notice the "dither" dropdown in the export menu? Did you make a selection? Did you also have a dither selected in your 2-buss compressor/limiter? Exactly how many dithers are you using at any given time? I know I've accidentally rendered with three, then another one in the mastering limiter as I was baking the CD. Obviously, it doesn't affect the file that iTunes sells in the least, but it is food for thought.

In any event, this seems like a fairly simple way to have a little bit of control over the dither, instead of just a checkbox, so I find it an interesting subject.

-CR

 
 

 
Sep.26.2007 @ 8:45 AM
giantm
I guess what you're avoiding here is what I'm assuming would be FFT / IIR / FIR / floating point error artifacts that come with digitally filtering and mixing what is generally a mostly random noise signal. However, without knowing how other dithers work, it's hard, or impossible, to make a technical comparison.

And, in retrospect, mixing in a product with a floating point mix bus would be bad again as it would most likely introduce another word length conversion after the dither signal had been added. So, really a program that just does an addition of the final 2 16 bit signals would be the ideal. The master of the track shouldn't exceed -.1 dBFS. In that situation, the dither should be able to be added without overs, which would probably be inaudible, occurring. Pretty much any other process is going to add back in floating point error and the like.

It's really hard to justify the work when we're dealing with what is more or less intended to be a "random" signal. Maybe I'll have to write said program and order the CD. A little java tool to add 2 raw 16 bit integer streams would be easy enough to write.

 
 

 
Sep.26.2007 @ 8:58 AM
puffer
I think I fall sort of between your two categories. I know (essentially) what dither is and what it's for. But because so much of it happens beyond what I can actually perceive I don't worry about it too much. I work at 44.1/24, and export to a 32bit wav. In SF I run my "mastering" chain on the 24bit file. Then I do the sample rate conversion with a noise-shaped dither directly from the SF process menu. Then I save as a 16bit wav. Sonar has an option that you can run dither through the whole process which I keep turned off, as I do when I export. What I always wonder is what's happening if I save a 24bit directly to 16bit without dither or bit depth conversion: does SF apply a dither or does that info just get chucked? Or does SF "know" it's down converting and apply a dither? I wonder because, if the latter than is it applying another dither when I save the 16bit file? I've never been able to get a straight answer on that one.
 
 

 
Sep.26.2007 @ 10:43 AM
D' MacKinnon
I've been wanting to pick up a FreqBox but none of the local music gear shops carry it and I've been too lazy to order it online.

Personally, I keep all my files at 24bit until mastering and then I use Ozone's MBit+

 
 

 
Sep.26.2007 @ 10:51 AM
Crashproof
Or we know what dither is for, but don't give a fuck because we make noisy glitchy stuff and often add digital noise, or run the whole mix through a ringmod or bitcrusher and mix that in, just to tweak noses.

Though there's a fine line between what sounds bad in a good way, and what sounds bad in a shitty way.

Sometimes I'll quasi-dither by using a just-slightly-audible stereo recording of the fan in my laptop, or the wind or something.

I do wonder what's so magical about this particular recording of analog noise, that you couldn't do yourself with a synth or running water or just about anything. This CD has a faint whiff of Silver Rock Signature Knob about it...

 
 

 
Sep.26.2007 @ 12:12 PM
Chris Randall
Yes, it would, except that then the CD would be $3000.

And the Silver Rock Signature Knob works! I can totally hear the expanded soundstage.

-CR

 
 

 
Sep.26.2007 @ 2:13 PM
Gibbon
"When you render straight from your DAW to 44.1/16, when you recorded at 44.1/24 or whatever, did you notice the "dither" dropdown in the export menu? Did you make a selection? Did you also have a dither selected in your 2-buss compressor/limiter? Exactly how many dithers are you using at any given time?"

Dithering should be the last thing in your chain after sample conversion (if necessary). Dithering adds a slight veil to the sound if applied once. Normally this is acceptable, but cummulative dithering becomes quite noticeable fairly quickly and will undo any advantages you'd gain from using it in the first place.

Thes best dithering in a plugin, hands down, is izotope ozone. Their MBIT+ is based on alexey lukin's extrabit/megabitmax dithering algorithm and you get a fair degree of control with it.

Alexey has technical papers and audio comparisons here: link [audio.rightmark.or...]">link [audio.rightmark.or...]

 
 

 
Sep.26.2007 @ 2:29 PM
synthetic
There's a good article on dither at the Izotope site, their Ozone processor is the nicest-sounding mastering limiter I've used. I really can't hear it working unless I really push it hard.

As for the CD, hmm. Be sure to color the edges green with a Sharpie first.

 
 

 
Sep.26.2007 @ 4:20 PM
blinkman
It's a tragedy that our industry continues jumping through hoops to "get the most" out of Red Book CD, when

a.) digital recording and data storage tech have evolved FAR beyond 44.1/16, making viable any number of high resolution formats (with the potential to compete with even the most pristine analog tech), and

b.) the delivery format that is actually dominating the market is even *worse* than CD, and buyers don't seem to mind.

Amazingly, the bizarre partnership between the consumer electronics and entertainment industries has brought the state of the art successively *lower* since analog tape and vinyl--technologies perfected in the 1960s! We almost got a popular hi-res format (two, actually, which surely was part of the problem), but while the DVD-A spec was still being decided, the public was discovering mp3. The writing was already on the wall by the time stores were installing the obligatory three rows of DVD-A and SACD offerings. I don't know if either format can be called "dead" just yet, but neither can survive in the new age.

It's not over though. As bandwidth and storage continue to improve, we will eventually be able to download and stream uncompressed, hi-res audio, even exceeding the specs of DVD-A and SACD... But will we? Will consumers know the difference, or even take an interest? Will the market pay for yet another round of Hendrix remasters? Will listeners (and record labels) discover that playback systems have volume knobs, and that the role of mastering should not be to make EVERYTHING SOUND AS LOUD AS FUCKING POSSIBLE?

We can only hope so.

c.

 
 

 
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