Dithering

  • Thread starter Thread starter darnold
  • Start date Start date
sonusman,

You have opened the flood gates. Recently I did a project after re-opening my small little studio here. Well, I kept noticing (using cool edit) that way down below on the screen it was saying:

48000 - 32-bit stereo

I didnt even think about it really. I just kept trucking along. Anyway, it cam down to mixdown of this particular song and when I "converted" the sample type (which I assume is dithering) we had some problems. It sounded just fine when played as the wav file produced. But, when I burnt it to a cdrom to give it the taste test on other systems, etc I noticed a crackling sound.

I was like: "What the fuck?"

So, I messed around with crap, thought it was my burner, bought a new one. Same deal. Burned a copy of a cd. No crackling. That was when I started thinking about that 32-bit crap down at the bottom of cool edit. So, I told the band I was working with that we would come back to that one and we moved on. Got the drum tracks moved onto my machine from tape and I made sure that the new session was 48000 - 16-bit. After everyone had left I mixed down just those drum tracks and converted it to 16/44 to be burnt on a cd. I played it and lo and behold. No crackling.

So, now I have been searching for an explanation of what was going on with this so-called 32-bit resolution. AND, I am trying to figure out how I am going to save that first session without making the band do it ALL over again.

So, any thoughts?
 
Version2

Dithering and sample-rate conversion are 2 different things. Dithering is related to bit depth - which is the resolution of each sample, sample rate is the number samples per second. There is no reason why either downsampling from 48K to 44.1, or going down from 32 to 16 bit should introduce crackling into the sound. Down-sampling sometimes introduces noise in the form of unusual harmonics, but a good converter shouldn't do this. Cool-Edit's converter works fine. So something is going wrong.
 
bdemenil said:
Version2

Dithering and sample-rate conversion are 2 different things. Dithering is related to bit depth - which is the resolution of each sample, sample rate is the number samples per second. There is no reason why either downsampling from 48K to 44.1, or going down from 32 to 16 bit should introduce crackling into the sound. Down-sampling sometimes introduces noise in the form of unusual harmonics, but a good converter shouldn't do this. Cool-Edit's converter works fine. So something is going wrong.
Click to expand...

And that is what I thought I understood about the whole process so I guess my fears are valid. I dont know exactly was has happened but I cant get a mixdown to burn from that session. Now, how do I tell the client? LOL.
 
Ok, here's your cool edit 32bit description.
If you use a 24bit sound card and setup a cooledit session by selecting file/new session and choosing say, 32bit 48Khz, when you start recording it is actually recording at 24bit 48 Khz and software converting it to cooledits higher internal 32bit file format that is native to cooleditpro only. Meaning that a saved wav file mix at 32bit 48Khz wont play through any other software other than cooleditpro. You can however save your mixdown file as a 24bit file in the options box in the file saveas dialogue box. And then take your 24bit file to any mastering facility and they will be able toread it. This is how I work myself.
Cooledits 32bit file format is a very good thing to use. Even though the sound quality is no different to the 24bit that was fed to it during recording. However having the extra bits to 32bit makes the mixing of all those 32bit tracks mixdown to a better stereo mixdown. And all the plugins in cooledit will work at 32bit making them all work better than say working on a 24bit or 16bit file. Its kind of like recording at 24 or 16bit but being able to mix all this at 32bit. Brilliant and it makes a big difference so you should use the 32bit file format in cooledit no matter whether you record at 16, 20 or 24bit.
Mixing digitally is getting closer to that SSL sheen by using even higer bit depth during mixing.
When you start a new mix in cooledit by clicking in the file menu for ....file / new, you will see options for 44Khz, 48Khz right up to 192Khz but there are only options for 16bit or 32bit. No 24bit you say, well its ok. By selecting the 32bit option means that you will record at 24 bit upsampled to 32bit. Hope you understand this. Because if you are recording in cooleditpro and you dont use the 32bit option in cooledit, your not getting the best quality mixes out of it. Even if your sound card is only 16bit. Some amazing mixes have come out of cooledit pro from 16bit cards due to its 32bit internal mixing and processing.
 
Hey version2, sorry, forgot to solve your cd burning problem.
Once youve mixed down your 32bit session its still in 32bit cooledit format. Save the file and try to play it in say winamp or mediaplayer and it will just crack out loud. Probly the same sound you heard from the first of your burnt cds. That mix you did in 32bits is ok man. Just when you mix down, convert it to 16bit 44.1kHz and save that file too. Now this file will be ok to burn or playback in winamp or media player. Just test them in other software like this to see if they sound ok before you burn.

Scott
 
So Sonusman...

Just to clear things up so a child (or I) could get it.

If I record in 16/44.1 (witch I have to sadly) then I would still have to dither in the mastering process because all processing I have done in the mix would increase bit deapth?
 
Scott Tansley said:
Hey version2, sorry, forgot to solve your cd burning problem.
Once youve mixed down your 32bit session its still in 32bit cooledit format. Save the file and try to play it in say winamp or mediaplayer and it will just crack out loud. Probly the same sound you heard from the first of your burnt cds. That mix you did in 32bits is ok man. Just when you mix down, convert it to 16bit 44.1kHz and save that file too. Now this file will be ok to burn or playback in winamp or media player. Just test them in other software like this to see if they sound ok before you burn.

Scott
Click to expand...

Scott, thanks for the posts and the enlightenment. Now, here something for you to chew on. When I mixed down after my 32-bit session (now the file should be 16-bit because that is how I am set up in cool edit). Then i convert the sample to 44.1. Now, we are 16-bit/44.1 and when you play the wave through winamp/media player it sounds great (if I do say so myself). But, burn it....and KSSCHSHDSSSS. Thats that damn crackling sound. Sometimes its worse, sometimes its a little better. And I have mixed this session down several times. It happens every time.

And, as luck would have it...I have one of my mixdowns on my laptop here. When I open it up, down at the bottom in cool edit it says:

44100 - 16-bit Stereo

And this is one of the mixdowns that crackles when burnt.

Ideas?
 
yeah, i've burned 24bit wav files by mistake. It comes out as white noise.
 
bdemenil said:
yeah, i've burned 24bit wav files by mistake. It comes out as white noise.
Click to expand...

Thats the problem though. These are not 24-bit. This mix that I am burning is 16-bit at 44.1. I have verified it several times.
 
Maybe the levels are clipping.
By this I mean hitting 0 db. Load up your mixdown file and go to transform / amplitude / hard limitting and in the "limit Max amplitude to" field type in -0.2 db. leave "boost input by" at 0.
This won't change the sound much at all but it will safely keep you sound away from 0 db.
Sometimes you only hear the clipping when you burn to cd too!
 
Thanks Scott (will try it)...and everyone else, for putting up with my yapping. I am now declaring this whole ordeal a freak of nature. I dont know whats going on and I am going to stop trying to explain it and move on.

Some things are just never meant to be explained. :p
 
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