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Post by Bob Olhsson on Mar 5, 2016 22:20:14 GMT -6
Incompetent software engineering is the only reason we even need to think about dither.
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Post by joseph on Mar 6, 2016 1:00:20 GMT -6
So regardless I should dither before any DAC hardware inserts on channels or auxes as well as dither on final output to file?
Or just when there's plugin DSP on any sources in submix or channel before hardware inserts?
So if the channel is recorded 24bit, not processed ITB or gain controlled/whatever but is left alone and then has a compressor hardware insert, it doesn't need dither?
And a final mix recorded to 24bit in Logic, for example, still needs to be dithered because of the DSP in project when bounced to a 24bit file?
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Post by tonycamphd on Mar 6, 2016 10:33:24 GMT -6
So regardless I should dither before any DAC hardware inserts on channels or auxes as well as dither on final output to file? Or just when there's plugin DSP on any sources in submix or channel before hardware inserts? So if the channel is recorded 24bit, not processed ITB or gain controlled/whatever but is left alone and then has a compressor hardware insert, it doesn't need dither? And a final mix recorded to 24bit in Logic, for example, still needs to be dithered because of the DSP in project when bounced to a 24bit file? yes, exactly. At least as I understand it
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Post by Johnkenn on Mar 6, 2016 10:36:17 GMT -6
Dither is just noise, right? Other than the obvious - adding noise - I just don't see why you wouldn't just add dither to every channel and not worry about when and where?
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Post by tonycamphd on Mar 6, 2016 12:30:48 GMT -6
Dither is just noise, right? Other than the obvious - adding noise - I just don't see why you wouldn't just add dither to every channel and not worry about when and where? dither is random noise, just adding many channels of the SAME NOISE arbitrarily is not a good idea imo, if you're ITB and you have everything routed to a master channel, just use a dither plug in the last position when you're bouncing to a reduced sample rate/bit depth. If you're dumping per channel D/A to an analog summing device/console, dither every output and consider using noise shaping to push the noise up/down, then you can filter it off OTB, as again, you don't want a build up of the SAME NOISE track after track
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Dithering
Mar 6, 2016 13:08:49 GMT -6
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Post by rocinante on Mar 6, 2016 13:08:49 GMT -6
Damn. Umm.. I feel foolish as I have no idea if I have ever apllied or even considered dithering. I have not. What kind of effect does dithering every channel out (like between 16- 24 channels) have on the cpu?
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Post by tonycamphd on Mar 6, 2016 13:19:37 GMT -6
Damn. Umm.. I feel foolish as I have no idea if I have ever apllied or even considered dithering. I have not. What kind of effect does dithering every channel out (like between 16- 24 channels) have on the cpu?can't say for sure, it's the reason why i chose the PSP X-Dither, it has digital black where it shuts off the CPU usage of the channel when nothing is present, i'm pretty sure PT's also does this now as well, so a little more investigation is in order for me on this exact question.
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Post by Deleted on Mar 6, 2016 13:43:27 GMT -6
I have not felt any difference on a today's machine (i7) when routing out 24ch to console with dither on or off. I.e. TPDF dither.
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Dithering
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Post by rocinante on Mar 6, 2016 13:58:18 GMT -6
Thanks. I need to investigate further. Usually I keep it at 24/96 with 32 bit float point but it never even occurred to me other than when I am 'mastering' something.
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Post by Johnkenn on Mar 6, 2016 14:10:46 GMT -6
I'll do a 8 channel bounce with and without dither. See if anyone can tell a difference.
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Post by Bob Olhsson on Mar 6, 2016 16:03:27 GMT -6
Dither sounds like noise but noise doesn't necessarily function as dither. It needs never be the same on more than one channel.
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Post by mrholmes on Mar 6, 2016 16:30:54 GMT -6
In Bob Katz book Mastering Audio is a very good read about hw self dither. Input dithering on digital consoles or interfaces. As well as dithering in general. I did always use input dithering in the days when all my HW was hardwired to the converters. IMO it helped the image and depth.....
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Post by jazznoise on Mar 6, 2016 16:53:24 GMT -6
Incompetent software engineering is the only reason we even need to think about dither. This.
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Dithering
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Post by mulmany on Mar 6, 2016 17:59:46 GMT -6
I started dithering before all my HW inserts, and I was playing around with dithering before plugins that I found harsh or the plugin effect less noticeable. I found that dithering made a noticeable difference in both locations. I also am using the PSP x dither plug.
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Post by M57 on Mar 6, 2016 18:17:37 GMT -6
So I'm looking at the plugs that come with Logic (It pretty much comes with everything), and I'm not seeing a dither plug (It does have dithering options for bouncing but not for sends). I'm shocked. Does anyone know if there is one?
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Post by Martin John Butler on Mar 6, 2016 18:43:13 GMT -6
OK, so, I'm using Logic. I track through my preamp > compressor > EQ > Apollo > DAW. I record at a 48k sample rate. I'd do 96 but my computer's long in the tooth and chokes on it. I add some plugs here and there to tracks, a track EQ,sometimes a Waves 1176, or Puigtec maybe a guitar pedal. For reverb, I first use UAD's Ocean Way, a little Relab, on their own buses. I occasionally bounce here, and master later, but often I just mix with maybe the ATR-102 tape plugin on the 2 bus, the Slate VBC, and an Apple compressor. Then I bounce both a WAV file and mp3 at the same time to my desktop.
Do I need to dither, and if I do, where is that setting in Logic?
I would like the bounce to sound loud enough to be sent to common sources like Soundcloud, You Tube, and sound professional. Later, I may use the track as is for an album on i-tunes or run a mix at lower compression levels for a mastering engineer.
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Post by M57 on Mar 6, 2016 19:26:12 GMT -6
OK, so, I'm using Logic. I track through my preamp > compressor > EQ > Apollo > DAW. I record at a 48k sample rate. I'd do 96 but my computer's long in the tooth and chokes on it. I add some plugs here and there to tracks, a track EQ,sometimes a Waves 1176, or Puigtec maybe a guitar pedal. For reverb, I first use UAD's Ocean Way, a little Relab, on their own buses. I occasionally bounce here, and master later, but often I just mix with maybe the ATR-102 tape plugin on the 2 bus, the Slate VBC, and an Apple compressor. Then I bounce both a WAV file and mp3 at the same time to my desktop. Do I need to dither, and if I do, where is that setting in Logic? I would like the bounce to sound loud enough to be sent to common sources like Soundcloud, You Tube, and sound professional. Later, I may use the track as is for an album on i-tunes or run a mix at lower compression levels for a mastering engineer. Far be it from me to answer the question. I'm just trying to figure it all out myself, but my understanding so far is that your tracking chain is irrelevant - the outputs (and inputs) of all those devices are analog. Same for any ITB plugs you use (there's no DA/AD conversion going on). Logic lets you choose your dithering type whenever you 'bounce.' that's the only place where I see dithering options. The issue I'm grappling with is, what happens when you want to send an analog signal from a track or buss out to outboard gear, and then back into the DAW? In this case, you need to dither (preferably before it hits the outboard device). Having a dither plug (last in the chain) right before the signal leaves the box sounds like what you need in those cases. If you consider the fact that Logic doesn't come with such a plug, and the fact that Logic and D/A devices like Apollo, Focusrite, insertyourdevicehere 'support' looping OTB and back in, you would think that dithering would be automatic if it is indeed necessary. That would be Logical, right? (pun intended). But based on the lack of information and disagreement and misunderstanding in general (even among the pros and industry insiders), who knows?
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Post by Bob Olhsson on Mar 7, 2016 0:08:34 GMT -6
There is no controversy among people who know DSP math! Unfortunately a LOT of DAW programmers don't know crap about DSP.
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ericn
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Dithering
Mar 7, 2016 8:20:43 GMT -6
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Post by ericn on Mar 7, 2016 8:20:43 GMT -6
There is no controversy among people who know DSP math! Unfortunately a LOT of DAW programmers don't know crap about DSP. So sad, but oh so true! Or to paraphrase a my computer guru. If you ever took a coding class and are out of work you build an app. If you out of work took a coding class and know 3 power cords you build a plugin!
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Post by Deleted on Mar 7, 2016 10:00:17 GMT -6
There are computer specialists that are good in making applications, GUIs, user friendly concepts etc.. And there are technical computer scientists and electronic engineers which know their stuff about DSP. This rarely meets in the same persons.
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Post by joseph on Mar 7, 2016 20:41:52 GMT -6
This would seem to be as fundamental as the compression algorithm when exporting a video or jpeg.
As a software engineer, how do you fuck this up?
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Post by jazznoise on Mar 7, 2016 20:54:38 GMT -6
This would seem to be as fundamental as the compression algorithm when exporting a video or jpeg. As a software engineer, how do you fuck this up? I'm not really of the opinion they do. The bottom bit at a 24 bit file is -144dBFS. Anyone running HW inserts @ 24bit does not have to worry. A dither at 16 will bring them back to square one.
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Post by joseph on Mar 7, 2016 20:59:06 GMT -6
Right, but if the noise/indiscernible hash accumulates across many tracks, line stages and buses...
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Post by Bob Olhsson on Mar 7, 2016 21:16:18 GMT -6
The problem as I understand it is that many just throw code libraries together much like throwing ICs together. What it really requires are people like Claude Shannon who really know math, programming and engineering. What floored me was when Jim Johnston told me that the digital audio in Shannon's telephone system is dithered! Dither doesn't mask the distortion, it prevents it! Maybe the best analogy is adding high frequency bias to analog tape recordings.
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Post by jazznoise on Mar 8, 2016 5:13:56 GMT -6
Right, but if the noise/indiscernible hash accumulates across many tracks, line stages and buses... Yeah but enough correlative noise to raise the noise floor to -120dB? I dunno. I run 24 bits in and out when I do use an analog HW insert (pretty rare, maybe a tape delay). Maybe if you've 50 channels you're running to and from it's a consideration. Reaper seems to have no discernible issues with quantization distortion, so I assume the upsampling of the engine isn't a problem or that the engine is indeed dither when it truncates to the DAC's because that's what it has to do for the stereo bus anyway.
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