Friends,
I have a book by Matt Hepworth on Wave Lab. He says that even if your clips are 16 bit / 44.1 in the montage for CD burn, it’s a good idea to use dithering again. The reason he says is because of the 32 bit engine in WaveLab. Is this needed? If all my clips have been edited and rendered in WL and I know their sample and bit why should I dither again? Any reason why this is a good idea ? I’m new to WaveLab … I’v been a Bias user until the company died.
Thanks
Mike
You need to dither if you have made any change (fade in/out, level change). If you have truly not changed the files in the montage, then you do not need to dither (going to float and back to 16-bit integer is an exact process and so doesn’t affect this decision - that statement is wrong).
It is rare to have a recording that is quiet enough that the noise from an extra application of dither is significant. My first commercial studio recording was of piano music, made in 16-bit (recorded on DAT), and then edited in a 16-bit program (CoolEdit-96) which added a new layer of dither for each operation resulting in a dozen dithers for some tracks - the end result was praised for its transparency in the first review.
Paul
One way to know is to use the bit-meter: if there are more than 16 bits, then some processing occurs somewhere and dithering is needed. Else it is not needed.
Thanks for the reply… I plan on doing all my editing and rendering to each clip… then load files to montage and prep for CD burn.
If I may follow up on a another question concerning Dither… I work in PT 10 and have used WAVES IDR and Pro Tools re sampler to get the song to 44.1 . I have also used BIAS. I want to try WaveLab’s re sampler and uv 22 instead of the IDR with noise shape. Have you had any success with WaveLab in this area. Thanks again for everyone’s expert input.
Mike
I don’t recommend dithering the individual clips. Dither the montage, at the end, instead.
Interesting … The files that I have will all be 48Khz 24 bit. I need to do some fade out and ins on each song (clip). So, what you are saying is… work on the files, save them, but do not dither or down sample clips until I import all of them into the montage. Then, at that point resample and dither.Am I correct on this procedure… Why wait for the montage and not work on them individually… I don’t understand.
Mike
You are understanding correctly, and this is exactly why the montage is so powerful - everything can be adjusted afterward again, without having to revert to ‘the old’ source file. The source file remains untouched because everything takes place non-destructively, and you have the bonus of having all tracks in context with the others. With each source file being a clip, you can have specific effects - or fades - on each clip (changeable at review), and common ones in the master section. Save various versions of such a montage (much less data) and have ultimate flexibility. As a montage user, I would ask back: Why work on the individual files separately?
Thanks Arjan for the reply… As a Bias user for many years this procedure is new to me. It’s hard to believe that in the montage you can re sample. and dither and burn a Red Book CD… without overwriting the files!!! I’ll give it a go and see what happens… Thanks for the expert advice…
Mike
To resample, there is possible but a bit more difficult, because you need to generate a file from the montage and recreate a montage from this file (this is done for you, if you specify it).
In next WaveLab version, this will be fully automated.
O.K. So then should I import my sound files individually and resample first, Save as new 44.1 file, then import files into montage for dithering? For now, all I want to do is edit my files with proper fades for beginning and end, re sample and dither. Most of my other effects on the files will be done in Pro Tools. But I need to have a Red Book CD. So, should I resample and edit in the WaveLab workspace first “Save as” then proceed to import files into the montage for assembly and dither to CD. How would you approach this ?
Mike
If I were you I’d just create a 48k montage, put all the source files in, create fades, effects, volume/pan envelopes where you want them. Then add a resampler plugin in the master section, add dither and render to separate files, CD or whichever output you want. No need for SRC on the way in (In that respect, I don’t really see what PG means).
O.K. Arjan… I’ll try your idea… Not sure what PG meant by difficult for Sample conversion. I’ll try all this in the montage. In Bias, this was never done at all. You always worked on separate files then created your CD. This is a change for me. Thanks for your input… I probably will have more questions as I work on my project. This “montage” is very powerful!!! Sample convert, dither and assembly of a CD all at one time!!!.. very powerful!!
Mike
Arjan,
The only disadvantage for using the montage for editing, dithering and resampling I can figure is that the masters are not future poof. If I edit, resample and dither each individual file I can open that file with any software. If I use the montage I need Wavelab to open it. Am I correct in this thinking? I’ll still use the montage, but I still might work on each file separately.
Mike
Mike, you are right, but that’s why I said ‘render to separate files, CD or whichever output you want’. So all work is done in WL, and when finished you output separate file. Then if you’re not happy after all, you can slightly edit a setting in the montage and render all out again. Much better than working on separate files.
Thanks for the reply Arjan… Let me make sure I understand (forgive me I’m an old Bias user separate file guy) I’m working in the montage with many files (clips) and of course I will burn a CD which will have separate files on the CD. You say output separate file… How can I separate the files in the montage without importing back from the CD? I’m rendering the whole montage I got that… now what if I just want 3 of those clips in the montage file… output separate file? not sure how this is accomplished. Sorry if the question is dumb… I just need to see how one works this WaveLab…
Follow up question…
How successful have you been with WaveLabs re-sampler and dither uv/22. I’m used to working with Waves IDR and Bias re-sampler… Many, Many thanks for your time on this subject…
Mike
There’s no such thing as a dumb question… But I see where you misunderstood. When rendering the montage (lower end of master section), you have several options: render clips to separate files, render CD-tracks (as defined) to separate files, render to DDP, render to new montage, to one big file etc. If you want 3 clips rendered, select them (they’re highlighted) and render with that option. These options may be present, depending on Wavelab version though, I’m only familiar with WL full version.
Crystal Resampler is fantastic IMO, especially in the Ultra setting, and UV22 works just fine too. I used Waves L2 (and its dithering) in the past, but find no particular differences.
Thank you Arjan for your expert and clear answers. I’ll give this montage a try with some files I’m working on and see what happens. I believe I have the full version… I may need to contact you again with more questions, If you don’t mind…
Mike
Hi, Folks!
Good explanations here.
I recall having similar concerns about dithering when I started Rendering wave files in WL 3.0 many moons ago 
!!!
However, whenever a digital audio file is “processed” and saved as a newer version of an older file, dithering is generally a very good idea, as it actually works to reduce distortions in digital audio material. Most of the impact is with the “least significant bits” (LSBs) in the processed (e.g. mathematically manipulated) digital audio. These are generally the lowest volume data points sampled in the files (which may well be the quiet parts or musical “rests” within the music). The purpose is to help remove the Analog to Digital “confusion” that happens at these low signal levels, where the conversion to an LSB of “0” or “1” may be difficult for the processing to determine and settle upon. This indeterminate LSB “state” can and does cause audible distortions during playback, which is what led people to incorporate “dithering” to digitized audio signals.
A very interesting side effect to adding dithering, is that it has been found through human A-B testing to extend the dynamic range of audibility below the actual level of the applied dither and bit limits of the 44KHz-16bit media, improving the audible noise floor of the recorded signal! It appears to partly be a psychoacoustic phenomenon that human hearing provides (penetrating through noise to selectively hear other sounds within the background), but its been statistically proven to work in a number of human research tests run over the past few decades.
In other words, if I recall correctly, a 44/16 CD’s theoretical dynamic range is 96 dB [20 log (2^16)]. By carefully adding shaped dither, this dynamic range is actually enhanced beyond this theoretical dynamic range limit, as people can actually hear dynamic material below the 96 dB point on digitally recorded material! When you realize that the human hearing apparatus is capable of about 130 dB dynamic range, 96 dB doesn’t sound like much. However, in most recordings, it’s very rare for the noise floor to fall below 65 dB. Even so, the sublties of dither do make a difference. Hence, whenever a file is manipulatively processed, dither is necessary to reduce distortion and improve audibility.
The real question becomes whether 24 bit files really need dithering as the dynamic range of 144 dB [20 log (2^24)]actually exceeds human hearing limits? The answer is “yes”, because it still has the capacity to reduce audible distortions caused by the indeterminate LSB issue discussed above.
So, at the risk of repetition, whenever an audio file is manipulatively processed, dither is necessary to reduce distortion and improve audibility.
FWIW, Arjan: There is at least a dumb question, the one that’s not asked!!! 
Hi AES, good contribution, and I didn’t know about human hearing being extended beyond the 16 bit ‘limit’; interesting! And yeah, you’re right about dumb questions being the ones not asked. But a philosophical issue remains: is a question that’s not asked really a question? 
Dither does not lower the noise floor; it raises it slightly. However, correct dither ensures that sounds below the level corresponding to the number of bits remain present and audible. This is not a side effect, but is the main function of dither (the loss of those signals is what causes the distortion that dither prevents); it can also be shown mathematically without having to fiddle around with tests and statistics.
Theoretically, dithering 24-bit signals is appropriate; I doubt that the effect of omitting that is ever audible, though, unless the signal is being handled at a very low level which is increased a huge amount later. But the overhead of dither is negligible, so there is no reason not to do it either.
In terms of preserving low-level signals, all correct dither implementations are equivalent. The only difference with the fancy ones is in the spectrum of the noise added by the dither. As for real signals this is usually below the studio or hall noise floor, this is not generally of any importance.
Paul