Robert Henke wrote:Dithering: dithering is a techique which shifts the spectral energy of quantisation errors once a file is put out into a digital analog converter.
I'd like to debate you on this.
The above statement is incorrect. Dither does not "shift spectral energy". It functions the same way bias works on an analogue tape machine. Dither randomizes low level quantization errors, thereby decorrelating the quantization error from the audio signal. However, noise shaping, which is a technique of "EQing the dither" (in simple terms), does shift the spectral energy of the resulting dither noise so that it is less audible by moving the energy of the dither into a higher frequency range where the human ear is less sensitive.
It is never recommended to add dither as long as you stay in the digital domain and are not creating a finished product which will not go thru any mastering process including changing the level even by a very smal amount. Dithering should be applied at the mastering studio as the very last step by someone who knows what to do.
False. Within the context of a DAW (ie-any software that mixes multiple digital signals, changes levels, etc), dither is *absolutely essential* for preserving sound quality and decorrelating quantization error. The cumulative effects of quantization error in any digital audio software are plainly apparent to a reasonably trained ear. Dither is always the best solution whenever the bit depth is reduced in a DAW -- which it always is - because anytime you change the gain on an audio signal, the math performed on the signal produces fractions which must then generate rounding errors due to the bit depth limitations of the system.
Unless you are doing music with _very_ quited parts you will not hear
the difference anyway. We are talking aobut the range of -80 dB and below....
False -- and true. If you are talking about adding dither to just a few tracks, then yes, the benefits may be negligible. But if you are talking about a large production within a digital audio workstation -- ie - 60 tracks of audio in Pro Tools, then the cumulative effects of quantization error are rather easily heard.
These are the facts. I have a history in professional mastering and vinly cutting and i am willing to discuss this topic in depth if needed. I can also point to literature.
Experienced analog mastering engineers are not always the best source of information regarding digital audio. No offense.
I know how much psychological factors determine our perception
and as i said at the beginnig, i am perfectly fine with what ever one
believes as long as it leads to good results,
I agree with that 100%...
but i am getting upset by this discussion about "sound quality of an audio engine". This is DIGITAL, not analog.
That statement is meaningless. "This is digital" implies what, exactly? There are in fact significant differences between implemenations of digital audio mixers, the precision of the math depending on the architecture of the system, the implementation (or not) of dither, etc. The word "digital" does NOT in and of itself imply that all things are equal in all software. That is totally false.
My old ENSONIQ ASR-10 sounds great beacause the digital to ANALOG converters do funny things.
True -- but that's a completely different point. There's two separate discussions here: there is the debate over what "sounds good", which is subjective, and then there is the debate about precision -- and how best to preserve the integrity of a signal throughout the various gain/pan/FX/processing stages of a digital mixer. When a user questions the "audio engine" they are talking about the cumulative effect of the sound of their audio as a result of all the methods implemented in the software to process their audio -- gain changes, panning, accuracy of the automation, precision of the math used to do all the calculations etc -- and in REAL WORLD USE -- all things are not equal and different digital audio mixers sound different.
I will be happy to refer you to a massive number of resources and discussion threads on the internet where you can delve into this subject more deeply if you are interested.
