Spratman wrote: ↑
Wed Jan 02, 2019 6:23 pm
I was playing with this one last night with some premixed material. It certainly gives a strong sense of position compared with toys I have used in the past - even when adding some reverb to it, which is often where other approaches seem to degrade a lot. Been thinking of getting this as a birthday present. Only thing that is slightly less desireable is the static positioning aspect, but I understand why as this wasn't really the intention. Going to play with dearVR next as that's also on sale atm. Binaural mixing is something that I've been wanting to do for a while. I realise these two products are a little different but for me being able to hear headphone mixes where elements are well positioned is something I look for when mixing audiodrama and there is some crossover between these products in that way.
Happy New Year
We have three modes complete in P now in our internal build. Here is a sneak peak of what they do:
Beta Mode is the default Alg Mode in Precedence. It uses a full suite of psychoacoustic principles to very specifically position source sounds within the stereo field. It makes full use of interaural time delays and other advanced time-based technices to achieve the most precise positioning possible. It can be considered a pseudo-binaural mode; it utilizes the most universal aspects of binaural hearing without the limitations of traditional binaural signal processing techniques, and works equally well over both speakers and headphones. The Beta name and symbol on the GUI is a pneumonic to remind users that some binaural aspects are utilized to achieve its highly specific positioning abilities.
The Beta Mode targets an average phase correlation of 0%, which means some specific frequencies can have negative correlation while others will have positive correlation. The exact correlation of the complex signal coming out of Precedence is completely dependent on the frequency content of the input signal. On musical signals it is possible to end up with strong negative correlation with some combinations of input signal and parameter settings in Precedence. This is true particularly if the input signal happens to have a narrow frequency range. This changes drastically, even chaotically depending on the input signal, and even different notes from the same instrument may have drastically different results.
This behavior is completely accurate to the real physical world and the same phenomena are created by stereo microphone techniques that employ any form of spaced microphones. If there is any space whatsoever between multiple microphones there will be at least one frequency that is exactly 180 degrees out of phase when measured at these two distinct points in space. The distance between microphones, or ears, determine what frequencies are out of phase. This is how a sense of width is created. This is an innate aspect of the psychoacoustics of spatial hearing.
Care has been taken to ensure the best possible mono-compatibility for this type of processing, but strictly speaking any form of interaural time delay is not perfectly mono-compatible in the mathematical sense. Some degree of comb filtering effects can result upon collapsing the signal to mono for the reasons above. Generally, these effects are limited to high frequencies in Precedence, and care has been taken to ensure good mono compatibility in the bass frequency range. Precedence is of course a product that has the explicit purpose of spatializing sounds in a stereo field. Mono is the degenerate case; it is not the primary target. The Beta mode therefore concentrates fully on making the stereo effect as good as it can possibly be, with reasonable mono-compatibility as a secondary consideration.
As in all modes, exactly perfect mono-compatibility is also possible simply by reducing the Width parameter to 0%. This does not completely defeat the benefits of Precedence. Later and depth positioning is still possible, and modulation is still active.
The Mu Mode was designed to provide enhanced mono-compatibility. It attempts to retain as many psychoacoustic localization principles as possible, within the constraint that the average phase correlation should be around +50%. Mu Mode does not allow strongly negative correlation, and is therefore a safer choice to use compared to the Beta Mode when mono-compatibility is of critical importance. Stereo imaging feels slightly more narrow than the Beta Mode, as indeed it is in the mathematical sense, but the Mu Mode still is able to retain many psychoacoustic benefits over standard gain panning, including rather surprisingly some degree of time differences. Mu Mode is able to create arrival time differences, as occur in Beta Mode, but does so in a way that retains as high of a degree of mono-compatibility as possible.
The greek letter "mu" is equivalent to the Latin/English letter "m", and users can use the pneumonic "mono", or perhaps "unity" given that lower-case "mu" looks like "u", to remind themselves that the focus of this mode is mono-compatibility.
The Omega Mode is a special effects mode that employs spectral shuffling to achieve width. This means different frequencies are panned differently within the spectrum to achieve width. Width can be controlled quite exactly in this mode by controlling how large the inter-channel spectral differences are. The result is similar to the effects caused by early reflections in real physical rooms, and indeed the Mu Mode allows exaggerated time constants to approach results normally associated with early reflections.
Unlike the Beta and Mu modes, some degree of coloration is imparted on the signal by the spectral filters employed in Mu Mode. Latteral positioning is possible, but is slightly less distinct as the Beta and Mu modes. Spectral magnitude differences can cause unavoidable panning effects, which vary with frequency and may partially confuse the position that the user is attempting to obtain. Some additional coloration is furthermore unavoidable when using extreme Angle values.
On the plus side, mono compatibly is exactly perfect when there is no panning (i.e. when Angle is exactly 0% in Precedence). Mono compatibly remains very good even at extreme Angle values, albeit the mono result will retain some of the coloration imparted by the spectral filters.
Omega Mode is more artificial and less connected to real-world psychoacoustic principals. It is supplied as a special effects mode that can be used on sound effects, synths, and within modern music production styles that are not particularly concerned with achieving a completely authentic acoustic result.
The version you guys have currently is only the Beta Alg-Mode. It remains mostly unchanged, although we did find and fix one or two minor bugs in it.
Inter-plugin communication between Precedence and Breeze has been established also. We are finishing up a few other things and hope to have it in your hands shortly.
anyway, that's the News from Lake Wobegon
as they say.