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Do you render/bounce individual mix tracks/stems for archive/safety?

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Re: Do you render/bounce individual mix tracks/stems for archive/safety?

Postby Hugh Robjohns » Sat Aug 15, 2020 11:31 am

Martin Walker wrote:The special feature of the Waves S1 Imager for me was its Blumlein shuffling, as I described in this SOS feature:

"S1 also has a very useful Shuffle control that lets you further increase stereo width at lower frequencies (typically below 600Hz, as set by the associated Frequency control). This compensates for the fact that the ear is less sensitive to stereo bass effects..."

Ahem... Kindly take your seats gentlefolk, and pay attention... l have a short history lesson for you... ;-)

Although the end result is much the same, the issue being compensated for in the Waves approach is actually the other way round! It's not that the ear being less sensitive to stereo bass effects, it's that the sense of hearing is actually more sensitive to HF stereo effects when listening over stereo loudspeakers.

And it's not Blumlein Shuffling either -- that's a similar technical process but performed on a different type of source material and for a very different reason. I'll return to that in a moment...

The function you've described and which Waves is trying to emulate in the S1 is actually called Stereosonic Shuffling!

In the 1950s the EMI boffins (many of whom had worked with Blumlein before the War) worked out that there was a fundamental flaw in Blumlein's format of conventional stereo from two-loudspeakers arranged in an equilateral triangle.

The stereo loudspeaker system basically works by converting inter-channel level differences between the signals fed to the speakers into inter-aural timing differences at the ears. However, the discovered 'flaw' was/is that in practice the perceived stereo image width is inherently exaggerated for frequencies above about 700Hz -- mostly because of the shadowing effect of the head. So this flaw effectively blurs the stereo image slightly, degrading the perceived imaging precision and focus.

Consequently, EMI's boffins developed a process which they subsequently called the Stereosonic Shuffler and it was later built into several of EMI's REDD mixing and mastering consoles.

The Stereosonic Shuffler was designed to compensate for the HF image exaggeration effect by attenuating the Sides signal above 700Hz, thus narrowing the stereo image for high frequencies slightly and realigning the spatial positions of low- and high-frequency components. EMI's implementation involved converting the left-right stereo signal to Mid-Sides, introducing a gentle -3dB shelf cut above 700Hz in the Sides signal, and then reconverting to left-right for replay over the speakers.

Obviously, attenuating above 700Hz has much the same effect as boosting below 700Hz... except that it has the benefit of not risking running out of headroom which the bass boost approach definitely does!

Note, the 700Hz figure is not an absolute -- it's a smooth crossover process and the the exact frequency depends on personal physiology, but it's generally somewhere in the 600-750Hz region for most people, and it's not that critical.

Also note that David Griesinger (of Lexicon fame) has made extensive studies of the significance of the relative stereo width at low frequencies and its effect on perceived imaging precision and the sense of spaciousness in stereo recordings.

Sadly, Stereosonic Shuffling never caught on as an 'essential process', mostly because the effects are relatively subtle and only really appreciated by someone sitting in the correct listening point between the speakers -- so great for mixing engineers, but pretty unlikely to get noticed by most domestic listeners! And EMI decided to drop the idea as the benefits weren't worth the efforts and technical challenges involved with the available electronic circuitry of the day.

However, as an accidentally discovered benefit, the EMI boffins also found that the same process improved the sound from coincident stereo mic arrays, and particularly crossed fig-8 (Blumlein) arrays.

The polar pattern of most directional mics naturally narrows with rising frequency, and this is often particularly noticeable on vintage ribbons... and EMI were fond of using coincident XY fig-8 ribbons for much of their classic music recording in the 50s and early 60s.

The polar pattern narrowing in an XY array increases the inter-channel level differences and thus exaggerates the stereo width at higher frequencies. Consequently, by using the Stereosonic Shuffler to reduce the Sides signal from the XY array above 700Hz, the stereo image width at HF was brought back into alignment with the image width at LF, thereby improving the overall image precision and focus.

Modern mics tend to have much more consistent polar patterns than those of 90 years ago, of course, and its really only the low bass that causes a problem as the mic degrades towards omnidirectionality -- thus reducing the interchannel level difference. So I've often found that often narrowing from above around 100Hz or thereabouts (or widening below 100Hz if you have the headroom) by 4-8dB is usually quite effective.

Historically, the Stereosonic Shuffler was used quite extensively by EMI on many of its classical recordings of the late 50s and 60s... but it wasnt adopted by anyone else and it quietly faded into obscurity as the REDD consoles evolved and were later replaced with more modern commercial third-party designs.

So... Stereosonic Shuffling to improve the precision and focus of stereo loudspeaker listening is a real thing, and the benefits can definitely be appreciated by those sitting at the correct listening position. Modern digital signal processing makes it a perfect and loss-less process too, which is more than can be said for EMI's original implementation with lots of transformers and passive balanced filters!

Next... Blumlein Shuffling.... Same term but different implementation and application!

Back in the 1930s when Blumlein was developing his stereo recording techniques, he came up with the idea of using closely-spaced omni-directional microphones, ideally with an acoustic baffle placed between them. This concept is better known today as the Jecklin Disc (and variations thereof), but Blumlein got there first, and then discounted the idea in favour of coincident arrays which gave better stereo imaging accuracy when auditioned over loudspeakers. (The close-spaced microphones idea worked well on headphones, though, and we know that today as Binaural recording -- Blumlein got there first!)

So Blumlein's close-spaced array involved mics 22cm apart, ideally with a (head-sized) baffle between them, although that seemed to be optional. Most of his tests used omni mics, although he also used forward-facing ribbon fig-8s -- an idea which Tony Faulkner re-invented in the 80s and is now known as the Faulkner Array.

When the outputs from these mics are auditioned on stereo loudspeakers the imaging is rather vague and the main reason is the lack of inter-channel level differences between the channels -- it's nearly all small timing differences at high frequencies, and only very small phase differences at low frequencies.

So Blumlein invented the 'Shuffler' to correct that, turning small LF phase differences between the channels into amplitude differences. Again, the process involves attenuating the Sides signal above about 700Hz, thereby expanding the stereo image at low frequencies relative to high frequencies... and it works quite well.

I've used it on recordings made with a Schnieder Disc (very similar to a Jecklin disc, but with an absorbent 'bulge' in the middle to better replicate the absorption of the human head!). it also works with ORTF recordings, bringing a little more focus and definition into the sound. It's subtle, and in no way a game-changer, but I think it can be beneficial....

Both forms of Shuffling are easy to implement and experiment with. You just need a pair of complementary LR-MS and MS-LR converters, and a shelf equaliser in the Sides path between the converters.

It's generally best to reduce the HF above about 600-750Hz, rather than boosting below, simply because bass signals are usually quite loud and boosting risks overloading the signal path. The amount of HF cut is largely a matter of taste, but I find 3-6dB is usually the right area. Try a shelf at around 350Hz for the ORTF array.

Okay... lesson over... thank you for your attention....now go out and play in the sunshine.... Matron has ice lollies for everyone :D
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Re: Do you render/bounce individual mix tracks/stems for archive/safety?

Postby The Elf » Sat Aug 15, 2020 11:40 am

Dr Huge Longjohns wrote:
I render EVERYTHING. Even one week down the line you may need to re-do something and you can't be sure you will be able to.

Do you keep both, then? The rendered and the raw tracks with plugs?
Yep. I have a folder called 'Attic' and in here is all the audio and MIDI for me to go back if need be.

So yes... raw, processed, unedited... I keep the lot. It's saved my life many, many times.
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Re: Do you render/bounce individual mix tracks/stems for archive/safety?

Postby Kwackman » Sat Aug 15, 2020 12:01 pm

Hugh Robjohns wrote:Kindly take your seats gentlefolk, and pay attention... l have a short history lesson for you... ;-)
[Big Snip]
Okay... lesson over... thank you for your attention....now go out and play in the sunshine.... Matron has ice lollies for everyone :D

Interesting stuff, thanks. :thumbup:
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Re: Do you render/bounce individual mix tracks/stems for archive/safety?

Postby Dr Huge Longjohns » Sat Aug 15, 2020 12:13 pm

Yep. I have a folder called 'Attic' and in here is all the audio and MIDI for me to go back if need be

Makes a lot of sense, thanks.
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Re: Do you render/bounce individual mix tracks/stems for archive/safety?

Postby blinddrew » Sat Aug 15, 2020 12:27 pm

Kwackman wrote:
Hugh Robjohns wrote:Kindly take your seats gentlefolk, and pay attention... l have a short history lesson for you... ;-)
[Big Snip]
Okay... lesson over... thank you for your attention....now go out and play in the sunshine.... Matron has ice lollies for everyone :D

Interesting stuff, thanks. :thumbup:
The "Every day's a school day" box has been ticked for today!
Indeed, filed away for reference. But noting also that as part of my 'mastering' stage I'll frequently cut low end from the sides signal and give it a bit of a boost to add width. But I guess we're talking different things here between improving the imaging of a specific stereo coincident source and broadening the width of a whole mix.
I have a recent track recorded entirely in M/S so I might go and have a bit of a play with some individual tracks at some point.
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Re: Do you render/bounce individual mix tracks/stems for archive/safety?

Postby James Perrett » Sat Aug 15, 2020 12:47 pm

Thanks for that very clear explanation Hugh. I don't think I had ever heard of Stereosonic shuffling before.
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Re: Do you render/bounce individual mix tracks/stems for archive/safety?

Postby ManFromGlass » Sat Aug 15, 2020 12:57 pm

In my younger days I wasn’t thinking ahead. Synths and samplers came and went, formats came and went and plugins didn’t get updated. So now I do some or all rendering.

I once contacted a programmer and asked how much he would charge to bring his plugin into the 64 bit world. He didn’t respond. I still miss that plugin to this day. I keep an old 32 bit machine around to run the plug.
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Re: Do you render/bounce individual mix tracks/stems for archive/safety?

Postby Hugh Robjohns » Sat Aug 15, 2020 2:40 pm

James Perrett wrote:Thanks for that very clear explanation Hugh. I don't think I had ever heard of Stereosonic shuffling before.

There was a lengthy paper from the EMI boffins covering it (amongst many other stereo-related things) written in 1957. It was reprinted in the AES journal the year after, and it has also been made available here:

http://www.pspatialaudio.com/stereosonic.pdf
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Re: Do you render/bounce individual mix tracks/stems for archive/safety?

Postby blinddrew » Sat Aug 15, 2020 4:30 pm

Hmm. Had a play around just taking a single source and raising and lowering a shelf. 'This is a very obvious effect' I thought, 'even at +/- 3dB, crank it to +/- 6dB and it's really apparent.'
Then the rest of my brain pointed out that what I was also doing here was just raising and lowering the overall level of the sides signal. :headbang:
Once I'd matched the gains it was indeed a more subtle, but still noticeable effect.
Being as my current preferred way of recording acoustic guitar is an M/S pair this is going to be very useful. Thanks Hugh. :thumbup:
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Re: Do you render/bounce individual mix tracks/stems for archive/safety?

Postby ManFromGlass » Sat Aug 15, 2020 5:10 pm

Would it be a clarity of signal above that base frequency issue? I’ve been re-reading a few times but am a bit slow to catch on. I think I’ve confused myself with altering width and clarity of the sound of the recording.
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Re: Do you render/bounce individual mix tracks/stems for archive/safety?

Postby RichardT » Sat Aug 15, 2020 5:40 pm

The Elf wrote:
Dr Huge Longjohns wrote:
I render EVERYTHING. Even one week down the line you may need to re-do something and you can't be sure you will be able to.

Do you keep both, then? The rendered and the raw tracks with plugs?
Yep. I have a folder called 'Attic' and in here is all the audio and MIDI for me to go back if need be.

So yes... raw, processed, unedited... I keep the lot. It's saved my life many, many times.

I’m going to bite the bullet and archive my mastered tracks - I know I should be doing it, but this gives me the spur to actually do it.

Elf, what archives do you keep of the MIDI data? Thanks!
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Re: Do you render/bounce individual mix tracks/stems for archive/safety?

Postby Martin Walker » Sat Aug 15, 2020 7:53 pm

Hugh Robjohns wrote:Okay... lesson over... thank you for your attention....now go out and play in the sunshine.... Matron has ice lollies for everyone :D

Bravo Hugh - that was a stunning explanation, and now I know so much more I don't need these specialist plug-ins (although it has to be said that Reaper's bundled JS: Stereo Enhancer does offer a 'Width High' control, to avoid any bass-end overload).

However, armed with my extra knowledge I've now created a suitable preset for my Tokyo Dawn Labs Slick EQ Mastering plug-in, with a 6dB shelving cut above 650Hz on the Difference signal, and I can most definitely hear the improvement in imaging focus on various material.

Another tool for the sonic toolbox!


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Re: Do you render/bounce individual mix tracks/stems for archive/safety?

Postby CS70 » Sat Aug 15, 2020 8:20 pm

I use pretty much the same plugins all the time, so it's difficult to think I won't have them.

It tricked me, however, when systems moved to 32 to 64 bits as Sonar did not recognize that a 64 bit version of a plugin was "the same" as the 32 bit, so for one songs I needed to work with a couple of years after finishing the mix, I had to basically re-install the 32 bit version, open the project, copy the setting, and re-insert the 64 bit versions in a new one. Luckily was a very small project so not much to do - it was a delay and perhaps one other effect.

I always keep all the project audio files. For clients, I always keep a regular mix and one without vox, just in case (when there's a vox, that is).
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Re: Do you render/bounce individual mix tracks/stems for archive/safety?

Postby Hugh Robjohns » Sat Aug 15, 2020 8:42 pm

Martin Walker wrote:Bravo Hugh - that was a stunning explanation...

:blush: Aw shucks... :D

Another tool for the sonic toolbox!

:thumbup:
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Re: Do you render/bounce individual mix tracks/stems for archive/safety?

Postby RichardT » Sat Aug 15, 2020 11:55 pm

RichardT wrote:
The Elf wrote:
Dr Huge Longjohns wrote:
I render EVERYTHING. Even one week down the line you may need to re-do something and you can't be sure you will be able to.

Do you keep both, then? The rendered and the raw tracks with plugs?
Yep. I have a folder called 'Attic' and in here is all the audio and MIDI for me to go back if need be.

So yes... raw, processed, unedited... I keep the lot. It's saved my life many, many times.

I’m going to bite the bullet and archive my mastered tracks - I know I should be doing it, but this gives me the spur to actually do it.

Elf, what archives do you keep of the MIDI data? Thanks!

Just tried it on a couple of tracks and I have to say (in Cubase at least) it’s remarkably easy.
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