What about a dual mid-side encoder project?

Where we discuss new analog design ideas for Pro Audio and modern spins on vintage ones.
User avatar
mediatechnology
Posts: 4888
Joined: Sat Aug 11, 2007 2:34 pm
Location: Oak Cliff, Texas
Contact:

Re: What about a dual mid-side encoder project?

Post by mediatechnology » Sat Sep 18, 2021 10:31 am

It seems that ideally you would need 5 outputs and 5 recorder tracks.

L and R for monitoring, broadcast and recorder and FRS for RAW capture.

It would also seem that a calibrated +/-6 dB? on the FRS inputs would be good for sensitivity calibration.

Would you want the pattern coefficients/polarity to only affect the LR fold-down and not the RAW outputs?
It seems like applying those in the RAW FRS outputs could possibly work against you later in post.

The option for a derived center using the Studer 90° Dome filter might make a better center for 5.0 than Mid Front.
https://ka-electronics.com

Covidland (The Movie) Part 1: Lockdown https://banned.video/watch?id=615f96b3aa816336dbd21792

Directing Orson Welles: "What Is It That You Want?": https://waynekirkwood.com/content/Orson ... u_Want.mp3
Americas Frontline Doctors Lawsuit Motion For Preliminary Injunction Of Covid-19 Vaccine Emergency Use Authorization: https://waynekirkwood.com/images/pdf/Am ... zation.pdf

emrr
Posts: 527
Joined: Sun Mar 02, 2008 11:27 pm
Location: NC, USA
Contact:

Re: What about a dual mid-side encoder project?

Post by emrr » Sun Sep 19, 2021 10:09 am

Yes, 5 outputs covers raw and encoded MS. Ideal. The raw can always go to a separate free-sync recorder in a limited console input situation.

Agree on +/- 6 control for F and R, though it would be redundant on S if there was a width control. One or the other.

Pattern control only on the LR.

True on the 90º filter, I've thought of and forgotten another possible use for it in the last few weeks. I suppose it depends on how it mixes back in.
Best,

Doug Williams
Electromagnetic Radiation Recorders

User avatar
mediatechnology
Posts: 4888
Joined: Sat Aug 11, 2007 2:34 pm
Location: Oak Cliff, Texas
Contact:

Re: What about a dual mid-side encoder project?

Post by mediatechnology » Sun Sep 19, 2021 2:17 pm

I think you would want separate S level controls, one Trim one Width.
The S trim control would make sure that the RAW outputs are in situ based on sensitivity.
Width, which also varies Side Level, would then have a range from -∞ to +6.
S Polarity should affect only the folded-down LR outputs.

By having separate controls for Trim pre-RAW Out and by making Width and Side polarity post-RAW output, RAW stays RAW.
With one S level if you wanted to change the pattern later in post with the RAW files you would have to apply counter-gain to actually get it back to what it was.

Question: If RAW went to a wild recorder doesn't that box you into conforming picture if you decide to use it later? Or would you be conforming anyway?
https://ka-electronics.com

Covidland (The Movie) Part 1: Lockdown https://banned.video/watch?id=615f96b3aa816336dbd21792

Directing Orson Welles: "What Is It That You Want?": https://waynekirkwood.com/content/Orson ... u_Want.mp3
Americas Frontline Doctors Lawsuit Motion For Preliminary Injunction Of Covid-19 Vaccine Emergency Use Authorization: https://waynekirkwood.com/images/pdf/Am ... zation.pdf

emrr
Posts: 527
Joined: Sun Mar 02, 2008 11:27 pm
Location: NC, USA
Contact:

Re: What about a dual mid-side encoder project?

Post by emrr » Sun Sep 19, 2021 3:36 pm

RAW to a wild recorder is easily synced for post, I have to do that all the time. The ability to split it from the same encoder, no matter where it goes, is what seems important.

I wasn't thinking of a polarity control for side - I'd swap the pan orientation at the console or swap the cables - but others probably want that.

I suppose gain and counter-gain in post seems trivial, yes best to have it right but gain/counter happens all the time. I don't see it disturbing anything crucial, and in the back of my mind I'm thinking of the simplest signal path that hits the necessary marks. To my immediate way of thinking S gain -trim is dealt with via width, or vice versa, M is the crucial trim, to be sure there's enough M. I'll have to think about that some more. Preamp gain, if in hand, takes care of it, BUT sometimes preamp gain is from an upstream console that's simply passing it through to broadcast as an amplified split, then you'd want steerage.

I should do a drawing - that would have been easier....this has been kicking around in my subconscious awhile, sorry I kicked out the initial thought to get it jumpstarted without a ton of clarity.
Best,

Doug Williams
Electromagnetic Radiation Recorders

User avatar
mediatechnology
Posts: 4888
Joined: Sat Aug 11, 2007 2:34 pm
Location: Oak Cliff, Texas
Contact:

Re: What about a dual mid-side encoder project?

Post by mediatechnology » Sun Sep 19, 2021 5:39 pm

Side polarity allows pattern changes to figure 8 and super cardioid.
https://ka-electronics.com

Covidland (The Movie) Part 1: Lockdown https://banned.video/watch?id=615f96b3aa816336dbd21792

Directing Orson Welles: "What Is It That You Want?": https://waynekirkwood.com/content/Orson ... u_Want.mp3
Americas Frontline Doctors Lawsuit Motion For Preliminary Injunction Of Covid-19 Vaccine Emergency Use Authorization: https://waynekirkwood.com/images/pdf/Am ... zation.pdf

emrr
Posts: 527
Joined: Sun Mar 02, 2008 11:27 pm
Location: NC, USA
Contact:

Re: What about a dual mid-side encoder project?

Post by emrr » Mon Sep 20, 2021 7:29 am

Think about that again. S only changes LR orientation. R polarity changes mid pattern on the 8 side.
Best,

Doug Williams
Electromagnetic Radiation Recorders

User avatar
mediatechnology
Posts: 4888
Joined: Sat Aug 11, 2007 2:34 pm
Location: Oak Cliff, Texas
Contact:

Re: What about a dual mid-side encoder project?

Post by mediatechnology » Mon Sep 20, 2021 7:42 am

You're right.
Side polarity simply flips Left/Right.

I read the second figure wrong on the pattern graphic.
MRear is the one needing the polarity reverse.
https://ka-electronics.com

Covidland (The Movie) Part 1: Lockdown https://banned.video/watch?id=615f96b3aa816336dbd21792

Directing Orson Welles: "What Is It That You Want?": https://waynekirkwood.com/content/Orson ... u_Want.mp3
Americas Frontline Doctors Lawsuit Motion For Preliminary Injunction Of Covid-19 Vaccine Emergency Use Authorization: https://waynekirkwood.com/images/pdf/Am ... zation.pdf

User avatar
mediatechnology
Posts: 4888
Joined: Sat Aug 11, 2007 2:34 pm
Location: Oak Cliff, Texas
Contact:

Re: What about a dual mid-side encoder project?

Post by mediatechnology » Mon Sep 20, 2021 1:39 pm

OK, I've re-thought this and agree two level controls plus MR polarity is all that would be needed.

I think MF should be fixed-gain with operating level set at the preamp.
Side and MR sensitivity calibrations would be set at the preamp.

MF level would be fixed at unity with Side Level and Mid Rear Level (and Polarity) variable.

Side level would span from -∞ to +6 dB for "0 to 200%" Width.
Mid Rear would vary from from 0 dB -polarity at CCW to -∞ in the middle and 0 dB +polarity at CW rotation.

The MId Rear control would span from Omni at CW to Figure 8 at CCW

The order would be Omni > Wide Cardioid > Cardioid > Super Cardioid > Figure 8.
Super Cardioid and Fig 8 would be on the left-hand half of the rotation, Cardioid in the Middle and Omni WIde Cardioid on the right-hand half.
(The rotation could be reversed if it makes more sense.)

Would that work operationally?
https://ka-electronics.com

Covidland (The Movie) Part 1: Lockdown https://banned.video/watch?id=615f96b3aa816336dbd21792

Directing Orson Welles: "What Is It That You Want?": https://waynekirkwood.com/content/Orson ... u_Want.mp3
Americas Frontline Doctors Lawsuit Motion For Preliminary Injunction Of Covid-19 Vaccine Emergency Use Authorization: https://waynekirkwood.com/images/pdf/Am ... zation.pdf

emrr
Posts: 527
Joined: Sun Mar 02, 2008 11:27 pm
Location: NC, USA
Contact:

Re: What about a dual mid-side encoder project?

Post by emrr » Mon Sep 20, 2021 5:24 pm

I think all that works. I added front/rear flip and S polarity for L/R flip.

I’d probably vote for omni CCW and figure 8 CW. I kept drawing this and realizing I had redundant features, then redraw. May help.
EA0E3B6B-94D7-47AB-A792-10DD6CB76E9C.jpeg
The build-out from here would be 3 preamps built in with the ability to bypass, or set unity, not sure the best approach there.

The surround version is probably useful to someone, that gets back to the 5 channel processed output, and of no interest to me currently. That’s always possible in post from the 3 raw files.
Best,

Doug Williams
Electromagnetic Radiation Recorders

User avatar
mediatechnology
Posts: 4888
Joined: Sat Aug 11, 2007 2:34 pm
Location: Oak Cliff, Texas
Contact:

Re: What about a dual mid-side encoder project?

Post by mediatechnology » Mon Sep 20, 2021 6:47 pm

I think all that works. I added front/rear flip and S polarity for L/R flip.
I think S polarity is an excellent idea because a polarity reversal, either electrical or acoustic, reverses the audio image relative to picture.

I remember watching an early analog MTS stereo version of Miami Vice and a car passed by that panned backwards from the action.
It was immediately obvious Left and Right were reversed but very disorienting.
With the perspective correct stereo TV worked much better for me.
https://ka-electronics.com

Covidland (The Movie) Part 1: Lockdown https://banned.video/watch?id=615f96b3aa816336dbd21792

Directing Orson Welles: "What Is It That You Want?": https://waynekirkwood.com/content/Orson ... u_Want.mp3
Americas Frontline Doctors Lawsuit Motion For Preliminary Injunction Of Covid-19 Vaccine Emergency Use Authorization: https://waynekirkwood.com/images/pdf/Am ... zation.pdf

Post Reply