Mid Side M-S Matrix Uses No Precision Resistors

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mediatechnology
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Re: Mid Side M-S Matrix Uses No Precision Resistors

Post by mediatechnology » Mon Jul 25, 2011 11:47 am

BTW an intersting factoid that you guys may already be aware of. My daughter is in management at Best Buy. She told me that for a couple of years now vinyl is outselling CDs both in units and dollars. I mentioned to Paul in an e-mail that when I moved the first thing I hooked up - before the DVD player and CD - was the SP-15 turntable. The DVD is still not hooked up. Shows you my priorities...
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Re: Mid Side M-S Matrix Uses No Precision Resistors

Post by emrr » Wed Jul 27, 2011 10:15 am

Wow, surprising, and not. Reinforces the bummer feeling we had when we started having to buy the small crappy package as opposed to the big one.
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Electromagnetic Radiation Recorders

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Re: Mid Side M-S Matrix Uses No Precision Resistors

Post by mediatechnology » Wed Jul 27, 2011 11:10 am

Somehow the Mexican food spread inside ZZ Top's Tres Hombres just wasn't the same in CD format :(

I've been planning a trip to Best Buy to see what they have on LP now. I have a mental image of the new Foo Fighters LP spinning on the turntable.
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Re: Mid Side M-S Matrix Uses No Precision Resistors

Post by Gold » Wed Jul 27, 2011 6:52 pm

Thanks Doug. I did a lot of planning so that if I don't like something I'm not locked into it. I'm thinking erector set. I think the overall approach and concept is sound. It's been five years in the works. It can be hard to keep focus because as i learn more I see more options. To my credit I have basically stuck with the plan I came up with five years ago. I have approached it as a learning experience. If I feel I need to acquire as skill to move forward I take the time to do it. For instance I had never worked with metal before. I've spent a lot of time, money and energy figuring out how to do what I want to do. At the expense of finishing more quickly.

Vinyl still doesn't sell anywhere near CD's. I do think the amount of vinyl sold is under reported. Many labels that release vinyl don't report to soundscan. I guess thee same could be said for CD's though. I don't think records are going anywhere.

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Re: Mid Side M-S Matrix Uses No Precision Resistors

Post by mediatechnology » Thu Jul 28, 2011 8:30 am

Paul - Do you suppose that the popularity vinyl released today (that presumably sounds better due to not being over-processed and slammed to the wall to the degree that CDs are) will somehow cause people in the labels to ask if this CD loudness war shoud be stopped? It's a hope of mine.

Is it even technically possible to master vinyl with it clipped and slammed to 100% without burning out the cutterhead?
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Re: Mid Side M-S Matrix Uses No Precision Resistors

Post by Gold » Thu Jul 28, 2011 2:35 pm

mediatechnology wrote:Paul - Do you suppose that the popularity vinyl released today (that presumably sounds better due to not being over-processed and slammed to the wall to the degree that CDs are) will somehow cause people in the labels to ask if this CD loudness war shoud be stopped? It's a hope of mine.
I don't think so. When records were the popular release format everyone wanted those loud too. At the detriment to sound quality.
Is it even technically possible to master vinyl with it clipped and slammed to 100% without burning out the cutterhead?
I actually haven't found clipping to be a problem unless there is audible distortion. Others report otherwise but I don't have a problem with it. I cut a lot of lo-fi stuff where clipping is part of the sound. It took me a while to figure out how to cut that stuff but I know how to do it now.

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Re: Mid Side M-S Matrix Uses No Precision Resistors

Post by mediatechnology » Thu Aug 04, 2011 8:54 am

raf - Jim's name sounds very familiar to me from radio I think. I would love to visit his store.

Paul - Well I can only hope we eventually return to sanity WRT levels. It's just fatiguing to me once all those harmonics start intermodulating and quit being musical.
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Re: Mid Side M-S Matrix Uses No Precision Resistors

Post by emrr » Thu Aug 04, 2011 9:42 am

raf wrote:This guy, Jim Cassero has been a close friend since 1967, and a member of my old prog band.
http://cotati.towns.pressdemocrat.com/2 ... in-cotati/

Jim's top 10 list is pretty impressive. I get a definite vibe!
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A Variable Width Circuit for the Precision M-S Matrix

Post by mediatechnology » Fri Oct 07, 2011 2:25 pm

I was contacted today by someone wanting to build the MS matrix. They had the simple question: "How do I add a width control?"

The obvious answer of course is to vary the ratio of mid to side between the encoder and decoder. If there's already a processor in that insert just use it's gain trim.

But what if I just want to hook up a pot to the board for a Width Control? Where?

Turns out it's pretty easy. I'll draw a schematic and post it. For now let's use the original block diagram.

Image

To make the board into a variable width circuit do the following:

Use the decoder as your encoder. The Left and Right Inputs are at "E." The PC board point marked "GL" (G Left) becomes "GM" or G Mid. "GR" becomes "GS" or G Side.

Add a two section 10K linear pot at insert point "G." Wire the pot so that at CW rotation mid is at full, side attenuated. Full CW rotation is zero width (Mono), full CCW is full Side.

Take the output of the "Encoder," which is Mid and Side and feed that into the "Decoder" inputs at point "A." Why the encoder/decoder role change? Because U9 is there to provide a buffer for the pot.

The Width-controlled Left and Right outputs are now taken from point "D."

Image
MS with variable width added.

Here's a short demo of the variable width control:

http://www.ka-electronics.com/content/M ... a_Live.mp3 (3.5 MB)
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Re: Mid Side M-S Matrix Uses No Precision Resistors

Post by mediatechnology » Sat Oct 08, 2011 11:05 am

I think you did Roger. And you can certainly use only a side pot here. I'll look for those drawings.

It's funny, those pads that you put there including the extra grounds makes wiring the pot a snap.

One thing I've found is that being able to rotate the control to full side allows one to hear all kinds of stuff that you didn't know were there. Good stuff and bad stuff. On some mixes the difference sounds like music, other tunes pure grunge.

The really, really squashed stuff - clipped - is particularly harsh in the difference channel. Stuff that's slightly panned and clipped has one channel clip before the other. This creates a lot of HF interchannel differences.

Being able to solo just side would seem to be a good diagnostic tool.
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