Matrix(ed) recordings

[Billster]

Though I've been trading a good while, I only fairly recently became cognizant of "matrix" recordings.

My two questions are - are matrix recordings essentially 2 or more recordings of the same event, combined into a single stream?

And second question, what is the value of matrix recordings? My assumption/guess is that the point is to use each recording to enhance the strong points of the recording so as to create a more full sound (appropriate crowd noise, bass but not too much, drums but not too much, etc) than either recording might represent standing alone - is this correct? Is this the spirit behind matrix recordings, and are there other reasons beyond this one for creating them?

[brainysod]

Originally Posted by Billster

My two questions are - are matrix recordings essentially 2 or more recordings of the same event, combined into a single stream?

Yes.

And second question, what is the value of matrix recordings? My assumption/guess is that the point is to use each recording to enhance the strong points of the recording so as to create a more full sound (appropriate crowd noise, bass but not too much, drums but not too much, etc) than either recording might represent standing alone - is this correct? Is this the spirit behind matrix recordings, and are there other reasons beyond this one for creating them?

Yes, mainly to polish a soundboard recording by adding in the audience and to make the instruments sound like they werent recorded in a room. And for the audience recording - to make the instruments clearer.

[ozzyzak]

I think that's right Bill....Aud/Sbd mix, I believe are so that you get the get instrument sound but without being sterile, so they might throw in a little aud for crowd noise/ambience. I'm not an expert but that'd be my guess.

[lucasweb]

Yea, the posts above are correct as far as i know, also i've seen matrixes done with multiple aud sources if there isn't a soundboard source available

[Billster]

Originally Posted by lucasweb

Yea, the posts above are correct as far as i know, also i've seen matrixes done with multiple aud sources if there isn't a soundboard source available

Yes, I think that's what was done with Radiohead 5/1/04, isn't it? Combined 3 different audience sources (I am 90% sure) into one...I guess the idea is to highlight the strengths of each....I assume fades and relative volume levels are used appropriately for this reason?

The 5/1/04 3-source matrix sounds remarkably like a good soundboard.

If anyone knows and wants to speak to how these matrices are actually made, I think it'd be interesting reading. What I mean is, is it a lot of trial and error to get a particular matrix sounding good, or do guys have a pretty good idea what role each of the 2, 3, whatever, sources needs to play?

[wazoo2u]

OK, here we go again. What are commonly (inaccurately) referred to as "Matrix" recordings are in fact "Blends" of independently recorded SBD and AUD sources of an event. In the audio world, a matrix recording is in fact:

Mid-side Matrix
One cardioid mic (M) points at subject (0°), and a figure-8 mic (S) picks up ambient sound by pointing at sides(90° and 270°).

The signals are then run through a decoder matrix (software or hardware) which creates two stereo channels:
n M+S = channel one
n M - S = channel two

One channel is a mix of M and S and the other be a mix of M and Sø (which means S is 180° out of phase)

n The more S, the stronger the separation.

MS Matrix recording is mostly used in acoustic concert settings to capture the true image of the hall.

One technique that Dan Healy perfected when mixing and recording the Grateful Dead, was to place a MS Matrixed microphone array at the mix position, and record it on a source that was locked to the same source as the SBD recording (assuring that the recordings were speed accurate to each other) What Dan called an "Ultra Matrix" was (as I understand it) actually a BLEND of a Matrix recording and a SBD recording. There are also time coincidence issues that are addressed when combining these sources.

Many "Matrix" recordings in circulation are simply blends of 2 different recordings and present a significant challenge in Post Production in terms of correctly time and pitch aligning the sources. The results of these efforts often sound really good, but are difficult to produce.

The cow has left the barn in terms of correcting the proper use of the term "Matrix", but in fact, it's nice to know the proper terms to apply to these very different methods.

[Billster]

Thanks wazoo, I didn't know any of that! Very interesting stuff.

[TheMamba]

Nice explanation. Thanks!

[feralicious]

wazoooooooooooooooooooooooooo...

doing his best to catch the cow.

[wazoo2u]

Originally Posted by feralicious

wazoooooooooooooooooooooooooo...

doing his best to catch the cow.

[jcrab66]

a true matrix is also the combined output of all single channel inputs into a soundboard through 2 channels

[wazoo2u]

Originally Posted by jcrab66

a true matrix is also the combined output of all single channel inputs into a soundboard through 2 channels

I've never heard the term applied to the configuration you describe. I would describe this (a regular soundboard recording) as a summed mix.

Actually, I would think that in concept, a matrix would exist within a soundboard as the relationship between all inputs and their ability to be selectively assigned to ALL outputs, at least, that's how I would commonly utilize any sort of routing or patching matrix, and that relationship is basically how a soundboard is defined ie: a rectangular array of elements (or entries) set out by rows and columns.

I believe that what we're discussing here is a recording technique that utilizes a specific kind of encoding, not routing. You can see the reference to MATRIX CO-EFFICIENTS in this description of MS technique: http://www.uneeda-audio.com/ms-mat.htm

Originally Posted by wazoo2u

OK, here we go again. What are commonly (inaccurately) referred to as "Matrix" recordings are in fact "Blends" of independently recorded SBD and AUD sources of an event. In the audio world, a matrix recording is in fact:

Mid-side Matrix
One cardioid mic (M) points at subject (0°), and a figure-8 mic (S) picks up ambient sound by pointing at sides(90° and 270°).

The signals are then run through a decoder matrix (software or hardware) which creates two stereo channels:
n M+S = channel one
n M - S = channel two

One channel is a mix of M and S and the other be a mix of M and Sø (which means S is 180° out of phase)

n The more S, the stronger the separation.

MS Matrix recording is mostly used in acoustic concert settings to capture the true image of the hall.

One technique that Dan Healy perfected when mixing and recording the Grateful Dead, was to place a MS Matrixed microphone array at the mix position, and record it on a source that was locked to the same source as the SBD recording (assuring that the recordings were speed accurate to each other) What Dan called an "Ultra Matrix" was (as I understand it) actually a BLEND of a Matrix recording and a SBD recording. There are also time coincidence issues that are addressed when combining these sources.

Many "Matrix" recordings in circulation are simply blends of 2 different recordings and present a significant challenge in Post Production in terms of correctly time and pitch aligning the sources. The results of these efforts often sound really good, but are difficult to produce.

The cow has left the barn in terms of correcting the proper use of the term "Matrix", but in fact, it's nice to know the proper terms to apply to these very different methods.

I think that is a technically accurate explanation,though the term has come to mean a mixed recording with dual sources,such as a board feed and a mic or two,with some % of each getting recorded. If it is an after the fact blending,it is often called a merge. There is a Hendrix New Years eve show that was merged,in large part because the board and a couple of auds each had significant shortcomings but blending allowed for a more listenable and complete show. A Source might have low hiss,but very weak bass,another may have hi-freq hiss,but full freq response while another has good vocal presence but is incomplete. With enough time and software it is possible to assemble a recording that is a better representation of the show than any one source.
For a mixed matrix'or "matrix" its about the SBD clarity and detail +the aud ambience,audience reactions.
At one point Healy used Beta HI-Fi with the board going through a PCM unit and an AUD feed going onto the Beta HIFI. That enabled a synched 4 channel recording that later could be mixed to the best ratio. The board rec was digital,the aud,analog,but Beta HIFI-or for that matter,VHS hifi,gives a good 20-20k response with a real nice SN ratio,enough for the job.

^^ I realize this is a very old thread, but I was wondering if there is a list of Healy Ultra Matrixes. I'm guessing a lot of the sbds that circulate from his era are U-mtx but I know it's not all of them.

[co9ol]

Hey guys, I was wondering if anyone out there would be interested in providing an in-depth tutorial on how to make a matrix/blend. I think it'd be really interesting and we could all learn a lot.