MS recording

[yayajohn]

I've been reading about this technique and I think I finally grasp a little of it. I understand that it was meant to be accomplished using 2 mics, 1 directional and 1 figure 8 on top of each other. Now I don't have the mics and nore would I even think about recording my squeaky voice but i've been trying to hook up my keyboard to achieve a similiar effect/enhancement within Scope but I have been unsure how to actually hook up a mono signal and a left and right stereo signal to a device that only has 2 inputs (like the BX)
This screenshot is what I came up with and I was hoping if someone could please tell me if this is the correct way.
Also maybe tell me if I'm wasting my time doing this without the mics? I can hear the mono signal and the stereo signal when I isolate them in the device but when I combine them i'm not sure if i'm just perceiving a better sound than just leaving it stereo.

BX DNA MS Compare.jpg (678.63 KiB) Viewed 3184 times

[jksuperstar]

The MS is also only 2 signals, one is only mono, the other is "left" when positive, and "right" when negative. The gain is not improved stereo separation, but in isolating the mid or mono channel. This is mostly used in video work, capturing voices nicely, and then panning them at will. The side or stereo channel, is just ambience that can be mixed in depending on how much is needed.

For effect on music, I still think of it as mono and side/ ambient channels, so you can have a very powerful mono component, and add reverb for example only to the side component. That keeps your bass focused, and not muddy. Or a lead, or a vocal. whatever is centered in the mix before the ms-encoder. Then add effects to either mono or side channels, Then you mix them back together, like this:

L = M + S
R = M - S, or M + -S (S inverted).

Use three channels on the mixer to do this:
1 = Mid/Mono
2 = S, left panned
3 = S, inverted, right panned.

[garyb]

when recording ms, the figure 8 mic is very important so that you get the proper phase cancellation from the inverted channel.

the figure8 mic is at a right angle to the the cardiod mic. the side mic really is listening to side reflections. the effect is as jksuperstar describes.

i guess you could approximate the figure8 with two cardiod condensor mics facing eachother overlapped slightly. then you could sum the two mics and then invert. it'd be scary connecting two mics to the same phantom source, so i'd sum after phantom, whetther an external box or the mic pre/mixer. it wouldn't be ideal, but you'd get the idea.

a technique like this is about micing a room, not close micing. it'll only sound good if the room sounds good...

of course a processor like the bx is a different thing used the same way.

[yayajohn]

Jk and Gary; thanks to both for sharing your knowledge.

Couple of quick questions:

Jk when you say "inverted" do you mean phase inverted?
The ambience is the effect I am trying to achieve so I think I will try to do as you listed.


Gary; so can the BX (or other MS devices like DNA equaliser) be used like this w/o mics to enhance the sound of say a keyboard or am I simply just recycling the signal path with no real enhancement to the sound?

Dan

[jksuperstar]

Yes, phase inverted (also sometimes called 180 degree shift, or in math multiply by -1).

When using the M/S mode, do these filters decode the MS components? or do they encode a stereo signal, allowing control over M and S separately, then decode back to stereo?

I would take the outs from your MS-Encoder, straight into the filters , but don't have the L/R linked, and don't enable M/S mode. Then, add some (mono) reverb (or phase/chorus) to the S channel to make the concept obvious to your ears, and finally put them through an MS-Decoder (or in a mixer like I described above).

[yayajohn]

Yes, phase inverted (also sometimes called 180 degree shift, or in math multiply by -1).

ok great that makes sense

When using the M/S mode, do these filters decode the MS components? or do they encode a stereo signal, allowing control over M and S separately, then decode back to stereo?

LOL! well that's what i've been trying to figure out with the BX since I bought it. This is my trend: I'll buy a device/plug that I have no idea what it's for or how to use it and then feel obligated to learn how since I paid all that money for it and wala; learning has occurred. Only problem is sometimes I bite off more than I can chew. It's been like that since my first Pulsar in 99 and it's been a wonderful educational journey with the help of all my friends here at PlanetZ

I would take the outs from your MS-Encoder, straight into the filters , but don't have the L/R linked, and don't enable M/S mode. Then, add some (mono) reverb (or phase/chorus) to the S channel to make the concept obvious to your ears, and finally put them through an MS-Decoder (or in a mixer like I described above).

Ok I will try that. May take me a while to get that set up straight though.

Thanks

[astroman]

a smart way to record acoustic guitars in M/S: put a figure-8 mic in front of the guitar
(turned 90 degrees so that top and bottom of the 8 point to the ends of the instrument)
then use the a built-in pickup as a virtual center mic

those pickups are usually piezo and come over less aggressive than usual

cheers, Tom

[garyb]

the BX's mid/side generation works with a stereo signal like a mix or a stereo synth, something that actually has panned elements. using the m/s generator on a mono signal is kind of pointlees.

[Liquid EDGE]

I could be wrong. But.

things like dna stereo equalizer, das master it eq and the bx eq.

They process stereo signals and enable you to eq the mono and stereo parts.

The only thing I know of for scope that can decode a ms signal. (one 8 direction signal and one mono signal) into stereo is a device called xenoncodec. That device also has inserts to apply effects to either signal.

[yayajohn]

ok thanks, that's what I thought when I first bought the BX but it didn't seem to work the way I thought it was going to. Wish there was a little bit more literature for the BX. I'm most likely tackling this in the wrong manner so time to study this a little bit more obviously. I appreciate the help on this guys.

Dan

[Liquid EDGE]

http://wolf-audio.com/wad/freebies/Entr ... Codec.html

This is the device. It can also turn stereo signals into an m /s
signal so you can do things like chain two xenoncodecs up.

Set the first one to turn a stereo signal into a m/s signal then feed that into a second xenoncodec which turns a m/s signal into a stereo signal.

You can now drop fx onto the mono and/or stereo(side) signals to enhance the sound with or without effecting the mono or stereo(side) signal etc. Blah. Blah.

With regards to stuff like bx, das master it and dna stereo eq when in m/s mode.

They are mainly designed for mastering. So you can eq stuff more precisely and effect the mono and stereo(side) content separately.

Also, m/s recording, to me. Is basically a recording technique that records how we "hear"

[astroman]

without having digged into math too deep...
M/S is a fairly simple logical connection of 2 Signals that you can do with any mixer (that can invert a channel)
the basic devices are just a convenience

stuff in the mastering position first of all takes care of side-effects that typically will show up in a DAW environment
the signal is very sensitive to any kind of phase alterations (think EQ, Comp, lookahead, buffers)
clever and (again) convenient, but no rocket science at all
most important are skills (experience) to handle it and careful listening

cheers, Tom

[Ricardo]

Just a mention that a Fig 8 mic doesn't have to be a major investment. There are some fine ribbon mics on the market (active and inactive) that do the job nicely and will give you a nice ambience as well. $150 should be plenty second hand. I bought a GAP mkIII just out of curiosity, and it gets used quite a bit.

[wolf]

http://wolf-audio.com/wad/freebies/Entr ... Codec.html

This is the device. It can also turn stereo signals into an m /s
signal so you can do things like chain two xenoncodecs up.

You can chain two Xenons but you don't need to .. it's all in one device and therefor better in regard to phase issues :

conversion left/right to mid/side -> separate inserts (mono of course) for mid & side signal -> conversion mid/side to left/right

This is basically, what all the previously mentioned devices do, btw.

have fun,
wolf

[Ricardo]

when recording ms, the figure 8 mic is very important so that you get the proper phase cancellation from the inverted channel.

the figure8 mic is at a right angle to the the cardiod mic. the side mic really is listening to side reflections. the effect is as jksuperstar describes.

i guess you could approximate the figure8 with two cardiod condensor mics facing eachother overlapped slightly. then you could sum the two mics and then invert. it'd be scary connecting two mics to the same phantom source, so i'd sum after phantom, whetther an external box or the mic pre/mixer. it wouldn't be ideal, but you'd get the idea.

a technique like this is about micing a room, not close micing. it'll only sound good if the room sounds good...

of course a processor like the bx is a different thing used the same way.

This link is a good start to get the idea:
http://www.recording-microphones.co.uk/ ... ereo.shtml
Also shows you how to do it without an encoder.

Enjoy