Mid Side Recording on Acoustic Guitar

[camerondye]

It seems like there is a lot of people trying to learn about M/S recording and I am messing around with a new mic so I figured I would post an mp3. It's about a minute long and has 5 sections...

1 - Only the Side mic files, both are in phase with each other
2 - Only the Side mic files, but out of phase with each other (:10)
3 - Only the Mid mic File (:20)
4 - Mid and Side mics, sides are in phase (:31)
5 - Proper M/S - Mid and Side mics, sides out of phase (:41 to end)

In the past I've had trouble getting this to sound right because I think I've been to close to the mics and this time I'm about 2 feet away from the 2 mic setup. The only effect on the recording is used to automate the phase of one of the side mics.
Cam

[gehauser]

Very enlightening to hear each element of the M/S with the phase combinations. I just recently obtained the necessary equipment/software to enable the M/S technique, so have not yet tried it. I had been wondering exactly what each of the M/S elements sounded like, and how it fits together. Boom, you nailed it.

Would be cool if you added one more full M/S sample where you vary the stereo width relative to that used in your last sample.

I think this would be a valuable, unique addition to the shootout contest - I guess you would have to parse the files, etc. to comply with the rules but you are nearly there.

Well done, and thanks for posting this.

[RKrizman]

I've never understood why you need special software for M/S recording. My understanding is that you copy the S figure 8 mic to two tracks, hard pan, and flip the phase on one channel. Bring the M mic up the middle. Is this not correct?

-R

[_Morph_]

Originally Posted by RKrizman

I've never understood why you need special software for M/S recording. My understanding is that you copy the S figure 8 mic to two tracks, hard pan, and flip the phase on one channel. Bring the M mic up the middle. Is this not correct?

-R

Yes, it is correct.
You can also route the S signal to another channel (via a send with unity gain) and hard pan the Side channels left and right, while flipping the polarity of the right channel.

[5down1up]

Originally Posted by RKrizman

My understanding is that you copy the S figure 8 mic to two tracks, hard pan, and flip the phase on one channel. Bring the M mic up the middle. Is this not correct?

-R

this is ... correct ! ( well, as far as i know @ least )

theres some mic pres with ms en & decoder. spits out a stereo track when decoding. theres some decoders in the box as well. might save some tracks, i prefer the 3 track routing as well.

[PVAUDIO]

These techniques all sound correct, but there is something I do that I don't think anyone mentioned. After I flip the phase on one of the side mics, I listen in mono, bring one side to 0 then I bring the other side up untill they cancel out completely. Then I switch back to stereo and blend In the mid mic.

[camerondye]

Originally Posted by PVAUDIO

These techniques all sound correct, but there is something I do that I don't think anyone mentioned. After I flip the phase on one of the side mics, I listen in mono, bring one side to 0 then I bring the other side up untill they cancel out completely. Then I switch back to stereo and blend In the mid mic.

You shouldn't have to do this though because since they are the same file panned and 1 flipped phase...they should always 100% of the time cancel at the same volume.
cam

Originally Posted by RKrizman

I've never understood why you need special software for M/S recording. My understanding is that you copy the S figure 8 mic to two tracks, hard pan, and flip the phase on one channel. Bring the M mic up the middle. Is this not correct?

-R

I think one of the reasons for a decoder is so you can listen to it in proper M/S while you are playing the original file. Other than that, I guess if you had to automate then with a decoder you would only automate mid and side and if you did it manually you would have to automate the mid and 2 sides (unless you bussed them to 1 track instead). Again...small gains but that's the only reasons I can think of.
cam

[RKrizman]

Fine, I just wanted to know if there was something esoteric about the process I was missing.

-R

[Old Goat]

Originally Posted by RKrizman

Fine, I just wanted to know if there was something esoteric about the process I was missing.

-R

I was initially confused about M/S recording and M/S processing--two totally different heads.

[Tim Spencer]

After reading this discussion I had some thoughts that might be useful. Maybe you guys already know this stuff, maybe not:

1) M= mid mic signal (mid mic can be cardiod, omni or figure 8) You can also think of this as the "Mono" component of signal that shows up in both the L and R decoded stereo channels.
2) S= side mic signal (side mic must be figure 8) This is the "Image" component that is added in-phase to the L channel and out-of-phase to the R channel (L= M+S , R= M-S). The amount of S signal added to L and R determines the stereo image width.
3) As you've noted, the decoding can happen in hardware or software. Software has the advantage that image width can be determined at mixdown. BUT if the original mic array placement was not good, you can't correct that. Hardware decoders have the advantage that you check out mic placement realtime. Then you can record decoded or undecoded, as you choose.
4) Hardware decoding via 3 channels on the mixer can yield less-than-wonderful sound because critical side channel signal usually goes thru an extra channel strip adding non-symmetrical noise/distortion and phase errors. It can sort of "mush out" the stereo goodness. That's why we put M/S decoders in our preamps that are minimal,passive and symmetrical.
5) When you get up close with an M/S mic array, and you get the main axis a little off center, you can get really unbalanced R and L. That's 'cause M and S can become almost equal. (Substitute S=M in the little formula in 2) and you can see why.)

Sorry to be so long-winded. Hope this is helpful in some way!

Tim

TRUE systems

[Heartfelt]

***M/S NOOB alert!***

Is M/S micing of acoustic guitar something reserved for acoustic style music or can it effectively be place in a general pop mix?

[Tim Spencer]

M/S mic technique can be useful any time you want to get a good stereo rendering of the talent and the acoustical space around the talent. It's used often for ensembles (choir, orchestra), but can be used effectively for almost any source. Some guys like it a lot for drum overheads. They can adjust the apparent width of the kit relative to other instruments in the mix. M/S mic positioning can sometimes be easier than XY, AB, etc. because you're not moving one mic relative to the other, in small increments, over and over, trying to get both good tonality and image. Frequently you can just "point and click" so to speak.

Tim

TRUE Systems

[Heartfelt]

Thanks Tim,

I guess then that the side doesn't have to be panned 100%?

I tried M/S a couple of times but failed. I think now that I can see it was do to the proximity to the mics. I think I should have been farther away to prevent skewing of the stereo stage.

good thread.

[5down1up]

the 3 track setup shouldnt change, speaking M, and the 2 S which the phase reveresed on 1 track and panned hard L&R.

i send it to a bus and do the panning from there, mostly using something like an imager ... how are you guys " panning " the ms ?

i found it a lot of times, that when using ms f.ex for an acoustic guitar that the s of course is louder in the body position compared to the neck side when the mic is kinda close. but thats a nature of the instrument itself, yes, no ?

cool thread & nice reading

[Tim Spencer]

The amount of S that you add determines the image width. If the S(ide) signal is turned down, you will hear mono signal in both the L and R channels from decoder (or mixer). Don't forget: +S (in phase) signal gets added to L, and -S (out of phase) signal gets added to R. I'm not sure what your particular setup is (hardware/software decoding), but you might take a look at my previous post to see if it helps you understand how to make things work.

Tim

TRUE Systems

[camerondye]

Originally Posted by Heartfelt

Thanks Tim,

I guess then that the side doesn't have to be panned 100%?

I tried M/S a couple of times but failed. I think now that I can see it was do to the proximity to the mics. I think I should have been farther away to prevent skewing of the stereo stage.

good thread.

I had the same problem getting it to work until I just backed the mics up some. I have never heard of people not panning 100%, I'm really not sure if it will work or not. Generally pan 100% and then control the width of the M/S recording with the volume of the Side mic tracks. Try it, switch it to mono and see if it cancels but I'm not sure if it will give any kind of bonus though...who knows.
cam

[5down1up]

was reading your replies and they are pretty clear.

still, when i set up f.ex an ms array feeding a pre and going with 2 outs in f.ex a daw and have 3 tracks running using the M-S setup ( m panned middle, 2*s panned hard L&R and one side phase reversed ) the summing of the tracks when used f.ex with an acoustic guitar is louder on the body side of the guitar.

had no problems with using a trim to correct the level difference in the summing.

does happen with piano as well, different with drums expect someones trashing the hihat.

have the 9098 dma which can do the coding, most often i do it in the daw.

[camerondye]

Originally Posted by 5down1up

was reading your replies and they are pretty clear.

still, when i set up f.ex an ms array feeding a pre and going with 2 outs in f.ex a daw and have 3 tracks running using the M-S setup ( m panned middle, 2*s panned hard L&R and one side phase reversed ) the summing of the tracks when used f.ex with an acoustic guitar is louder on the body side of the guitar.

had no problems with using a trim to correct the level difference in the summing.

does happen with piano as well, different with drums expect someones trashing the hihat.

have the 9098 dma which can do the coding, most often i do it in the daw.

Probably you are too close to the source, I was having the same problem at first. Once I backed up the mics and tried it worked amazingly. I've also heard issues with some people having 2 mics that are too different, but I wouldn't see why but who knows.
cam

[5down1up]

na the mic isnt the problem, tried it with several and usually i use the akg 422 for stuff like that.

the problem is that the mics to close, thats right. but i LOVE it when its close

have not really a problem with it, but i thought ... hmmmm, lets hear some jedi tricks

[3evil3mpire]

What do you guys consider close or far enough??

I just did an acoustic guitar recording and got the skewed image.