Topic: M/S vs Hypers/Wides/etc for Live Recording?

[stevetoney]

Besides getting the tracks aligned in post (taking the two tracks from the show and assigning them to three tracks in your DAW, then swapping polarity in the two mid tracks) isn't mixing just a matter of adjusting the relative level of the mid source to a level that sounds best to you? 

What else can be done with an m/s source, such that you guys are saying that you fiddled with it for days? 

I think they're mainly just fussing with the stereo width interminably.  To me, it seems pretty obvious when it's "right", or at least as right as it's going to get.

However, you can try boosting the bass a bit in the side (perhaps with a corresponding cut in the mid), which can give a bit more of a spacious feel.  I guess because mics are usually less directional in the bass, thus your stereo image will be compressed in the low frequencies if you don't compensate somehow - this may be part of why a lot of folks prefer time+intensity differences rather than just intensity.

Thanks Will.  Your answer is kinda what I figured. 

[Gutbucket]

For me it was partly an issue of fiddling with the ratio, but I could dial that part in pretty quickly.  It was more of an issue of the sound of the mic I was using- I got deep into eq'ing the Mid differently than the Side to get the sound that was in my head to come out of the speakers.  The technique opens up a lot of options which is nice, but options can be a Pandora's box.  I did get the sound I wanted, but you can always do a little better right?

General eq balance issues aside, boosting the low end of the side mic can be done to compensate for the difference in low end response between the mid and side mics.  Its more of a low frequency width issue than an eq balance. The figure-8 low end response roll off is usually more pronounced than the mid mic.  That translates as less side information than mid information at the lowest octaves, making the very low bass more mono than the rest of the spectrum for any given overall M/S ratio.

Buy eq'ing the mid and side signals separately, you are actually changing the M/S matrix ratio for those frequencies and changing the width of the stereo image.

Instead of doing the M/S decoding the old way with 3 tracks, check out the free Voxengo MEed plugin.  It's simple and can decode, encode, or both (which allows you to simply adjust the width/pattern of a non-M/S recording).

Even if you don't end up using the mic'ing technique much, playing with M/S in the DAW can be a valuable hands-on auditory learning tool to wrap you brain around.

[Will_S]

The figure-8 low end response roll off is usually more pronounced than the mid mic.  That translates as less side information than mid information at the lowest octaves, making the very low bass more mono than the rest of the spectrum for any given overall M/S ratio.

As a practical matter, I'm sure this plays into why "spatial equalization" works well with M/S recordings, but I've also seen the same approach (boosting the bass in a derived side channel) advocated for recordings made with a pair of cardioids.

[Gutbucket]

True, I bet the root of that is the same though- most cardioids get more omnish at the bottom so a stereo pair would have more mid and less difference in the stereo signal down there.  But here could be some psychoacoustics going on too.

Will, do you know if boosting the bass in a derived side signal is what a 'Blumlein Shuffler' circuit does?

[Will_S]

Will, do you know if boosting the bass in a derived side signal is what a 'Blumlein Shuffler' circuit does?

I don't think so, or at least that's not all it does.  I have a book at home that I think offers at least a basic explanation, I'll check it out tonight.

[boojum]

True, I bet the root of that is the same though- most cardioids get more omnish at the bottom so a stereo pair would have more mid and less difference in the stereo signal down there.  But here could be some psychoacoustics going on too.

Will, do you know if boosting the bass in a derived side signal is what a 'Blumlein Shuffler' circuit does?

Does this answer the question?

http://www.technicalcrew.com/modules/wordbook/entry.php?entryID=20

[Gutbucket]

Thanks Boojum, that link implies that boosting the bass in the side signal can be a side effect of the shuffler circuit which is primarily designed to convert the phase differences to amplitude differences.  It would appear it's perhaps related but not the same thing.

The Blumlein shuffler is a real mystery to me and I'd like to understand it's implications better.  Before inventing the mic technique that bears his name, he used omnis with a baffle disk and that shuffler circuit.. inventing an advanced Jecklin disk technique in 1932-33.  Amazing.  Yet I haven't found much more in depth information about it on the web than basic descriptions like the one linked above.  Could be interesting to experiment with for a jecklin disk or spaced omnis.

I'd love to know what you dig up Will.

[Will_S]

I'd love to know what you dig up Will.

My book doesn't really go into much more detail than that link, unfortunately. 

[DSatz]

Gutbucket, your statement:

> [ ... ] most cardioids get more omnish at the bottom so a stereo pair would have more mid and less difference in the stereo signal down there.

... doesn't generally apply to single-diaphragm cardioids, which can very well maintain their directional pattern down to the lowest frequencies in their range. The difference in effect is considerable, both for M/S and X/Y stereo recording, since the listener's sense of spaciousness is closely tied to the difference in low-frequency energy between channels (more specifically, to low correlation between the two channels at low frequencies). Dual-diaphragm cardioids are basically wide cardioids at low frequencies, so the low-frequency pickup of a stereo pair of them tends to be very nearly mono.

Incidentally (or not), this phenomenon is probably responsible for the mistaken impression that large microphones have better bass than small microphones. Nearly every large-diaphragm microphone ever made has had a dual-diaphragm capsule. A large dual-diaphragm "cardioid" microphone will pick up low-frequency sound energy from all directions in a room, while its pattern will become narrower than a true cardioid at high frequencies. See the attached polar diagram for a microphone based on a dual-diaphragm capsule design which has been very important in the history of recording. Along with that I've attached the polar diagram for a good single-diaphragm cardioid from the same manufacturer, which remains a cardioid all the way down. Similar examples could be shown with microphones from other manufacturers.

--best regards

P.S.: With regard to Alan Blumlein's "phase shuffler," you have to realize that Blumlein mostly didn't use what is now called the "Blumlein" stereo recording method, and didn't do so at all in the beginning. One of his patents describes the method in principle, and many years later the method of using crossed figure-8s was named in his honor. But as I recall no figure-8 microphones were available to him at the time of his early stereo recording experiments (though they certainly existed), so he devised the phase shuffler to help emulate their effect with near-coincident omni (!) microphones. I'll try to dig up some references.

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True, I bet the root of that is the same though- most cardioids get more omnish at the bottom so a stereo pair would have more mid and less difference in the stereo signal down there.  But here could be some psychoacoustics going on too.

I've wondered about that, I get my spaciousness of the room/soundstage/whatever in my MS stuff from those bottom frequencies and not in anything above about 3k.

Maybe I'm misinterpreting your remark (or my hearing really sucks that badly... eithers possible)

[Gutbucket]

I'll try to dig up some references.

I'd love to hear more about this.

[stevetoney]

Took the plunge and bought Pilgrims AK20.  Good deal for $700, but now I have to figure out how to pay for it.  Oh the joys of taping.  My motto when it comes to gear; leap then look.

[rowjimmy]

Late to this thread but I thought I'd chime in as a sort-of n00b in m/s in a live setting.

I use m/s at home to record acoustic guitar + vocal demos and I freakin love it. So, I went to a show recently and ran m/s. It was one where I usually see other tapers so I wasn't worried about being the only taper and making a shitty tape. Experimenting was more interesting anyway.

So, I get there and I'm the only taper. Given that I had just become a section of one, (plus my one blocker) I retreated to the sbd and took my chances. the results were pleasing but not perfect. Ideally I would have been closer with the config but the recording certainly sounds a lot like what I heard at the show.

rig was as follows: Studio Projects B1 (mid) + Cascade Fathead Ribbon (side) > SD MP-2 > nJB3
I used the voxengo MSed plugin in post (very easy plugin and FREE!) and got it tweaked to my satisfaction.

You can listen here http://www.archive.org/details/kw2008-12-26.rj  but, it's Keller Williams so I won't be surprised if you don't.