Better Understanding The 3:1 Rule Tracking Drums

[Derrick]

OK, so I have lots of new equipment to get fammiliar with and I am beginning this task with laying down drum tracks. Mainly, I think this question applies to OH micing. I'm not sure if there is a sience to how high the mics need to be off the set, but in a home based studio where you may only get a spaced pair say... 3 feet above the toms (cymbals probably 2 feet?), I wouldn't be following the 3:1 rule right?

If both mics are getting the mounted tom 3 feet away, wouldn't the spaced pair need to be 9 feet apart from each other? I guess overall, I'm trying to better understand OH mic placement (both mono and spaced pair) on a drum kit.

[trodden]

OK, so I have lots of new equipment to get fammiliar with and I am beginning this task with laying down drum tracks. Mainly, I think this question applies to OH micing. I'm not sure if there is a sience to how high the mics need to be off the set, but in a home based studio where you may only get a spaced pair say... 3 feet above the toms (cymbals probably 2 feet?), I wouldn't be following the 3:1 rule right?

If both mics are getting the mounted tom 3 feet away, wouldn't the spaced pair need to be 9 feet apart from each other? I guess overall, I'm trying to better understand OH mic placement (both mono and spaced pair) on a drum kit.

I'm interested as well derrick. I bounce back and forth between spaced pair and x/y. Never really know which is the right to use in what situation. Normally just decide on how big the kit is and what kind of drum/cymbals i need to hear and how. I'll fuddle with the overheads for awhile longer than most mic apps, just making sure there isn't too much wierdo phase stuff going on but a good stereo spread. Yeah, i said it, i like stereo oh's even though the mono overhead has worked well for me in the past. Usually though i'm more worried about oh's making hi hat bashers and china bashers not so harsh if thats ever really possible.

[nacho459]

The 3:1 rule applies to stereo micing where the two mics are on the same plane and point the same direction. So if you have two mics that are 3 feet above the kit, placed parallel to the ground, and positioned so the diaphragms are pointed perpendicular to the floor they need to be 9 feet apart to get an "acceptable" amount of stereo separation and very little phasing.

Like all recording rules this is just a guideline. The easiest way around the 9 feet thing is a little setup known as ORTF where you place the mics about 17cm apart, and splay them away from each other. However this was developed by the French radio engineers and what the hell do they know?

Me, I'm an American so I just put stuff where it looks cool.

Actually I usually do a mix between a spaced pair and ORTF usually about one to two feet apart, and splayed out. I like a really wide image, but I also don't want stuff in the middle to disappear, so again always listen to the mics before you hit record.

[trodden]

Me, I'm an American so I just put stuff where it looks cool.

Actually I usually do a mix between a spaced pair and ORTF usually about one to two feet apart, and splayed out. I like a really wide image, but I also don't want stuff in the middle to disappear, so again always listen to the mics before you hit record.

Ha! me as well!

forgot what i was doing is actually a bastardized basement version of ORTF rather than "true" spaced pair.

but the cool looking factor is always important as well!

[joelpatterson]

All the science, I don't understand, but after a long torturous path of experimentation--I experiment alot for someone who isn't a scientist--I've got two Marshall MXL V57Ms placed about seven feet high, about 7 feet apart from each other, equally astride the kit.Scientifically in a straight line that passes over the equator of the snare.

If there was just two tracks for a drumkit, that would be fine. Add a kick and snare mics, and these four tracks IS really fine.

If you think of the drummer and his kit suspended in a bubble, then the ideal miking, at least in a quantum way, would be mics all over the surface of the bubble--the V57M's being over Alaska and Norway, respectively.

Of course, there are others who can explain it better than I can.

[joel hamilton]

If I have ever measured anything at all, and that is a big IF because i NEVER do it, it was AFTER I set up the mics, and happened upon a particularly pleasing phase relationship between a center ambient mic and a kick drum, or maybe a nice snare/ OH relationship. I porbably measured it, tried it again and realized it was not applicable anymore and got on with my life.

For real this time: There are NO rules to this. There are certain techniques that yield results time and again, but they are not, and never were "rules" for recording. There are things with names, like "blumlein" or "mid-side" and they are just things someone FIGURED OUT THROUGH EXPERIMENTATION, and because they figured out something good and gave it a name... here I am typing about it.

Anyway: HIT RECORD. Try stuff. Make it sound great. One day kids will be asking about the method YOU came up with....

[soundguy]

well, blumlein and ms kinda dont work unless you set them up right but if you arent concerned with true stereo imaging its such a better use of your time to figure out where you can put mics so the shit sounds good versus where you should put mics to conform to some rule you read about on the internet. If you are using close mics on a drum kit in conjunction with any kind of overheads or ambients you are going to have to deal with phase relationships one way or another. The thing about learning about a 3:1 rule is that it really discounts the acoustics of the space you are in. If you have a drum kit right next to a wall, versus out in the middle of a room or outdoors, that first reflection has the potential to completely fuck with the present sound of the kit even if you take that identical micing setup that has this ruling phase relationship "by the book" and move it out into a less reflective or dead space. If you think about the correlation with the introduction of close mic'ing drumkits as a serious trend and dead spaces, its no coincidence, its MUCH easier to do in a dead space than it is in a live one. Easier for me at least. In a lot of ways learning about some of these things is good but its sorta like learning all about baseball and never exercising and then expecting to be a good baseball player. The idea of being a fat guy with a mouth full of tobacco having to run around in a circle is a whole lot different than actually being a fat guy with a mouth full of tobacco actually running around in a circle. the real acoustic issues with any kind of micing setup (micing setup meant to mean in this example any time you are alive where you plug a cable into a microphone with the intent of recording something with it) will always dominate and determine what the setup becomes based upon what it sounds like, that is, if you are doing your job. Sure, the theory can help you solve problems and is not entirely worth discounting, but its also not something to spend time stressing about. If you use morre than three mics on a kit, its hard to have everything to conform to a 3:1 rule, yet there are ways to use more than 3 mics on a drum kit and have it rule while breaking the rules. Worry about it sounding right in the speakers. Ive found electronic theory which is not tied to case specific and constantly varying acoustic info will get you a lot further than this type of stuff if you want to learn and apply theory in a session. The mic stufff is easy, point it where it sounds good, put it where it works with the other mics and your source. Eaiser to remember than the 3:1 rule.

dave

[Professor]

It seems 3:1 comes up pretty regularly, and always with all sorts of confusion which has me convinced that it is either not taught wel, or overemphasized as a critical element of mic technique. And I always list these three very simple comments to help clear up the confusion (as best as I can).
1- As dave said, it's not a RULE, but simply a recommendation. Yes, it's a recommendation that is there for your own good because the intent is to minimize phase issues when two mics are capturing the same source. But it's still just a recommendation.
2- It's not just the 3:1 recommendation, but really the "greater than or equal to 3 recommendation". This is important to consider because some people get hung up on the multiple of three and worry that it isn't right if it's a 4:1 ratio. In fact, that's even better for controlling phase issues.
3- It's a ratio and damn it, ratios are reversible!!!!! This is the big one that bugs me, especially when someone gets confused about recording in stereo with XY or ORTF or some other format when they are 10' from the source. You see, if the distance between the mics is 1' and they are 10' from the source, then you are at a 10:1 ratio ( or 1:10 if you prefer) and therefore well past the 3:1 recommendation. If your mics are 4' above a drumset and 1' apart, then your at a 4:1 ratio, and while there will be phasing differences between the channels, that will serve to heighten the stereo imaging beyond just the volume differences caused by the mics' polar patterns.

And of course, even if you're close micing, your OK, because the ratio between the source and any pair of microphones is going to observe the 3:1 recommendation, and its reversed 1:3 recommendation. Think about it, if those mics are 4' up and 1' apart and you have a spot mic 0.5' from the individual drums, then you have a 1:4 between source and the two overheads, a 1:7 ratio between spot mic and the overheads, a 1:8 ratio between the source, close mic and either overhead, and anyway you slice it, you're within the boundaries of thie "rule".
But, if you start spreading those OH mics to perhaps 4' up and 2' apart, well then now you're at a 2:1 ratio and would be in danger of causing audible phase disortions, though not necessarily creating them. But your close mic at 0.5' is still in a better than 3:1 ratio with regards to the source and OH mics.

-Jeremy

[Derrick]

Thank you guys for your replies! It should go without saying that I should experiment and find what works for me as well as try to develop my own characters. However, I'm making a large jump from someone who always recorded in larger studios, observed, and tried many things on my own with the meager equipment I had at home... for years. I have now made a huge jump to owning proper equipment and I am trying to get information on some basics/starting points. I always take in information then do my own thing, but you gotta have foundation to start.

With that said, I usually see two mics above the kit, but want to know about how people choose their placements. This brought up the 3:1 question so I'm wondering about both of these aspects. I've read many practices on this board for micing acoustic guitar that would seem to induce phase issues as well.