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Drum Overhead Spread Problem Condenser Microphones
Old 19th December 2010
  #31
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Quote:
Originally Posted by u b k View Post
Again, this is not the 3:1 rule, if anyone's interested my earlier post in this thread explains what the 3:1 rule is and where it applies.

https://www.gearslutz.com/board/6124318-post9.html


Gregory Scott - ubk
Hey ubk, I appreciate all the knowledge you share here, but I am confused, this is a direct excerpt from the 'modern recording techniques' book:

"Whenever individual instruments are being miked close (or semi-close) it is generally wise to follow the 3:1 distance rule. This principle states that, in order to reduce leakage and maintain phase integrity, for every unit of distance between a mic and its source a nearby mic (or mics) should be separated by at least three times that distance".

-Danny
Old 19th December 2010
  #32
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NOS61's Avatar
 

Quote:
Originally Posted by unitymusic View Post
Hey ubk, I appreciate all the knowledge you share here, but I am confused, this is a direct excerpt from the 'modern recording techniques' book:

"Whenever individual instruments are being miked close (or semi-close) it is generally wise to follow the 3:1 distance rule. This principle states that, in order to reduce leakage and maintain phase integrity, for every unit of distance between a mic and its source a nearby mic (or mics) should be separated by at least three times that distance".

-Danny
Complexe thing here: "Whenever individual instruments are being miked close (or semi-close)"

It works for a 2 mic setup on a sax, or a gtr if you wish...

That 3:1 rule does'nt apply to a multi-miced drums setup... The 3:1 rule is based on the source as its reference for 1 mic to the other.....Since you have multiple sources in this case, what would be the reference ?
With OH,even if you aim at the cymbals, few iches away you have the toms, and further away , the snare, and so on...
Here is an exemple how 3:1 would apply: you would put mics for the cymbals + mics for the OH... Then you could make sure that you keep the 3:1 between Oh and cymbal mics and toms mics and so on...

Salute !
Old 19th December 2010
  #33
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Hi Danny,

UBK put it a little confusingly, but he's right.

If you're micing two toms, lets say, using two mics, the first tom is going to get picked up by both mics, as is the second. So, the mic on the second tom needs to be at least 3x as far from the first tom as the first mic, otherwise you'll get comb filtering, because the relative levels will be too close, and the time delays different.

If you have two mics on the same source, they also will benefit from the 3-1 rule, such as an acoustic guitar. If you have a mic on the soundboard, and a second up on the 12th fret, they need to be close enough to the guitar that the distance ratio is 3:1, in relation to the point on the guitar that they're micing. So the 12th fret mic doesn't need to be 3 times as far from the guitar, just 3x as far from the area of the soundboard that the other mic is focused on.

This gets complicated on things like drum sets, where there are many sound sources. You can avoid most of this comb filtering business by using a stereo mic or coincident pair. ORTF or NOS will avoid most, as well, but not all, when collapsed to mono. When using a spaced pair, you want to try to be equidistant from the snare, to avoid comb filtering on the snare that is picked up by the OHs. It's not possible to be equidistant from the toms, but as they don't have that much high frequency content, the comb filtering is a bit less apparent. Quite often high-passing the OHS is beneficial with spaced pairs, to avoid lower frequency phase issues with toms and kick.


It all relates to the falloff level as you move away from a sound source. Every time you double the distance, you get 1/4th the level, by being 3x as far away you get 1/9th the level in the second mic:

Inverse Square Law for Sound

This means that the bleed shouldn't be loud enough to compete with the close mic on that source.

Of course you can get good results with a mono overhead and close mics on cymbals, and good room mics. Sometimes it's much better than stereo overheads, depending on the situation!
Old 19th December 2010
  #34
Gear Nut
 

Thanks a million for all the replies.. I have another question about a technique to throw out there.. Im not even sure if this technique is used much at all, or what the benefits and disadvantages of it are, but i read about it once in Kurt Cobains journals i think so i just thought I'd throw it out there!!!:-P

Its where you record the drum kit without cymbals and then overdub the cymbals after. I had considered trying it for the fun of it but im not sure if there is any advantages in doing it? Probably more of a disadvantage then anything..

I just thought by trying it you would be able to push and experiment with the room mics more and wouldnt have as much cymbal bleed etc on all the other mics.

What i was wondering though is how exactly this is done when tracking.. Do you leave the hi hats and ride to track with the cymbals? Is there some kind of pads you can get for the drummer to hit while tracking without the cymbals etc?

Its probably a fairly stupid technique but i just thought id throw it out there to see what ye think of it?

Cheers
Old 19th December 2010
  #35
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Quote:
Originally Posted by leitrim_lad View Post

Its probably a fairly stupid technique but i just thought id throw it out there to see what ye think of it?

Cheers
No rules, it's all situational and personel dependent.

Probably, for most drummers, you will get the best feel and performance from them playing the kit as a whole. But, you can certainly play some interesting games with the cymbals independent of the rest of the kit if you record them separately - reversed cybals, reverse reverb, delays etc.

Plus, having a close mic'd snare track with no high hat would be really nice - but performance always has to trump all other concerns.

Experiment when you have the luxury, otherwise document to the best of your ability, and do your best not to f**k it up.
Old 19th December 2010
  #36
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John Suitcase's Avatar
 

It goes on and on, there are a zillion ways to do this stuff. Tracking cymbals separately is something I haven't done, but I've heard of people doing it successfully. I just never saw the point, myself.

For the room sound, some people use a speaker and reamp the close mics, snare, toms, kick, but not cymbals, then record that with room mics, one at a time (left, then right.)

Another easy tip is to get the cymbals and hihat up as high as possible, where the drummer is still comfortable, but there is room to get mics in, with good isolation. Makes a huge difference on snare, in particular, as well as ride/floor tom...
Old 19th December 2010
  #37
Gear Maniac
 

For years I used a spaced pair but nowadays I prefer NOS on O/H, but ORTF give excellent results also. It's not so much the stereo spread but the more focused central image. Try all the different techniques, you'll find the one that best suits your sensibilities. Oh, and the other week for giggles I tries a Blumlein pair about 4 ft in front of the kit and about 6 feet up. Sweet sound, good room though.
Old 19th December 2010
  #38
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Quote:
Originally Posted by u b k View Post
The 3-to-1 rule is for multiple mics on multiple sources, not for multiple mics on one source. The idea is that if you put mic A on source A at a distance of Q, then you need to make sure mic B on source B is at a distance of at least 3x Q from source A.

Quote:
Originally Posted by unitymusic View Post
Well the 3:1 rule would mean that if you have the Left Overhead 2 ft from the left cymbal, the Right Overhead would have to be at least 6 feet from the left cymbal, not the other mic.
I still don't understand how this wouldn't be the 3:1 rule, if the left cymbal is source A and the left mic is mic A, the right cymbal would be source B and the right overhead would be mic B. If "Q" for source A and mic A is 2 feet mic B would have to be 6 feet from source A, no?

Of course this would apply to every mic and source in the setup.


Quote:
Originally Posted by u b k View Post
When stereo mic'ing a single source, *most* phase-coherent mic positions involve having the mics very close together, often as close to touching as possible, regardless of how far they are from the source. 3-to-1 does not apply in these scenarios.
It is my understanding that the 3:1 rule doesn't apply here because you are ideally placing the mics in a manner where the source sound(s) will reach both mics at as close to the same time as possible, minimizing or eliminating as much of the phase issues as possible.

I'm not trying to be argumentative, I just don't understand the distinction, or maybe it's a communication breakdown, I don't know. Thanks everyone for the replies though.

-Danny
Old 19th December 2010
  #39
Gear Nut
 

ceiling treatment

I found hanging heavy blankets in a tentlike pattern above the drum kit and fastened to the ceiling really helped getting a clear stereo spread on the cymbals. I record a lot of jazz (where cymbals rule) and this was a problem for me as well. Stuff on the ceiling completely cleared it up. YMMV
Old 19th December 2010
  #40
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John Suitcase's Avatar
 

Quote:
Originally Posted by unitymusic View Post
I still don't understand how this wouldn't be the 3:1 rule, if the left cymbal is source A and the left mic is mic A, the right cymbal would be source B and the right overhead would be mic B. If "Q" for source A and mic A is 2 feet mic B would have to be 6 feet from source A, no?

Of course this would apply to every mic and source in the setup.
Yep, that's how it would work. That's why spaced pairs can sound swishy on the cymbals, if you're not careful. You need to get the pair in a little close, so that the cymbals on the near side are much louder than the bleed from the far cymbals.

Quote:


It is my understanding that the 3:1 rule doesn't apply here because you are ideally placing the mics in a manner where the source sound(s) will reach both mics at as close to the same time as possible, minimizing or eliminating as much of the phase issues as possible.
the 3:1 rule doesn't apply if you can get the capsules to be equidistant, either as a coincident pair, or carefully measured from the source. Of course, with something like a drumset, it's hard to be equidistant from every source!

Quote:

I'm not trying to be argumentative, I just don't understand the distinction, or maybe it's a communication breakdown, I don't know. Thanks everyone for the replies though.

-Danny

It's kind of hard to understand on a drumset, because it flies in the face of many drum mic'ing techniques. But it's still valid, and should be kept in mind when setting up mics.

It's also important to keep in mind that a reverberant room will have more indirect signal, so separation becomes much more difficult, and comb filtering more prevalent. In my experience, small rooms and very live rooms benefit from fewer mics on the drums. A deader, good sized room can tolerate more mics on the kit without issues.
Old 19th December 2010
  #41
Gear Maniac
 

the 4th dem

Quote:
Originally Posted by SRS View Post
Couple things... I read through the post and did not catch a few very important elements. First, how high is your ceiling? Is it treated, like with a cloud directly above the kit to help give the illusion acoustically of a much higher ceiling? Also, the drum kit is one instrument and should be first and foremost approached as such. After capturing the best overall balance of the kit (cymbals and drums) with the overheads, bring in the spot mics on the individual drums to fill in the holes and add beef.

Taking away the comb filtering and direct first reflections from the ceiling will go a long way to getting the clarity and cymbal spread you are seeking during initial tracking.

(bump)
What are the drum room / booth. . .L x W x H ?
C
Old 20th December 2010
  #42
Gear Guru
 
u b k's Avatar
 

Quote:
Originally Posted by unitymusic View Post
I still don't understand how this wouldn't be the 3:1 rule, if the left cymbal is source A and the left mic is mic A, the right cymbal would be source B and the right overhead would be mic B.

It's a fair question. The answer is that we're not talking about two sources, cymbal A and cymbal B; we're talking about one single source: the drumkit.

OP, at least as I understand it, is looking for more 'spread' from his overheads, which to me means he wants a wider stereo image. Stereo imaging comes from two mics on one source (which can then be augmented with spot mics).

The 3:1 rule exists to help engineers increase isolation in live, multi-instrument recording situations. Increased isolation by definition reduces crosstalk; stereophony by definition *requires* crosstalk.

The solution to OP's woes is to find the stereo mic technique that gives him the kind of image he wants to hear, and use that to capture his kit, or overheads, or whatever it is he wants to use as the basis of the stereo image of the drums. Coincident pair, spaced pair, whatever... all these techniques have their sound and they all image differently, so experimentation and exploration is key. thumbsup


Gregory Scott - ubk
Old 20th December 2010
  #43
Gear Addict
 
David Watts's Avatar
 

Quote:
Originally Posted by leitrim_lad View Post
Its where you record the drum kit without cymbals and then overdub the cymbals after. I had considered trying it for the fun of it but im not sure if there is any advantages in doing it? Probably more of a disadvantage then anything..

I just thought by trying it you would be able to push and experiment with the room mics more and wouldnt have as much cymbal bleed etc on all the other mics.

What i was wondering though is how exactly this is done when tracking.. Do you leave the hi hats and ride to track with the cymbals? Is there some kind of pads you can get for the drummer to hit while tracking without the cymbals etc?

Its probably a fairly stupid technique but i just thought id throw it out there to see what ye think of it?

Cheers
Yeah man, this is a pretty tried and tested technique - Josh Homme has done it on every QOTSA record since Rated R. Like you say, you can really squeeze some power out of the room mics. It can sound a little unnatural, so it really depends on the situation.

And yes, you should use pads to replace the cymbals.
Old 20th December 2010
  #44
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Quote:
Originally Posted by u b k View Post
It's a fair question. The answer is that we're not talking about two sources, cymbal A and cymbal B; we're talking about one single source: the drumkit.

OP, at least as I understand it, is looking for more 'spread' from his overheads, which to me means he wants a wider stereo image. Stereo imaging comes from two mics on one source (which can then be augmented with spot mics).
Well I should apologize because I never addressed the OP or his questions/concerns, I was merely replying to the original post I quoted. And I understand that for practical purposes regarding the OP's question that a drumkit is one source, but as far as physics is concerned each individual drum and/or cymbal is its own unique sound source, so I still don't understand how my original post you quoted does not pertain to the 3:1 rule.

-Danny
Old 20th December 2010
  #45
Gear Maniac
 

Quote:
Originally Posted by unitymusic View Post
Well the 3:1 rule would mean that if you have the Left Overhead 2 ft from the left cymbal, the Right Overhead would have to be at least 6 feet from the left cymbal, not the other mic.
Well I was trained otherwise I guess, but the correct definition (if you look it up) it says that placing the second mic three times the distance from the first mic that the first mic is from the source is the 3:1 rule. In layman’s terms, if the first mic is 1 foot from a source, the second mic should be placed 3 feet from the second mic.
Old 20th December 2010
  #46
Gear Guru
 
u b k's Avatar
 

Quote:
Originally Posted by unitymusic View Post
...so I still don't understand how my original post you quoted does not pertain to the 3:1 rule.

On that we agree.


Gregory Scott - ubk
Old 20th December 2010
  #47
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I don't know if you have any figure-8's but I'm really liking a blumlien setup for overheads here lately. I find that it's very easy to setup and gives you very good width. Much more natural sounding to me than a typical x/y with cardiod and with a stronger center than a/b. An added bonus is that since the mics are over the center of the kit they usually are further away from the cymbals than with an a/b setup which always helps IMO. As a drummer/engineer I think cymbals sound better/smoother when the mics are not right on them. Blumlien does bring the room out more so this could be a problem if the room isn't great.
Old 20th December 2010
  #48
Gear Maniac
 

The 3:1 rule will definitely help with spread. Less phase issues = more true representation of the sound, thus helping with the stereo image.

TO THE TC: How about you try a little experiment...

Try setting up MANY stereo techniques in one recording such as ORTF, XY, DIN, NOS, Blumlein, and M/S all behind the drummer or 50/50 (behind the drummer, as well as on top of the kit/cymbals.) The techniques should be one behind the other, like in a straight line. Then, record the drums with all of the mics open. During mixing, determine which felt wider to you. Combine it with an A/B spaced pair on top of the kit and presto! A good experiment with great results.

It will save you from opinionated forum headaches :P
Old 20th December 2010
  #49
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Quote:
Originally Posted by lrichner View Post
... but the correct definition (if you look it up) it says that placing the second mic three times the distance from the first mic that the first mic is from the source is the 3:1 rule. In layman’s terms, if the first mic is 1 foot from a source, the second mic should be placed 3 feet from the second mic.
That's exactly the problem you run into with 3-1 as a stereo technique/guide line- Which source', or how many?
Take an acoustic guitar. It radiates coherently (if that's the right word use) in most all directions, with various tones depending on where you focus on this radiating sphere of sound. Given a pair of mics at equal distance at any number of placements are whole ranges of useful mostly in and partly out of phase combinations. Even not depth aligned is done all the time that induces even more phase variation.
How about piano hammer board close micing? A whole string of sources, 88' various distances and phase combinations in a sliding scale of attenuation. (This is a tough one in particular for me to get my head around- I defer. heh
A drum kit- several sources- in 3D' just to the 'OHs, let alone bringing in the close mics.
Old 20th December 2010
  #50
Gear Maniac
 

Plus you will learn the effect of the most popular stereo techniques, so you no longer need to ask in GS, since you will already know. It’s a great educational experience!

I tried the experiment myself and it is really cool to be able to quickly compare techniques with one push of a button
Old 20th December 2010
  #51
Gear Maniac
 

Quote:
Originally Posted by Wayne View Post
That's exactly the problem you run into with 3-1 as a stereo technique/guide line- Which source', or how many?
Take an acoustic guitar. It radiates coherently (if that's the right word use) in most all directions, with various tones depending on where you focus on this radiating sphere of sound. Given a pair of mics at equal distance at any number of placements are whole ranges of useful mostly in and partly out of phase combinations. Even not depth aligned is done all the time that induces even more phase variation.
How about piano hammer board close micing? A whole string of sources, 88' various distances and phase combinations in a sliding scale of attenuation. (This is a tough one in particular for me to get my head around- I defer. heh
A drum kit- several sources- in 3D' just to the 'OHs, let alone bringing in the close mics.
You are right. It all depends on the source. That’s why it takes pros time to figure out the right sound needed to capture using many techniques. Recording a Piano is actually one of the hardest instrument IMO to record. It takes many A/Bs to determine the “appropriate” location of the microphones. It’s all subjective and it takes a while heh
Old 20th December 2010
  #52
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Quote:
Originally Posted by u b k View Post
On that we agree.


Gregory Scott - ubk
Haha, I'm done. Thanks for taking the time to explain.

-Danny
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