Drum Phase

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Nick Sevilla
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Post by Nick Sevilla » Sun Nov 28, 2010 3:14 pm

@?,*???&? wrote:
ashcat_lt wrote:
@?,*???&? wrote:
Nick Sevilla wrote:
kRza. wrote:nice pic.

I knew this would open up a can of worms. Thanks for all the replies, i think. Okay voodoo masters, I'll give, what the fuck is 3:1?

To clarify: I am recording myself drumming, so can't do the listen while recording trick. I totally understand the math and logic of phase - have done this shit countless times, but what I'm after here is preventing the phase prob before mixing.
I've got a project starting soon & am going to try out several different combined micing tricks (mccarthy's Spoon snare trick, etc...), all of which mean adding extra mics that I don't normally use.
3:1 rule was born eons ago.

It has to do with LEVELS. There will be here some who don't have a clue, and say it has to do with where the microphone is. This is the furthest thing from the 3:1 rule ever imaginable.

This is the rule, paraphrasing here so don't shoot me...

Your DIRECT SOUND SOURCE MUST BE 3 TIMES LOUDER THAN YOUR INDIRECT SOUND SOURCE.

In plain simple terms, the thing you are trying to record should be, AT LEAST, three times louder than anything else the microphone is hearing, ie background noise, room noise, another instrument, such as another tom, etc.

And, just for kicks, because I know someone is going to say I'm wrong, I will say it again, so I can be properly "ridiculed" :

The 3:1 rule has nothing to do with distances, only with levels.

Cheerio.
Dude, you're so wrong with your definition it's almost insane.

Buy the book and you will be educated.

Somehow you're confusing the Inverse Square Law with this.

And the flag goes up. That definition comes from a guy working professionally in Los Angeles.
Then why don't you enlighten us?

How does all this dick waving - saying "I know the 3:1 Rule better than you!" - help anybody or contribute anything useful to this thread?

Do you get royalties or commission from the sale of that book?
*cough*

http://www.wikirecording.org/3_to_1_Rule

and

"Inverse Square Law - States that direct sound levels increase (or decrease) by an amount proportional to the square of the change in distance. "
Oh my... quoting Wikipedia from a Sweetwater source. Very enlightening. Hey, do they happen to sell a tape measure at Sweetwater too?

I just will do everyone a favor and piss off, since apparently you all know what you are doing... as is usual on the interwebs.
Howling at the neighbors. Hoping they have more mic cables.

ashcat_lt
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Post by ashcat_lt » Sun Nov 28, 2010 3:22 pm

@?,*???&? wrote:*cough*

http://www.wikirecording.org/3_to_1_Rule

and

"Inverse Square Law - States that direct sound levels increase (or decrease) by an amount proportional to the square of the change in distance. "
*ahem*
Unless I missed something, that link explains nothing. It states the "Rule" and offers some pretty pictures. Worse, it seems to imply that 3:1 is the only answer, completely ignoring - as many people do - the "at least" part. 4:1 is theoretically better, and 20:1 is much better still!
qued wrote:The important concept in that sentence is ?? must be correlated ??. When a drum is struck, different regions throughout the room will have different proportions of direct and diffuse sound. Mathematically speaking, all of the reflections/diffraction/diffusion responsible for the diffuse sound field is so complex, that the diffuse sound can be considered uncorrelated to the direct sound or early reflections.
I dig where you're going here, but it at least seems to say that the inverse-square law somehow works differently in a highly reverberant space then it might in a dead room. That's not true. It's the proportion of diffuse to direct sound to which you're referring. With a dead room we might be tempted to gain up the room mic to add more "air" or "ambience" to the mix. In so doing, we also increase the direct sound from the drums themselves, which might lead to "phase issues".

It does, though, bring up the idea that we can even end up with phase interaction with one microphone. It is quite possible that the first reflection off a wall, floor, or ceiling, could hit the mic at very close to the same level, and very shortly after, the direct sound.
Another important aspect when considering 3:1 in regard to distances is the assumption of a non-directional source. For directional sources, say the high frequency ?crack? coming off a snare head, sound decay does not follow the 9 dB per 3x increase in distance for all directions. Add to this mic?s that do not have omni pickup patterns and it gets more complicated still.
That's a good point, too. In my example I specified an omnidirectional mic, but probably should also have specified an omnidirectional point source, rather than saying "snare drum".

It's an important point to make, though, and leads back to the argument that it really has nothing to do with distance. We can (and should, and usually do) use the directional properties of both source and microphone to get our 9db difference. We can (and do) also leverage difference in frequency response, and even the proximity effect, for the same purposes.

I think it all comes back to what losthighway was saying, though. There's no good reason for an engineer to be out on the tracking room floor with a tape measure! These guidelines are good to keep in the back of your mind, and some basic knowledge can help to avoid problems to begin, but all that really matters is what it finally sounds like in the mix.

Set up the mics. Listen. Move them if they aren't doing what you want.

Somebody else mentioned that sometimes phase interactions (it ain't always cancellation, folks!) can be an important part of the specific sound we're looking for. The mix comes first.

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Brett Siler
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Post by Brett Siler » Sun Nov 28, 2010 4:42 pm

The direction this thread went in bums me out. Feels like more attitude and ego and little information.
To the original poster, don't worry about the 3:1 rule. Put some mics on the kit, record some for a sec and just pull up your overheads and push the phase flip button on one of them, if it sounds worse unflip it. Then pull up your kick with the overhead(s), flip the kick, if it sounds fuller keep it, if not unflip it. Do that to the rest of your kit until it all sound good together and then you can move on. All this works best in mono, pan stuff after you checked all the phase relationships.

Thats how I've always do it and it's worked for me.

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Post by MoreSpaceEcho » Sun Nov 28, 2010 4:51 pm

that's pretty much what i do too.

getting away from theory for a sec....

has anyone else ever encountered some weird phase interactions betwixt a front of kit mic and an overhead? specifically, i've noticed on several occasions that the kick will be in phase between the fok mic and the overhead, but the snare will be out. (assume that the close kick and snare mics are in phase with the overhead).

SOMETIMES the phase cancellation on the snare from the fok mic sounds good, as it's cancelling in the lower mids, and you end up with a nice "already eq'd to sound like a legitimate record" kinda sound. usually though, it thins out the meat of the snare too much. to this end, i haven't used a fok mic in awhile.

anyone?

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Post by kRza. » Sun Nov 28, 2010 5:26 pm

When I post here - I always imagine in my head that my tone of voice is just like that of The Dude in the big lebowski when he's talking to the kidnappers on the cell phone "yeah right,...just tell me where the fuck to go man!".

Condescending douche bags. Jesus - some you guys need pussy, or weed - or both. So, let's take it back a notch and remind ourselves that very few people are going to give a fuck about the records we're making, alright?

Again - I got phase sorted when it comes to mixing. Kill that shit like a ninja.
I was trying to get info on sleuthing it before mixing - which from best I can gather from all the dick wagging, just means to make sure that if I have two mics on one source (2 snare mics) make sure the bottom one is 3 times as far away from the original sound source (where the stick hits the top head), than the mic on the top head.

so can we hug now and talk about music again y' douches?

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Post by ashcat_lt » Sun Nov 28, 2010 5:48 pm

Somebody along the way took the bait and asked what the 3:1 Rule was all about. I tried to offer some insight and call bullshit on some other folks who chose not to provide meaningful input.

Your thing with the top and bottom mics - it's quite possible (almost likely) that one will be "pushing" while the other is "pulling" for most of the frequencies of interest. This is more correctly a polarity issue, and exactly what the "phase" switch is for. The 3:1 Rule might not help here, because you're maybe going to want to balance the "crack" from the top with the "wires" from the bottom, and will end up setting the faders to a point where the "body" (present in both) is close enough in level on both channels, and starts to comb out.

Put up your mics where each sounds good. Listen. Maybe flop the phase switch. Move mics and repeat until it sounds right in context.

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qued
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Post by qued » Sun Nov 28, 2010 6:02 pm

ashcat_lt wrote: ... seems to say that the inverse-square law somehow works differently in a highly reverberant space then it might in a dead room. That's not true.
You?re right about that, and my first post isn't. Direct sound should follow inverse square regardless of the room.

In any case it seems a bit of theory isn't welcome. I thought it was on a tangent, but still an interesting addition to the thread. Seriously, no slight or offense intended to the original question or previous opinions.

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eeldip
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Post by eeldip » Sun Nov 28, 2010 10:56 pm

is there a way to slowly turn threads blue as they get more gearslutty?

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losthighway
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Post by losthighway » Mon Nov 29, 2010 5:46 am

I just want to state for the record that you're all great and I value your insight. :)

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@?,*???&?
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Post by @?,*???&? » Mon Nov 29, 2010 9:29 am

losthighway wrote:I just want to state for the record that you're all great and I value your insight. :)
Thanks man. This means a lot. ;-)

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vxboogie
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Post by vxboogie » Mon Nov 29, 2010 9:35 am

losthighway wrote:I just want to state for the record that you're all great and I value your insight. :)
Ditto, TOMB has given me access to a lot of expertise and information that I would never have in my daily adventures in amatureland. Thanks!
Mark - Listen, turn knob, repeat as necessary...

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Brett Siler
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Post by Brett Siler » Mon Nov 29, 2010 2:11 pm

MoreSpaceEcho wrote: getting away from theory for a sec....

has anyone else ever encountered some weird phase interactions betwixt a front of kit mic and an overhead? specifically, i've noticed on several occasions that the kick will be in phase between the fok mic and the overhead, but the snare will be out. (assume that the close kick and snare mics are in phase with the overhead).
Yea or on room mics with the overheads. I'll pull up just the overheads and room mics and flip one of them and usually the kick will sound so huge but the snare sounds smaller or vice versa. I just try to find the best compromise. I usually go with what makes the kick or toms sound bigger, and if there is a close mic on the snare then can add some beef to the snare. If I need more girth for the snare I'll reach for the eq.

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