Nov 24, 2006 10:35 pm Nice find. I haven't read that one as of yet. Looks very interesting though as you said.
Time aligning drums
Posted on Nov 24, 2006 07:06 pm
BeerHunter
www.TheLondonProject.ca
Member Since: Feb 07, 2005
Here is an interesting read;
recdiy.com/MicPlacementGu...ntFrameSet.html
I have not yet tried this technique but I'm looking forward to trying it. Logically it makes a lot of sense.
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Nov 24, 2006 10:35 pm Nice find. I haven't read that one as of yet. Looks very interesting though as you said.
Nov 25, 2006 02:10 pm i read it and hope that some noobs just don't confuse time aligning with phase polarity. time doesn't equal phase.
A mic on the beater side will pick up the rarefraction, or the skin moving away from the mic first (think -) and the mic on the front of the drum will pick up the compression (+), or the skin moving toward the mic. Note that these 2 mics could be still in time, or equadistant from the skins, but still out of polarity. This could cause combfiltering on the kick which will sound bad
Nov 25, 2006 04:45 pm Call me a noob, but isn't phase just a time difference between one signal recorded at different sources?
Wouldn't the mic's in your example, simply be out of phase because of the delay between the beater skin and the resonant skin?
If not, can you explain? Might not understand fully.
Nov 25, 2006 06:03 pm Well honestly you can compare the two and they are very similar. But that said, they do become separate entity's for different reasons. The difference in in distance will only effect both at certain points in the measurement. Until the difference reaches approx. 20 ms or so it will really only effect the time difference. Once over that phase does come into play and begins to turn things to mush. Under that point though it is only effecting the timbre of the sound by giving two or more distinct sounds recorded by each mic in the set up. What you can tell once your ear becomes accustomed to it is subtle tone/timbre changes to the sound or sounds. It can be very tough to hear sometimes but it is always there. Sometimes as with some guitar tracks it adds what we are looking for in thickening up the sounds. But with more percusive sounds like drums even bass it can tend to give a much different sound then we are looking for. Sometimes a very untrue sound.
The phase issue will rear its ugly head to a rather large amount of time in that spectrum. With two mic's it is sometimes easy to solve. With more it can get tougher. And once there time can come into play once again. In those cases I will simply record the track and then time align them. Other times a simple flip of the phase will do the track as long as it isn't so far out of time.
If I missed something let me know and I'll try to go deeper into it.
Nov 25, 2006 06:30 pm ...trying to explain more clearly...
phase is time...however distance alters the frequency respose of the waveform (proximity effect) so if you take an out of phase signal and line them up in time you still get a tone difference related to the distance each mic had from the source...therefore the waveform cannot match up 100% ... and only those that do match up are amplified... everything else is subtracted.
Nov 25, 2006 06:33 pm ..also bear in mind in drum physics the resonant head produces sound first because the beater mutes the batter head...
Nov 25, 2006 06:48 pm Thanks for the info, but I still don't understand the difference. I mean sure, the signals will never be indentical, but the base of phase is still a time difference right?
Quote:
..also bear in mind in drum physics the resonant head produces sound first because the beater mutes the batter head...
Never ever thought of that. Cheers Zek.
Nov 25, 2006 07:54 pm Yes, the base of phase is time. But as I stated above it does not come into play until at least 20 ms and can be out as far as 30 ms. Until that point it is only really noticed as an echo. Once it has reached the 20 to 30 ms range is when it then starts to cause the phase effect we hear. Which worsens until it reaches the farthest point in time and starts to become an echo once again.
Much of this can be room Dependant as well. So each situation is different from the next. Unless you are using the exact room with mic's placed in exactly the same spots.
When it comes down to it and if it is effecting my mix entirely to harshly I will actually set a delay to compensate for those type of things.
Nov 25, 2006 09:19 pm Ok, got a bit confused there. I thought you guys were trying to say they were two totally different things, but they're just very similar.
BTW Noize, are you still coming to NZ?
Nov 25, 2006 09:21 pm If I do it is going to be closer to spring now then I thought. I was hoping for some time this winter but it isn't looking like it will be until later. I'll surely keep you posted though.
Nov 26, 2006 07:09 am ok colonel.....it's like this.....
you can have the two kick mics (ie) 'in phase'...which means the one on the beaterside reads negative while the inside kick mic reads positive....BUT they could be outta TIME....meaning...sure, the sine wave crests and troughs 'match up' but are the SAME ones matching up? what if you're matching a trough that's three troughs ahead of the one you're "matching"....that's TIME vs. Phase....sure they're 'in phase'....but time aligning is WHICH (#) cycle of phase are WE on here?
Nov 26, 2006 04:54 pm I'll have to draw it...
give me a few minutes...
Nov 26, 2006 05:49 pm 
The third example is what most of us run into with muliple tracks... the solution is EQ and mic placement.
Nov 27, 2006 02:33 am Umm... ok... i just got some questions, which just might be me not understanding the whole thing but..
1. Do you base all the alignment off of one drum? coz if u didnt.. ud wouldnt u have to end up moving everythign ot accomodate different things.. like the overhards would be much further from the kick than the snare.. so if u delay them to align with snare.. then where does that leave the kick?
2. I know the movements r minute.. but isnt their the off chacne say if u move the cymbal track over .25 seconds to align with the snare track.. doesnt that mean the cymbal is now being played .25 seconds off beat from where it was suppose to be played, since the mic closest two it would have the timing right, delaying to another mic that is too far would put it out of time??
Nov 27, 2006 11:46 am Heya crux/all,
I'm not sure if I am doing this correctly or not but I used my right overhead as a starting point. I aligned the snare to that. I then aligned the right tom to the snare. Then I aligned the left tom to the left overhead. Then I aligned the kick and reversed the phase (I could see the inverted peak) on it. I did not move either overhead although I suppose the left overhead should have been moved as well. I didn't do this however and it still sounded great.
These changes were very subtle. I zoomed in really close and lined up the peaks of the wav's. The results were awesome. Since these peaks were easy to see, aligning it was really fast and easy. I will be using this technique from now on.
Nov 27, 2006 12:00 pm let me correct what i posted earlier. phase is time but frequency specific and has polarity
as far as drums go, i wouldn't go overboard with time aligning everything to everything else, just won't happen. I will time and/or phase align mics with the same source like two mics on kick or 3 on snare and i will have any stereo room or overheads keep the snare and kick in the center of the image. phase is how we hear distance and height so considering how drums are setup i wouldn't go so far as to try to make everything sound like it's coming from the same exact space.
also, you can have phase problems with just one mic
Nov 27, 2006 07:16 pm I have to agree with el musico. IT would be almost impossible to align everything perfectly. Getting it close and paying the most attention to the close micced drums is what will get you the most benefit.
BeerHunter, you did pretty much exactly what I do when things are out and noticeable. That honestly is one big reason I really push from using the trigger kit here. It really saves a big load of time. And if using proper drum samples and the like, it is damn hard to tell the differance.
Nov 27, 2006 08:53 pm Hey Noise/all,
One of the reasons I try and capture the sounds of a real drum kit is for the experience... and I like doing it (I guess in some sort of twisted way - lol). Keep in mind that I only have a Pearl Export to work with so the sounds of the kit are somewhat limiting. However, I'm still not capturing the kit as the way it sounds in the room which of course has nothing to do with the kit (I think). Right now I have placed my overheads UNDER the crash and ride pointing up and I seem to be getting better results. I'm thinking that part of the problem I was having before is the room. This setup will reduce or eliminate the need to time align the tracks.
But now let's talk about phase for a minute...
el musico mentioned something about phase which was Quote:
you can have phase problems with just one mic I understand it this way...
positive phase would push out a woofer, and negative phase will suck it in. Both events will produce a sound but optimum would be to have a positive phase.
When you strike a snare that is mic'd top and bottom the skin will be moving away from the top mic (negative) but the bottom mic will have the skin moving towards it (positive). For this reason you would flip phase the top mic to produce a positive phase.
Is this correct? I could have the positive and negative thing reversed but this is how I think it works anyways.
take care,
BH
Nov 27, 2006 10:46 pm BeerHunter, indeed real drums are the perfect thing for that rock sound. I do agree there. And honestly I do like recording real drum's as well. But as you are finding out, the room can really be a pain to try and get to work properly for miccing a kit up. But with time and a little experimenting you can always find a way to get it sounding pretty good.
Nov 28, 2006 07:40 am also, be aware your overhead mics are point up (away from the kit) this could be causing issues with your WHOLE drum sound because they are outta phase with the tom mics and snare, and possibly the kick if you have one on by the drummers foot.....i don't think i've ever tried puttin' overheads under the cymbals....
a neat trick you can try if you don't like your overheads over the drummers head, try puttin' a spaced pair of 'em about chest height 3-8 feet infront of the kit, and 3 or 4 feet apart (depending on how 'wide' you want the sound) facing the drummer's eyes....this is a good substution for overhead micing......if you want the kit "to sound exactly the way it does in the room" put out a spaced pair of omni mics in roughly the same place and you WILL get the sound of them in that room.
also try using an extra mic (dosn't matter what kind/type) as a 'wild card' mic and place it somewhere further away, perhaps facing a corner...or behind a closed door...8 times outta 10 you'll end up liking the 'flavor' mic....just blend it in real lightly to add flava.
Nov 28, 2006 10:54 am Thanks for the input guys. WYD, the "underhead" mics are just experimental. I have only recently tried this but the results were good. I didn't notice any phase issues (but I'll double check) I do not have a mic on the beater but I have a PZM stuffed inside and a "speaker" mic about a foot in front. I use the PZM to trigger Drumagog and the speaker mic to blend with the substituted kick. This has worked very well. I've been known to throw out the "rule book" at times and this is sort of where I am at right now. Haha, who needs rules anyways? (especially when you don't know all the rules) I also use a LDC about 6 feet in front and 2 dynamics that I do your "flavour" thing with. I'm reasonably happy with the sound now. The snare can give me troubles from time to time but this is the only weak link that I have to worry about right now. I may even substitute the snare as well but we'll see. I'm trying to avoid this though as I'm trying to stay somewhat "au natural".
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