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#1
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time aligning a spot microphone the simple way
Hi Guys,
here is how to get a spot microphone just right if you again forgot measure or record a clap near it: 1) know the order of magnitude of the required delay so that you start out close to right 2) pan suitable main pair microphone fully left or right 3) pan spot mic fully right 4) get volume reasonably balanced this does it! 5) adjust delay for proper center image of spot microphone sound source /this does it! 6) add a few milliseconds if spot microphone sound source protrudes when properly mixed. Note: adjustment sensitivity is single milliseconds. May for some be easier when listening via headphones and for some be easier when listening via loudspeakers, not fully verified what works best, try both! Kind regards Peter Larsen |
#2
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time aligning a spot microphone the simple way
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#3
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time aligning a spot microphone the simple way
"Peter Larsen" writes:
Hi Guys, here is how to get a spot microphone just right if you again forgot measure or record a clap near it: 1) know the order of magnitude of the required delay so that you start out close to right 2) pan suitable main pair microphone fully left or right 3) pan spot mic fully right 4) get volume reasonably balanced this does it! 5) adjust delay for proper center image of spot microphone sound source /this does it! Not sure I follow... Step 2: you mean, just one of the main pair mics? What flavor of stereo pair are we talking about? AB? ORTF? NOS? XY? MS? (etc) Step 3: should the spot pan be opposite pan of the selected main pair mic (assuming you're just using one from the main pair). If I understand it correctly I like the approach, but anticipate some little gotchas with this method. Want to make sure I fully understand it and then try it. I used to take clicks and clacks but found that it's just easier to start with your steps 1 and 4, then single-sample step a delay on the spot channel and listen for the best results. Once found, the spot level is often pulled back, lessening any remaining artifacts. Often as I do the initial step-through of delay values there will be more than one delay that will sound good. I'll note them all then do a second pass to winnow those delays to the absolute ideal. Once in a while I'll even automate a delay factor as the same delay might not sound as good in one piece as in another (featured instrument/voice picked up by the spot has shifted their position, changing the spot/main pair geometry). 6) add a few milliseconds if spot microphone sound source protrudes when properly mixed. Yes, you can do this to push the spot out of comb filtering. Just don't hit the Haas boundary, unless you want the effect. Note: adjustment sensitivity is single milliseconds. May for some be easier when listening via headphones and for some be easier when listening via loudspeakers, not fully verified what works best, try both! If it's a good room with good monitors free of their own time problems, speakers generally are a little more revealing for this. I find millisecond steps can be too large; single sample steps can be better. Quite often the ideal delay is only 3 samples wide (44.1K); go one sample out on either side and you lose the good sound. Thanks for the idea; will be interested in clarifications. Frank Mobile Audio -- |
#4
Posted to rec.audio.pro
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time aligning a spot microphone the simple way
Remind me why it is necessary to time align a spot microphone. I understand your
procedure, and it makes a lot of sense, but I don't know when or why you would use it. On 1/28/2012 12:50 PM, Peter Larsen wrote: Hi Guys, here is how to get a spot microphone just right if you again forgot measure or record a clap near it: 1) know the order of magnitude of the required delay so that you start out close to right 2) pan suitable main pair microphone fully left or right 3) pan spot mic fully right 4) get volume reasonably balanced this does it! 5) adjust delay for proper center image of spot microphone sound source /this does it! 6) add a few milliseconds if spot microphone sound source protrudes when properly mixed. Note: adjustment sensitivity is single milliseconds. May for some be easier when listening via headphones and for some be easier when listening via loudspeakers, not fully verified what works best, try both! |
#5
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time aligning a spot microphone the simple way
On Jan 28, 3:01*pm, mcp6453 wrote:
Remind me why it is necessary to time align a spot microphone. I understand your procedure, and it makes a lot of sense, but I don't know when or why you would use it. Google "comb filtering". Peace, Paul |
#6
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time aligning a spot microphone the simple way
here is how to get a spot microphone just right if you again forgot measure or record a clap near it: Pretty much how I work (Your description (3) was clearly truncated, though). I prefer headphones and - as with manual focus on my camera lens - I find it helpful to go deliberately 'beyond the good point' then come back from the other side. I may even oscillate to and fro between the two points where a sound is just discernibly early or late, and note those time values as a sanity check (final chosen time should lie approx half way). And I regularly swap channels, as a precaution against bias or a too vivid imagination ;-) -- Tom McCreadie |
#7
Posted to rec.audio.pro
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time aligning a spot microphone the simple way
Sean Conolly wrote:
"Peter Larsen" wrote in message k... Hi Guys, here is how to get a spot microphone just right if you again forgot measure or record a clap near it: 1) know the order of magnitude of the required delay so that you start out close to right 2) pan suitable main pair microphone fully left or right 3) pan spot mic fully right 4) get volume reasonably balanced this does it! 5) adjust delay for proper center image of spot microphone sound source /this does it! 6) add a few milliseconds if spot microphone sound source protrudes when properly mixed. Note: adjustment sensitivity is single milliseconds. May for some be easier when listening via headphones and for some be easier when listening via loudspeakers, not fully verified what works best, try both! This is one case where I prefer to use my eyes: in the DAW drag the spot mic back (time delay) until it lines up with the main mics. You just have to find a place in the music where the instrument being spotted is prominant enough to see in the main waveform. Sean Works when using a DAW, but not for situations where one will be capturing a stereo mix. It can be helpful in the latter setting to get it as right as possible from the gitgo. When in the DAW, I will use my eyes to get close, and then close my eyes to listen until I lke it. Sometimes I will get down to nudging by the sample. -- shut up and play your guitar * http://hankalrich.com/ http://www.youtube.com/walkinaymusic http://www.sonicbids.com/HankandShaidri |
#8
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time aligning a spot microphone the simple way
"PStamler" wrote in message
... On Jan 28, 3:01 pm, mcp6453 wrote: Remind me why it is necessary to time align a spot microphone. I understand your procedure, and it makes a lot of sense, but I don't know when or why you would use it. Google "comb filtering". Peace, Paul And also Phase Coherence, which is the more important reason IMHO. Sean |
#9
Posted to rec.audio.pro
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time aligning a spot microphone the simple way
On Sat, 28 Jan 2012 18:50:57 +0100, "Peter Larsen"
wrote: Hi Guys, here is how to get a spot microphone just right if you again forgot measure or record a clap near it: 1) know the order of magnitude of the required delay so that you start out close to right 2) pan suitable main pair microphone fully left or right 3) pan spot mic fully right 4) get volume reasonably balanced this does it! 5) adjust delay for proper center image of spot microphone sound source /this does it! 6) add a few milliseconds if spot microphone sound source protrudes when properly mixed. Note: adjustment sensitivity is single milliseconds. May for some be easier when listening via headphones and for some be easier when listening via loudspeakers, not fully verified what works best, try both! Kind regards Peter Larsen I have two ways. The first way is to stand where the spot-miked instrumentalist will be and clap my hands. Alignment is simple. The second is to do the job properly and measure the paths to the two mikes. The speed of sound (just over 340 m/sec) then gives the delay needed on the spot mike. d |
#10
Posted to rec.audio.pro
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time aligning a spot microphone the simple way
Frank Stearns wrote:
Not sure I follow... Step 2: you mean, just one of the main pair mics? What flavor of stereo pair are we talking about? AB? ORTF? NOS? XY? MS? (etc) I used just the one on that side - ie. the right one and panned the spot mic left, dunno which to choose with MS, it was AB, 50 centimeters between 4006's, piano mic a single KSM 141. I ended up redoing it because it didn't integrate properly when listening to the final 44.1-16 and moved the KSM 24 milliseconds instead of 22, so I don't really know. Step 3: should the spot pan be opposite pan of the selected main pair mic (assuming you're just using one from the main pair). If I understand it correctly I like the approach, but anticipate some little gotchas with this method. Want to make sure I fully understand it and then try it. My R44 gave me the idea when recording a piano quartet, there's no way to pan on it and the time difference when listening with the spot mic on channel 3 was very disturbing, but hearing it like that made it very easy to move it around at the "far end" of the piano to get its tonal balance to match the 4006 pair, not mine. The Fostex MR8-HD has better ergonomics, but the R44 has more bits and more portability. That Fostex remains a surprisingly bag for audio at a very nice price. I find millisecond steps can be too large; single sample steps can be better. Quite often the ideal delay is only 3 samples wide (44.1K); go one sample out on either side and you lose the good sound. ! - certainly a point confirming the feel I'm slowly getting, one of preferably using an ORTF type setup if spot(s) will be required in case of AB. This also because that quartet in two other rooms is "just right" on my C42's. It ended up being "too hi-fi" .... ! - also a point confirming my feel that using just one spot mic on piano is less problems than using two. Comments appreciated. Thanks for the idea; will be interested in clarifications. I found it a time-saver. Now if onlý I had a big round button labed "time" on the arm-rest for it - some computing is best done on a real chair sitting at a real desk, but to me the best daw'ïng is via remote operating the daw from an armchair using a laptop. To those suggesting looking at the waveform: yes ... but there's nothing obvious to look at with such a recording. I have a supersonic range finder that uses a ""+20 kHz click"" - firing it near the spot could in theory be a good method, but my ears always hurt after using it and it would certainly annoy the practicing musicians. Frank Mobile Audio Kind regards Peter Larsen |
#11
Posted to rec.audio.pro
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time aligning a spot microphone the simple way
mcp6453 wrote:
Remind me why it is necessary to time align a spot microphone. I understand your procedure, and it makes a lot of sense, but I don't know when or why you would use it. When actually recording stereo instead of building it from tracks. That said, I rapidly ended up doing temporal alignment to get layering right when practicing on the tracks from http://raw-tracks.com. Kind regards Peter Larsen |
#12
Posted to rec.audio.pro
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time aligning a spot microphone the simple way
Don Pearce wrote:
I have two ways. The first way is to stand where the spot-miked instrumentalist will be and clap my hands. Alignment is simple. Should'a done, but plain forgot. The second is to do the job properly and measure the paths to the two mikes. The speed of sound (just over 340 m/sec) then gives the delay needed on the spot mike. I kinda do want a laser measuring device for that .... just never made it to the top of the shopping list. Also at an AES meeting at DR (Danish State Radio) they explained that they used the laser measured distance X 0.66, that was what sounded right. To me that gives audible doubling .... d Kind regards Peter Larsen |
#13
Posted to rec.audio.pro
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time aligning a spot microphone the simple way
Sean Conolly wrote:
"PStamler" wrote in message ... On Jan 28, 3:01 pm, mcp6453 wrote: Remind me why it is necessary to time align a spot microphone. I understand your procedure, and it makes a lot of sense, but I don't know when or why you would use it. Google "comb filtering". Peace, Paul And also Phase Coherence, which is the more important reason IMHO. Sean Right, but the lack of phase coherence results in comb filtering. -- shut up and play your guitar * http://hankalrich.com/ http://www.youtube.com/walkinaymusic http://www.sonicbids.com/HankandShaidri |
#14
Posted to rec.audio.pro
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time aligning a spot microphone the simple way
"Peter Larsen" writes:
Don Pearce wrote: I have two ways. The first way is to stand where the spot-miked instrumentalist will be and clap my hands. Alignment is simple. Should'a done, but plain forgot. The second is to do the job properly and measure the paths to the two mikes. The speed of sound (just over 340 m/sec) then gives the delay needed on the spot mike. I kinda do want a laser measuring device for that .... just never made it to the top of the shopping list. Also at an AES meeting at DR (Danish State Radio) they explained that they used the laser measured distance X 0.66, that was what sounded right. To me that gives audible doubling .... With all respect to those who want to simply measure to derive the delay factor (via a tape measure, spikes on the waveforms, whatever), you're being a wee bit simplistic. And I include my earlier self in that group. I used to all the time use and promote the use of a dog training clicker (makes a nice visual on the waveforms; way better than a clap), but then reality eventually caught up with me. w Here are the problems with simple measurment: - with a single, small point-source instrument, theoretically your measurements will work, ASSUMING that the point source, spot, and main pair are in a line. (Somewhere it was noted that DGG made sure that instruments, spots, and mains were each on a line.) But if they are not in a line (for any number of practical reasons), **and the player or singer moves** the alignment veers as the player moves; then you have variable comb filtering that can sound pretty wonky. If things are in a line, this problem is mitigated, but things still might not be ideal. - with a wider source that you're spotting, say a wind section, choral section, even a large piano, you might clap or click at just one place, but what about a few feet to the left or right? Your path distances change, as must your delay -- but for which location? And if the spot and mains are not in a line, and your spotted source has depth, now you have compromised settings forward and back as well. - I too use 50 cm AB... So, which main pair mic should you align to? If to a phantom point between the AB microphones, the alignment for both are wrong (and audible) and becomes even more wrong (for at least one of the microphones) as the point source is farther left or right. Visualize those vectors in 3D; note the problems. This is why I've switched to aligning by ear. Sometimes the alignment is close to what distance measurements might suggest, sometimes more, sometimes less. Every now and then you get a serendipity of comb filtering that actually helps the overall tone (though rare). More often the delay will be a bit more than what distance might suggest, but less than Haas. You're out of the worst potential comb filtering whether the player moves or not. The more-than-needed added delay can "outline" the spotted instrument so that you can actually use a bit less in the mix and still get the highlight you want. (And using a bit less is good, because you further reduce audibility of residual problems.) My $0.02. As always, YMMV. Frank Mobile Audio -- |
#15
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time aligning a spot microphone the simple way
On Sun, 29 Jan 2012 10:30:58 -0600, Frank Stearns
wrote: "Peter Larsen" writes: Don Pearce wrote: I have two ways. The first way is to stand where the spot-miked instrumentalist will be and clap my hands. Alignment is simple. Should'a done, but plain forgot. The second is to do the job properly and measure the paths to the two mikes. The speed of sound (just over 340 m/sec) then gives the delay needed on the spot mike. I kinda do want a laser measuring device for that .... just never made it to the top of the shopping list. Also at an AES meeting at DR (Danish State Radio) they explained that they used the laser measured distance X 0.66, that was what sounded right. To me that gives audible doubling .... With all respect to those who want to simply measure to derive the delay factor (via a tape measure, spikes on the waveforms, whatever), you're being a wee bit simplistic. And I include my earlier self in that group. I used to all the time use and promote the use of a dog training clicker (makes a nice visual on the waveforms; way better than a clap), but then reality eventually caught up with me. w Here are the problems with simple measurment: - with a single, small point-source instrument, theoretically your measurements will work, ASSUMING that the point source, spot, and main pair are in a line. (Somewhere it was noted that DGG made sure that instruments, spots, and mains were each on a line.) But if they are not in a line (for any number of practical reasons), **and the player or singer moves** the alignment veers as the player moves; then you have variable comb filtering that can sound pretty wonky. If things are in a line, this problem is mitigated, but things still might not be ideal. - with a wider source that you're spotting, say a wind section, choral section, even a large piano, you might clap or click at just one place, but what about a few feet to the left or right? Your path distances change, as must your delay -- but for which location? And if the spot and mains are not in a line, and your spotted source has depth, now you have compromised settings forward and back as well. - I too use 50 cm AB... So, which main pair mic should you align to? If to a phantom point between the AB microphones, the alignment for both are wrong (and audible) and becomes even more wrong (for at least one of the microphones) as the point source is farther left or right. Visualize those vectors in 3D; note the problems. This is why I've switched to aligning by ear. Sometimes the alignment is close to what distance measurements might suggest, sometimes more, sometimes less. Every now and then you get a serendipity of comb filtering that actually helps the overall tone (though rare). More often the delay will be a bit more than what distance might suggest, but less than Haas. You're out of the worst potential comb filtering whether the player moves or not. The more-than-needed added delay can "outline" the spotted instrument so that you can actually use a bit less in the mix and still get the highlight you want. (And using a bit less is good, because you further reduce audibility of residual problems.) My $0.02. As always, YMMV. Frank Mobile Audio You can still fine-tune by ear, but measuring will get you 99% of the way very quickly. And of course comb filtering is always going to be a problem - you just have to minimize it by making sure on mic is dominant in the mix. Whether tone filtering is a problem in practice depends on all sorts of things, of course. If the mains are in a reasonably diffuse sound field the phase is already pretty jumbled, and the spot will mix ok. And it may be that the mains are positioned beyond the phase-coherent distance of the source to start with. More than about 30 feet will do that. d |
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