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#1
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Delay between room and spot mics
How do you fix the delay between a room stereo pair and spot mics? Do
you record a spiky sound like a cowbell hit and visually align the peak? Measure the distance between the mics with a tape measure and calculate it? Slide the tracks and adjust by ear? At what distance does this become a problem? Thanks much, Tim Sprout |
#2
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Delay between room and spot mics
On 4/23/2014 12:32 PM, Tim Sprout wrote:
How do you fix the delay between a room stereo pair and spot mics? Do you record a spiky sound like a cowbell hit and visually align the peak? Measure the distance between the mics with a tape measure and calculate it? Slide the tracks and adjust by ear? Any of the above will work. Recording a spike that reaches all the mics is probably the most accurate method. At what distance does this become a problem? The critical comb filtering region, where combining mics at close to the same level will cause raggedness in the frequency response, is roughly 0.5 to 5 milliseconds, which roughly corresponds to about 1/2 to 5 feet difference between the source and each mic. It takes about 30 milliseconds (30 feet) before you can perceive the difference as an echo. In between, your ear is the best guide. -- For a good time, visit http://mikeriversaudio.wordpress.com |
#3
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Delay between room and spot mics
Mike Rivers writes:
On 4/23/2014 12:32 PM, Tim Sprout wrote: How do you fix the delay between a room stereo pair and spot mics? Do you record a spiky sound like a cowbell hit and visually align the peak? Measure the distance between the mics with a tape measure and calculate it? Slide the tracks and adjust by ear? Any of the above will work. Recording a spike that reaches all the mics is probably the most accurate method. Dog trainer clicker available for $1.50 at most pet stores works great. Just make sure you originate your clicks at the right place (where the instrument will be). At what distance does this become a problem? The critical comb filtering region, where combining mics at close to the same level will cause raggedness in the frequency response, is roughly 0.5 to 5 milliseconds, which roughly corresponds to about 1/2 to 5 feet difference between the source and each mic. It takes about 30 milliseconds (30 feet) before you can perceive the difference as an echo. In between, your ear is the best guide. Indeed. And this might be the only way to make the adjustment if there are multiple varied paths involved -- there will be no "correct" solution. So, do it by ear; use the spot as little as possible and still get the sound you want. Sometimes you'll only have a 3-5 sample window where things sound sweetest. A delay with sample resolution and that you can single-sample step is useful. Also beware of musicians who move around a lot. This might mean you have to dynamically change your delay in post, depending on the geometry of the stage layout and microphone heights. Frank Mobile Audio -- |
#4
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Delay between room and spot mics
Tim Sprout wrote:
How do you fix the delay between a room stereo pair and spot mics? Do you record a spiky sound like a cowbell hit and visually align the peak? Measure the distance between the mics with a tape measure and calculate it? Slide the tracks and adjust by ear? At what distance does this become a problem? Slide the tracks and adjust by ear. You will hear it when it pops into place. In general about 1ms/ft. It will be more obvious with the spot mike up very loud... get it right, then drop the level back down to normal. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#5
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Delay between room and spot mics
Scott Dorsey wrote:
Slide the tracks and adjust by ear. You will hear it when it pops into place. When sliding tracks, I find it easier to home in on the registration point if I mono the mains and route it to one headphone channel, while the similar level spot is routed to the other ear. Adjustment is akin to manually focusing a camera: you typically have to first go beyond the synch point and ease back again. I'd then confirm with the cans reversed on my head. But of course precise time registration of the spot may not give the optimum audio result. -- Tom McCreadie Sudden Death Syndrome? Sounds serious - what are the symptoms?" |
#6
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Delay between room and spot mics
In article ,
Tom McCreadie wrote: Scott Dorsey wrote: Slide the tracks and adjust by ear. You will hear it when it pops into place. When sliding tracks, I find it easier to home in on the registration point if I mono the mains and route it to one headphone channel, while the similar level spot is routed to the other ear. Adjustment is akin to manually focusing a camera: you typically have to first go beyond the synch point and ease back again. I'd then confirm with the cans reversed on my head. But of course precise time registration of the spot may not give the optimum audio result. Makes you wonder how anything sounded decent in analogue days. ;-) -- *Work like you don't need the money. Love like you've never been hurt. Dave Plowman London SW To e-mail, change noise into sound. |
#7
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Delay between room and spot mics
"Dave Plowman (News)" writes:
In article , Tom McCreadie wrote: Scott Dorsey wrote: Slide the tracks and adjust by ear. You will hear it when it pops into place. When sliding tracks, I find it easier to home in on the registration point if I mono the mains and route it to one headphone channel, while the similar level spot is routed to the other ear. Adjustment is akin to manually focusing a camera: you typically have to first go beyond the synch point and ease back again. I'd then confirm with the cans reversed on my head. But of course precise time registration of the spot may not give the optimum audio result. Makes you wonder how anything sounded decent in analogue days. ;-) Well, often they didn't. Badly done multi-microphones on orchestra and chorus was fairly awful, but it was "accepted." When we were finally able to do it right and use aligned spots only as clearly needed rather than just because they were there, it was a whole new improvement in the art. Frank Mobile Audio -- |
#8
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Delay between room and spot mics
Dave Plowman (News) wrote:
In article , Tom McCreadie wrote: Scott Dorsey wrote: Slide the tracks and adjust by ear. You will hear it when it pops into place. When sliding tracks, I find it easier to home in on the registration point if I mono the mains and route it to one headphone channel, while the similar level spot is routed to the other ear. Adjustment is akin to manually focusing a camera: you typically have to first go beyond the synch point and ease back again. I'd then confirm with the cans reversed on my head. But of course precise time registration of the spot may not give the optimum audio result. Makes you wonder how anything sounded decent in analogue days. ;-) 1. Folks avoided spot-miking when they had mixes based around a main pair (which is still a good idea) or they avoided using a main pair for mixes based around spots (which is sometimes a good idea but usually not in my opinion). 2. Folks specifically positioned the main pair far enough back from the stage that the delay to the main pair was exactly the delay between the record and play heads on the tape machine and then they used sel-sync to line them up. This worked really well on an ATR-104 but worked very poorly on older machines whose audio quality in sync was poor. 3. Rock bands made "live albums" that were, in fact, almost completely retracked in isolated studios. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#9
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Delay between room and spot mics
"Dave Plowman (News)" wrote in message ...
Makes you wonder how anything sounded decent in analogue days. ;-) Who said it did? |
#10
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Delay between room and spot mics
I'm not sure any method really works, except by ear in some idealy controled environment. Align all spot mics to main paair, and have them all remain unaligned with each other. In small rooms, with loud bands where each mic is picking everything...
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