Home |
Search |
Today's Posts |
|
#1
|
|||
|
|||
would this phase correction idea work?
hello everyone,
let's say you 2-miked an instrument and recorded it as a stereo file into the DAW. then when you listened back, you thought it sounded out of phase. would it make sense to simply de-couple the stereo file in a wave editor and then nudge one of the left or right tracks a few samples to get it in phase? |
#2
|
|||
|
|||
an easier route would be to usa a program like audition or pro tools or
anything and use a phase canceler/converter/changer/whatever plugin to adjust the phase and just move the slider a little and listen. i would personally use the phase analysis tool in audition as it will tell you to an extreme degree of accuracy wether the tracks are in phase or not. they may also be 180 degrees out of phase as thworing may have been mixed up somewhere alon your signal path. try inverting one of the tracks to see what happens. i would not try to manually change the phase as your soundcard is probably not good enough to be sample accurate and differentiate the differance if a sound file is ten samples delayed or something, did that make sense? whatever. give it a shot. |
#3
|
|||
|
|||
siguy wrote:
an easier route would be to usa a program like audition or pro tools or anything and use a phase canceler/converter/changer/whatever plugin to adjust the phase and just move the slider a little and listen. i would personally use the phase analysis tool in audition as it will tell you to an extreme degree of accuracy wether the tracks are in phase or not. they may also be 180 degrees out of phase as thworing may have been mixed up somewhere alon your signal path. ....snip.. Hmmm, this has me wondering: What phase analysis tools are out there in common use? For that matter, are there any good articles or books that address phase issues in modern audio work [i.e.: radio, live sound, mastering etc.] ? I'd like to learn a bit more on the subject, both theory and applied. Later... Ron Capik -- |
#4
|
|||
|
|||
Ron Capik wrote:
Hmmm, this has me wondering: What phase analysis tools are out there in common use? Soundcraft's small B100 and BVE100 broadcast mixers have an onboard phase meter. rd |
#5
|
|||
|
|||
RD Jones wrote:
Ron Capik wrote: Hmmm, this has me wondering: What phase analysis tools are out there in common use? Soundcraft's small B100 and BVE100 broadcast mixers have an onboard phase meter. Yes, and there are a lot of the outboard meters like the Dorrough and RTW meters that have basic phase metering. I never found these to be all that useful, though. They don't really tell you anything that mono summing doesn't tell you, and they aren't any help for getting a sense of stereo imaging in bad monitoring situations. An X-Y display like the Tektronix audio monitor is very useful for getting a sense of stereo imaging when you can't trust your monitors, and it can be very handy for broadcast and record-cutting work where the sum and difference channels are asymmetric. But you very seldom see them any longer. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#6
|
|||
|
|||
Scott Dorsey wrote:
RD Jones wrote: Ron Capik wrote: Hmmm, this has me wondering: What phase analysis tools are out there in common use? Soundcraft's small B100 and BVE100 broadcast mixers have an onboard phase meter. Yes, and there are a lot of the outboard meters like the Dorrough and RTW meters that have basic phase metering. I never found these to be all that useful, though. They don't really tell you anything that mono summing doesn't tell you, and they aren't any help for getting a sense of stereo imaging in bad monitoring situations. An X-Y display like the Tektronix audio monitor is very useful for getting a sense of stereo imaging when you can't trust your monitors, and it can be very handy for broadcast and record-cutting work where the sum and difference channels are asymmetric. But you very seldom see them any longer. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." So in effect you're saying that, despite all this talk about group delay and such, there aren't any tools in common use that quantify these effects? Later... Ron Capik -- |
#7
|
|||
|
|||
One of the best phase-analysis tools is an oscilloscope -- left channel to
vertical, right to horizontal. |
#8
|
|||
|
|||
William Sommerwerck wrote:
One of the best phase-analysis tools is an oscilloscope -- left channel to vertical, right to horizontal. OK, but how does one quantify said output? Later... Ron capik -- |
#9
|
|||
|
|||
Ron Capik wrote:
William Sommerwerck wrote: One of the best phase-analysis tools is an oscilloscope -- left channel to vertical, right to horizontal. OK, but how does one quantify said output? This is what the Tek phase display does.... it's really a scope in disguise. If a signal is mono and common to both channels, you get a diagonal line /. If it's got reversed polarity, you get a reversed line \. As there are phase differences between channels, the line opens up into a circle. With some practice you get a sense of what things should look like with a minimalist miking set, which can help you place mikes when you cannot trust the imaging of your speakers in the field. You also get a sense of problems like out-of-phase bass. If the display skews vividly northwest when there is a kick drum hit, you have a problem trying to cut that to LP. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#11
|
|||
|
|||
On Thu, 13 Jan 2005 01:10:31 GMT, Ron Capik
wrote: One of the best phase-analysis tools is an oscilloscope -- left channel to vertical, right to horizontal. OK, but how does one quantify said output? Why do you want numbers? The display will tell you what's wrong and when you get it right. So will your ears. But 'scopes do have calibration marks. CubaseFAQ www.laurencepayne.co.uk/CubaseFAQ.htm "Possibly the world's least impressive web site": George Perfect |
#12
|
|||
|
|||
something i forgot to soay is that if you 'nudge' the file at all you
will be adding delay to the track introducing a possible flanger type effect, ugly. |
#13
|
|||
|
|||
A "flanger" effect would be a delay but a varying length of delay, i.e.
an "out of phase" pair of signals that change their phase relationship over time. Unfortunately, what arrived at the two microphones is a complex picture of the instrument, and moving the two mics in a time relationship to each other will not likely fix the problem. However, subjectively, the sound may improve, although I doubt it. It may be the case, as someone else pointed out, that simply changing the polarity of one of the mics may make the most improvement (if one of the mics was out of polarity in the first place). Phase and group delay are not necessarily interchangeable... Karl Winkler Lectrosonics, Inc. http://www.lectrosonics.com |
#14
|
|||
|
|||
|
#15
|
|||
|
|||
No ! The result will not be mono compatible.
And it will only work if the sound is one single frequency. There is a difference between electrical phase and temporal (time, for you earthlings) displacement. If the 'phase' problem was created by latency then yes - you correct the difference by slipping one file to line up with the other. If the problem is one side electrically "out of phase" then the entire right (or left) channel needs inverted (polarity) but not slipped in the time domain. rd |
#16
|
|||
|
|||
Assuming that the temporal delay was entirely due to distance from the
speaker in question, why would this not be the exact same thing as latency? tak On 2005-01-11 02:26:52 -0500, "RD Jones" said: No ! The result will not be mono compatible. And it will only work if the sound is one single frequency. There is a difference between electrical phase and temporal (time, for you earthlings) displacement. If the 'phase' problem was created by latency then yes - you correct the difference by slipping one file to line up with the other. If the problem is one side electrically "out of phase" then the entire right (or left) channel needs inverted (polarity) but not slipped in the time domain. rd |
#17
|
|||
|
|||
Takeshi Yama****a wrote: Assuming that the temporal delay was entirely due to distance from the speaker in question, why would this not be the exact same thing as latency? tak If the 'phase' issue is due to time delay from differing distance, then the effect is similar to that of latency. But slipping the 2 back into phase with each other will create it's own effect. Are the 2 signals both centered and at the same level ? Better to lower the level of the secondary (delayed) signal until the phase effect is reduced, or better yet: Center or near center the first arriving signal, and hard or far pan the secondary signal. Hendrix used this effect and I like his work. The question is what's causing the phasing sound latency/time issues or electrical polarity ? And is it objectionable ? rd |
#18
|
|||
|
|||
No ! The result will not be mono compatible.
Don't ya just love Usenet. bg Mark "In this business egos can be wonderful, but they also can be a curse." Michael Wagener |
#19
|
|||
|
|||
|
#20
|
|||
|
|||
wrote in message
ups.com hello everyone, let's say you 2-miked an instrument and recorded it as a stereo file into the DAW. then when you listened back, you thought it sounded out of phase. would it make sense to simply de-couple the stereo file in a wave editor and then nudge one of the left or right tracks a few samples to get it in phase? No, you'd just invert the phase of either of the channels. |
#21
|
|||
|
|||
Well, the problem is if you "just invert the phase of either of the
channels" and then listened back in mono, the channels would cancel each other out and you would end up with a very thin sound. If you're listening back to the track in the context of the whole mix, it will probably sound like it just dissappeared! If you can re-record it, that's the better alternative. If you can't, then try any of the suggestions you've gotten here and make sure you go back and forth between mono and stereo to see how the sound changes. You should always do a stereo/mono comparison flipping back and forth when recording any stereo track . If you are going to re-record it, there's an easy way to make the mics more in phase with each other - While positioning the mics, flip one side out of phase, listen in mono, start with no EQ or effects on either and get a good solid sound with your first mic. Then with the second mic, find the position where the sound cancels the most or sounds the thinnest. The closer you are micing, the more pronounced the effect will be. Then ,flip the out of phase side back into phase and do your mono/stereo comparison. This also works better if the mics are closely matched. This technique also works great when recording bass using a mic and a direct box. Start with the direct sound and then, starting about an inch away from the speaker, move the out of phase mic away from the speaker until the sound almost completely cancels and then flip it back into phase. This will get you the strongest signal. Since bass is almost always in mono it can mean the difference between a solid or a weak bass sound - and of course - a weak bass sound means a weak mix! |
#22
|
|||
|
|||
wrote in message
oups.com ] Well, the problem is if you "just invert the phase of either of the channels" and then listened back in mono, the channels would cancel each other out and you would end up with a very thin sound. If you're listening back to the track in the context of the whole mix, it will probably sound like it just dissappeared! I'm keying off the OP, which said "let's say you 2-miked an instrument and recorded it as a stereo file into the DAW. then when you listened back, you thought it sounded out of phase." I'm presuming that somehow polarity got flipped during the recording process. That's what the post says to me. |
#24
|
|||
|
|||
Laurence Payne wrote:
On 11 Jan 2005 05:17:27 -0800, wrote: Well, the problem is if you "just invert the phase of either of the channels" and then listened back in mono, the channels would cancel each other out and you would end up with a very thin sound. If you're listening back to the track in the context of the whole mix, it will probably sound like it just dissappeared! But he think's the problem may be due to one mic being out of phase in the first place. Then call it "reversed polarity," which is what it is, and not "out of phase" which is a general phrase that can encompass a whole lot of unrelated things. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#25
|
|||
|
|||
"Scott Dorsey" wrote in message
Laurence Payne wrote: On 11 Jan 2005 05:17:27 -0800, wrote: Well, the problem is if you "just invert the phase of either of the channels" and then listened back in mono, the channels would cancel each other out and you would end up with a very thin sound. If you're listening back to the track in the context of the whole mix, it will probably sound like it just disappeared! But he think's the problem may be due to one mic being out of phase in the first place. Then call it "reversed polarity," which is what it is, and not "out of phase" which is a general phrase that can encompass a whole lot of unrelated things. I didn't call it "out of phase" which I agree can be vague and can be easy to misunderstand. I said "invert the phase" which has a pretty unique meaning in most places. We all seem to know that the problem I was addressing was polarity. Furthermore, the meaning of the phrase "invert the phase" was even correctly deduced by the person who took exception to my suggestion. So, let's review: I knew what I meant and everybody who read it seems to know what I meant. Leaves only one question - where's the beef? |
#26
|
|||
|
|||
|
#27
|
|||
|
|||
Laurence Payne wrote:
On 11 Jan 2005 05:17:27 -0800, wrote: Well, the problem is if you "just invert the phase of either of the channels" and then listened back in mono, the channels would cancel each other out and you would end up with a very thin sound. If you're listening back to the track in the context of the whole mix, it will probably sound like it just dissappeared! But he think's the problem may be due to one mic being out of phase in the first place. In which case the fix is to reverse the polarity of the inversed channel, it can not be addressed in any other way. It may be possible to determine which channel that has been inverted with some, but not perfect, assurance if the recorded signal is naturally asymmetric. CubaseFAQ www.laurencepayne.co.uk/CubaseFAQ.htm "Possibly the world's least impressive web site": George Perfect Kind regards Peter Larsen -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
#28
|
|||
|
|||
Well, the problem is if you "just invert the phase of either of the
channels" and then listened back in mono, the channels would cancel each other out and you would end up with a very thin sound. If you're listening back to the track in the context of the whole mix, it will probably sound like it just dissappeared! If you can re-record it, that's the better alternative. If you can't, then try any of the suggestions you've gotten here and make sure you go back and forth between mono and stereo to see how the sound changes. You should always do a stereo/mono comparison flipping back and forth when recording any stereo track . If you are going to re-record it, there's an easy way to make the mics more in phase with each other - While positioning the mics, flip one side out of phase, listen in mono, start with no EQ or effects on either and get a good solid sound with your first mic. Then with the second mic, find the position where the sound cancels the most or sounds the thinnest. The closer you are micing, the more pronounced the effect will be. Then ,flip the out of phase side back into phase and do your mono/stereo comparison. This also works better if the mics are closely matched. This technique also works great when recording bass using a mic and a direct box. Start with the direct sound and then, starting about an inch away from the speaker, move the out of phase mic away from the speaker until the sound almost completely cancels and then flip it back into phase. This will get you the strongest signal. Since bass is almost always in mono it can mean the difference between a solid or a weak bass sound - and of course - a weak bass sound means a weak mix! |
#29
|
|||
|
|||
If it sounds "out of phase," the error is a heck of a lot greater than nudging
one channel a few samples can fix. Are the mics the same model? Are they the same distance from the instrument? Is there a possibility of polarity inversion somewhere in the chain? |
#30
|
|||
|
|||
On 10 Jan 2005 22:49:11 -0800, wrote:
let's say you 2-miked an instrument and recorded it as a stereo file into the DAW. then when you listened back, you thought it sounded out of phase. would it make sense to simply de-couple the stereo file in a wave editor and then nudge one of the left or right tracks a few samples to get it in phase? If you suspect one recording channel was wired backwards, you need to reverse the phase of that channel, not delay it. If you feel one mic was closer than the other, a simple delay may help. Look at the waveforms at high magnification and nudge one until they align. Maybe you should just discard one channel - you may have a perfectly good mono recording of this instrument. CubaseFAQ www.laurencepayne.co.uk/CubaseFAQ.htm "Possibly the world's least impressive web site": George Perfect |
#31
|
|||
|
|||
Laurence Payne wrote:
If you feel one mic was closer than the other, a simple delay may help. Look at the waveforms at high magnification and nudge one until they align. It is not *that* simple - it would be if it was a recording in a sound dead room, but it isn't - listening is also required and what is perceived right may not "look right". Great caution is adviced ..... including listening on several loudspeaker setups. CubaseFAQ www.laurencepayne.co.uk/CubaseFAQ.htm Kind regards Peter Larsen -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
#32
|
|||
|
|||
One more thing you might try that hasn't been suggested yet - Just use
the one side you like best and send it through a stereo plug-in or reamp it out to an amp and mic it. And of course, as always, do the mono/stereo comparison to check the integrity of your signal. |
#33
|
|||
|
|||
hello everyone, let's say you 2-miked an instrument and recorded it as a stereo file into the DAW. then when you listened back, you thought it sounded out of phase. would it make sense to simply de-couple the stereo file in a wave editor and then nudge one of the left or right tracks a few samples to get it in phase? Yes, that will work for a PHASE problem. It will not work on a POLARITY problem. Phase involves time and polarity does not. If you have a polarity problem, simply invert one of the files. Richard H. Kuschel "I canna change the law of physics."-----Scotty |
#34
|
|||
|
|||
|
#35
|
|||
|
|||
I was not aware the one could hear phase inless it is changing.
Bob "Mike Rivers" wrote in message news:znr1105461896k@trad... In article writes: Yes, that will work for a PHASE problem. It will not work on a POLARITY problem. Hey, he said "sounds out of phase." Most people don't know what "out of polarity" sounds like. When you put two mics on a guitar, unless thery're coincident, there will be a time offset between them, which can indeed sound "out of phase." If there's a time offset as well as a polarity difference, they'll still sound "out of phase" only different. -- I'm really Mike Rivers ) However, until the spam goes away or Hell freezes over, lots of IP addresses are blocked from this system. If you e-mail me and it bounces, use your secret decoder ring and reach me he double-m-eleven-double-zero at yahoo |
#36
|
|||
|
|||
sycochkn wrote:
I was not aware the one could hear phase inless it is changing. Depends on what "phase" is. Absolute or relative polarity? Group delay in a channel? Comb filtering effects? All get called "phasing" by people. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#37
|
|||
|
|||
|
#38
|
|||
|
|||
On Tue, 11 Jan 2005 01:49:11 -0500, wrote
(in article . com): hello everyone, let's say you 2-miked an instrument and recorded it as a stereo file into the DAW. then when you listened back, you thought it sounded out of phase. would it make sense to simply de-couple the stereo file in a wave editor and then nudge one of the left or right tracks a few samples to get it in phase? absolutely. Ty Ford -- Ty Ford's equipment reviews, audio samples, rates and other audiocentric stuff are at www.tyford.com |
#39
|
|||
|
|||
"Ty Ford" wrote in message
On Tue, 11 Jan 2005 01:49:11 -0500, wrote (in article . com): hello everyone, let's say you 2-miked an instrument and recorded it as a stereo file into the DAW. then when you listened back, you thought it sounded out of phase. would it make sense to simply de-couple the stereo file in a wave editor and then nudge one of the left or right tracks a few samples to get it in phase? absolutely. I don't think so. If you want to de-couple tracks enough to make a difference, you need to nudge them many milliseconds. You want them to be far enough apart so that they sound different from each other, but not far enough to create an audible echo. |
#40
|
|||
|
|||
I don't think so. If you want to de-couple tracks enough to make a
difference, you need to nudge them many milliseconds. Not at all. A nudge of a millesecond or less can result in a substantial timbre shift. Scott Fraser |
Reply |
|
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Phase Correction | Pro Audio | |||
mixed crossover phase question | Tech | |||
Richman's ethical lapses | Audio Opinions | |||
Transient response of actively filtered speakers | Tech | |||
Negative/Positive Phase Shift in a Transformer | Pro Audio |