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Post by jin167 on Jun 18, 2016 8:10:19 GMT -6
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ericn
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Balance Engineer
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Post by ericn on Jun 18, 2016 17:25:46 GMT -6
If you can detect absolute polarity on a recording, yes it could matter to you, but I doubt anyone could tell after mixing mastering and codeine for download! Now in the studio you might notice some polarity issues on some gear depending on what leg and if it inverts or doesn't relevant to everything else on that leg. Polarity is the simplest issue to deal with between wiring switching and patch bays !
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Post by drbill on Jun 18, 2016 17:33:28 GMT -6
Many engineers can hear absolute phase i.e.: polarity.
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ericn
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Post by ericn on Jun 18, 2016 17:53:02 GMT -6
Many engineers can hear absolute phase i.e.: polarity. Bill I'm talking about in the audiophile sense, where somebody is talking about a finished production, where you have all kinds of phase shift induced by every stage blurring the absolute polarity, now I can hear where one channel of stereo is inverted real stove to the other, but trying to tell if the polarity of say Stairway To Heaven or a track in the record no ! I have endured audiophile conversations where somebody swears something is inverting phase , brought out the old clicker to hear the clicker is broken or that the CD must be a different mastering !
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Post by drbill on Jun 18, 2016 17:56:43 GMT -6
I know what you meant. I wasn't talking about one side of a pair reversed. Even a semi-deaf person can hear that. I was talking about absolute polarity of audio signal - especially with transient related material - like songs with drums.
I know engineers who can hear the polarity of a recording they are working on and that they are FAMILIAR with. i.e.: whether or not the speaker pushes or sucks back in on first transient impact. (Easily accomplished on the console) In fact one used to taunt me about it, and I often tried to mess him up during sessions, but he came back "right" a scary percentage of the time. Just sayin'.....
I can't do it consistently. I can SOMETIMES do it with a single source like a kick drum under a microscope. But I think it's a freak kind of thing like perfect pitch, or the guy (I know em) who can feel the difference between sliding regions that are groove oriented 20 or 50 samples. (No kidding)
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ericn
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Post by ericn on Jun 18, 2016 18:15:05 GMT -6
I know what you meant. I wasn't talking about one side of a pair reversed. Even a semi-deaf person can hear that. I was talking about absolute polarity of audio signal - especially with transient related material - like songs with drums. I know engineers who can hear the polarity of a recording they are working on and that they are FAMILIAR with. i.e.: whether or not the speaker pushes or sucks back in on first impact. (Easily accomplished on the console) In fact one used to taunt me about it, and I often tried to mess him up, but he came back "right" a scary percentage of the time. Just sayin'..... The familer with is key , but as I have said 9 times out of 10 when the system was checked.. And that's the thing I learned early on for everyone there are 9 who can't that will say they can! It's one of those Audio terms guys learn to impress, but many don't understand that phase is shifted through out a recording and the total effect can result in 180 or close of phase shift and if we add in the fact that their are very few dynamic speaker systems that are phase coherent through their entire operating range ( the lowest operating range of any driver requires a lot of phase correction ) and very few mics are phase coherent !
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Post by jeremygillespie on Jun 18, 2016 19:16:53 GMT -6
"on the page 8 it says 'The phase of the AC supply can make a significant difference to the sound"
Wouldn't the phase of an AC line not matter after the signal is converted to DC in the gear that we use? Maybe I'm not understanding the question correctly?
I can hear a 50 sample nudge when messing with drum/bass gtr relationships. Its usually the number I have my nudge function set to in PT. 20 samples is insane haha. I don't think I'd be able to pick that up.
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Post by Ward on Jun 18, 2016 21:22:48 GMT -6
What's hilarious about many of those who pontificate just to seem 'grand' is their lack of understanding of electricity in general.
Many electrical circuits are not just positive (black) negative(white) and ground (green) but also contain a 'feed line' which is red. a feed line defies polarity in the AC circuit and almost behaves like a direct current line. YET, it is part of the Alternating Current spec. And then there's 'residual return'... and three phase power, up-conversion and down-conversion, electrical current purity loss (85% at best) etc etc... and that's just what I have learned as a layman through various electrical and electronic pursuits.
Anyhow, a great electrician is vitally necessary for any recordist or audiophile, one who will specify current flows, as much current purity as possible and of course, power conditioning.
Be well folks, and don't lick the black or red wires.
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Post by jin167 on Jun 18, 2016 22:26:49 GMT -6
"on the page 8 it says 'The phase of the AC supply can make a significant difference to the sound" Wouldn't the phase of an AC line not matter after the signal is converted to DC in the gear that we use? Maybe I'm not understanding the question correctly? I can hear a 50 sample nudge when messing with drum/bass gtr relationships. Its usually the number I have my nudge function set to in PT. 20 samples is insane haha. I don't think I'd be able to pick that up. Exactly my thought. As a matter of fact, I've never seen a downstep transformer having a 'phase' or a 'polarity'. Also, in my country most households use a single phase power outlet so I really don't get this AC 'phase' or 'polarity' thing.
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Post by drbill on Jun 18, 2016 22:53:00 GMT -6
I can hear a 50 sample nudge when messing with drum/bass gtr relationships. Its usually the number I have my nudge function set to in PT. 20 samples is insane haha. I don't think I'd be able to pick that up. I worked with a very famous guitarist known for his killer groove parts that was producing an artist - and I was engineering for that record. He asked for anything from 10-50 sample nudges, and I couldn't believe it, but he could reliably feel 20 samples. I purposefully tried to trick him, moving 10 forward and then 10 back, and he would say...."hmmmm....doesn't feel like they moved. Give em another 20." And then he was satisfied. After working on the most incredible minutae, I began to be able to start feeling it too. BUT, I don't WANT to go that crazy. Not for me. Music is not about perfection for me. Point being - if you CARE that much to listen THAT hard, and you are gifted in that aspect of sound, it's amazing what you can hear.
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Post by drbill on Jun 18, 2016 22:54:01 GMT -6
Be well folks, and don't lick the black or red wires. Note to self......... heh heh heh <thumbsup>
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Post by Johnkenn on Jun 18, 2016 23:40:08 GMT -6
Wow, Interesting. I haven't poured over ever word of this thread, but are you guys saying that AFTER you've recorded someone, they think that it's 20 samples behind?
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Post by Johnkenn on Jun 18, 2016 23:41:35 GMT -6
BTW - I don't believe in any kind of electrical BS. But I'm always willing to be proven wrong....
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Post by keymod on Jun 19, 2016 6:04:50 GMT -6
In the old days of two-prong, non-grounded receptacles it was possible to plug in a two-prong power cord "backwards" and everything would still work, although at an increased possibility for a shock hazard. This was because "hot" would be on everything that was supposed to be "neutral", and vice-versa. There was nothing on the receptacle or the power cords to designate direction or polarity. You can see this on old guitar amps. Sometimes flipping the cord cap in the receptacles would minimize noise/hum. After a while devices were manufactured "double-insulated" to reduce that shock hazard. Also, as time went on, receptacles were manufactured with one slot larger than the other and the plugs on the power cords were designed to match. The larger slot designates the "neutral" current-carrying conductor while the small slot designates the "hot" current-carrying conductor. And of course, at some point in time, a grounding pin was added which results in the modern three-pin receptacles and cord caps that are in use today, at least here in the United States. But be aware - just because a receptacle has a grounding pin does not mean that that point of utilization is properly grounded! It should be noted that "neutral" and "hot" are NOT THE SAME as positive and negative. This is a common misconception. There is usually more line "noise" on the neutral than on the hot. This is because all of the return current throughout the premises is picking up garbage as it flows throughout all of the various circuits throughout the building. All of the neutrals are tied together at the service panels and this tends to amplify all of the line noise. ( this is a very, very simplistic explanation ) We've all heard that our audio power source should not be on the same circuit/phase/leg/etc. as florescent lighting or lighting with dimmers or appliances such as refrigerators and the like. So, with regards to audio equipment, if it's possible to plug in a device "backwards"- as described above - , then it's possible that that device can pick up more line noise and not operate as efficiently or quietly as designed. I think this is what is being alluded to on page 8 of the user guide. However, they are using the term "phase" erroneously. And, if the premise wiring is correct, with a properly installed three-prong receptacle, this should be a non-issue anyway because their device is manufactured with a three-prong IEC power connection which (should) make it impossible to be plugged in and powered incorrectly. Basically, what they are saying is make sure your point of utilization is wired correctly.
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Post by jin167 on Jun 19, 2016 6:17:25 GMT -6
In the old days of two-prong, non-grounded receptacles it was possible to plug in a two-prong power cord "backwards" and everything would still work, although at an increased possibility for a shock hazard. This was because "hot" would be on everything that was supposed to be "neutral", and vice-versa. There was nothing on the receptacle or the power cords to designate direction or polarity. You can see this on old guitar amps. Sometimes flipping the cord cap in the receptacles would minimize noise/hum. After a while devices were manufactured "double-insulated" to reduce that shock hazard. Also, as time went on, receptacles were manufactured with one slot larger than the other and the plugs on the power cords were designed to match. The larger slot designates the "neutral" current-carrying conductor while the small slot designates the "hot" current-carrying conductor. And of course, at some point in time, a grounding pin was added which results in the modern three-pin receptacles and cord caps that are in use today, at least here in the United States. But be aware - just because a receptacle has a grounding pin does not mean that that point of utilization is properly grounded! It should be noted that "neutral" and "hot" are NOT THE SAME as positive and negative. This is a common misconception. There is usually more line "noise" on the neutral than on the hot. This is because all of the return current throughout the premises is picking up garbage as it flows throughout all of the various circuits throughout the building. All of the neutrals are tied together at the service panels and this tends to amplify all of the line noise. ( this is a very, very simplistic explanation ) We've all heard that our audio power source should not be on the same circuit/phase/leg/etc. as florescent lighting or lighting with dimmers or appliances such as refrigerators and the like. So, with regards to audio equipment, if it's possible to plug in a device "backwards"- as described above - , then it's possible that that device can pick up more line noise and not operate as efficiently or quietly as designed. I think this is what is being alluded to on page 8 of the user guide. However, they are using the term "phase" erroneously. And, if the premise wiring is correct, with a properly installed three-prong receptacle, this should be a non-issue anyway because their device is manufactured with a three-prong IEC power connection which (should) make it impossible to be plugged in and powered incorrectly. Basically, what they are saying is make sure your point of utilization is wired correctly. Thank you. Your explanation is basically what I've learned in my first year at the university so it's good to know that I haven't mistaken anything. I thought it was very weird of them to say something like 'phase' or 'polarity' while dealing with a single phase power supply. But how would plugging in a device 'backwards' induce noise in any way? I mean with the way the rectifier and transformer works I see no issues with having a device plugged in 'backwards'.
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Post by keymod on Jun 19, 2016 6:35:12 GMT -6
It really shouldn't matter with modern equipment that uses properly designed power supplies. Svart seems to be the resident guru here on RGO with regards to this sort of thing. Hopefully he will chime in.
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Post by Pueblo Audio on Jun 19, 2016 10:04:08 GMT -6
Common single-phase US power is distributed at 240Vac which is then split into two 120Vac legs by a center tap transformer. One leg is inverted from the other. There is no actual phase shift, but it is standard jargon to call them "phases". 3-Phase Ac power does have actual phase shifts, but that's not relavant here.
These two "phases" can be supplied to a facility. Smart studios will isolate non-tech loads (lights, hvac, etc) on one phase, audio tech loads on the other. This helps minimize noise and interference.
Theoretically there should not be any power quality difference in either phase. They both come from the same transformer. If there is a problem, it might stem from interference and noise manifested by poor wiring/interconnection/circuit choices between the phases. It's in the implementation.
Be careful not to confuse AC power phase with audio signal polarity. One has nothing to do with the other.
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Post by jin167 on Jun 19, 2016 11:01:55 GMT -6
Common single-phase US power is distributed at 240Vac which is then split into two 120Vac legs by a center tap transformer. One leg is inverted from the other. There is no actual phase shift, but it is standard jargon to call them "phases". 3-Phase Ac power does have actual phase shifts, but that's not relavant here. These two "phases" can be supplied to a facility. Smart studios will isolate non-tech loads (lights, hvac, etc) on one phase, audio tech loads on the other. This helps minimize noise and interference. Theoretically there should not be any power quality difference in either phase. They both come from the same transformer. If there is a problem, it might stem from interference and noise manifested by poor wiring/interconnection/circuit choices between the phases. It's in the implementation. Be careful not to confuse AC power phase with audio signal polarity. One has nothing to do with the other. Exactly. In our country, I don't think we even use a center tap transformer. So I guess I can safely disregard an idea of a single phase power outlet having a 'polarity' or 'phase' and having a neutral and live wire inverted shouldn't make any difference as long as the gear I'm using has a proper PSU circuit built in it.
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Post by Pueblo Audio on Jun 19, 2016 23:03:49 GMT -6
So I guess I can safely disregard an idea of a single phase power outlet having a 'polarity' or 'phase' I think so. having a neutral and live wire inverted shouldn't make any difference as long as the gear I'm using has a proper PSU circuit built in it. Well, I am not sure what criteria would constitute a "proper" power supply design, but I like to think the Pueblo Audio PS34 power supply is one. Even so, if it's connected to an outlet with hot, neutral or ground wired improperly, then fidelity reducing error currents may still manifest between it and other connected devices in the network. Again, it's about how things are implemented rather than innate qualities. One should never disregard implementation. Set ups should be tested and errors resolved. Just exercise a little attention to detail and basic audio engineering. It costs little really. I always say great audio is rarely about doing something amazing. Rather it's about avoiding common, every day errors.
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