Cinco is absolutely right, the mirror convention is that a driver moves outward with red connected to plus.
A more interesting matter imo is that condensor and dynamic microphones have different phase characteristics. Dynamic microphones have their maximum output where the sine crosses the zero. They pick up velocity. Condensor mikes have maximum output at the extremes of the sine. They pick up pressure. So, they are 90 degrees out of phase.
When you can sim this in your mind, it is an easy question to answer which one of the two types is leading.
Since electromagnetic transducers have the identical phase relationship to the electric signal, there is a point to be made that dynamic microphones should be used in order to reproduce the human voice most faithfully. ESL's would sound best with condensors.
That is, if the human ear were to be sensitive to wave form. And the above proves that they are not. The best regarded studio microphones are all condensor mikes afaik, and no studio I have ever been in has ESL's.
Paul
A more interesting matter imo is that condensor and dynamic microphones have different phase characteristics. Dynamic microphones have their maximum output where the sine crosses the zero. They pick up velocity. Condensor mikes have maximum output at the extremes of the sine. They pick up pressure. So, they are 90 degrees out of phase.
When you can sim this in your mind, it is an easy question to answer which one of the two types is leading.
Since electromagnetic transducers have the identical phase relationship to the electric signal, there is a point to be made that dynamic microphones should be used in order to reproduce the human voice most faithfully. ESL's would sound best with condensors.
That is, if the human ear were to be sensitive to wave form. And the above proves that they are not. The best regarded studio microphones are all condensor mikes afaik, and no studio I have ever been in has ESL's.
Paul
As a starter: A very good 2nd and 3rd harmonics generator is the plugin Reviver from Fielding DSP (www.fieldingdsp.com). It includes a "phase" button. It is very clean sounding, since it produces very little aliasing.
It's OK - Heck, I lost my book! So I cant even post a line or two about what it said on the subject of absolute phase 😉
So whats the polarity of a far miced snare drum with the skin parallel to the mic, like you would hear in the audiance? 90 degrees??? How?
A further distinction is that cardioid condensers pick up the pressure gradient, while only omnidirectional condenser microphones pick up pressure.
Soundwise you get a cleaner bass, and no proximity effect, with omnis.
I am not sure if those differences lead to a difference in relation to phase. Phase is more a topic in large diaphragm vs. small diaphragm, and headbasket reflections. And then there are also reflections in the membrane itself. That's why there are rectangular capsules (Milab, Pearl, Audio Technica) and even triangular capsules (Ehrlund). They are less prone to reflection issues than round diaphragms.
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Maybe it's too late at night for me to think clearly... Does the fact that the electric and the magnetic field are 90 degrees apart play a(n additional) role in all this? The dynamic microphone would be affected by this, or is this late night thinking?
I found the plugin: https://www.hornetplugins.com/plugins/hornet-harmonics/
Voxengo Shinechilla is another interesting one.
The aforementioned plugin I didn't know. But it doesn't seem to be very useful if the level of the harmonics is indeed fix and static. This is contrary to analog equipment that saturates more as the signal gets louder.
The Hornet and Voxengo plugins are signal-dependent.
Voxengo Shinechilla is another interesting one.
The aforementioned plugin I didn't know. But it doesn't seem to be very useful if the level of the harmonics is indeed fix and static. This is contrary to analog equipment that saturates more as the signal gets louder.
The Hornet and Voxengo plugins are signal-dependent.
I don't think this is correct, but my knowledge of acoustics is not that good, so I hope someone who understands acoustics better than I do will correct me if I write nonsense. What I think will happen is:
The sound pressure and volume velocity are proportional in the far field without any frequency dependence, so it shouldn't matter what type of microphone you use when it is in the far field and is equalized for a flat far field response.
In the near field, you get extra bass with a directional microphone due to proximity effect (disturbed relation between volume velocity and sound pressure). The phase relation is then indeed disturbed, but you correct for that when you equalize it out using a minimum-phase equalizer or use a directional microphone of which the response corrects for it (like an SM-58 that only produces bass when the singer almost eats it up).
Besides, there are dynamic microphones with an omnidirectional response that must therefore sense the sound pressure rather than the volume velocity. The Sennheiser MD-21 is an example. Condenser microphones also come with various directional patterns.
The mikes we actually use, it is not true. Remember they phase and frequency response are always linked. Dynamic omnis are loaded with resistance to flatten their velocity motor into pressure sensitive. Likewise ribbons are made small and open-back to spoil their rising response and phase-advance into a flat response.
After years of working between live and Memorex (or Maxell), I think absolute phase is sometimes audible but I never know which way is right.
I also think that 97% of listeners can't tell. Even relative phase. Unless it comb-filters. And even then.
I know all-pass filters are one of the many tricks used to make radio transmitters sound louder - not better, just louder.
True, but when you use a minimum-phase equalizer to equalize out some abberation caused by a minimum-phase thing, the equalizer's phase response actually corrects for the phase shift of the thing. Typical example: the usual minimum-phase RIAA correction networks correct for the phase shift of the RIAA filters used during recording.
I think PRR's second sentence also means that everything he knows of that causes tilted frequency responses in microphones is minimum phase, therefore the phase response is automatically corrected when you flatten the magnitude response with some minimum-phase means.
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I have built ESLs, tractrix horns, long ribbon tweeters. I can hear horn tweeters before I see them when walking into a venue with horns. I have owned Altec Lansing Voice Of The Theater mid-tweets and measured them acoustically and listened to them.
Horns have enormous phase wrap. To me they sound like horns and not like musical instruments when music is eminating from them. They sound like what chearleaders sound like when they yell into a conical plastic device.
Group delay is the first derivative of phase. In sub-woofers, closed box systems have the flattest group delay. Vented systems have more group delay peak than closed box systems. Passive radiator systems have more of a group delay peak than either of the previous two. Passive radiator systems sound boomy to me and not like musical bass from real instruments.
It helps if you spend time with real acoustic instruments. I played woodwind and brass instruments for years in school bands as well as acoustic guitar and I have sung in many choirs over decades.
Learning to hear "phasey" speaker behavior is possible. You have to have a frame of reference. If you had a good ribbon tweeter alongside a garden variety horn tweeter, you could find source material that would easily let you hear the difference. I think that the difference is excessively added group delay as Mr. Pass discussed. The added group delay is the result of optimixing for the most SPL possible.
Horns have enormous phase wrap. To me they sound like horns and not like musical instruments when music is eminating from them. They sound like what chearleaders sound like when they yell into a conical plastic device.
Group delay is the first derivative of phase. In sub-woofers, closed box systems have the flattest group delay. Vented systems have more group delay peak than closed box systems. Passive radiator systems have more of a group delay peak than either of the previous two. Passive radiator systems sound boomy to me and not like musical bass from real instruments.
It helps if you spend time with real acoustic instruments. I played woodwind and brass instruments for years in school bands as well as acoustic guitar and I have sung in many choirs over decades.
Learning to hear "phasey" speaker behavior is possible. You have to have a frame of reference. If you had a good ribbon tweeter alongside a garden variety horn tweeter, you could find source material that would easily let you hear the difference. I think that the difference is excessively added group delay as Mr. Pass discussed. The added group delay is the result of optimixing for the most SPL possible.
"Absolute phase" ... that's the 1st time I've ever heard the term ... what is the potential "absolute phase" difference between a pair of ears?
When I play around with my DSP crossover I often play around with the absolute polarity also. With some recordings there is a distinct difference. I can often clearly say which one I like better but I am not sure whether the one I like better is actually the correct one.
The reason for this is that many signals are asymmetric and the ear's perception is also asymmetric (mechanical "half wave rectification"). Therefore the difference in perception.
And yes, there seem to be recording engineers who don't pay attention to polarity.
Regards
Charles
The reason for this is that many signals are asymmetric and the ear's perception is also asymmetric (mechanical "half wave rectification"). Therefore the difference in perception.
And yes, there seem to be recording engineers who don't pay attention to polarity.
Regards
Charles
Clark Johnsen was a friend. I was attracted to his idea of absolute phase and have attempted to find it over the last thirty years. As with many enthusiasms it begins with assurances of something that can be found and with time one discovers it is not as clear as one would wish all things in life would be.
I think the point Clark wanted to make is there is one polarity that sounds better and not necessarily hugely better and on many occasions hardly noticeable but it is always worth the trouble to try them both if your system allows. One must remember that when Clark began his explorations he would change the wires between the amps and the speakers - something I would never have the patience to do. I initially used a switch between the phono cartridge and the phono stage.
Like phase accurate I use a DSP box to control my speakers so it as simple as a poke of the finger on the Iphone to change.
I can say the better I have learned to tune my system, thanks to the literal audio magic of the xilica SOLARA dsp box and REW, once you learn what it is telling you instead of what you want it to say, the clearer the differentiation can be. By that I mean it is easy with practice to hear a difference. The tricky part is figuring out which polarity is best. Many times one way makes an aspect of the performance better while the other does the same for another.
I have never made written records of which sounds better with recordings and it would be amusing to see if there is consistency. I think there would be some but not enough to prove anything.
I figure it is like the Great One has always cautioned us IT IS ENTERTAINMENT and what pleases you is all that matters. I keep this in mind at all times. I am in complete agreement with the also great PRR in his assessment based upon experience far beyond mine.
So I think it is worthwhile yet the ability to say what is best remains elusive and I suspect this is part of what makes our noble insane hobby so much fun
I think the point Clark wanted to make is there is one polarity that sounds better and not necessarily hugely better and on many occasions hardly noticeable but it is always worth the trouble to try them both if your system allows. One must remember that when Clark began his explorations he would change the wires between the amps and the speakers - something I would never have the patience to do. I initially used a switch between the phono cartridge and the phono stage.
Like phase accurate I use a DSP box to control my speakers so it as simple as a poke of the finger on the Iphone to change.
I can say the better I have learned to tune my system, thanks to the literal audio magic of the xilica SOLARA dsp box and REW, once you learn what it is telling you instead of what you want it to say, the clearer the differentiation can be. By that I mean it is easy with practice to hear a difference. The tricky part is figuring out which polarity is best. Many times one way makes an aspect of the performance better while the other does the same for another.
I have never made written records of which sounds better with recordings and it would be amusing to see if there is consistency. I think there would be some but not enough to prove anything.
I figure it is like the Great One has always cautioned us IT IS ENTERTAINMENT and what pleases you is all that matters. I keep this in mind at all times. I am in complete agreement with the also great PRR in his assessment based upon experience far beyond mine.
So I think it is worthwhile yet the ability to say what is best remains elusive and I suspect this is part of what makes our noble insane hobby so much fun
I do wish we would describe signal inversion/non-inversion "polarity" instead of "phase."
"Up" (pressure at the ear) for asymmetric waveforms usually sounds better to me but that doesn't mean that one polarity is better for an entire track when the various elements may be a hodge-podge with vocals inverted and sax non-inverted. The choice that sounds best during a solo may not sound best on the overall track.
To my ear inverted sax is one of the most obvious. You can often get improvements in tone by hitting the polarity button that you could never get with EQ and dynamics.
Saturated hyper-compressed mixes with the life squeezed out of them will produce no difference at all because there's no asymmetry.
https://ka-electronics.com/shop/
"Up" (pressure at the ear) for asymmetric waveforms usually sounds better to me but that doesn't mean that one polarity is better for an entire track when the various elements may be a hodge-podge with vocals inverted and sax non-inverted. The choice that sounds best during a solo may not sound best on the overall track.
To my ear inverted sax is one of the most obvious. You can often get improvements in tone by hitting the polarity button that you could never get with EQ and dynamics.
Saturated hyper-compressed mixes with the life squeezed out of them will produce no difference at all because there's no asymmetry.
https://ka-electronics.com/shop/
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Why don't you make some example clips ... I'm sure many would be interested in hearing that.
I'm surprised none of you guys use audio goniometers, that's what most recording engineers use to check polarity/phase ... you can get lots of complex info from them ... 🙂
I use a goniometer and a 'scope on the bench quite often particularly with my work developing a second-order Elliptic EQ for vinyl mastering.
("Elliptic EQ" is a vinyl term of art not to be confused with an elliptic filter.)
Here are two 35 second cuts of commercial material. Since they're short and educational I claim Fair Use. They are the same file: One is inverted with respect to the other.
https://proaudiodesignforum.com/content/Renee_Olstead-Someone_To_Watch_Over_Me_Cut_1.wav
https://proaudiodesignforum.com/content/Renee_Olstead-Someone_To_Watch_Over_Me_Cut_2.wav
I've got some solo sax cuts I need to find as well. Almost any brass instrument will produce asymmetry.
("Elliptic EQ" is a vinyl term of art not to be confused with an elliptic filter.)
Here are two 35 second cuts of commercial material. Since they're short and educational I claim Fair Use. They are the same file: One is inverted with respect to the other.
https://proaudiodesignforum.com/content/Renee_Olstead-Someone_To_Watch_Over_Me_Cut_1.wav
https://proaudiodesignforum.com/content/Renee_Olstead-Someone_To_Watch_Over_Me_Cut_2.wav
I've got some solo sax cuts I need to find as well. Almost any brass instrument will produce asymmetry.
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Credit to Chris Botti for the Renee Olstead solo...
Here are two baritone sax files for comparison from the THAT Corporation "Hard Nasty Tracks" test CD.
https://proaudiodesignforum.com/content/Baritone_Sax_1.wav
https://proaudiodesignforum.com/content/Baritone_Sax_2.wav
Here are two baritone sax files for comparison from the THAT Corporation "Hard Nasty Tracks" test CD.
https://proaudiodesignforum.com/content/Baritone_Sax_1.wav
https://proaudiodesignforum.com/content/Baritone_Sax_2.wav
Yeah that is interesting, I prefer the inverted Renee Olstead, the original is almost grating when loud, is that straight from the original mix?
The baritone files are difficult to judge because both could sound good depending on the context but yeah I wouldn't normally have tried flipping the phase on a sax recorded with a single mic.
It would be interesting to hear an entire track that you have re-mastered flipping phase where you think it improves the track ... vs the original.