Holmz
Major Contributor
It is not correct.
But whether one hears it or not is subjective.
-
Welcome to ASR. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!
Fixing inverted polarity of a multi-driver IEM.
- Thread starter Jean-Paul Petrosyan
- Start date
But whether one hears it or not is subjective.
Soandso
Major Contributor
- Joined
- May 30, 2022
- Messages
- 2,144
- Likes
- 4,761
Replying to O.P.'s #18 comment: " … to understand it ...."
In multiple-driver iem's inverting the wired polarity of the two signal channels (popularly referred to as "+" and "ground" at a plug) to any one driver in effect lessens the sound pressure level (decibels) there. The well known Fletcher-Munson data explains how in comparison to mid-level frequencies we have lower perception of loudness for low frequencies (bass), and to a lesser extent high frequencies.
Inside the housing of a multiple-driver iem at least the small bass driver(s) will logically be wired for positive polarity. Thus if you re-wire that iem's exterior jack plug to a different polarity that will have the effect of inverting the music signal channels' input at the bass driver(s) itself (and some similarly wired high frequency driver).
In practical words: if simply change the iem's plug wiring polarity that will invert the stock polarity in side the housing at the bass driver itself. So before re-wiring the stock iem for polarity make a short reversed polarity adapter plug (this receives the music player's normal output signal and inside the plug invert the wiring polarity), connect that to the stock iem signal input wiring. My guess is interventions inverting polarity will be counter-acting this iem's built in multiple-driver design feature to (theoretically) somewhat equalize comparative loudness in favor of bass and you'll thus be inclined toward turning up the volume.
In multiple-driver iem's inverting the wired polarity of the two signal channels (popularly referred to as "+" and "ground" at a plug) to any one driver in effect lessens the sound pressure level (decibels) there. The well known Fletcher-Munson data explains how in comparison to mid-level frequencies we have lower perception of loudness for low frequencies (bass), and to a lesser extent high frequencies.
Inside the housing of a multiple-driver iem at least the small bass driver(s) will logically be wired for positive polarity. Thus if you re-wire that iem's exterior jack plug to a different polarity that will have the effect of inverting the music signal channels' input at the bass driver(s) itself (and some similarly wired high frequency driver).
In practical words: if simply change the iem's plug wiring polarity that will invert the stock polarity in side the housing at the bass driver itself. So before re-wiring the stock iem for polarity make a short reversed polarity adapter plug (this receives the music player's normal output signal and inside the plug invert the wiring polarity), connect that to the stock iem signal input wiring. My guess is interventions inverting polarity will be counter-acting this iem's built in multiple-driver design feature to (theoretically) somewhat equalize comparative loudness in favor of bass and you'll thus be inclined toward turning up the volume.
Holmz
Major Contributor
How does that work exactly?
The current will be flowing the other way, but the motor force will of the same magnitude.
Just 180 degrees out in its direction.
^Almost certainly not.^
One can hook a speaker up with the + and - reversed, only the impulse response gets flipped.
And an IEM is like a miniaturised version of a speaker.
OP
Jean-Paul Petrosyan
Member
- Joined
- Jul 16, 2023
- Messages
- 65
- Likes
- 36
- Thread Starter
- #24
It seems like Nova actually has correct polarity, judging by what I've scraped up on the net. It seems that the measurement rigs themselves ivert the polarity, at least some of them do. Looking at the impulse response of Moondrop Variations, for example, it seems like it has correct polarity, but multiple sources state that it, in fact, doesn't.
Sorry, I won't be able to respond to individual posts for some time. Please, don't think that I'm ignoring them or something.
Sorry, I won't be able to respond to individual posts for some time. Please, don't think that I'm ignoring them or something.
Soandso
Major Contributor
- Joined
- May 30, 2022
- Messages
- 2,144
- Likes
- 4,761
Replying to Holmz (#23 comment) with my conceptualization of "… how does that work ...?"
When supplied energy if there's reversal of polarity in any one of an iem driver's wiring connection there is some by-product of heat induced by eddies in the current flow, which leads to a relative reduction in the speed of that frequency's electrical motive force.
As for our ear mechanics here's one summary from the O.P.'s above Reddit link regarding what is called "hair cell receptor potential":
Quote=
Also my reply to : "IEM is like …a speaker."
The iem isn't likely to have a cross-over which are commonly integrated into speakers, whereby speaker impulse response ties phase into the functional polarity. Of course I have read bloggers complaining that multiple-driver iems can be prone to presenting phase issues and there my thinking is that with inverted driver polarity(s) can affect impulse response.
When supplied energy if there's reversal of polarity in any one of an iem driver's wiring connection there is some by-product of heat induced by eddies in the current flow, which leads to a relative reduction in the speed of that frequency's electrical motive force.
As for our ear mechanics here's one summary from the O.P.'s above Reddit link regarding what is called "hair cell receptor potential":
Quote=
Also my reply to : "IEM is like …a speaker."
The iem isn't likely to have a cross-over which are commonly integrated into speakers, whereby speaker impulse response ties phase into the functional polarity. Of course I have read bloggers complaining that multiple-driver iems can be prone to presenting phase issues and there my thinking is that with inverted driver polarity(s) can affect impulse response.
Last edited:
OP
Jean-Paul Petrosyan
Member
- Joined
- Jul 16, 2023
- Messages
- 65
- Likes
- 36
- Thread Starter
- #26
Shouldn't modular cables with 4 pin connectors allow to invert the polarity by plugging the connector the opposite way? That would be quite convenient.
How do I determine polaity of an IEM cable and polarity of amplifier's output with multimeter?
How do I determine polaity of an IEM cable and polarity of amplifier's output with multimeter?
Last edited:
Soandso
Major Contributor
- Joined
- May 30, 2022
- Messages
- 2,144
- Likes
- 4,761
Acoustic polarity seems informatively illustrated by the following two representations of a single struck snare drum with separate recording microphones arrayed both above and below.
What is being revealed is that upon hitting the snare skin it's upper surface moved away from the top microphone while it's lower surface moved toward the bottom microphone.
When an acoustic waveform moves forward (toward a microphone, or an ear) it adds quantity (amplitude); some popularly call it a state of "positive" ("+") polarity however technically it is known as the "compression" state of polarity. The dark black lines chart the "compression" polarity. What needs to be understood at this point is that acoustic polarity is determined by the initial wavefront. Above we can see the snare drum fundamental, which is 150-250 Hz clearly has amplitude with "+" compression polarity.
Meanwhile the above light gray line charts the waveform of the drum head moving away from it's microphone. This is an inverse state from "compression" and is technically known as a "rarefaction" state of polarity, sometimes called "negative" ("-") polarity. As can be seen at the initial wave form of the snare drum's fundamental frequency (150-250 Hz) there is sparse amplitude in the case of "-" rarefaction polarity; which we can take to mean not much forward/onward sound pressure. Another way of describing what is revealed being when "bass" polarity is inverted from "+" compression polarity it is less loud.
Music playing often has asymmetrical waveforms. If look at an oscilloscope's rendering of musical note and see asymmetrical spikes leaning forward that is the initial leading wave front. When there are asymmetries and a speaker's (driver) cone excursion is displaced forward that is a state of "+" compression polarity. Musical instruments aren't perfect and can make asymmetrical compression.
In addition to the 150-250 Hz fundamentals of both "+" compression polarity and "-" rarefaction polarity we can see their somewhat inverted harmonics. The harmonics do not determine polarity, nor change the classification of polarity determined by the initial leading wave front. Just to help viewers identify some of the snare drums' (average) 200 Hz frequency fundamentals here are a few: 2ndH = 400 Hz; 3rdH = 600 Hz ; 4thH = 800 Hz; 5thH = 1,000 Hz; and skipping to 40thH = 8,000 Hz.
Next we can see what happens when the normally acoustically struck snare "+" compression polarity waveform is reversed (inverting it's polarity). The black line below is the only one changed to it's opposite polarity; the grey line is the same originally graphed "-" rarefaction polarity waveform first shown in the illustration above.
What do we see directly above when a bass frequency (fundamental 150-250 Hz) has it's polarity inverted to "-" rarefaction polarity? The amplitude of the bass fundamental is diminished. In practical terms it seems fundamental's (200 Hz) sound pressure level decreases. Yet the harmonics of that bass fundamental shift as well, although not in a linear fashion. Inverted polarity seems to significantly increase the amplitude of 3rd harmonics (600Hz), yet notably decrease 5th harmonic's (1,000 Hz) amplitude.
It should be understood that acoustic polarity is a monaural effect; it is not a stereo effect. In the early period of it's scientific discovery since phase was already know it was described by some researchers as "monaural phase" and by some equipment manufacturers as "absolute phase."
Possibly the phenomena's first report came from the Harvard team W.Rosenblath and W.Rosenweig in the early 1950s stating "… the [ears'] …response reverses when polarity of the electrical … pulse fed into the earphone is reversed…." A further report that headphone lead reversals present a compressed sinus signal as a rarefaction signal came from Univ. Texas Defense Research laboratory team J.Craig and L.Jefferies stating "… sound different … when presented to the ear as rarefaction than it dis when the headphone leads were reversed and … presented as a compression…."
One last observation: our Western language speech normally drives air past the mouth glottis in one (forward) direction. This establishes the "+" compression waveform's polarity and depending on the acoustic fundamental frequency the related harmonics and any event asymmetry contributes to what our ears experience. Yet when our diaphragm spasms we may suck in air past the mouth glottis and still make a sound, but that'll be a state of "-" rarefaction polarity. This is how we can belch real loud but our hiccups aren't loud.
END (unedited, pardon any errors)
---------------------------------------
What is being revealed is that upon hitting the snare skin it's upper surface moved away from the top microphone while it's lower surface moved toward the bottom microphone.
When an acoustic waveform moves forward (toward a microphone, or an ear) it adds quantity (amplitude); some popularly call it a state of "positive" ("+") polarity however technically it is known as the "compression" state of polarity. The dark black lines chart the "compression" polarity. What needs to be understood at this point is that acoustic polarity is determined by the initial wavefront. Above we can see the snare drum fundamental, which is 150-250 Hz clearly has amplitude with "+" compression polarity.
Meanwhile the above light gray line charts the waveform of the drum head moving away from it's microphone. This is an inverse state from "compression" and is technically known as a "rarefaction" state of polarity, sometimes called "negative" ("-") polarity. As can be seen at the initial wave form of the snare drum's fundamental frequency (150-250 Hz) there is sparse amplitude in the case of "-" rarefaction polarity; which we can take to mean not much forward/onward sound pressure. Another way of describing what is revealed being when "bass" polarity is inverted from "+" compression polarity it is less loud.
Music playing often has asymmetrical waveforms. If look at an oscilloscope's rendering of musical note and see asymmetrical spikes leaning forward that is the initial leading wave front. When there are asymmetries and a speaker's (driver) cone excursion is displaced forward that is a state of "+" compression polarity. Musical instruments aren't perfect and can make asymmetrical compression.
In addition to the 150-250 Hz fundamentals of both "+" compression polarity and "-" rarefaction polarity we can see their somewhat inverted harmonics. The harmonics do not determine polarity, nor change the classification of polarity determined by the initial leading wave front. Just to help viewers identify some of the snare drums' (average) 200 Hz frequency fundamentals here are a few: 2ndH = 400 Hz; 3rdH = 600 Hz ; 4thH = 800 Hz; 5thH = 1,000 Hz; and skipping to 40thH = 8,000 Hz.
Next we can see what happens when the normally acoustically struck snare "+" compression polarity waveform is reversed (inverting it's polarity). The black line below is the only one changed to it's opposite polarity; the grey line is the same originally graphed "-" rarefaction polarity waveform first shown in the illustration above.
What do we see directly above when a bass frequency (fundamental 150-250 Hz) has it's polarity inverted to "-" rarefaction polarity? The amplitude of the bass fundamental is diminished. In practical terms it seems fundamental's (200 Hz) sound pressure level decreases. Yet the harmonics of that bass fundamental shift as well, although not in a linear fashion. Inverted polarity seems to significantly increase the amplitude of 3rd harmonics (600Hz), yet notably decrease 5th harmonic's (1,000 Hz) amplitude.
It should be understood that acoustic polarity is a monaural effect; it is not a stereo effect. In the early period of it's scientific discovery since phase was already know it was described by some researchers as "monaural phase" and by some equipment manufacturers as "absolute phase."
Possibly the phenomena's first report came from the Harvard team W.Rosenblath and W.Rosenweig in the early 1950s stating "… the [ears'] …response reverses when polarity of the electrical … pulse fed into the earphone is reversed…." A further report that headphone lead reversals present a compressed sinus signal as a rarefaction signal came from Univ. Texas Defense Research laboratory team J.Craig and L.Jefferies stating "… sound different … when presented to the ear as rarefaction than it dis when the headphone leads were reversed and … presented as a compression…."
One last observation: our Western language speech normally drives air past the mouth glottis in one (forward) direction. This establishes the "+" compression waveform's polarity and depending on the acoustic fundamental frequency the related harmonics and any event asymmetry contributes to what our ears experience. Yet when our diaphragm spasms we may suck in air past the mouth glottis and still make a sound, but that'll be a state of "-" rarefaction polarity. This is how we can belch real loud but our hiccups aren't loud.
END (unedited, pardon any errors)
---------------------------------------
Last edited:
Similar threads
