To my layman’s understanding (which is not good) it’s because of electronic resonance. In other words, how cables can give off/pick up radio waves.
In early radio, this was a problem with microphones picking up signal from radio transmissions, which obviously is unwanted when you’re trying to have people hear your voice, and not your voice mixed with competing radio signals.
From what I understand, when it comes to microphones, there is a “hot” a “ground” and a “cold”, and the cold is the same signal as the hot but inverted, and apparently this helps prevent picking up radio signals. It is called “balanced,” and I’m not sure why other than the inverted signals. So while it looks like a standard stereo cable with three connections, it’s apparently actually a standard microphone cable.
There’s a lot more radio/electric wizardry going on than that, but that’s my understanding of it, as a person who thinks Electricians are real life Wizards. This is based on some cursory internet research, so please anyone with more understanding correct me if I am wrong.
“Cold” suggests you’re thinking of balanced signalling. You don’t have any balanced options with standard headphones and computer PC jacks, everything is unbalanced. Both the 4-connector (TRRS) and 2x3-connector (TRS) variants of your headphone connectors are unbalanced audio.
There might be a difference in crosstalk between the speaker and mic wires (ie signals going to your speakers leaking through the wire insulation and into the mic wires), but it should be inaudible if the cables and headset are designed correctly.
You’re describing balanced/differential signalling. This is used in stage or professional audio (typically over XLR connectors, but not always).
The 3.5mm TRS connectors that the OP has pictured are extremely unlikely to be using balanced signalling. If they did then they would not be compatible with the headphones jacks on computer motherboards or case fronts which follow the AC’97 or Intel HD Audio standards.
To my layman’s understanding (which is not good) it’s because of electronic resonance. In other words, how cables can give off/pick up radio waves.
In early radio, this was a problem with microphones picking up signal from radio transmissions, which obviously is unwanted when you’re trying to have people hear your voice, and not your voice mixed with competing radio signals.
From what I understand, when it comes to microphones, there is a “hot” a “ground” and a “cold”, and the cold is the same signal as the hot but inverted, and apparently this helps prevent picking up radio signals. It is called “balanced,” and I’m not sure why other than the inverted signals. So while it looks like a standard stereo cable with three connections, it’s apparently actually a standard microphone cable.
There’s a lot more radio/electric wizardry going on than that, but that’s my understanding of it, as a person who thinks Electricians are real life Wizards. This is based on some cursory internet research, so please anyone with more understanding correct me if I am wrong.
Is this better than a normal 4 contact jack without the cold?
“Cold” suggests you’re thinking of balanced signalling. You don’t have any balanced options with standard headphones and computer PC jacks, everything is unbalanced. Both the 4-connector (TRRS) and 2x3-connector (TRS) variants of your headphone connectors are unbalanced audio.
There might be a difference in crosstalk between the speaker and mic wires (ie signals going to your speakers leaking through the wire insulation and into the mic wires), but it should be inaudible if the cables and headset are designed correctly.
“Better” in terms of less radio interference? I suppose, probably.
I am not an audio engineer. It fascinates me, but most of it is beyond me.
Like how Apple used to be able to send video out of an iPod over a 1/8th connector, using the “sleeve” part as a 5th connector for video.
You’re describing balanced/differential signalling. This is used in stage or professional audio (typically over XLR connectors, but not always).
The 3.5mm TRS connectors that the OP has pictured are extremely unlikely to be using balanced signalling. If they did then they would not be compatible with the headphones jacks on computer motherboards or case fronts which follow the AC’97 or Intel HD Audio standards.