I noticed a while ago that when headphones with 4 pin jack have their cable damaged, what happens is that a part of the tracks from the music are lost, but you start hearing parts that you couldn't hear anyway.
I also found that one of the Skullcandy 4pin headphone cables outputs sound this way by default. They have a manufacturing flow, when you plug the cable into devices, it is not aligning properly, and this strange 'filtering' starts to happen. But it is very useful, I learn rhythm guitar tracks from songs that would be difficult to hear other way. It works better most of the time than extracting such tracks with AI. There is more detail. So I saved that cable for this purpose and keep it as a valuable treasure at a safe place.

Here is an example for this filtering:
1. the original tune:

2.the filtered version:

The only problem is that I cannot record this filtered signal on most recording devices. I have an old iMic recording interface for example. I play the song I want to filter in Windows Media Player, plug the Skullcandy able into the laptop output. I can hear in the headphone attached that the song is being filtered. But when I plug the end of the cable into the recording input of the iMic instead, and I press record in Goldwave for example, the resulting recording is not filtered, but it is the original, untouched song that becomes recorded.

How is this possible??? Something happens with the signal when it enters iMic.

I also tried with an Alesis iO4, and the same result. This was done by plugging the Skullcandy cable into a jack-phono adaptor, and plug the phono adaptor into the iO4. However, I tried borrowing another phono adaptor from my friend, plugging that into the iO4, and TADAAM, it worked.

But why is this happening? That sometimes the signal is restored, sometimes not, and why doesn't it work with the iMic? And anyway, how is it possible at all that you can hear tracks from the songs that sometimes totally unnoticeable in the original recording???

 

it's most likely because there is a electrical short in the cable/wiring somewhere. Damage, low quality parts, poor design are your general causes; especially in low-cost consumer electronics.

Think about what a "short" really is. Google answer: A short circuit (sometimes abbreviated to short or s/c) is an electrical circuit that allows a current to travel along an unintended path with no or very low electrical impedance. This results in an excessive current flowing through the circuit.


Then ask why it has this effect:

why do electrically shorted headphones produce more midrange?
ChatGPT said:


When headphones are electrically shorted, the impedance of the driver is significantly reduced. This can affect the frequency response, particularly boosting midrange frequencies. Here's a breakdown of why this happens:

1. Impedance Changes: Headphones have a specific impedance, which is a measure of resistance. When headphones are shorted, the impedance drops dramatically. This change can cause an imbalance in how frequencies are produced.
   
   
2. Frequency Response Shift: The frequency response of headphones is influenced by their impedance. Lower impedance can lead to changes in how different frequencies are reproduced. Typically, reducing impedance can accentuate midrange frequencies because the drivers are less able to handle the extremes (bass and treble) as effectively.
   
   
3. Driver Behavior: The drivers in headphones are designed to work within a certain impedance range. Shorting them disrupts this balance, and drivers may become less effective at reproducing very low or very high frequencies while emphasizing the midrange.
   
   
4. Power Handling: Shorting the headphones can also lead to excessive current flowing through the drivers. This can cause the drivers to distort or shift their response characteristics, often making the midrange more prominent as a result.
   
   
5. Damping Factor: The damping factor, which is the ratio of the headphone's impedance to the source's output impedance, also changes when the headphones are shorted. A lower damping factor can affect how well the drivers control the movement of the diaphragm, which can impact frequency response.

Overall, the electrical short alters the impedance and frequency response of the headphones, leading to a noticeable increase in midrange frequencies.

 

Last edited: Sep 8, 2024

Take any plugin with mid/side management and listen to the side signal only, done. That's what happens when your headphones connector is losing ground and is exactly what can be heard in your "filtered" example.

 

Can you link a possibly free plugin like that?

 

https://www.voxengo.com/product/msed/