Removed my sennheiser HD4.40 bluetooth module, soldered the lefts, rights, to a 3.5 mm jack wire. Why are they sounding sooooo flat?

[GenZphile]

I had these headphones and it somehow got an issue where only the blue light was blinking and no buttons worked. The whole button pannel seemed dead.

What my poor pocket and commerce grad engineer blood said was damn wireless and get it wired. It had a 2.5mm jack, which too seemed dead. No output.

So, since the bt module of the headphones were dead, I decided to remove the guts (whole circuit board, battery) and hardwire the left, right positives and negatives of the headphones and added a 3.5 mm to them.

While the loudness and working is perfect, the sound does not have any soul. Its feels very flat and has 0 bass. Why did I messed up here? Teachers, please help me.

 

[Passive_audio_enthusiast]

All these Bluetooth speakers will have some sort of DSPs built in which boosts some frequencies to reduce some others so that they can slap in a cheaper driver(speaker) inside which shouldn’t be natively having the bass you are looking for or the treble. Basically you removed the stock dsp which means that you have to now use the equaöizer on your phone or computer to get the same sound.

 

[GenZphile]

All these Bluetooth speakers will have some sort of DSPs built in which boosts some frequencies to reduce some others so that they can slap in a cheaper driver(speaker) inside which shouldn’t be natively having the bass you are looking for or the treble. Basically you removed the stock dsp which means that you have to now use the equaöizer on your phone or computer to get the same sound.

Oohh, darn, can i salvage the dsp from the circuit then?

 

[availlyrics]

also check if you have reversed the polarity during soldering the drivers, making the sound out of phase