Headphone Cups/Ears Sound Different

[IsaacOscar]

Is it normal or problematic for one side of a headphone to sound different from the other?
In my case I have a Sennheiser HD 558, and the left cup has noticeably more bass than the right-cup.
(To confirm this, I played a piece of music that I converted to mono and then back to stereo, and alternatively removed the cup from an ear and placed it to the side).

I haven't noticed any lopsidedness or other issue when listening with them normally, only when wearing them asymmetrically.

Note: I recently opened up my headphones to try the "foam" mod, which involves removing a piece of sticky tapped foam from the inside of the back of each cup. But I then put the foam back. Is it possible I broke my headphones?

EDIT: I think my ears are the problem (swapping the headphones around causes the same issue).

 

[solderdude]

Normal.. no but not uncommon even when new from the factory.
I have even seen this with reputable brands.

When it happens after a modification first undo the modification or ensure both sides are done exactly the same way.
When the the difference is in the bass/lows (after you opened them up) it usually is a seal issue in the cups or between the pad and cups.
Could be pads not sealing (clicked) fully on the baffle or a baffle not properly installed or for closed headphones some sealant that has gone bad.
Closed headphones are far more sensitive to seal issues than open headphones.
Be careful with replacement pads even if the seller claims they are suited for specific model(s).
They usually only mean they will mechanically fit, not that they won't affect sound.

Be careful with mods that aren't supported by measurements !

 

[IsaacOscar]

Wow, thanks for the quick response!
After some more testing, I've discovered that the problem is me: if I swap my headphones around, I still get more bass in the left ear. So maybe I need to clean my ears, or shave sideburns or something...

When it happens after a modification first undo the modification or ensure both sides are done exactly the same way.

As I said above I did undo the mod (the mod made things horribly bassy!)

When the the difference is in the bass/lows (after you opened them up) it usually is a seal issue in the cups or between the pad and cups.
Could be pads not sealing (clicked) fully on the baffle or a baffle not properly installed or for closed headphones some sealant that has gone bad.

I removed the pads and had the same issue (although it was less noticeable, and the sound was horrible without the pads)

Closed headphones are far more sensitive to seal issues than open headphones.

Mine are open.

Be careful with replacement pads even if the seller claims they are suited for specific model(s).

The pads I have are ones that came with Sennheiser HD 560s (so same brand), as my original ones peeled apart after several years (I did also buy some non-genuine pads online, but they weren't as comfortable; I still have them if though).

Be careful with mods that aren't supported by measurements !

Others said the mod changed the sound, so I just wanted to see what it sounded like and if it was nicer (I have seen some measurements for them before, but I can't find them now...)

 

[IsaacOscar]

My ears have no recovered, and I compared the sound of my earphones on the same ear (but different cups). They were definitely different. Unfortunately, I then broke the right driver when I opened the headphones up to see if it was the drivers being different, or something about the headphone casing.
So I've now bought a HD 550 (which sounds even better than the HD 558!), and both of its cups are identical.

This time I will not open them up (unless they're already broken enough to justify buying new ones). I'm too scared of breaking them or slightly altering the sound like I may have done with my HD 558.

 

[LTig]

My ears have no recovered, and I compared the sound of my earphones on the same ear (but different cups). They were definitely different. Unfortunately, I then broke the right driver when I opened the headphones up to see if it was the drivers being different, or something about the headphone casing.

You could try to get a replacement driver.

 

[IsaacOscar]

You could try to get a replacement driver.

For a discontinued headphone? (I could get a used HD 558 for 32% of the price of my brand new HD 550, but it would take ages to be delivered, and the HD 550 sounds better anyway).

The only thing I'm annoyed at is that there weren't any other open-back Sennheiser's in the store to try (I would've liked to try the HD 600). (I tried all the other headphones, and none of them where anywhere near as comfortable as the Sennheiser HD 500 series is).

 

[LTig]

For a discontinued headphone? (I could get a used HD 558 for 32% of the price of my brand new HD 550, but it would take ages to be delivered, and the HD 550 sounds better anyway).

Depends on the price. You could fix it and either sell it or keep it as backup.

 

[IsaacOscar]

Depends on the price. You could fix it and either sell it or keep it as backup.

Well if someone sends me a link to a cheap HD558 driver, sure I'll be interested.
However, I couldn't find one, and I'd also be worried if it wasn't genuine (I did find drivers that look like they're the same size, so I could use them, but they where visually different so I suspect the sound would be different).

I also already have a perfectly working HD 560S as a backup (I don't like the sound though, the soundstage is too small). I should probably sell them though.