Sennheiser HD558 mods

When the headphones I’d been eyeing suddenly dropped in price by 60%, I had to take the plunge. At $120, I’d never spent this much on headphones before, but that didn’t stop me from ripping them apart right away. :P

Acoustic mods: less is more #

The following Sennheiser headphones are ordered left-to-right by price low-to-high: HD558 ($180), HD598 ($250), and HD600 ($400).

Sennheiser has added extraneous sound-shaping materials to the cheaper models, opting to leave the higher-end headphones more open. Can you upgrade the HD558 to HD600 performance just by removing stuff? Probably not, but it makes sense to remove it anyway.

Speakers of all kinds are prone to comb filtering …

Instructions #

1. Inside grill removal #

Remove the earcups. Remove the inside grills. Do not replace the earcups yet.

2. Outside grill foam removal #

One at a time, unscrew and carefully remove the drivers. Remove the foam strip on the inside of the grill.

3. Outside grill cloth removal #

With an upside-down craft knife, cut cloth and peel off the outside grill. The cloth is spray-glued to the grill, but is easy to remove once you get started.

4. Outside grill felt logo mod #

Remove shiny logos from the grill. There is a large flat plastic area underneath. Cut this out and replace with felt. Replace logos if desired.

5. Customize fit #

Selectively compress or thicken the earcups and headband until the desired bass response is achieved. The closer your ear is to the driver, the more bass is perceived. (Adding felt to the sides of each earcup removed an unwanted low-mid peak, on my head.)

Results #