Covering the damping paper surrounding headphone drivers... Anyone tried it?

Many of you will have heard about the Fostex T50RP series having vents letting pressure out to the ear-side of the driver. The result is less sub bass, and closing it off results in more sub bass.

Most dynamic driver headphones have this white driver paper covering the baffle, which is like a spider web. Most of it is open. So this paper regulates the pressure being blasted back from the cup.

So say you took a pair of HD600's and covered all of that paper with something completely airtight... What would change?

 

Not very much, due to its openness, but effect is very strong on closed back headphones, or headphones with lether pads.

 

The main effect of baffle vents is indeed that of pressure regulation. To put it simply: less venting = more bass pressure = more bass that is more sensitive to seal.

This applies to the HD series as well, but the effect is not quite as pronounced due to the leaky earpad design. I played with this and gained ~2dB of bass extension and a warmer overall sound. It results in more closed-in sound as well.

 

Actually quite a lot. A lot more lower midrange (<1kHz). Less upper midrange around 2kHz. A thin paper filter or even the stock foam already give you a few dB more lower mids. The Bill-P mod uses an additional paper filter, for example. A very thin piece of cloth can also give you a pretty big FR difference. Overall I wouldn't mess with it, only very slight mods can make a positive difference (like 1 ply TP).

Blocking it completely might give you like 6db more <1kHz. I can't say as I've never blocked it completely.

What you will not get is more bass extension

Edit: Saw spoony above mention you get more extension. Huh, don't think my measurements showed that. Maybe 1db at 20Hz or so? The overall level increases, but not the relative extension. Best to think of it as a shelf filter for <1kHz.

It's generally a midrange filter, unless it's punctured at which point you will lose all bass. I like a tiny bit more material here to make the upper mids stand out less, but that will also darken the treble. Because of this it works better on the HD600 or HD580 than the HD650

 

Yep, pretty much this, effective extension would come with additional back-damping to flatten the increased bump.