On the modification of Sony MDR-1R: It's as easy as ABC

Several months ago, a friend of mine asked me to see if there is a chance of modification with Sony MDR-1R. So here I am at it. The goal of this modification is to be quick, simple, and reversible, while taming the mid-bass range effectively. All you need here is a scissor, a masking(duct) tape, and a screw driver! (And preferably some foam pads with various density)




Behind the baffle

The design of MDR-1R's acoustic vent is rather simple. It consists of a rectangular-shaped opening, which is damped by a porous nylon mesh, and a small undamped hole.

I do not recommend tempering with these vents, as they are there for a good reason: sub-bass equalization. Unless you are familiar with designing an acoustic low-pass filter, don't even bother to touch these.


In front of the baffle

 

Since MDR-1R's ear pad is proprietary, third-party pads can't be used. A piece of foam may be utilized behind the ear pads to damp the mid range. And in order to decrease the mid-range hump, an annular-shaped foam padding can be sandwiched between the ear pad and the pad mesh to increase the distance between the user's ear and the driver.

The annular padding not only damps the mid-range, but also should help tame the peak at 10 kHz. Blocking the frontal baffle vents amplifies the mid-bass range up to 5 dB.


Inside of the baffle

There are two porous acoustic resistors attached on the rear side of the driver, and they can be tweaked greatly for the modder's advantage.

Unlike the classic CD-series, of which a dense damping material has been incorporated by the manufacturer, there is nothing behind the driver of MDR-1R.

Some examples

While I really like the second one, since the goal I've been assigned is to decrease the mid-range hump, the design has to further improve.

And here's my final version of MDR-1R, modified. This version may become available for sale for fundraiser.