Recently, I bought a secondhand set of Sennheiser HD1 headphones (a slightly updated version of the Momentum 2.0). While in great condition from the seller, and beautiful in design, it did have a few issues I had to address in order to be able to be satisfied with them. Here, I am going to detail what those issues were and how I fixed them (or didn’t).

Small Earcups

Brainwavs vs Senn pads

Materials/tools required:

Brainwavs vs Senn pads

In photos, the earcups on the HD1 look nice and roomy. In real life, they are somewhat cramped and shallow. If you have ears that stick out like mine (specifically, the part of the ear called the Anti Helix, in my case), they might come into contact with hard parts of a set of headphones, which causes a sharp stinging pain after a few minutes.

It just so happened that I had a pair of Brainwavs Sheepskin Memory Foam earpads. I bought them for my Philips Fidelio X2HRs, but didn’t end up using them, and so the pads sat in a box for months. Now, I tried them on the Sennheiser HD1, and this felt to me a large improvement in both comfort and sound quality. However, my ears still contacted the inside of the headphones, and the fit was sloppy.

Earpad with oval insert on left, unmodified earpad on right

To solve this, I decided to use something to fill in the slack. I chose 5mm black craft foam. I created a printable template with two 11×8.5cm ovals with 1.5cm inner offsets. Given that the Brainwavs pads are 10cm circular, I decided on an oval shape in order to force the Brainwavs pads into a shape that matched the Senn earcups better. I printed this out and and taped it to my foam. I then used a hobby knife to carefully cut them out. Note: If you use the template I provided here, BE SURE to turn print scaling off. Check the dimensions with a ruler to make sure.

Finally, I stuffed the foam inserts underneath the leather pads, on the side that faces the ear. It’s a tight fit. There is some buckling. It may settle down with time.

Hard Headband

Materials/tools required:

The next issue is the headband. When I am using a pair of headphones with a narrow and stiff headband, no matter how generously padded, it will eventually cause pain to the crown of my head. For this reason, I have a great preference for headphones with suspension headbands, such as my Philips Fidelio X2HR. Unfortunately, this is not a common feature in the bluetooth noise-cancelling market segment.

The Sennheiser HD1 similarly comes down on the head on two hard points that are padded only by the leather that covers them. Fortunately, the HD1 (and Momentum 2.0, but not the Momentum 3) has four screws on either side of the headband, just above the hinge. This is a perfect point to attach a headband I made myself.

After some careful measurements, I created a printable template and taped it to a piece of black leather scrap of about 1.5mm thickness. I used a hobby knife to cut the leather through the template, and a 1/16″ drill bit to make the holes.

Before attaching the headband, now is a good time to adjust the clamp force of the headphones by bending it (at your own risk), because it will be more difficult after this mod. It is also a good idea to thoroughly oil the leather headband (and the other leather parts on the HD1 if you like) in order to soften it.

Now, I used a T6 screwdriver to remove the four screws above the hinges. The screws were not long enough to reach the threads through the new leather. Fortunately, they seemed to have the same diameter and thread pitch as some longer laptop screws I had around. I used those to attach my new headband. I chose to have the grain side against my head, mostly for aesthetic reasons.

Once the new band is attached and the headphones are spread out to a distance similar to that while being worn, the band creates a gap and acts as a suspension headband which is significantly more comfortable for me than the original direct contact of the hard bars.

Sliding Earcups

Materials/tools required:

Unlike most headphones I have used, the HD1s do not have a clicking mechanism to hold its height adjustment. Instead, it has some sort of a friction lock that tends to slip over time. To fix this is easy. Stretch a rubberband over the discs (with the Sennheiser logo) a few times. Or, if you have some extra keyboard dampener O rings, two of those will work nicely and be nearly unnoticeable.

Nonstandard Analog Input Jack

Materials/tools required:

The HD1 includes a jack for analog input. Problem is, it’s 2.5mm, recessed into the right earcup, and the recessed hole has two tabs that act as a locking mechanism for the Sennheiser cable that comes packaged with this headphone. In this state, it’s practically impossible to use any third party cable.

Fortunately, the locking tabs are made of plastic. I was able to use a small hobby file to remove them and fit one of my thinner 2.5mm cables in it.

Now, I would like to be able to use my other 3.5mm cables with these headphones on occasion. To facilitate this, I bought a 2.5mm Male to 3.5mm Female adapter, but the 2.5mm side is too thick. I used a knife to shave down the diameter of the plug until it fit comfortably.

I have some shrink tubing on order, and I will try to use it to strengthen this connector and make it look nice. I will update this section if it turns out well.

Note: the common metal ones like this one do not fit.

Sound Signature

The one issue I haven’t been able to fix is sound-related. When connected to Bluetooth or USB input, it is a bit on the bassy side for me. It also does not get as loud as I’d like.

Once I fixed the jack on the HD1, I plugged it into my Sound Blaster G5. The sound was brighter, and more to my tastes. I then tried turning the headphones on, to engage the noise cancelling feature. Upon doing so, the sound signature turned bassy again. This indicates to me that the DAC and amp inside the HD1 are probably capable of a more neutral sound, but the signature is being changed by the headphone’s DSP for extra bass.

Unfortunately, these headphones are too old to work with the Sennheiser app, and I don’t know if I could turn off the internal EQ even if it did. Source-side equalization does some good to counter Sennheiser’s, but I’d rather that the sound not be modified in the first place. If anyone knows how to permanently adjust or disable the equalization inside the headphones, I would be grateful for the information.


Not quite as stylish as the original look, but much more comfortable.

The little white thing on the USB port is a magnetic connector for matching cables. It allows me to quick connect/disconnect, and to use the same cable for Micro-B, USB-C, and Lightning devices. Pretty nifty.