Beyond the Tape Mod for Pads

Reading though discussions on "Grado-style" DIY headphones, there's a consensus that one of the most impactful mods is modifying pads. Grado's are notorious for their underwhelming bass, and there is a lot of focus is on tape mods which boost bass by adding a non-porous layer around the foam pads. The drawbacks to using tape are numerous and obvious.

I'm experimenting with a better mod - using 3D printed shells around the pads. Benefits include:

- much tighter control over the dimensions and uniformity
- pressure fit for slide-on, slide-off fitting. No sticky tape residue
- comfortable - very light and no impact on comfort
- meta-material acoustics where the shape of the print can be set precisely to define the acoustic effects

Here's v1: single thread 'spiralized' 0.4mm shells.



I'll call v1 a success because they demonstrated a acoustic effect - boosting bass and reducing the airiness of the LTS V1's. The effect was too much, so I decided not to focus on constrained and solid shells but rather more open ones.

For v2 I've used the same solid object file (STL), and used Cura's 'Wire Printing' mode to create a lace-like structure, woven from a single continuous thread (no retraction) for strength.



These work well. They restore the openness of high frequencies while providing a boost to a range of bass frequencies. I'll experiment further and welcome suggestions.

 

You can also flip most of the pads backwards too. Many of the pads are made from multiple foam pieces of varying density, so forward vs backward positioning can give pretty significant sonic variation. Of course the distance from ear to driver and the width of the opening makes a difference too. I love foam pads. Cool to see more of this type of experimentation

In my testing, the more airflow you block by throttling the pad perimeters, the less energy in the 3-6khz you get as a trade off for the greater midbass amplitude. The bass boost Q is usually pretty broad as well so you might get a bit of a downslope from low to upper mids. LF extension generally won't significantly improve, but sometimes a bit extra midbass is all that's needed to give some foundation down low.

Unfortunately (at least in my designs) these tweaks don't work well with the full sized bowl pads, because those pads already generally give a bit less energy in the presence region and the effect of closing off the perimeter airflow will basically miss the mark and make them even more V in tone. Different driver treatment altogether is needed to get the bowls sounding fairly even in tone...

Looking forward to seeing what else you try, happy experimenting!

 

Thanks Ed! There's a ton of insight you've packed into a few words. It might take me a while to unpack it all.

To check this out, I made some shells for smaller pads. The effect wasn't as expected -- the boost didn't seem to be greater, but it did seem much broader even extending up to mids.


Sidenote: these were printed with more standard Cura settings, not spiralized - so you can see the layer-changing 'seam' that results.

@E_Schaaf : Any thoughts about the acoustic effect of making shells that are thicker / perforated / with internal cavities?