HEK Acoustic Coupler Mod
Apr 2, 2018 at 2:32 PM Thread Starter Post #1 of 2


Headphoneus Supremus
Oct 15, 2010
HEK Acoustic Coupler Mod:

Today we will give the HEKV1 the maximum mods to bring it closer to a HEKV2...
Ok here we go...

My take , personally is that HEK V1 presentation was definitely intentional to be a surreal large extended soundstage.
Just like the HD800 was designed to have its own large soundstage and presentation with it's own design.
So today we will mod the HEK to have a more accurate presentation...

Upon inspection and as a comparison, you notice how the HD800 uses a medium between the driver and the earpad creating distance, (metal mesh/basket) to propagate it's soundfied...
So too, the HEK also has an area between the driver and the earpad, which does a similar effect..

There is a "channel" all around the inside perimeter of the cup!
From eyeball observation(I'm lazy to measure), it looks to be a gap of about 6mm tall and maybe 10mm deep.
The sound travels out to this area, bouncing all along the dry wood inner casing, which then also contributes to the sound with its own soft wood resonances,
and then reflects and bounce back into the driver/pad center area...
How nice!..(NOT!)

Ok, so today we will address this issue, to the alleviate the negative/vague aspects this has caused, (which Version2 eliminates.)
What is needed, is a type of "acoustic coupler" from the driver to the pad,
which will cover the surrounding perimeter area of empty space, (that cause reflection)...

As stated, this is EXACTLY area that the HEKV2 eliminates.
So as a result, we can have a MOD solution which give these benefits:
1-acoustically couple driver to pad.
2-eliminate reflections with more direct sound wave.
3-improve treble response and linearity.
4-improve trebles, detailing, breath and nuance.
5-improve bass impact.
6-improve overall solidity of image.
7-more clear, non-ethereal sound
8- a touch more presence,
9- slight reduction of the smooth ambiguous boundaries of the soundstage.
Ok so now we will move onto the actual mods....
The BEST aspect of this "Acoustic Coupler" mod is that it is the most important non-invasive, simple mod ever(!) for the HEKV1,
and with "Rear Strips Mod" may be enough for many users..

First off:
Grab the pads, squeeze them slightly in middle, for the inner tabs to lessen their grip to pull off...
Now this time to look carefully inside...

Take note that the WHOLE width and length of this AREA, IS THE DRIVER!
It is actually one HUGE INVISIBLE diaphragm/membrane that goes ALL WAY to the top and bottom edges,
not just the middle area...

Now that I have sufficiently scared you, we will move onto the super easy part..
The installation of the "Acoustic Coupler"..!!

Follow these FOUR steps:


Other types of foam and variations of thickness also were tried but in the end all that was needed was this foam.

2- CAREFULLY cut open these pads!

Notice how It has the PERFECT FIT, SHAPE, THE OUTER DIAMETER, of this foam to
sit perfectly inside driver area.
Some have used window foam or other type long foams with lesser different results.
My recommendation is to use original material posted for least noticable effect of the dreaded "Coupler proximity effect" (hearing an additional closed in or tunnel effect)
It is important you don't want any "tunnel effect" sound from harder foam surfaces.

3- TRIM foam inner diameter, and height, for a DROP IN acoustic coupler!

As you can see I am not the best at cutting, but the irregular inner surface is ACTUALLY A PLUS (for diffraction).



Well, not exactly.
You need more info...

Step 4:
4- Details on what to cut and why:
Just cut inner diameter to size, (so it will rest on the yellow plastic edge) and drop in!
Never a danger to touch the driver ..
It is the safest "one piece" solution.

5- Cut to thinness as pictured , and not leave thicker,
as there is no benefit, and can also add to "proximity effect" we dont want.
So not much is needed to cover this gap.

Ok, that is the end...
"Acoustic Coupler" mod is accomplished..
Enjoy new found Sonic benefits!

As stated before, this part of the mod alone is MASSIVE in benefits,
and substantial enough for most users.
But if you want MORE (don't we all), then proceed to other mods like Rear damping Mod or rear strips Mod .
Apr 17, 2019 at 3:24 PM Post #2 of 2
Thanks to member here who posted out the serial number on the pad is different t than when ordering, so here is the link for the pads to cut the foam out:

Brainwavz Hybrid Memory Foam Earpad - Black PU/Velour - Suitable for Large Over The Ear Headphones - AKG, HifiMan, ATH, Philips, Fostex https://www.amazon.com/dp/B00ZGGG3KY/ref=cm_sw_r_cp_apa_i_CT3TCbZGFDW2X

$25 pads but worth it as Peter materials tried weren't as good.

Anyone with other foam suggestions welcome.

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