[assassin10000]

I don't like K's Bell (cheap version). The comfort is great, but due to the lack of back vent, there is almost no bass. NiceHCK EB2 seems to have probably the best vent system
but the driver is not at the same level as the competition. Moondrop has too large back holes but I don't see how it looks inside. Probably not look like concepts below
It's interesting how many solutions can be done here.

The Little Bell (cheaper) and Bell Ti (TOTL) both have the 3 side vents on both sides. The LB has lots of mid bass and lower mids, its a very warm bud.

The LB has foam over all 6 holes. If one was uncovered it may be the right amount of airflow. Just a matter of tuning, like every other bud.

__________________________


After 4 months my set of MMCX ends showed up, so I could finally make a straight down cable.

Yesterday my second set of these slightly oversized PK shells also arrived, so I could finally compare them.

Modding the shell and using short MMCX connectors leaves me with almost the same length as the original. So they can still be used cable down with no issues.




Not looking forward to modding more shells, it's time consuming and tedious lol.

 

[Sunstealer]

After 4 months my set of MMCX ends showed up, so I could finally make a straight down cable.

Yesterday my second set of these slightly oversized PK shells also arrived, so I could finally compare them.

Modding the shell and using short MMCX connectors leaves me with almost the same length as the original. So they can still be used cable down with no issues.




Not looking forward to modding more shells, it's time consuming and tedious lol.

What drivers are you using?

I presume you used a Dremel or similar to cut down the stems?

 

[assassin10000]

What drivers are you using?

I presume you used a Dremel or similar to cut down the stems?

Currently I have the N55 64Ω drivers on them. I've also put 150Ω PK1 redfilm, my original Yuin PK2, the 32Ω bass unit ones on this style shell.

I use a small hobby hacksaw (6" blade maybe 1/4" wide) to remove most of the stem. Then a fine metal file to smooth it and bring it down the last 0.1mm - 0.5mm and finally a small precision file to round the edges.


Info on what I did to use these shells:

I'll need to file or sand down the opening so there isn't an air gap.

Took a few minutes with a small fine metal file I have and made them fit the wire mesh drivers properly.

Continued on with modding these larger PK shell's. I had success fitting 2 sets of drivers to the shells and MMCX modding them.

I use the 'center' of the normal tuning foams, flip it upside down, use a sharp knife/exacto to score the adhesive and tweezers to remove the area where the vent goes.




Had to do some delicate filing to get my original (ie: legit) Yuin PK2 drivers to fit. I'm glad I was able to without any issues. I don't think these are available anymore. (I sold the shells to someone who damaged their PK1 shells and needed Yuin donors.)

 

[furyossa]

This is the last part ie. Part 3 of the project where I analyze three metal shells with different cavity sizes in combination with beryllium coated 130ohm driver.
Previous posts INTRO, PART 1 , PART 2.
For this earbuds all parts can be found on Ali : Driver, Shells, Cable
The shells are a bit heavy (not aluminum) which is perfect for "over-ear" wearing.
It lies very nicely in the ear and doesn't allow the cable to move them out.

The only modification on the shell is the widening of the vent holes.
I added tuning foam on the inside to soften the reflection of the sound wave and cover the 2 vents. 3rd vent inside the "neck" of the shell is not covered.
To prevent the mmcs connector from unscrewing, I put on a rubber ring that is used for the same purpose with darts.

The following diagram shows a cross-section through the shell itself

Blue text represents PROS, red CONS, and BLACK shared opinion or comments.
1. "Concave arc" shape allows a very comfortable fit, and depth is small.
For permanent connection, you need to use glue because the driver cover diameter is larger than a shell.
In my case, I use "double-side" duct tape
2. The cavity space is small. Although we have side vents, the sound is a little more reminiscent of "closed-back" headphones.
We lose spaciousness and a bit of bass and putt mids in front. This can be good or bad and it depends on the driver.
For me, I like this setup only with a driver which has preceded mids.
3. Due to the size of the shell itself, we do not have many possibilities for internal modification.
First I try with tuning paper with a small hole for wires to block empty chamber ("neck" where is MMCX) space.
After that, I decide only to use tuning foam.
4. A very good connection between MMCX and shell. The shell has screw threads in the "neck" so glue is not needed.
5. Darts rubber ring secures the connection from unscrewing.
6. The angle between the shell and the neck axis 90 degrees with MMCX socket

In conclusion, I can say that I managed to achieve the desired result with this project, and that is open-back (PART 1),
semi-open back (PART 2), and closed-back (PART 3) sound signature. To my taste, the score would be next:
1. "medium" cavity size shell - best comfort, balanced sound
2. "semi-large" cavity size shell - average comfort, spacious sound
3. "small" cavity size shell - good comfort, intimate sound

 

[willyboyaudio]

Hello Friends, I hope you are well. I have a question: When a 15.4mm driver is available with a steel net cover or a plastic cover, is there a difference in sound? Which one will you choose? Thanks a lot!

 

[assassin10000]

Hello Friends, I hope you are well. I have a question: When a 15.4mm driver is available with a steel net cover or a plastic cover, is there a difference in sound? Which one will you choose? Thanks a lot!

If no foam use I'd go with the plastic covers. Otherwise is it wire mesh or drilled holes? Drilled holes if foam use.

 

[willyboyaudio]

I typically always use full foams with my earbuds.
I'm talking about the drilled holes one. So if using full foams, the drilled holes one is preferable?
Thanks a lot.

 

[assassin10000]

I typically always use full foams with my earbuds.
I'm talking about the drilled holes one. So if using full foams, the drilled holes one is preferable?
Thanks a lot.

Yep. More openings.

 

[captione]

Drilled holes? Like the kramer mod?

 

[willyboyaudio]

No mods, just asking whether the type of cover matters, and which one is preferable.
I hope this is also your understanding, @assassin10000 the right one is "drilled holes" right?

 

[assassin10000]

@willyboyaudio exactly.

I'm not at home or I'd take a pic of the backside to show how much more open they are internally.

 

[captione]

Almost thought it was the kramer mod lol.
I honestly prefer the "drilled holes" or the metal meshed ones when it comes to foams but it honestly depends on the sound signature.

 

[furyossa]

No mods, just asking whether the type of cover matters, and which one is preferable.
I hope this is also your understanding, @assassin10000 the right one is "drilled holes" right?

For some reason I prefere more plastic cover.
For example HE150ohm has plastic cover and HE150 pro metal mesh cover. This is the same driver for sure and even though all the other parts are different (and better on Pro), original version sounds superior then Pro. I know that 400ohm graphene coated driver has also plastic and metal-mesh cover but at the moment I have a plastic version so I can't compare them.
The plastic cover directly blocks the sound wave, while in the case of metal one, the plastic part behind the mesh that has four radially placed openings (as a sniper's sight) is the first block and the metal mesh blocks after. So basically we have two filters. Also the diameter of the plastic cover is slightly smaller than metal mesh cover

 

[captione]

I was thinking of whether to put a really dark sounding driver on a metal grill, since there's no obstruction of some sorts, what do you guys think?

 

[assassin10000]

Backside of a 14.8mm covers which are slightly different from 15.4mm ones. In 14.8mm covers both are good. I'm not a fan of the wire mesh ones, although they may be fine sonically.

I was thinking of whether to put a really dark sounding driver on a metal grill, since there's no obstruction of some sorts, what do you guys think?

Worth a try if you have them already.