[Xymordos]

Some information: 
I have the UERM and the internals look very simple. It seems to be two of same high and mid drivers with a bass driver, which is likely a CI22955, and both high and mid drivers goes into one tube. Both all 3 drivers uses white filters. There are 3 components in there, which looks like 2 capacitors and a resistor/diode. Need to look closer for the connections however. 
 
Also, I want to ask what is the center tab for?
 
Edit: Are there more information about the phases of the drivers?

 

[tomscy2000]

Quote:

Some information: 
I have the UERM and the internals look very simple. Its a TWFK with Ci22955, and TWFK goes into one tube. Both TWFK and CI uses white filters. There are 3 components in there, which looks like 2 capacitors and a resistor/diode. Need to look closer for the connections however. 
 
Also, I want to ask what is the center tab for?
 
Edit: Are there more information about the phases of the drivers?

 
The UERM does NOT have a TWFK. Those two mid/high drivers are not even the same size. They're more akin to the size of two EDs or an HC/WBHC driver. It's also very possible they use the Sonion 2300 series. And please don't quote a model number like "22955" unless you actually see those numbers on the side of the driver, even though it's highly likely that the low driver is a CI.

 

[Xymordos]

The UERM high and mid drivers are the same size and are stuck together. I'm not sure where you got the conclusion that they are not the same size.
 
However, I would like to apologize for my mistake. TWFK has one sound tube, while the UERM one has two. However, the bass driver is definitely a CI series (I compared the pictures online), and probably a 22955.
 
Taking a closer look my high and mid drivers looks like two of the same drivers stuck together.
 
I have edited my previous post to correct my mistake.

 

[tomscy2000]

I meant to say that the TWFK isn't the same size as those mid/high drivers. I think I was distracted when I wrote that.

 

[Xymordos]

Yeah, sorry about that. Knowles doesn't seem to produce drivers like this. A Dual driver with 2 nozzles, and the drivers for mid and highs might just be the same.

 

[Nixon]

Quote:

. Is this why Sony's XBA series doesn't use a crossover? 

Sony went another direction and ended designing each driver to only produce certain frequencies. Think it's classed as a mechanical crossover.

 

[piotrus-g]

Quote:

Interesting read. From forums in China some DIYers, after testing their own DIY iems, commented that the crossover does have little effect on the sound. However, the filter, and tube length/material has a great effect on sound. Is this why Sony's XBA series doesn't use a crossover? 

Well I will say that it's not true. Crossover has big impact on how the driver performs. Of course between 1,3kHz high pass and 1,5kHz high pass you wouldn't probably notice the difference in the final product. However it makes the difference if you leave driver as a full range or make low pass/high pass on it. Different wiring of driver makes different sound signatures. Say in triple driver on which I worked recently I could have made bass heavy or pretty bright just by changing wiring in crossover.
I'd say that there's less effect to how long the tube is or how big the damper value is than to how you wire drivers and caps.
Quote:

Hi, maybe somebody knows -  exactly which Knowles BA drivers used in Meelec A161P?
Thanks.

I would hazard a guess that it's Sonion 2300 judging by its sound. Though if you're sure that it's Knowles it would be ED driver I guess.

 

[tomscy2000]

Quote:

Well I will say that it's not true. Crossover has big impact on how the driver performs. Of course between 1,3kHz high pass and 1,5kHz high pass you wouldn't probably notice the difference in the final product. However it makes the difference if you leave driver as a full range or make low pass/high pass on it. Different wiring of driver makes different sound signatures. Say in triple driver on which I worked recently I could have made bass heavy or pretty bright just by changing wiring in crossover.
I'd say that there's less effect to how long the tube is or how big the damper value is than to how you wire drivers and caps.

 
Agree.

 

[piotrus-g]

Although, It's important to know how to combine all of these factors to find a golden spot.
 
Tube length can have an impact on the phase so it's quite important to be aware of that in multi-way IEM. But again - it's important to know it all combines.

 

[Mython]

I know almost everyone here has a high level of technical knowledge, but just for those H-F members who may be new to balanced armatures and who may be browsing this thread in order to learn, the following video is of relevance:
 

 
 
 
 
and, strangely, unless I've overlooked it in this long thread, no-one seems to have posted the following vids of the manufacturing process, which are highly relevant to the topic at hand:
 
Ultimate Ears / Logitech

 
Westone

 
1964 Ears (thanks to average_joe & tomscy2000 for the links)

 

[kaixax555]

hmmm I actually browsed through the entire 98 pages (to realize I posted here over 1 year ago)
 
feels like a surge of new knowledge flowing in my head?
 
So after reading I am still slightly confused... is there an affordable way to make transparent shells?
 
I think I should sort out all the information here into simpler form (and hopefully share with you all)... you can practically write a book from all the knowledge in this thread...

 

[kaixax555]

Oh and I have been reading marozie's instructibles...
 
he simplified some stuff for me but I think there is still much to learn from this thread

 

 

[kaixax555]

Hi guys I have compiled information in the form of Google Docs so that the knowledge found in the 98 pages here can be consolidated and allows people who want to build their own DIY IEMs and customs to do it more easily
 
https://docs.google.com/document/d/1CsSNzCCrE3Yu1qAty2la_TMmw6DAUv18LJ8ef4Y-ztw/edit
https://docs.google.com/document/d/1vpjf2uKD58DtqIFQFNHv5E83rrWG_PBQ-W9rW4M5G0s/edit
 
I believe I need to thank the people who have spent their valuable time researching and working on these ideas for the benefit of the DIY and head-fi community.
If there are any problems in the documents, feel free to edit

Since I am free for the next few months, I have the time to try out this project
 
Now I need more "resources" so that I can gather the require materials and start on it

 

[bonebrain]

This is awesome.  This is going to be very helpful but it appears as though the first link provides a blank document

 

[kaixax555]

This is awesome.  This is going to be very helpful but it appears as though the first link provides a blank document

ah yes the first link is currently blank as I am in the process of consolidating the technical information presented in this thread (there is a lot) and I am thinking about how it should be presented

so for now it is blank, feel free to add on if you have any information to share, anyway for now anyone who knows this link should be able to edit the document