Multiple balanced armature speaker systems with crossover networks

[Moz-Art]

Hi,
 
I'm starting this thread to share information about crossover networks for In Ear Monitors (IEM) with balanced armature speakers (BA). Please share your thoughts and experience.
 
In this thread I will be talking about my experience while I do a trail and error process, making custom in ear monitors (CIEM) in a three way setup with a passive crossover. I'm ordering my stuff online from Mouser.com and I'm still looking for an analyzing tool like a 711 coupler to simulate the ear canal and test frequency respons from my setup cause I think that is a very important step in the trail and error stage. I will also share all the documentation on the products and processes that I use.
 
What's the goal for me? Find the best speaker with the best frequency response for the chosen bandwidth or frequency and fitting crossover to create a reference speaker sound in a three way system.
 
 
Resources:
 
Speakers: Knowles speakers (www.knowles.com) or Sonion (http://www.sonion.com/) but you can't seem to buy these in small quantities
Inductors : Still reading on best quality brands
Capacitors: Still reading on best quality brands, these are the most expencive and difficult things of the crossover network.
Resistors: Same as for the inductors, still looking and reading
 
All of the above available at www.mouser.com
 
Cables:
 
You can a cable from Westone and make the female connector:
http://www.westone.com/store/index.php/westone-music-products/accessories/epic-replacement-cables.html
 
I prefer the Amphenol coaxial MMCX connector. You might know them from the Shure IEM. They are available at Mouser too.
 
Equipment:
 
You'll need a decent soldering station with tempature control. BA speakers are very sensitive for tempature and if it's a bit too hot, they brake.
 
If you really wanna go the whole nine yards it would be best to have an artificial ear simulator.
You can find one here http://www.bksv.com/Products/transducers/ear-simulators/ear-mouth-simulators/4157?tab=accessories
There is a lot of software out there to use with this tool. I will post more about that later.
 
You'll need to put all this in a shell but I don't want to focus on that as there are other threads that cover that. So please, let's talk about sound, speakers and crossovers.
 
I have some documents I will share in my next post.
 
Hope you join in and share.
 
 
English is not my native language so forgive me for my errors.

 

[Moz-Art]

Some documents for reading time:
 
https://dl.dropboxusercontent.com/u/85757794/CIEM/711%20receiver%20response%20and%20impedance%20rev%201.2.pdf
 
https://dl.dropboxusercontent.com/u/85757794/CIEM/Earphone%20Design%20Guide.pdf
 
https://dl.dropboxusercontent.com/u/85757794/CIEM/Knowles%20Earphone%20BA%202014%20ver%204.pdf
 
 
https://dl.dropboxusercontent.com/u/85757794/CIEM/Crossover%20Networks.pdf

 

[Moz-Art]

Here you can find the Shure connector type in plastic shape
 
http://effectaudio.com/product/shure-se535-connectors/
 
They are expencive but sure look good!
 
You can get cheaper ones at Mouser.

 

[Moz-Art]

In a normal situation where you would have three classic speakers, you would create a crossover network using capacitors, resistors and inductors. Sonion writes on its site that balanced armature speakers are highly inductive and using inductors as a low pass filter is not very effective.

So the low pass filter should be created using a resistor and a capacitor in series.

I'm wondering if there are any problems using inductors at all in a crossover network for BA speakers.

A high pass filter can be bet made with a capacitor, also because capacitors are more predictable then inductors.

Better check out how to best make the band filter for the mid range without using inductors.

Anybody who knows more about the use of inductors with balanced armature speakers, let me know.

 

[MuZo2]

As far as I know 99% use RC crossover with acoustic filters  sometimes for low pass.

 

[Moz-Art]

I know. Most of the brands say they use a three way crossover network but most of the time it's only a high pass you'll find.

That is what I want to find out. Is it possible to use a real three way crossover network with balanced armature speakers inside the environment of a in ear monitor.

 

[MuZo2]

I dont think its possible.

 

[Moz-Art]

Would you like to go demper intro that?

Edit *Damn autocorrect. It should have been "Would you like to go deeper into that"*

 

[MuZo2]

 
Two way designs  use tweeter with cap. Woofer with resistor & acoustic damper.
Three way would be additional mid driver with rc band pass.
So there are no real speaker like passive crossovers.

 

[Moz-Art]

This is what Westone say on their website:
 
Individually hand-crafted in Colorado Springs, Colorado, the UM Pro 30’s superior build quality and sound signature are unmatched. Tuned for performing artists, the three-way crossover is matched to individual low, mid and high frequency drivers to make your mix smooth and balanced across all frequencies.
 
Basically they are lying? Or is it possible?

 

[MuZo2]

 

[Moz-Art]

Thanks MuZo2.
 
From what IEM is this picture?

 

[MuZo2]

  From what IEM is this picture?

W3

 

[Moz-Art]

I should have guest that.
 
I've been talking to a CIEM designer this morning and it seems that a "way" system is a wide term in CIEM. It's mostly a combination of some capacitors to make a high or low pass filter and sending full range signals to speakers that have a specific and narrow frequency respons. Or they just send full range signals to every speaker and us acoustic filters to filter and damp out unwanted frequencies.
 
Correct me if I'm wrong here.
 
But it is possible to make a threeway crossover network using only resistors and capacitors. Apparantly you can use inductors too with BA speakers but they are less predictable and more expensive. So it's just a matter of testing the best combination speakers and see if they even need a filtered signal or can handle the full range signal.

 

[Moz-Art]

Not many people here that are trying this kind of stuff anymore.