[musmecca]

Questions regarding designing crossover circuit for multi BA iem:

1. Regarding RC low pass filter, is the direction of the capacitor flow from BA out to BA in? All RC filter diagrams I've seen had no indication on which side of the capacitor is the (+) or (-), so I'd like a confirmation.

2. Is it possible/practical for all BA drivers to share one capacitor? I've seen the tuning circuit diagram of a 2 BA iem build on Youtube, and the guy only used one 10 uF capacitor shared between both BAs, so I wonder if that is okay in order to save space within the shell.

This is the basic pass calculator I use. Since the flow of energy in an IEM is more ALTERNATING versus direct current and are of negligible voltage, directionality of +- on a cap is inconsequential, but it's placement in the circuit is. Also, it is standard practice to use the correct value for a particular driver and not to share caps. https://sengpielaudio.com/calculator-RCpad.htm

 

[swtnate]

This is the basic pass calculator I use. Since the flow of energy in an IEM is more ALTERNATING versus direct current and are of negligible voltage, directionality of +- on a cap is inconsequential, but it's placement in the circuit is. Also, it is standard practice to use the correct value for a particular driver and not to share caps. https://sengpielaudio.com/calculator-RCpad.htm

SM Ceramic capacitors donot require polarity.

 

[tonybuild]

Hi guys, what is the best glue for gluing drivers to the wall inside the shell?

I made ciem for my friend, and after 6 months, and he told me that the drivers unglued from the tubes and fall off .
I usually use egger to glue them , but sometimes its pretty fragile . Specially if you accidentally drop them

 

[Benyboy]

Hi guys, what is the best glue for gluing drivers to the wall inside the shell?

I made ciem for my friend, and after 6 months, and he told me that the drivers unglued from the tubes and fall off .
I usually use egger to glue them , but sometimes its pretty fragile . Specially if you accidentally drop them

I'm still new at this but I've tried glueing drivers in the Shell with uv resin which for now hold fine, I use a small syringe to place drops.

 

[SamIem]

I'm still new at this but I've tried glueing drivers in the Shell with uv resin which for now hold fine, I use a small syringe to place drops.

Personally I use Fix and Flash from bostik. It is green until it has been UV cured, then it becomes transparent.

 

[swtnate]

Hi guys, what is the best glue for gluing drivers to the wall inside the shell?

I made ciem for my friend, and after 6 months, and he told me that the drivers unglued from the tubes and fall off .
I usually use egger to glue them , but sometimes its pretty fragile . Specially if you accidentally drop them

For fixing tubes to drivers, I use loctite uv glue designed for medical devices. It is not cheap but lasts forever and doesnt crack over time or slip off from the drivers. For gluing drivers to the inside shell I use clear patch resin.

 

[tonybuild]

Wow. Thank you guys. Its helpful

 

[ttf97]

Hi guys, I have been trying to understand more about driver tuning. I was studying the resonant frequencies between the followings:

1. Open ear (~3 kHz for an average ear canal length)
2. Universal IEM (Assume at 1st bend ~12mm, close-close tube resonance frequency ~7 kHz)
3. Custom IEM (Or deep fit IEM, after 2nd bend, I cannot find data about this, but the resonance frequency should be higher than 2.)

Therefore, I think the tuning for an Universal and a Custom IEM should differ a bit.

I want to tuning a CIEM such that it can resemble the experience of listening to a pair of speaker in a room. So I think mitigating the resonance peak at the resonance frequency for 3. and recreating the ~3 kHz peak could be a good starting point.

Does anyone has experience they can share?

Thanks!!

 

[shade105]

Another question: Does the usual RC low pass filter work as well with a DD as it would with a BA? What should I take into consideration if I want to use a DD for bass and lower mids?

 

[swtnate]

Another question: Does the usual RC low pass filter work as well with a DD as it would with a BA? What should I take into consideration if I want to use a DD for bass and lower mids?

Yes and no.
BA’s are incredibly inductive. Hence, not using inductors as passive components. They same can not really be said for dynamic drivers.

 

[shade105]

Yes and no.
BA’s are incredibly inductive. Hence, not using inductors as passive components. They same can not really be said for dynamic drivers.

So you're saying capacitor and resistor low pass filter can work with dynamic drivers, just not inductor and resistor ones.

 

[swtnate]

So you're saying capacitor and resistor low pass filter can work with dynamic drivers, just not inductor and resistor ones.

Common designs only feature RC circuits. No inductors are used.

 

[zie5522]

Im sorry if this already being asked. Any tips to improve height, depth, stereo imaging/panning?

 

[swtnate]

Im sorry if this already being asked. Any tips to improve height, depth, stereo imaging/panning?

Tons of resources for general troubleshooting in the previous 1,000+ comments. When you have a better picture of what you are trying to accomplish, we can offer a better explanation toward your project.