[pc27618349]

I think initially a lot of us love the deep dark bass that dynamic drivers provide. I haven't had luck getting that same sound from BA's and I slowly became ok with that and began to appreciate the bass I was hearing even though it's different than what I was used to. I haven't heard any high end IEMs so maybe you can achieve that subwoofer type bass.

I'm sure the GK crossover question has already been answered already on this forum as to which driver is being x-overed and what the crossover frequency is.

About your tack layer on your shells, I never had this problem that you are describing. It almost sounds like you did the initial cure, the brushed on another coat of gel, put it in glycerine then tried to cure it. That's wrong. You need to do a long cure first to try and catalyze as much of the acrylic as possible before you put it in glycerine. If you're trying to cure a fresh wet layer of gel in the glycerine, you'll definitely run into problems you have described. It did that once or twice and after much cursing, learned that lesson the hard way. What kind of UV light are you using? A handheld LED flashlight or some UV bulb setup? I use both.

Acetone will certainly strip off that tick layer as well as the cured layer. It's powerful stuff. I use isopropyl alcohol but unfortunately both acetone and isopropyl alcohol can leave the surface cloudy which is astetically unpleasing to some. You can get a really nice shine by doing your final coat in gloss and then curing that tack layer in glycerine. At least that's what I do and it's worked pretty well.


 

 

  After first curing and pouring out uncured material, place it under UV for a 2-3min, then remove the shell from your negative form (avoid touching surface with fingers, use some tweezers) and then place it glycerin and then post-cure for 2-3more minutes. That should solve your problem and should leave no tacky residue.

I see - I think my mistake was pouring out the uncured material and immediately pouring in the glycerin for the post-cure. I thought the idea was to avoid exposing the resin to the air and so any leftover resin left in the shell when i poured in the glycerin floated around and caused a big mess. Thanks for the clarification.
 
 
 
 

  OK guys,
 
here's the "cool" project... ("super cool" will have to wait till it's measured, because I don't want to put up something that doesn't work)
The design below is quite easy (took me 5min to sketch and it's pretty much bullet proof if you wire it correctly - as in the picture).
 
First of all I figured if @pc27618349 is using GK why not reuse parts from it, and since the GK is using 22uF cap and the idea is for more neutral sound we can allow for higher resistor lower cap combo for lowpass.
Secondly I provided you with two possible resistor values and cap values to have a bit of wiggle room if you want to add small changes without throwing everything out of order. The same goes for tubing and damper values.
 
Finally, if R₁ value goes up TWFK output will increase, so by increasing R₁ you not only move cut off slope back to the left on graph but also decrease the output in that range relative to 1kHz.
If the sound is still too bass-heavy you can put R₂ of 20-40Ohms on the second CI (the one w/o lowpass). This will "speed-up" the bass, lower the CI's output and increase relative TWFK's output.
 
Happy tuning!

Thanks for the design, piotrus! I'll give it a shot and let you know how things turn out. The great benefit of using this clear polycarbonate faceplate is that the UV acrylic adheres enough to keep it on but the surface is smooth enough for me to pop it off for quick access
 
Do you have any recommendations on where to put the dampers in the tubing? Closer to the driver/away from the driver?
 
Also, if I'm reading it correctly, you're using one CI at full range, one with a low pass, and what does the cap on the TWFK do? 

 

[piotrus-g]

   
I see - I think my mistake was pouring out the uncured material and immediately pouring in the glycerin for the post-cure. I thought the idea was to avoid exposing the resin to the air and so any leftover resin left in the shell when i poured in the glycerin floated around and caused a big mess. Thanks for the
Thanks for the design, piotrus! I'll give it a shot and let you know how things turn out. The great benefit of using this clear polycarbonate faceplate is that the UV acrylic adheres enough to keep it on but the surface is smooth enough for me to pop it off for quick access
 
Do you have any recommendations on where to put the dampers in the tubing? Closer to the driver/away from the driver?
 
Also, if I'm reading it correctly, you're using one CI at full range, one with a low pass, and what does the cap on the TWFK do? 

Yup, don't be afraid to take time when pouring out material, make sure that shell is empty and then post cure it w/o glycerin, then put whole shell into glycerin, not just inside. After last curing rinse with water then with spray with isopropanol - you'll be good to go.
 
Put dampers in the middle of tubing, no need to over-complicate it.
Yes, one CI is working as fullrange and one with low pass. Cap on TWFK works as high-pass filter.

 

[ForceMajeure]

Guys what glue do you recommend for attaching the tubes? I see that Egger (hearing aid supplies) have a cyanoacrylate based glue called uniglue,..
Also do you glue the drivers inside the shells so they stay in place?

 

[pc27618349]

  Yup, don't be afraid to take time when pouring out material, make sure that shell is empty and then post cure it w/o glycerin, then put whole shell into glycerin, not just inside. After last curing rinse with water then with spray with isopropanol - you'll be good to go.
 
Put dampers in the middle of tubing, no need to over-complicate it.
Yes, one CI is working as fullrange and one with low pass. Cap on TWFK works as high-pass filter.

I'm in the middle of ordering the components - I'm planning on using a 10 ohm pot + 30 ohm resistor to be able to freely adjust the crossover point for the filtered CI.
 
Is there a capacitor type that lends itself well for audio applications? I heard tantalums being thrown around this thread but they're rather big for my shells...
 
 

Guys what glue do you recommend for attaching the tubes? I see that Egger (hearing aid supplies) have a cyanoacrylate based glue called uniglue,..
Also do you glue the drivers inside the shells so they stay in place?

I've been using the same material I use for the shells to attach the tubes to the drivers (and to the shell). I dab a little on the end of the tube and hold the pieces together under my UV lamp. The trick is to make sure the glue also extends a little around the driver casing (just a few tendrils of glue, not a whole new shell for the driver) so that the glue has something to hold onto.

 

[Furco]

Guys what glue do you recommend for attaching the tubes? I see that Egger (hearing aid supplies) have a cyanoacrylate based glue called uniglue,..
Also do you glue the drivers inside the shells so they stay in place?

I've had luck using both thin and thick superglue (cyanoacrylate). I have had mixed success using UV curing gel; it just doesn't hold like cyano does and that's can be a big deal when I'm trying to run the acoustic tubes through tight openings in the IEMs.

 

[ForceMajeure]

So, I have ordered most of the materials I need, I got my hand on yellow(4700ohm), red(2200ohm), green(1500ohm) and white(680ohm) dampers.
 
Now, I am on the fence about getting grey dampers (330ohms), Do you think they are necessary or their value is too low? Do you guys use them?
 
Also if there are other dampers colors that are essentials tell me about them?

 

[tranhieu]

Here's how I often use dampers:
 
For tweeters (>5khz): grey/brown//white 
For woofers (1.5khz-5khz): brown/white/green/red/orange (in some extreme cases)
For sub woofers (<1khz): red/orange/yellow
 
Long story short, just get all the colors.

 

[Furco]

Agreed! You'll thanks yourself later when trying to tune drivers with known dampers as opposed to winging it with homemade/DIY dampers, like me.

Here's how I often use dampers:

For tweeters (>5khz): grey/brown//white 
For woofers (1.5khz-5khz): brown/white/green/red/orange (in some extreme cases)
For sub woofers (<1khz): red/orange/yellow

Long story short, just get all the colors.

 

[ForceMajeure]

Agreed! You'll thanks yourself later when trying to tune drivers with known dampers as opposed to winging it with homemade/DIY dampers, like me.

I actually thought of doing it
 
Today I just ruined a perfectly fine microphone that I intended to use for measurement. Didn't have a chance to use it arghhh...
 
Its the Dayton imm-6, I put a tight rubber ring (from silicon tube) over it, then another piece of tube with a larger diameter over the ring.
I tried to pull my little construction back and it just pulled with it the imm-6 tip with the little condenser microphone in it, ripping the wires and pads that was soldered on it... made me  so angry...
better use blue tack next time to attach the tube to the imm-6.
 
So people be aware the edge of the imm-6 with the microphone in it is actually glued and is very easy to pull out

 

[tsn141]

@piotrus-g
I saw some designs, it is a good chance to see a commercial designers design
Very interesting and also very different XO approach than mine
 
Those are good example for me.

out of topic:
How much time do you need to develop a commercial XO or design?

 

[honame]

This that might be of your interest. It actually shows you which tools you need, working temperature and how to properly solder the drivers: http://www.knowles.com/eng/content/download/2783/32742/version/6/file/TB-04.pdf

 

[Furco]

@piotrus-g

I saw some designs, it is a good chance to see a commercial designers design
Very interesting and also very different XO approach than mine

Those are good example for me.


out of topic:

How much time do you need to develop a commercial XO or design?

I think what you're asking is for him to reveal his "intellectual property". That's similar to asking the Cocacola company what their recipie for Coke is.

Development time is largely based on what sound signature you're attempting to achieve and the economics behind manufacturing it.

 

[piotrus-g]

  @piotrus-g
I saw some designs, it is a good chance to see a commercial designers design
Very interesting and also very different XO approach than mine
 
Those are good example for me.

out of topic:
How much time do you need to develop a commercial XO or design?

Heh, thanks, I guess there's probably no "right" or "wrong" here unless you go "all wrong" and end up with one big phase canceling
 
It really depends on design, but typically few months. It's has to do more with whole sound signature in general, than crossover in itself.

 

[tsn141]

@piotrus-g yes there is not strict true ot false, but there is some big mistakes and bit tricks. Not only iem, all areas of engineering just know principle, and solve problems. Yes my approach is differant from you but your approach give me another point of view


I asked the time needed for developing for ı saw you done some designs at very short time, and it is too difficult for a commercial product( not jus one person or puvlic design). Your answer, halp me about that.

 

[BLaRMan]

Hey Guys,

I 'm pretty new to this thread, but as I was searching on the web for instructions to building a CIEM, I came across this thread at instructbles.com :

http://www.instructables.com/id/DIY-In-Ear-Monitors/

It sounds like as if it is a pretty good home made CIEM, but since I am not familiar with the settings used, can you take a look at it and see if it is a appropriate setup?