[fredcrys]

Hello all,

I have in mind another project, perhaps a Frankenstein project. I have bought This IEMs, CCA-C16 8BA drivers. I bought them from amazon but Aliexpress shows more pictures. They are OK but too bright for my taste, however, works fine for playing live. I am able to hear all the instruments but the bass-guitar needs more bass and the cymbals peak the high frequencies, and as a drummer, I want to hear everything.... is too much asking?

My plan is to open the headphone and put the drivers in a custom mold, perhaps re-using the 3D printed acoustic driver structure and add one tube from the structure. I would like to pick you guys brains on how to modify the sound. I want to add more bass and lower or filter the high frequencies. Adding a Zobel would help??

What do you guys think? good-bad idea? let me know your thoughts.

Thanks,
Fred

 

[eunice]

Probably bass will already increase by using a custom mold, but the peaks at the highs might even get worse (probably will get worse). In addition you will lose any tuning the IEM manufacturer did, so expect a ton of peaks and valleys in the frequency response, it will definitely take long time and hard work to make it sound any good in a different shell. Tuning 8BAs is like herding cats.

So it might be easier to start with a well known recipe and get some experience and then move up to your 8 BA flagship later on.

 

[shrewdgamer]

What equipment would I need to make my own IEMs?

Bose SoundTrue Ultra's were the most comfortable earphones I have used till now, but they have stopped working. I saw a video of opening up the earphones using heatgun, when I tried to open them up using a cheap heatgun, I melted one of the earphones. I want to recreate the damaged earphone.

 

[Cevisi]

Whit wich iems is the belssing 6 zobel build comparable ?

 

[fredcrys]

Probably bass will already increase by using a custom mold, but the peaks at the highs might even get worse (probably will get worse). In addition, you will lose any tuning the IEM manufacturer did, so expect a ton of peaks and valleys in the frequency response, it will definitely take a long time and hard work to make it sound any good in a different shell. Tuning 8BAs is like herding cats.

So it might be easier to start with a well-known recipe and get some experience and then move up to your 8 BA flagship later on.

I am very sure that the manufacturer has its own PCB-crossover board in the shell, so as you @eunice say, it may take time to tune it outside that board. My idea was to approach the project from the drivers perspective, taking them out and creating a crossover that suits my needs. I want to take advantage of the drivers. I am very sure that there are other drivers better than these but since I already invested in the CCA-C16, why not experiment.

Let's go back to basics. I think this was discussed here before but could not find the thread. To avoid high frequencies in a mid-bass speaker, what should I use? i.e., resistor, capacitor, inductor, etc.? and how to prevent low frequencies from sneaking into a tweeter? Understanding these principals will help me to do calculations for the elements I will need to use based on the model of each driver.

Thanks.

 

[fredcrys]

What equipment would I need to make my own IEMs?

Bose SoundTrue Ultra's were the most comfortable earphones I have used till now, but they have stopped working. I saw a video of opening up the earphones using heatgun, when I tried to open them up using a cheap heatgun, I melted one of the earphones. I want to recreate the damaged earphone.

@shrewdgamer
This is a list that I compiled to create the IEMs from scratch. If you follow that thread there are others commenting good suggestions and alternatives for materials as well. The project is a Bellsing-6 BA driver with Zobel. There are other recipes to make your own from single driver to 10 drivers. The first step How many drivers? and then go from there.

@Ivan TT, @eunice, @dhruvmeena96, and everyone else.

Here is the list that I have gathered so far to build the DIY-IEM. Most of you have built these IEMs, so the list will look familiar. I have to confess that I have not searched deep on these forums for a materials list, in any case, I would like for the community to give me your suggestions and comments to enhance this shopping list. The prices are in US dollars and links point at Amazon USA and Aliexpress-soundlink.

Total: $283.88
Impression and Casting materials

1. DIY Ear impression kit (4 sets)
   1. $18.00 - https://www.earplugstore.com/diyimpkit.html
2. Acrylic Mold Resin - Nice-Fit (Soundlink has other options for Resin Acrylic)
   1. $51.15 x 8oz - 250g - AliExpress_link
3. Negative mold Clear/translucent SORTA-Clear 37 (Smooth-On) - You can use Agar-agar as well and is cheaper
   1. $44.36 by 2Lbs - Amazon_Link
4. Rotating display Battery
   1. $6.48 - Amazon_link
5. Natural Soy Wax or Clear-Seal Silicone Coating (Lacquer or Nail Polish)
   1. Natural Soy Wax
   2. $10.85 - Amazon
6. Casting ring cup for Negative mold
   1. $2.55 x 2=$5.10 - Aliexpress
7. UV Light Nail machine
   1. $25.99 - Amazon_link

Total: $151.50

IEM Cable and accessories

1. Armatures Drivers
   1. 2PCS Bellsing 10013 Balanced Armature Driver 6 Way BA Full Range
   2. $65.86 (Pair) - Aliexpress_Link - As of 08/26/2019 the price shown has a 26% discount
   3. Zobel network materials (Cap + Res) are no more than $5.00
2. Sound Dampers filters
   1. $2.46 x 7=$17.22 to get all of them just in case
   2. Aliexpress_link
      1. Damper install Tool_Link - $5.01
3. MMCX Terminals
   1. Female terminal
   2. $3.82 (2p) - Aliexpress
4. MMCX headphone cable 64in long
   1. $28.00 - Aliexpress
5. Enameled copper wire 31awg - Red & Green
   1. $5.37 x 2=$10.74 (pack of 10 shorts) - Aliexpress
6. OuM Kit Accoustic tubes
   1. Acoustic tube Ø 2,0mm outside / Ø 1,2mm inside
   2. Acoustic tube Ø 3,0mm outside / Ø 2,0mm inside
   3. $1.73 - Aliexpress

Total: $132.38

 

[shrewdgamer]

@shrewdgamer
This is a list that I compiled to create the IEMs from scratch. If you follow that thread there are others commenting good suggestions and alternatives for materials as well. The project is a Bellsing-6 BA driver with Zobel. There are other recipes to make your own from single driver to 10 drivers. The first step How many drivers? and then go from there.

Thanks.

 

[eunice]

You can reuse the cross over, that should ne possible . But it has only limited influence on the sound, since IEM operate in a closed space, acoustics are very important. Having a tube 1mm longer than another is already a huge difference. Add to the fact that most drivers are broadband, not the dedicated woofers / mids / tweeters as in loudspeakers, and you will get to the conclusion that the crossover plays a different role in an IEM than a speaker.

Having said that, it’s next to impossible to build significant inductors in an IEM, they are just too large. You’ll need inductors in milli Henry range and up, they get huge quickly.

Search for RC Filter to learn how to calculate and build crossovers with resistors and caps alone. You’ll need to measure inductance and impedance of your drivers for meaningful results though.

You can also do low-pass using dampers.

 

[J-breezy]

Hey Guys. I’ve only ever built things like the Knowles HE, GK, GV, etc. never done anything more elaborate. I was wanting to try the Bellsing 6 with zobel.
I’ve seen some of the diagrams on how to wire it and I think I understand. But could someone verify the values of capacitor and resistor?
Also, where do y’all buy your capacitors and resistors that small?
Thanks so much

 

[eunice]

BS6 Zobel by @Ivan TT is 22uF and 25Ohms.

I use 1206 smd ceramic caps and 1206 or 0805 smd resistors. The caps are usually 10% tolerance, so you will need to buy a few of them and measure them with a capacitance meter (or a multimeter that is able to measure caps) to find matching pairs.

 

[tomekk]

and measure them

@J-breezy I recommend you to use

 

[Ivan TT]

BS6 Zobel by @Ivan TT is 22uF and 25Ohms.

I use 1206 smd ceramic caps and 1206 or 0805 smd resistors. The caps are usually 10% tolerance, so you will need to buy a few of them and measure them with a capacitance meter (or a multimeter that is able to measure caps) to find matching pairs.

I used 0805 XR5 caps (22uF seems to be the highest value available in this size), but avoid Y5V as they have bad tolerances and fluctuate with the temperature.
Caps could also be paralleled (and resistors too), this helps to get over tolerances (as these average out), I usually use x2 or even x4 resistors in parallel if I don't have required values handy.
I'd say 10 or even 20% variation in values is not an issue as zobel has minimal effect on FR and also works due to capacitors reactance, which is not changing in line with the capacitance as much.

 

[eunice]

@J-breezy I recommend you to use

These don’t have a high accuracy. I think they are worse than 10%. I use them to check whether I soldered the Zobel correctly, as they can measure the resistor and cap in series.
But for selecting caps I use a multimeter with capacitance measurement, it has 1% accuracy and is generally a useful tool to own.

 

[Kulgrinda]

I am very sure that the manufacturer has its own PCB-crossover board in the shell, so as you @eunice say, it may take time to tune it outside that board. My idea was to approach the project from the drivers perspective, taking them out and creating a crossover that suits my needs. I want to take advantage of the drivers. I am very sure that there are other drivers better than these but since I already invested in the CCA-C16, why not experiment.

Let's go back to basics. I think this was discussed here before but could not find the thread. To avoid high frequencies in a mid-bass speaker, what should I use? i.e., resistor, capacitor, inductor, etc.? and how to prevent low frequencies from sneaking into a tweeter? Understanding these principals will help me to do calculations for the elements I will need to use based on the model of each driver.

Thanks.

Hi,

Here is a diagram of basic crossover. I've seen preinstalled filters on Knowles GK and Bellsing 6 drivers bundle, they only have a capacitor and a resistor. So basic principle is resistor will low-pass, capacitor will high-pass. Values depend on the driver.

Smaller diameter tubing also works as a low pass filter. Higher value damper works as a low-pass.

Horn shaped end of the tube will increase high frequencies.

As for the problem you have, maybe you can simply try adding dampers through the nozzle of the IEM to reduce intrusive high-frequencies. You can also add acoustic foam between the nozzle and the eartip, sound might become more enjoyable.

I personally would not open up this 3D printed, 8 driver per side small IEM. I would assume tolerances there are so minimal you would not be able to put everything back let alone change some drivers.

 

[kmmm]

Faceplates with holographic flakes for MASM7 coming up!