[Choy Wei De]

Tubeless build??
I am not getting a clear idea
If you mean the shell, and placing driver...

Nice..

Well the first shift of diameter from 1.2mm to 2mm makes a very slight low pass

A. Low pass resonator
B. Resonant damper
C. High pass
D. Helmholtz resonator


Secondly

It reduces the air pressure hitting ear drum



And smoothens out the sound profile of treble..(micropeak damping

After that is a gradual increase of diameter to have stepped horn, so I can have some increase of High frequency as RAB has steep roll off after 8kHz~10kHz.

Damper goes in horn, and it damps the midrange peak at 3kHz, damps tube resonance, horn resonance and ear resonance.

Brown for neutral bassy, white for brighter profile


Zobel is needed in this setup to compensate the variable diameter tube acoustic impedance shift.



First of all, the series low pass resonator of such a small size doesnt effect FR in huge manner..it is for very fine tuning on soundstage

@Choy Wei De will explain how it effects the soundstage..

Bigger resonator makes sound take some distance, mid bass thinner and subbass rumble.

We both tuned it in such a way, that we can have desired decay in bass and good treble extension..

@homerograco

The way I understand is very unique.
A smaller ID tube is like a river with rushing water. The surface of the water is not travelling the same speed as underwater, not cohesive.

When a river flow to a bigger tube, ‘pond’ or ‘lake’, the surface of the water slow down and back in sync with underwater. With the correct size of the pond, when the water enters into a smaller river. The surface of the water is right at the same speed as underwater. If the pond is too small, the surface of the water is still faster than the underwater. If the pond too big, the water is too calm and the sound will become muddy. Just need the right size of pond.

The horn is like when a river adapt to a delta and flow into a ocean. If you use a hair dryer, the wind is very narrow and very forceful. But if you maintain same energy and spread it wide like a using chinese hand fan or use a big styrofoam as a fan, the end result is quite smoothing and very cohesive.

Weird explanation, but it helps me understand tube design and soundstage.

 

[stephensynanta16]

You don’t need a pcb for Zobel. It’s Just a resistor and capacitor, you can just solder them together and cover them with a few drops of resin.

You know...this thread is doing zobel back from pg500’s

And has moved so much that we have ED29689 zobel
Which I have done with my etymotic er4s build. Distortion drop was huge as the frequency moved up.

No need to put it into cable...dont actually...it will make cable proprietary to iem..

You can fit smd components.....

They are small..

If you are not able too..just make the shell slightly longer

Thx for reminding me guys, maybe i'm too caught up in my own thinking of kit-styled build.
Currently experimenting with pcb printing, 1 cm x 1 cm double layer board for MASM7 zobel, gonna share the gerber someday. Hope it's gonna make it easier for everyone to build.

@eunice

[

@stephensynanta16 you wanted to see crazyness of this thread....right



@Jedrula1 designed it, I calculated it...

We can control sound without having damper in straight acoustic path of driver, increasing detail...and while damping specific frequency I was able to boost RAB 10kHz to 8dB...

And for crazy experiment, used new path line damping tube schematics to band pass the driver (experimental)


You haven't seen @piotrus-g Dual CI and TWFK Scary build....its the hardest build to begin with...sounds fantastic but is also scary to build...as its electrical design seems simple but soldering breaks a person willpower..

Sound is mild V-shape with Bass digging deeper than dynamic or planar.

The single variable diameter RAB design is actually one of the simpler ones

My gosh, what is that thing!? the tube... is it connected to the vent of the BA?

Might be interesting to make it into 3d model, we could make those path spiralling on the main tube, something like this:

The footprint will be smaller, easier to integrate into shell

 

[eunice]

Printing a small spiral is ridiculously hard with SLA printers. If you figure out how it works, please share.

 

[stephensynanta16]

Printing a small spiral is ridiculously hard with SLA printers. If you figure out how it works, please share.

i haven't tried it, gonna share it once i succeed printing one

 

[eunice]

i haven't tried it, gonna share it once i succeed printing one

The problem is that the resin takes to long flowing out of the spiral and the remaining droplets clog the spiral.

 

[Jedrula1]

i haven't tried it, gonna share it once i succeed printing one

The problem is that the resin takes to long flowing out of the spiral and the remaining droplets clog the spiral.

You need high resolution, good quality DPL printer and take time to post-process the spiral to make sure all resin is washed and blown out before final curing. I am able to get more than 10cm of a spiral tube with a diameter of less than 0,5mm in very small print that fits custom shell easily. Ultrasonic cleaner with isopropyl alcohol makes the work done. Then syringe with alcohol to clean spiral with alcohol pressure. It took me a few attempts to get spiral DLP print works fine.

 

[eunice]

I have an anycubic photon, dunno if this qualifies as a high resolution DLP in your eyes. It can print 0.5mm holes no problem, but in a spiral it tends to clog.
How do you do the cleaning with alcohol pressure?

 

[Jedrula1]

I have an anycubic photon, dunno if this qualifies as a high resolution DLP in your eyes.

Unfortunately this is not 'high resolution' printer if you want me to be honest

How do you do the cleaning with alcohol pressure?

Get a syringe filled with alcohol, then put the tip at the end of the spiral and squeeze the syringe to make alcohol flow trough spiral. Repeat few times to get the best effects.

 

[homerograco]

You know...this thread is doing zobel back from pg500’s

And has moved so much that we have ED29689 zobel
Which I have done with my etymotic er4s build. Distortion drop was huge as the frequency moved up.

No need to put it into cable...dont actually...it will make cable proprietary to iem..

You can fit smd components.....

They are small..

If you are not able too..just make the shell slightly longer

This is probably what I will try. I got pretty much no space left, but I think I can move the mmcx connector a little bit. Need to go back to the drawing board...

 

[homerograco]

@homerograco

The way I understand is very unique.
A smaller ID tube is like a river with rushing water. The surface of the water is not travelling the same speed as underwater, not cohesive.

When a river flow to a bigger tube, ‘pond’ or ‘lake’, the surface of the water slow down and back in sync with underwater. With the correct size of the pond, when the water enters into a smaller river. The surface of the water is right at the same speed as underwater. If the pond is too small, the surface of the water is still faster than the underwater. If the pond too big, the water is too calm and the sound will become muddy. Just need the right size of pond.

The horn is like when a river adapt to a delta and flow into a ocean. If you use a hair dryer, the wind is very narrow and very forceful. But if you maintain same energy and spread it wide like a using chinese hand fan or use a big styrofoam as a fan, the end result is quite smoothing and very cohesive.

Weird explanation, but it helps me understand tube design and soundstage.

Thanks a lot for the ELI5, loved it.

 

[eunice]

Get a syringe filled with alcohol, then put the tip at the end of the spiral and squeeze the syringe to make alcohol flow trough spiral. Repeat few times to get the best effects.

Thank you, sometimes I am too dumb to see the simple solutions. I will try again.

BTW: Thats what I am working on. I build an insert into a CIEM that I can quickly switch out so I do not need to build a new shell for every iteration of a design.

This is not yet acoustically tuned, that's just a proof of concept for an "inner shell" inside a CIEM. So no spiral yet

 

[ForceMajeure]

Thank you, sometimes I am too dumb to see the simple solutions. I will try again.

BTW: Thats what I am working on. I build an insert into a CIEM that I can quickly switch out so I do not need to build a new shell for every iteration of a design.

This is not yet acoustically tuned, that's just a proof of concept for an "inner shell" inside a CIEM. So no spiral yet

thank you for using the "Section Analsys" option to show us

 

[eunice]

thank you for using the "Section Analsys" option to show us

To be honest I had to search 10 minutes to find out on how to turn it off again

 

[ForceMajeure]

To be honest I had to search 10 minutes to find out on how to turn it off again

one of the latest update they have done to the UI is getting me confused. I have a hard time adjusting to the new icons

 

[eunice]

one of the latest update they have done to the UI is getting me confused. I have a hard time adjusting to the new icons

I am a complete noob to CAD/CAM. First I refused to buy into that cloud stuff (why can't I export to a STL without going over their servers?) and "free as long as we like" licenses. In fact the Fusion License just changed.

My first try was with FreeCAD which I like a lot more. Really, Fusion trys to hide the mathematical construction and ends up very confusing in comparison. For example why is the distance constraint part of the "Create" menu while the dimension of a circle is part of the circles properties and most other constraints are in the "Constraints" menu?

In FreeCAD this is much clearer, there is additive shapes, substracting shapes and constraints. It's up to you how you constrain the shapes. But it freezes a lot on my mac and it became so annoying that after 5 hours I gave up and recreated the design in Fusion.

Sorry for the rant. Are there any alternatives for the complex shapes we need for IEMs?

And I'm still looking for a way to simulate the acoustic properties, I think Comsol is too expensive for me. Does anyone have ideas on how to do simulation?