[eunice]

All this talk of the polarity of caps is kind of pointless. We're discussing audio signals here. By definition, they are AC. That means that no matter which way you orient the cap, signal is flowing "backwards" through it half the time. Please correct me if I'm wrong, with proof. I do like learning new things.

Signal is flowing backwards half the time, but the question is how does a polarized capacitor behave if signal is flowing backwards? Some of us are not hearing any difference at all, while I convinced myself that I did hear slight distortion with polarized caps. I also read that a cap becomes a short for voltage flowing backwards.

That's why I did investigate.

Turns out: A polarized cap is a capacitor regardless of the direction of current, but it basically breaks if the current flows the wrong way for too long. I think you can use polarized tantalum caps rated 12V or up for CIEMs without problems, according to the NASA paper that should be ok. You probably cannot use electrolytics because they will fail over time.

But of course you can always use two polarized caps in series with reversed polarity or unpolarized caps to avoid any of these risks.

 

[Bassiklee]

Its not about signal but burning capacitor up

Tantalum's work, but burns up(it won't on small signal like iem, but degradation happens)

I think you missed my point. We're not talking about DC. There really is no polarity to an audio signal.

 

[Firedrops]

Parallel RAB32257 + 11ohm resistor + new zobel with 3.9mH inductance and 22ohms DCR as new standard for measuring and calculating
Flattest impedance, Flattest phase and way better than series parallel

Does this mean you've finalised the zobel for 1 RAB?

Also, has anyone ever heard of/tested 1audio drivers? I just randomly stumbled upon their TB shop, they seem to be imitating Knowles' numbers, but also with some really weird stuff like these dual RAB32257 drivers with 1 combined spout. Not really sure if they're "real" 32257s, just guessing from the name. Seems like a timely listing for everyone testing multi-RAB setups

 

[dhruvmeena96]

Does this mean you've finalised the zobel for 1 RAB?

Also, has anyone ever heard of/tested 1audio drivers? I just randomly stumbled upon their TB shop, they seem to be imitating Knowles' numbers, but also with some really weird stuff like these dual RAB32257 drivers with 1 combined spout. Not really sure if they're "real" 32257s, just guessing from the name. Seems like a timely listing for everyone testing multi-RAB setups

I have warbler prelude, jomo Hakka, FIBAE 1, FIBAE 3, Fiio FA1

Friend has FIBAE black.

Single driver needs a lot more tuning but they sound extremely fabulous. They sound more coherent and more stitched in together compared to multi driver.


Yes RAB single driver is perfected for now....just some small tube tuning going on for getting perfect head structure heatmap(tuning soundstage and energy) and acoustic pressure distribution for fatigue free listening and bigger headscape experience.

For dual driver, I have very flat impedance and phase, but it sounds standard.. It doesnt have horn and resonator (muffler) stuff

For now





Well, I think we have talked about advantages about flat phase and linear impedances....but I think, sensei(@piotrus-g ) should throw some light on the advantages of flatter impedances and linear electrical phase. Because he pioneered it


Sensei means teacher by the way(in Japanese)

 

[dhruvmeena96]

I think you missed my point. We're not talking about DC. There really is no polarity to an audio signal.

I Agree completely , except polarised electrolyte.
They dont work, if you dont set them properly according to polarity. If you can spread some light on it.



Try it, and you will get it.

 

[Firedrops]

Yes RAB single driver is perfected for now....just some small tube tuning going on for getting perfect head structure heatmap(tuning soundstage and energy) and acoustic pressure distribution for fatigue free listening and bigger headscape experience.

Thanks! Keen to start building it. Just to confirm, according to your last posted spec, the zobel is
Cz = 4.6uF
Rz = 41ohms,
with a series resistor 20ohms?

 

[dhruvmeena96]

Thanks! Keen to start building it. Just to confirm, according to your last posted spec, the zobel is
Cz = 4.6uF
Rz = 41ohms,
with a series resistor 20ohms?

Zobel is 4.6uF and 41ohms

Series resistor value range from 10ohms to 33ohms
It all depends on taste

And the zobel you mentioned will only work with
RAB32033
RAB32257
RAF driver

The real game will begin with tuning the tubing and dampers like @Choy Wei De

 

[Xymordos]

Does this mean you've finalised the zobel for 1 RAB?

Also, has anyone ever heard of/tested 1audio drivers? I just randomly stumbled upon their TB shop, they seem to be imitating Knowles' numbers, but also with some really weird stuff like these dual RAB32257 drivers with 1 combined spout. Not really sure if they're "real" 32257s, just guessing from the name. Seems like a timely listing for everyone testing multi-RAB setups

I bought a bunch of these from them:
https://item.taobao.com/item.htm?spm=a1z0d.6639537.1997196601.451.340174844g84BV&id=581311508669

...and some "SWFK" drivers, but never got around to using them. Dunno how they sound unfortunately.

 

[zekester]

I am curious how people are terminating the tubes in their shells. I think that is the sloppiest part of my build right now. I have experimented with a single bore and backfilling around the pvc tubes as well as boring each tube individually. I haven't figured out how to get the tube ends to look recessed or super finished. Anybody have any pointers?

 

[dhruvmeena96]

I bought a bunch of these from them:
https://item.taobao.com/item.htm?spm=a1z0d.6639537.1997196601.451.340174844g84BV&id=581311508669

...and some "SWFK" drivers, but never got around to using them. Dunno how they sound unfortunately.

Man, I am seeing those driver for the first time

 

[Xymordos]

I am curious how people are terminating the tubes in their shells. I think that is the sloppiest part of my build right now. I have experimented with a single bore and backfilling around the pvc tubes as well as boring each tube individually. I haven't figured out how to get the tube ends to look recessed or super finished. Anybody have any pointers?

Not the best way to do it, but if they stick out a little, I use the middle part of the soldering iron and really quickly smooth it over.

 

[Xymordos]

Man, I am seeing those driver for the first time

It's their original dual drivers. The seller told me they're for mids or mid-highs, but when I told him the graph looked like it'll be good for bass, he said it should be pretty good for bass too...

As I've never tested them I won't know until later

 

[eunice]

I am curious how people are terminating the tubes in their shells. I think that is the sloppiest part of my build right now. I have experimented with a single bore and backfilling around the pvc tubes as well as boring each tube individually. I haven't figured out how to get the tube ends to look recessed or super finished. Anybody have any pointers?

What I do is I stick the metal tips of syringes into the tubes (they happen to fit perfectly into 2mm ID) and then apply some more resin.

After that I carefully rotate the metal tips out and carefully sand and polish (very careful)

 

[Bassiklee]

Pictures?

 

[eunice]

Pictures?

I will post some when I build the next pair. But it will take some time, maybe a week or two.