[Aldo40]

Some questions please.
On the 2389D the center tap , reduces the impedance ? If yes have anyone measure it ?

If I use a big resistor value will effect the sound quality ?

yes I already made measurements
Center Tape is a half-coil connection, so half the inductance and half the resistance.
the impedance is divided by 2 and the gain is a little higher than some db.

As we know, impedance increases with frequency. this is something to take into account
when choosing the transition frequency.
there are circuits that linearises impedances like zobel or lpad, on the configuration
proposed by Dhruv, a Lpad on a driver for example sufficed linearized
the impedance of a driver.
LPAD and Zobel are not compulsory circuits, there are severial methods.
then you have to deal with all these proposed solutions, but you can confide in Dhruv he has a very good experience in IEM
what do you call big resistance? a big value?
I don’t think you have to worry about that if you put a 2 ohms or 10 ohms does not affect the sound, the goal is to adjust it to the rest of your config, and maybe you won’t need it, you will see when designing if it is necessary

 

[528367]

 

[Aldo40]

Thx for the info.
Big value i mean 60 ohm and above.

I ask because I want to make all Drivers play max spl and I will need big value resistors for this .

For the max SPL, it will be necessary to adapt the strongest drivers on the weakest drivers.
A driver can have a given constructor max of 115 db, once filtered or with the damper to eliminate any peak the efficiency will no longer be the same, I take for example a SWFK with 114db max, it will no longer 114db max once in place.
You can’t increase a driver’s performance, you can decrease it.
To increase efficiency, the solution is to double them.
Also take into account that the target total frequency is not linear.

 

[528367]

 

[dhruvmeena96]

@Aldo40
@dhruvmeena96

How it looks ?
This will work you think ?

Connection 2x 38D1XJ00 all parallel

6.2 ohm resistor in series + 100 uf ceramic capacitor in parallel = 256 hz low pass filter

For the 2389D connection in series

8.2 ohm resistor in parallel + 47 uf ceramic capacitor in series = 412 hz high pass filter.

For the EST65QB02 one 3.3 uf ceramic cap = 14.18 khz
Highpass filter

I will share tube for both 38D1XJ00
1 tube for the 2389D
And 2 tubes for the EST65QB02
4 tubes , 4 bores

Then all connected in series.
Im thinking of doing this one .

Does now matters the impedance of the driver (connection series parallel) since i will use crossover ?

What it will be the total impedance from this set ?

And what kind of resistors do you recommend ?
Do you any specific resistor you recommend ?

I will use this for the crossover design.

first get a breadboard and experiment with crosses as those online calculator doesnt take BA specific impedance and its default frequency response in consideration.
if you have a coupler
i have a suggestion
measure all the drivers individually(impedance and FR graph on specific tube)
and import it in vituix cad
and then work from there(but this might be hard, to make yourself your own FRD and ZMA files for specific BA)

but then, if this is a fun project, this should work, just check the phase and if something doesnt sound right, invert the phase of the driver and you are ready to go

 

[528367]

 

[Aldo40]

To extract the ZMA files (impedance curve ) it is done from your impedance measurement hardware example DATS V3 or other. To extract the FRD((SPL curve) measurement files, it is by measuring with your IEC711. A.must recover your FRD and ZMA files, it is necessary to integrate them in vituixcad to simulate your filter. Of course it does not make everything but it allows to leave on good bases

 

[528367]

 

[Aldo40]

The software that you use to measure usually offers registration in these formats. Otherwise SPLtool integrated in vituixcad will help you

 

[Masaikem]

Pretty funny

 

[dhruvmeena96]

I must measure the frequency response ,save it and the change the extension of the file to frd
And for the impedance, measure , save and then change the extension to zma ?
This will work ?

https://toidsdiyaudio.com/2018/01/0...cer-html-2018-01-the-best-frd-and-zma-tracer/

Make an impedance measuring rig and do this

Pretty funny

???????
Atleast quote what's funny bro
We also need a laugh

 

[Aldo40]

Pretty funny

 

[Wgibson]

Driver inside a zobel update, took some impedance measurements with a CI-30120 and Raf-32873 because the numbers worked out pretty well on paper. CI alone, then with regular zobel, then with Raf as the Rz, then zobeled the Raf.

Have not measured frequency response yet, but this should be a functional 2 driver design (or 5 driver, if you did 4 Rafs in 2x2 series/parallel) as the cap inside the CI's zobel would put the Raf at about 330hz high pass filter. And you could mechanically low pass the CI, with small ID/long tube, and/or dampers.

Next step is to get individual driver frequency measurements to see if they are in the right ballpark to play together as far as volume goes.

 

[dhruvmeena96]

Driver inside a zobel update, took some impedance measurements with a CI-30120 and Raf-32873 because the numbers worked out pretty well on paper. CI alone, then with regular zobel, then with Raf as the Rz, then zobeled the Raf.

Have not measured frequency response yet, but this should be a functional 2 driver design (or 5 driver, if you did 4 Rafs in 2x2 series/parallel) as the cap inside the CI's zobel would put the Raf at about 330hz high pass filter. And you could mechanically low pass the CI, with small ID/long tube, and/or dampers.

Next step is to get individual driver frequency measurements to see if they are in the right ballpark to play together as far as volume goes.

Next step is to see frequency response and if RAF is causing a dip
Then inverting it's phase or the whole zobel (+ to - side and - to + side).. if it is causing a dip in normal setup

 

[Wgibson]

It is workable, could use some help on the high end. The 0.2mm ID brass tube is almost impractically small, but clearly functions as a low pass filter. Maybe just use a short section of it as an orifice, and maintain more of the subbass volume. Lots of physical tweaking to do if I decide to finalize it. This was mostly just for proof of concept, and electrical practice.

The Raf 330hz high pass showed up as pretty much as expected. No cancelation issues either.

Edit: in theory, I could close the gap on low/mid range between the blue and yellow curves, by adjusting the CI tubing.