[Xymordos]

Made some progress on the 4xRAB build. Used an SWFK as highs, and a BK21610 as subs. My god the RABs sound great. It is a buttery smooth mids, sounds similar to my planar driver. I used a 15mm x 2mm diameter PVC tube with a white damper on the RAB. Mids are perfect.

Need some work on the bass though. Without a bass driver it's pretty thin. With a bass driver it can get a bit muddy. I used a regular 15mm length tube with a 2nd order low pass this time without the usual 50mm long tube I usually use. Maybe I should try a longer tube...

Spoiler: Picture

Spoiler: Frequency & Impedance

 

[dhruvmeena96]

Made some progress on the 4xRAB build. Used an SWFK as highs, and a BK21610 as subs. My god the RABs sound great. It is a buttery smooth mids, sounds similar to my planar driver. I used a 15mm x 2mm diameter PVC tube with a white damper on the RAB. Mids are perfect.

Need some work on the bass though. Without a bass driver it's pretty thin. With a bass driver it can get a bit muddy. I used a regular 15mm length tube with a 2nd order low pass this time without the usual 50mm long tube I usually use. Maybe I should try a longer tube...

Spoiler: Picture

Spoiler: Frequency & Impedance

Nice build...actually FR looks amazing
But why is there a 5kHz dip?
And how you shifted the 3kHz peak to 2.5kHz with so less kurtosis or so much balanced approach.

The impedance and electrical phase looks flagship like. If I have the circuit design, i can make the 20ohm DCR settle down to 13ohms, so you can achieve max electrical impedance and phase flatness.. It may resolve the muddy ness

Or use a HODVTEC with zobel built in and crossed properly with vent sealed


Side note:
I was thinking something like Freqphase....

And yahh, I think it is a flagship tuning

 

[Cevisi]

Made some progress on the 4xRAB build. Used an SWFK as highs, and a BK21610 as subs. My god the RABs sound great. It is a buttery smooth mids, sounds similar to my planar driver. I used a 15mm x 2mm diameter PVC tube with a white damper on the RAB. Mids are perfect.

Need some work on the bass though. Without a bass driver it's pretty thin. With a bass driver it can get a bit muddy. I used a regular 15mm length tube with a 2nd order low pass this time without the usual 50mm long tube I usually use. Maybe I should try a longer tube...

Spoiler: Picture

Spoiler: Frequency & Impedance

What is this for a shell is it selfmade ?

 

[dhruvmeena96]

Made some progress on the 4xRAB build. Used an SWFK as highs, and a BK21610 as subs. My god the RABs sound great. It is a buttery smooth mids, sounds similar to my planar driver. I used a 15mm x 2mm diameter PVC tube with a white damper on the RAB. Mids are perfect.

Need some work on the bass though. Without a bass driver it's pretty thin. With a bass driver it can get a bit muddy. I used a regular 15mm length tube with a 2nd order low pass this time without the usual 50mm long tube I usually use. Maybe I should try a longer tube...

Spoiler: Picture

Spoiler: Frequency & Impedance

Nice build...actually FR looks amazing
But why is there a 5kHz dip?
And how you shifted the 3kHz peak to 2.5kHz with so less kurtosis or so much balanced approach.

The impedance and electrical phase looks flagship like. If I have the circuit design, i can make the 20ohm DCR settle down to 13ohms, so you can achieve max electrical impedance and phase flatness.. It may resolve the muddy ness

Or use a HODVTEC with zobel built in and crossed properly with vent sealed


Side note:
I was thinking something like Freqphase....

And yahh, I think it is a flagship tuning

Formula for phase adjusted tubing(its not freqphase)

1 : 1.2 : 2

Where 1 is Bass driver
Where 1.2 is mid driver
Where 2 is tweeter.

The con of this design is that tweeter will loose its sparkle as it has to go in a tube which is twice longer than bass tube to match its physical time


If we go as per the above convention, then

10mm tube to BK21610
12mm tube to RAB
20mm tube to SWFK

Making too long of a tube can make C80 and D50 clarity take a hit, due to internal tube added reverb with delay which can be more than 50ms, because bass is slower and delay comes out apparent. Until or unless, you dont want to make a physical crossover, the idea for long tubing can be detrimental some time. Treble are better in this area as they are very fast. Mids are worst in long tube reverb as we are the most sensitive to mid region. A note for 50mm tubing



Another suggestion that I can give is to get rid of BK and change RAB32063 to RAB32257, but then it will take away the effortlessness of the RAB set. It will be still better than BK if bass is your concern, but mids won't be that amazing(it would be still better than other drivers, but not to the level of RAB32063)

But still, that FR looks very crazy level

note:
The 5kHz dip and 8kHz roll off looks off.

 

[Xymordos]

What is this for a shell is it selfmade ?

Bought some universal shells of Taobao

 

[dhruvmeena96]

Bought some universal shells of Taobao

Link please

 

[Xymordos]

Formula for phase adjusted tubing(its not freqphase)

1 : 1.2 : 2

Where 1 is Bass driver
Where 1.2 is mid driver
Where 2 is tweeter.

The con of this design is that tweeter will loose its sparkle as it has to go in a tube which is twice longer than bass tube to match its physical time


If we go as per the above convention, then

10mm tube to BK21610
12mm tube to RAB
20mm tube to SWFK

Making too long of a tube can make C80 and D50 clarity take a hit, due to internal tube added reverb with delay which can be more than 50ms, because bass is slower and delay comes out apparent. Until or unless, you dont want to make a physical crossover, the idea for long tubing can be detrimental some time. Treble are better in this area as they are very fast. Mids are worst in long tube reverb as we are the most sensitive to mid region.

But still, that FR looks very crazy level

note:
The 5kHz dip and 8kHz roll off looks off.

The 5kHz dip is there in the original 4x RAB setup actually. The SWFK just didn't help when filling in as a super tweeter.

How did you get your freqphase calculations btw :O

Currently my circuit looks like this (did some trial and error on the zobel to get an approximate value):
BK21610 - Zobel: 4.7uf + I forgot what I used for the resistor oops (think it was 25ohms?), 2nd order low pass: 47uf+10ohm x 2 (15mm length, 2mm diameter, white filter)
4 x RAB32063 - series-parallel - Zobel: 5uF + 38ohms, 30ohms in series (15mm length, 2mm diameter, white filter)
SWFK31736 - 0.33uf + 0.2uf series (15mm length, 1mm diameter)

 

[Xymordos]

Link please

The seller actually only sells molds for universal shells, I had to ask the seller to make the shells and sell me finished shells since I don't like making the shells.
https://item.taobao.com/item.htm?spm=a1z09.2.0.0.49232e8d7RDvlx&id=561980218822&_u=6kqv5elafa3

 

[Ivan TT]

Made some progress on the 4xRAB build. Used an SWFK as highs, and a BK21610 as subs. My god the RABs sound great. It is a buttery smooth mids, sounds similar to my planar driver. I used a 15mm x 2mm diameter PVC tube with a white damper on the RAB. Mids are perfect.

Need some work on the bass though. Without a bass driver it's pretty thin. With a bass driver it can get a bit muddy. I used a regular 15mm length tube with a 2nd order low pass this time without the usual 50mm long tube I usually use. Maybe I should try a longer tube...

Spoiler: Picture

Spoiler: Frequency & Impedance

Can you tell more about how tubing is connected to the nozzle please?
Is the nozzle 1 way or 3 way and how do you approached feeding tuning through the nozzle, that’s something I still figuring out...

 

[Xymordos]

Can you tell more about how tubing is connected to the nozzle please?
Is the nozzle 1 way or 3 way and how do you approached feeding tuning through the nozzle, that’s something I still figuring out...

I stick all three tubes to the mouth of the nozzle and use a toothpick to fill in the gaps with resin and cure it. Then when the nozzle is sealed I use a syringe to fill the inside of the shell.

 

[dhruvmeena96]

The 5kHz dip is there in the original 4x RAB setup actually. The SWFK just didn't help when filling in as a super tweeter.

How did you get your freqphase calculations btw :O

Currently my circuit looks like this (did some trial and error on the zobel to get an approximate value):
BK21610 - Zobel: 4.7uf + I forgot what I used for the resistor oops (think it was 25ohms?), 2nd order low pass: 47uf+10ohm x 2 (15mm length, 2mm diameter, white filter)
4 x RAB32063 - series-parallel - Zobel: 5uF + 38ohms, 30ohms in series (15mm length, 2mm diameter, white filter)
SWFK31736 - 0.33uf + 0.2uf series (15mm length, 1mm diameter)

Its easy to fix

SWFK can do 5kHz while acting as a super tweeter, for a distortion increase 2%

BK should be low passed slightly more. RAB bass overtone is muddying BK as BK is not a strong woofer can get effected with RAB bass (the weak bass act as secondary tone or structure tone). Slightly more low passing BK can fix, but has to be hit and trial as I dont know where the mudding will stop. And best part is that you will have more linear and clean mids as a bonus.




And how did I calculated the tubes..

I was actually observing freqphase tubing length on this thread and some other company method. And I observed that tubing of tweeter is double of woofer and mid tube ratio was averaging at 1.2(some had 1.5, some were 1.1)

And best part is that tweeter can have its damper removed plus you can have strongest SWFK 31736 in a long tube.


Flat impedance benefits are that without signature swing we can add resistance in series to control volume and reduce noise and distortion.. Even to whole circuit.

If you add series resistance to your setup, you will tighten the bass + some bass increase due to +7ohm in bass area

 

[Xymordos]

Its easy to fix

SWFK can do 5kHz while acting as a super tweeter, for a distortion increase 2%

BK should be low passed slightly more. RAB bass overtone is muddying BK as BK is not a strong woofer can get effected with RAB bass (the weak bass act as secondary tone or structure tone). Slightly more low passing BK can fix, but has to be hit and trial as I dont know where the mudding will stop. And best part is that you will have more linear and clean mids as a bonus.




And how did I calculated the tubes..

I was actually observing freqphase tubing length on this thread and some other company method. And I observed that tubing of tweeter is double of woofer and mid tube ratio was averaging at 1.2(some had 1.5, some were 1.1)

And best part is that tweeter can have its damper removed plus you can have strongest SWFK 31736 in a long tube.


Flat impedance benefits are that without signature swing we can add resistance in series to control volume and reduce noise and distortion.. Even to whole circuit.

If you add series resistance to your setup, you will tighten the bass + some bass increase due to +7ohm in bass area

I'll see if increasing resistance helps on the BK. If not I might try replacing the BK with a 3700 to see if it helps. The 3700 has better low end extension but I like the BK's punchiness.

Currently all my tubes are the same length actually - should I change them? i.e., 12.5mm for BK, 15mm for RAB, 25mm for SWFK? I did try 30mm for SWFK but that created phase issues and actually muted the treble.

Also, right now this set up is harder to drive than my planars. I can only use it on my desktop amp to drive it properly.

 

[dhruvmeena96]

I'll see if increasing resistance helps on the BK. If not I might try replacing the BK with a 3700 to see if it helps. The 3700 has better low end extension but I like the BK's punchiness.

Currently all my tubes are the same length actually - should I change them? i.e., 12.5mm for BK, 15mm for RAB, 25mm for SWFK? I did try 30mm for SWFK but that created phase issues and actually muted the treble.

Also, right now this set up is harder to drive than my planars. I can only use it on my desktop amp to drive it properly.

Tweeter always go double of woofer, you have to set mid driver to help with phase issues.
This setup will work, according to calculation. since the electrical phase is pretty linear, It would be easy to adjust in the tubing.

Just tune the BK tubing and mostly everything would work.
If phase cancellation do occur, then adjust SWFK tubing only(it can be double(25mm) or half the lenght- I mean 6.25mm)

And do make sure that SWFK 5kHz fills the RAB dip(very slightly as your design is universal, the dip is important, but the dip width need some elevation as it looks more apparent).
If you are going with smaller tube version, then make sure you used damped SWFK like 32254

Smaller tubing is phase linear too, but issue is that treble driver can become faster on time domain. The feeling of treble cymbal becoming faster rather than their airy end normal decay. Smaller length tube driver can be slowed down by resonator or expanding chamber or muffler

 

[dhruvmeena96]

@Xymordos
I was simulating the design as per your specs.
BK is fine on bass....you just have to shift a little lower, that's all. It will clear up the muddy ness.

Even the dip is good for universal.

 

[MuZo2]

Is that tubing connected to shell?