big bandpass The fatboy

[AndrewT]

inconsistent units

what stupid way to specify units for formulae.
Especially since he says Xmax in mm and then converts Litres back to cub metres by dividing by a 1000. OOPS, Xmax must be in cm for this stupid method to work.

Far better to do everything in metres.
The answer comes out as 0.109m. Everyone knows that's a port you can slide a small hand through, or lose a smallish pet!

 

[inertial]

30Hz-80Hz is 2,33 octave Paolo.

No mine friend! It is 1,33 octave.

 

[AndrewT]

30Hz to 60Hz is one octave.
60Hz to 80Hz is a lot less than one octave.
How can 30Hz to 80Hz be greater than two octaves?

I'm still trying to come up with a formula.

 

[Helmuth]

No mine friend! It is 1,33 octave.

I think your right.

then is the question how the others specify their bandwith.

22-110Hz -10dB would be 2,25 octave.

The reason of the band with is the result of the efficiency of a 8" woofer.
A Q of 0,75 and strait response between 30-80Hz at a spl of 88dB.

If you want more bandwidth you end up with lower spl. Then you need a bigger woofer with responsible spl to get the same level again.

Pure physics nothing else.

 

[inertial]

Yup !😀 😀 😀 😀

 

[Helmuth]

Filter op midrange. New layout for mega-Q coil.

The high pass of the 2 TI100 is shifted to prevent the impedance of becoming to low.
A higher Q to increase the spl of a single TI100.

At 2500Hz I hear interference of the dáppolito set-up.
That is why I filter it 1180 Hz. also the level increases of the TI100 this will also be compensated by it.

An externally hosted image should be here but it was not working when we last tested it.

To prevent a dip above 3kHz and to become a steeper fall of to prevent the rising of 7khz, is here a higher Q chosen.

The total overview of the setup in win-isd.
Bleu bandpass
filtered 1st oct 440Hz with 1.5mH also the series coil of 1,6mH plays a important roll. It is not really a filter but impedance control above 150Hz
grey TI100 94Hz-1180Hz
yellow TI100 210Hz-4080Hz

Regards Helmuth

 

[Helmuth]

Phase

 

[Helmuth]

Very nice Mkp capacitors of Claritycap 100uF each😀
See the mega size of them compared to the phone.

The photo is taken with the filters lying on the top cover of the box. A birch plywood of 8mm covered with velours chocolate colour.


Regards Hemuth

 

[inertial]

Hi Helmuth🙂 ,

IMO now you are going on the "right" road!

We are curious to see measurements......

Cheers,
Paolo

 

[Helmuth]

Yes me to can't get the hardware working with the measurement software. Those nasty windows settings I don't know where it is fault

 

[Helmuth]

To get the maximum detail out of the driver I bought a nice cable.

It is a biwire cable made out of a copper silver mix. With massive fork connectors.😀

See the hiny of the fatboy

 

[inertial]

Cool!😎

Just a thing I do not understand so clear:
seems to me your two Visatons, have different excursion in the "bass" zone. Am I right?🙄

Cheers,
Paolo

 

[Helmuth]

Cool! Just a thing I do not understand so clear: seems to me your two Visatons, have different excursion in the "bass" zone. Am I right? Cheers, Paolo

Yes.

 

[inertial]

Why?🙄

Paolo

 

[Helmuth]

The high pass of the 2 TI100 is shifted to prevent the impedance of becoming to low. A higher Q to increase the spl of a single TI100.

Thats why.

 

[inertial]

Ok, your tube amp has problem with bad loads.

But you are wasting the opportunity to equally condivision of the excursion of the double 4" Visatons ! 😀

Cheers,
Paolo

 

[Helmuth]

Agreed,
made confusion with X-max an X- peak to peak !😀

Ok , 30% seems good for a BR as I understand the formula.
But you have a bandpass..........this is my point (derived by my
empirical experiments).
Bass reflex and bandpass require different sizing IMO.
In a bass reflex the pipe "cover" a extremly narrow band, no?

In your case you have very narrow band ( quite unusual) but normally others have two octaves ( like the Boston,Kef) . Thus the pipe become more sensible to "chuffing" and you have to increase the section.

Cheers,
Paolo

O.K Paolo BR port resizing. 😀

37% bigger.
And it is 30% of the cone size.

The layout of the filter will also be chanced to second order. And I go to a dome tweeter and other XO.😉

 

[inertial]

Looks good, mine friend!

Interesting the thing about the dome......jet annoied with the planar?😀 😀

Cheers,
Paolo

 

[Helmuth]

Looks good, mine friend!

Interesting the thing about the dome......jet annoied with the planar?😀 😀

Cheers,
Paolo

Hi paolo,


The planar does nothing wrong. Maybe I can say more when the dome is mounted.
Now I want to XO at 1900hz to avoid the spl rising at around 2500Hz and ctc spacing problems.

The second octave filter is needed to match the fase of the sub and mid.

 

[inertial]

Hi paolo,


The planar does nothing wrong.

Exerpt it do not have the bandwith ...... 🙂

Maybe I can say more when the dome is mounted.
Now I want to XO at 1900hz to avoid the spl rising at around 2500Hz and ctc spacing problems.
[/B]

Oh, 1900 Hz much better I presume for CTC but worse in musical terms because it is right in the middle of the "voice" ! :-(

The second octave filter is needed to match the fase of the sub and mid. [/B]

Yup, and maybe also it can help to protect/limiter the excusion ( extrusion?) of the Ti100s, 🙂

good work, Helmuth
and have a fun !🙂

Paolo