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-   -   big bandpass The fatboy (http://www.diyaudio.com/forums/multi-way/137036-big-bandpass-fatboy.html)

Helmuth 21st January 2009 06:52 PM

big bandpass The fatboy
 
Hi every body,

I want to show my project witch I made for my self.

http://i220.photobucket.com/albums/d...3/DSCF0290.jpg

Pure by luck I saw some second hand good as new special Vifa PL26 woofers.
http://i220.photobucket.com/albums/d...lilm3/pl26.jpg
They are very suitable for a closed box.

I want to make a band pass because they combine the impulse behaviour of a closed box with the sub low of a bass reflex and reduce distortion of the membrane it self. And with reasonable efficiency so they became big.:D

The simulation of a closedbox and a bandpass with the same driver.
http://i220.photobucket.com/albums/d...lilm3/spl2.jpg

To morrow more.

Regards Helmuth

Helmuth 22nd January 2009 12:10 PM

The midrange I use is the TI100 of visaton with a titanium cone driver. I have them bought in 2000 and used them for a back loaded horn.

http://i220.photobucket.com/albums/d...m3/hoorney.jpg

The sound of the TI100 is bright and detailed. And has a very high Qms to what some people say this is a indication for a good sounding speaker.
And looks great to.
Fs 62Hz
Rdc 6,0 Ohm
Qms 7,05
Qes 0,40
Qts 0,38
Vas 6,9 l
Sd 54 cm²
Mms 4 g
Bxl 4,8 T m
L 0,7 mH

http://www.visaton.de/bilder/fotos/gross/ti100.jpghttp://www.visaton.de/bilder/ausschw...s/ti100_zd.gif

http://www.visaton.de/bilder/frequen...ti100_8_fs.gif

The isodynamic tweeter I use is the RT1 of Swans. A very good neutral sounding low distortion ribbon tweeter.

http://i220.photobucket.com/albums/d...lm3/RT1C-A.jpg

inertial 22nd January 2009 12:19 PM

Hi Helmuth!:)

Nice to see your Fatboy . Do you have listened ? How does it sound?

Cheers,
Paolo

Helmuth 22nd January 2009 01:18 PM

Quote:

Hi Helmuth! Nice to see your Fatboy . Do you have listened ? How does it sound? Cheers, Paolo
Hi Paolo,

How does a speaker sound with -3dB at 30Hz -6DB 25Hz with a Q of 0,75. It is to early to give a final commend, now I hear this

The sound is warm and quite neutral with sub low finishing.

No astonish dynamics over the frequency range.
The mid range is transparent sounding witch is nice, the Isodynamic Ribbon does not attract my attention, it seems to do his yob perfect with out trying to come on the foreground.

The appearance of the speaker is brute, and makes a appearance that the will be plenty of low frequency.
But the low frequency is well controlled and doesn't over run the mid and high even at low spl it ads the low frequency's to the image. You don't have to play loud to hear the sub low.

It is a speaker that doesn't want to show off, but wants to do his yob well behaved from 22Hz to 40000Hz with low distortion.


I am not ready with the final layout of the filter. That concerns tuning the XO of the 2 TI100.
I have done some experiments it is sensitive to change that can make or brake the sound of the Fatboy.

inertial 22nd January 2009 01:31 PM

Glad to hear it, and.... have a fun!:cool:

P.S.: what is that rectangular port below the mid? A reflex? Oh, my God!:hot:

Cheers,
Paolo

Helmuth 22nd January 2009 01:47 PM

Quote:

P.S.: what is that rectangular port below the mid? A reflex? Oh, my God!
Yes it is a BR as a closed box it doesn't fit the band pass. At has the following advantages.

It has the same group delay as the bandpass
It has less cone extrusion therefore less Doppler effect, and doesn't run against the Xmax.
And the -3dB point is exactly on the right spot to match the sub.

some screen shots of the simulation.
http://i220.photobucket.com/albums/d...untitled-2.jpg

inertial 22nd January 2009 02:00 PM

OK,

So you have choiced bandbass for the sub because it performs better Q ( than BR) and you have choiced BR for the mids?
Ala Wilson, SonusFaber, and so on?

Mmmmmmhhh, I'm very skeptical about it ;
Wilsons and big SF are not so clear on the midbass/foundamentals,
I have listened and was not happy:angel:

Take this with Humor, you know I am "fastidious bad boy"

just my 2c:D

Paolo

Helmuth 22nd January 2009 03:27 PM

Quote:

OK, So you have choiced bandbass for the sub because it performs better Q ( than BR) and you have choiced BR for the mids? Ala Wilson, SonusFaber, and so on? Mmmmmmhhh, I'm very skeptical about it ; Wilsons and big SF are not so clear on the midbass/foundamentals,
Again I had no other choice, then to go for BR.

The BR is tuned to it own Fs(62Hz) this shout give the tightest response. To gather with the low energy storage off the TI100 it gives acceptable clean low mid.

The BR doesn't effect the mids, for higher frequencies the port is closed so above tuning the TI100 sees a closed box of 9 litre.

This is a better solution then BR for a big woofer with larger energy storage. This wouldn't fit nice my tube amp.

inertial 22nd January 2009 03:50 PM

Understood , Helmuth

but I remain skeptical, perdone me. I'm just searching to make constructive critique, not other:angel:

Have you measured the output of the pipe in the near field?:rolleyes:

Theory is one thing, pratic can be different........
pipes are "tremendous", with a two way only you have no other alternative, but with 3 you can eliminate it.

Normally a 4" is crossed slightly more high than 80 Hz, and the bandpass can give you a lot of "free" in the alignement.
See the old KEF with a double 10" bandpass + the famous 5 1/4" bextrene midwoofer( closed): they was crossed at about 150Hz I believe and STILL max output power was a issue for the mid:rolleyes:

just my 2c

Paolo

RJ 22nd January 2009 04:13 PM

What is the secondary port resonance of that BandPass Sub?
How are you dealing with it?
Very curious as I've had a similar design brewing in my head.


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