Dual B-139's

[Moondog55]

fwiw, the B139's don't like to be overdriven -- but they are very easy to repair if you fry the voice coil -- obviously I have done this several times
I was awarw of this, which is why I have waited until I had a quad of them, but you then have the problem of the distortion most amps have ( I know this is a smallish factor) when driving nominally low impedance loads ;-0 when looking for perfection or a close aproximation you need to look at everything don't you?
"Borjno"
wuold it make much difference to the if the drivers were aligned vertically?? Verticall alignment of the woofers would have a greater WAF in the narrower box, I can go taller more easily than I can go wide, and a low cross-over point is not going to be a problem if I Bi-amp or Tri-amp.
Thanx for all the input so far

 

[planet10]

but you then have the problem of the distortion most amps have ( I know this is a smallish factor) when driving nominally low impedance loads

Wire then in series or just use 4 amps. We have a gainclone with high V rails (larger than max spec). And it is very happy and sounds really good driving 16 ohms.

wuold it make much difference to the if the drivers were aligned vertically??

aligned vertically? I don't get the question.

they are drawn oriented vertically (with a ghost of horizontal...

dave

 

[Moondog55]

I meant with the vertical axis of the driver aligned with the vertical axis of the speaker box, specifically Bjornos style of box, to give a more narrow and wife acceptable style of cabinet.
WAF is part of the desiign parametre

 

[planet10]

I meant with the vertical axis of the driver aligned with the vertical axis of the speaker box, specifically Bjornos style of box, to give a more narrow and wife acceptable style of cabinet.
WAF is part of the desiign parametre

I'm still guessing what you are trying to describe. If you mean can the box be folded yes. If you mean can you stack the drivers one on top of the other on the same side, then you would lose out on the BIG advantage push-push gives you.

If you are after a specific shape then the existing box can be manipulated.
ishas got to be 50 cm anyway... the one i drew is 34 cm (and could be narrower -- you do realize the B139 are mounted on the sides of the box?)

dave

 

[Moondog55]

Dave we are talking about 2 different styles of box, while I love your design it will not fit into my room, so i was looking at Bjorno's folded line, my question about stacking drivers vertically was only directed at his style of folded line.
As far as push push goes I am experimenting in that direction with a sub project for home theatre, but too many projects started not enough finished

 

[planet10]

we are talking about 2 different styles of box, while I love your design it will not fit into my room

The size of the box is the size of the box. Mine folded would be ~ 34x125x70cm (wxhxd) ~0.3m^3, Bjornos' 50x120x60 ~0.36m^3

As long as line length & cross-section remain the same, the dimensions can be mutated to optimize the shape.

dave

 

[Moondog55]

Thank-you I did not understand that

 

[Moondog55]

OK the B-139 seller has renegged and so this project will not be going ahead for quite a while, saw plenty on Ebay UK but i am not going to pay twice selling price for postage.
looks like I better finish one of the other projects first;-( probably just as well as I could not get a reasonable fit with the Midrange I have .
Still saving for Vifa P-13's while they are still avaliable
thanx for all the input