TangBand W69-1042 XO at 900 Hz - opinions ?

[LineArray]

http://www.partsexpress.com/pe/showdetl.cfm?Partnumber=264-837


Questions:

1) Is this driver still produced ?


2) What are your opinions/experiences to crossing
it at 900-1000 Hz ?


Cheers

 

[LineArray]

The idea behind that is somewhat perverted:

W69-1042 could be dirt cheap killer applied to open
baffle, when driven with a series resistor.

The diaphragm seems capable to work properly in the
midrange. Tangband offers some bass-mid units with
similar diaphragm but different motor and suspension.

Main reason for W69-1042 to be usable as subwoofer
only is the very high voice coil inductivity (around 3,2mH)
causing rolloff above 200 Hz. That seems to be the
price to pay for the long throw voice coil design.

Connecting a series resistor Qes is pushed up and the
hump/rollof in frequency response should be smoothed.

4 of them have a cone area about 900cm2 ... and
excursion is fairly high with Xmax of 7mm, maybe linear
excursion is 4mm only i don'd know.

It seems that the driver is still on shelf but it belongs to
SU (Subwoofer) series now.

The high voice coil inductivity could be used to design
a crossover without external inductances using a
capacitor only ...

DisplacementVolume / Dollar ratio is is e x t r a o r d i n a r y
good, and the quality of the driver is really ok, i use two
of them as subwoofers in a BR design.

Cheers Oliver

 

[bjorno]

…What are your opinions/experiences to crossing it at 900-1000 Hz ?…

IMO, XO-ing at 900 Hz is too high for the Tb woofers if placed near the floor level due to the driver Le.
Look at the submitted pictures: 1(5)-5(5).

b

1(5)

 

[bjorno]

2(5)

 

[bjorno]

3(5)

 

[bjorno]

4(5)

 

[LineArray]

Thank you for your work !

I did not see the pictures immediately.
But i think i would use a series resistor of higher value.

And i will use 2 drivers, which will have higher directivity then.
There will be around 50 cm distance to the floor.

 

[bjorno]

5(5)

 

[LineArray]

This is the OB design (just a thought)

http://www.diyaudio.com/forums/showthread.php?s=&threadid=124672

Your graphs show, that early rolloff > 300Hz is
mainly introduced by combination of baffle step and
crossover ...

This can be circumvented by using different baffle size and
positioning of drivers.

Crossover has to be adapted too.

 

[bjorno]

Hi Oliver,

Since I’ve studied your other tread I tend to agree with your comments and as someone noticed in that tread: a simulation parameter mistake must exist when comparing to the parameter settings using only one driver, I’ve taken action to correct this discrepancy too. See the pictures in 1(9)-7(9)

b

1(9)- 7(9)

 

[bjorno]

2(9)

 

[bjorno]

3(9)

 

[bjorno]

4(9)

 

[bjorno]

5(9)

 

[bjorno]

6(9)

 

[bjorno]

7(9)

 

[bjorno]

8(9)

8(9)-9(9) added: 2x Tb W69-1042 OB, mounted vertically or horizontally.

 

[bjorno]

9(9)

 

[skorpion]

Hej BjörnO,

I think you got it right now. May be the VAS-figure took it all wrong earlier. But simulating at 60 watts is perhaps not the greatest idea either. However I would like to point you to a modelrelated paper by Martin J King which deals with using two equal units in his simulation tool: http://www.quarter-wave.com/General/Two_Drivers.pdf Using this extends the usefulness of MJK's models quite a bit. And certainly predictions are accurate.

Skål !

/Erling

 

[LineArray]

Hi bjorno,

again thank you very much for your investigations !

It seems that you'd prefer a lower XO frequency and
build a FAST system, i understand that ... it is maybe
the more "natural" option.

But i think a 900 Hz XO variant is possible using the
2.5 Way option. With the pair of mid-woofers mounted
higher on the baffle. Baffle step has to be designed
not to disturb upper midrange.

What do you think concerning those drivers in
OB in general ?

What do you think concerning the 2.5 Way Version
with 900Hz XO to the tweeter ?

When building the 300 Hz XO Version, would you still use
a separate low pass with lower XO for the pair of
woofers below ?

Best regards