OB concept study using inexpensive bass drivers

[LineArray]

Just an idea for a reduced size OB, using
inexpensive bass drivers. The OB will be
floorstanding.

This is just a concept, exact positions
of drivers will have to be fine tuned.

XO for the 2 lower drivers <180 Hz
lowpass only.

XO for the 2 upper drivers dependent
on Tweeter (Fullrange ?) used,
typically 1Khz, lowpass only.

[bigwill]

Should work - but don't expect any deep bass with smaller drivers - but you might be surprised at the nice fast quality of the midbass, especially with higher Qts drivers (the lower variety rolling off too soon giving a thin unsatisfying sound)

[LineArray]

Originally posted by bigwill
Should work - but don't expect any deep bass with smaller drivers -

Tangband W69 1042 has 225 cm2 cone area.
(x 4) ...

[bigwill]

Ok - I should have paid more attention to the driver choices when I said "should work"...

Do not build this.

If you want to use 6x9s, use ones with a higher Qts value for the bass. This may mean cheaper drivers too, which isn't necessarily a bad thing. Are you sure you want to spend 8 x $60 on unsuitable woofers?

These tang bands are sub woofer drivers and cannot be crossed over to a tweeter particularly well.


I recommend four cheap high Qts 6x9s per side and a nice tang band fullranger for everything above 200hz. Designed properly this may indeed be a very good sounding speaker.

[LineArray]

I intend to push up Qes by using a series resistor ...

Dirty thought, isn't it ?

[LineArray]

Concerning bass response bjorno showed,
that this works rather well.

http://www.diyaudio.com/forums/showt...27#post1536627


Concerning XO 0.9 to 1 Khz i cannot see impossibilities.
Pic 4(5) of the mentioned thread shows a red dashed line,
which would be the response in an infinite baffle.

One can approximate that response by keeping the baffle
step far lower than the crossover frequency.

Maybe it is possible to reach -3 dB at 1Khz by doing
nothing (no crossover). Filter rollof has to be set above
1Khz. An "acoustical" filter has to be designed, which
integrates into the whole system.

[bigwill]

I think a single Eminence Alpha-15 per side will be MUCH cheaper and you will be happier with it (And it wont take up much more room)

[skorpion]

Oliver,

I am sorry, but I think something is wrong with bjorno's simulation. I have calculated it myself with his adjustments and with this result for the bassresponse (1 TB-driver 10" above floor 1 watt input):



The input figures bjorno present is not consistent with the bafflefigure in the second picture

/Erling

[LineArray]

Originally posted by bigwill
I think a single Eminence Alpha-15 per side will be MUCH cheaper and you will be happier with it (And it wont take up much more room)

hi bigwill,

i had a look at the Eminence 15" drivers. Very interesting
for that purpose ...

Do you have experience with Alpha 15 or Beta 15 ?

Can you say something concerning mid range performance ?

[LineArray]

Originally posted by skorpion
Oliver,

I am sorry, but I think something is wrong with bjorno's simulation. I have calculated it myself with his adjustments and with this result for the bassresponse (1 TB-driver 10" above floor):

Hi Erling, did you use a series resistor ?