Small Size Open Baffle Question

[Gunawan W]

KYW,
in my case, according your advice it's better using a driver with fs=75-80Hz and Qt>0,7, but the Vas affect SPL on your spreadsheet result. It's hard to find 6" driver with big Vas to get SPL around 95dB.
I read somewhere that Vas can be ignored in calculation because there is no box, is it true?

Sheldon,
good idea even better with motorized baffle wing!

See you.

[ThorstenL]

Konnichiwa,

Originally posted by Gunawan W
in my case, according your advice it's better using a driver with fs=75-80Hz and Qt>0,7,

Yup.

Originally posted by Gunawan W
but the Vas affect SPL on your spreadsheet result.

Of course it does. My spreadsheet calculates the absolute SPL for 2.83V applied and 1m distance. Most Box Calculation programes only provide a relative SPL calacuation. A larger Vas meas a more efficient Driver.

Originally posted by Gunawan W
It's hard to find 6" driver with big Vas to get SPL around 95dB.

I am not surprised. You are running up against the little thing called Physics.

Originally posted by Gunawan W
I read somewhere that Vas can be ignored in calculation because there is no box, is it true?

Of course not.

Sayonara

[Gunawan W]

Hi,
apparently I reach the limit of small OB, with 6" driver and 40x60cm baffle size (folded), passive filtering, the result is not efficient, limited flat FR (200Hz to 12000Hz), so I drop to build it, am I give up to soon?

Happy New Year 2004, to all you guys, may audio be with you!

[ThorstenL]

Konnichiwa,

Originally posted by Gunawan W
Hi,
apparently I reach the limit of small OB, with 6" driver and 40x60cm baffle size (folded), passive filtering, the result is not efficient, limited flat FR (200Hz to 12000Hz)

That comes from using unsuitable drivers (Low Qt and low sensitivity) and way too small size baffles (remember, folding gains you only minimal LF extension over the front section of the baffle on it's own.

Do the job right (Suitable driver, sufficiently large baffle) and the result will be very good.

Sayonara