need advice on crossover

[phatkev]

Hi

Im planning on building my first set of speakers these are the drivers i have
Goldwood GW-8028 8" woofer - 8 ohm
Audax TW025A2 1" Textile Dome Tweeter, 4 ohm
Goldwood GM-85/4, 5" Midrange, 4 ohm

was planning on building a 3-way passive cross-over. but i dont no where to strat. could anyone give me an idea of what cross-over frequencies i should use or how i could find out

all help would be greatly appreciated

 

[kyheng]

The below is my way(maybe wrong) :
1. knowing each driver's FS value
2. knowing their others specs and design the enclosure.
3. design the crossover

As your midrange range is not that good(500-15000Hz) and very limited spec published. So I will be going :
woofer : 1000Hz, LPF
midrange : 1000-8000 or 10000Hz, band pass
tweeter : 8000Hz HPF
Is a reference only, I maybe wrong.

 

[John Sheerin]

To find out, measure the drivers acoustically. See where the response is well behaved / not well behaved. See where the polar pattern narrows. Then match them up as best as possible or get different drivers. To do this initial evaluation, you could measure the drivers on an IEC baffle (large sheet of wood with the driver a bit offset from the center). If you determine they're worth bothering with, design a box for them, mount them in the box and then remeasure to get the data to design the crossover. Also measure impedance in the box if you're designing a passive crossover.

 

[phatkev]

Cheers thanks for the help.

 

[kyheng]

John : Good idea you have.... I learn something again.... Just if I have all the needed equipments and it will be good.

 

[ftpols]

Please could you advise on the layout and circuitry of the attached crossover.

- L1 and L2 are 8cm center-to-center; L2 and L3 centers are 10 cm center-to-center.

- C3 = 20 µF + 16 µF.

- R4 = 2 x 12 ohms.

All other values and tolerances per schematic.

Many thanks for any help.