Crossover advice

[zega55]

Hi , guys

I am building a 2-way loudspeaker.
I have two Peerles 831882
and two Seas 27TFFC

The box will be 8.6L BR.
Tuned to 57hz.

Can you give me a advice about the crossover network?
Could I use a crossover design from here
I found this project , and it uses almost the same driver.
The woofer is the same one , but the tweeter is the one without ferroflouid and it has a soft polymer surround , while mine has
sonolex surround.

[sdclc126]

Good choice of drivers.

Someone may design a crossover for you here, but why not learn how to do it yourself?

http://www.rjbaudio.com/Audiofiles/FRDtools.html

Also this site will be useful - read the driver test pages:

www.zaphaudio.com

[zega55]

Thanks for the advice.
Zaph pages ware the guideline in chousing the woofer , and the looks of the woofer had to do somethig with it.
It has low distortion , and a nice response.

I wanted only an advice where to cross , and what type of a crossover should I use.

Well , I know that 6db per octave wouldn"t work.
And I know about the woofers response it has a bump after 2kHz.

[infinia]

Originally posted by zega55

And I know about the woofers response it has a bump after 2kHz.

That's the result of picking a driver with a pole piece, i.e. extended response inc. the cone breakup. Makes the crossover more difficult/complicated now. IMO concave cone shapes allows use of combined acoustical rolloff with the electrical response much simpler.


compare to http://www.tymphany.com/files/products/pdf/832873.pdf

lower Fs as well
I guess it's not as sexy looking tho.

[HK26147]

zega55
I would suggest 2Khz.
I would also use a more aggressive slope than 12db/octave.
Since this is an untested design(?), I would be tempted to outboard the xover to allow for experimentation and evaluation.
One of the advantages of active crossovers is more aggressive filter rate 24 - 48db/octave which allows for a lower xover point and easy of experimentation.

[infinia]

As suggested LPF at 2KHz seems to make sense.
Could use non-textbook 2nd order (low Q) and space the HPF further up to sum better on axis.

[sreten]

Originally posted by zega55

Could I use a crossover design from here
I found this project , and it uses almost the same driver.
The woofer is the same one , but the tweeter is the one without ferroflouid and it has a soft polymer surround , while mine has
sonolex surround.

Hi,

That design appears to have no BSC and thus is not recommended.

I'd suggest you learn what you are doing to choose the c/o point,
the acoustic slopes of the crossover and the electrical components
required to reach your targets.

e.g. :

The crossover is an acoustic 4th order at 1950 Hz, and is nearly a symmetrical Linkwitz-Riley thanks to the woofer's shallow acoustic center. To reach the target slopes, 2nd order electrical plus an L-pad was used on the tweeter, and 3rd order electrical was used on the woofer. The tweeter has an impedance peak to deal with, but I was able to get enough damping out of the shunt resistor to not need an impedance flattening LRC circuit. The woofer has a breakup node but it was high enough to not require extra components in the crossover.

/sreten.

[zega55]

By BSC you mean baffle step compensation?

[sdclc126]

He does.

[Jay_WJ]

Originally posted by zega55
Can you give me a advice about the crossover network?
Could I use a crossover design from here
I found this project , and it uses almost the same driver.
The woofer is the same one , but the tweeter is the one without ferroflouid and it has a soft polymer surround , while mine has
sonolex surround.

Right, the crossover you linked in your post has nearly zero baffle step compensation.

I can model a crossover for you. What's your baffle size? What's your speaker placement?

-jAy