AudioRoundTable.com: Pi Speakers

Home » Sponsored » Pi Speakers » crossover help

Show: Today's Messages :: Navigator :: Polls
E-mail to friend

crossover help [message #43334]

Thu, 11 December 2003 10:11

gazzamongo
Messages: 25
Registered: May 2009

Chancellor

i've got altec 806/811's and am trying to piece a system together...i got a behringer cx3400 crossover which hisses like a cheap fm tuner between stations and generally sounds nasty so i'm thinking about going passive instead

my altecs will sit atop a karlson 15 with klipsch k33e-s (not built yet)

would anyone be willing to share their crossover circuit design or point me to some resources on this subject as i have little knowledge of crossover design and could use the help

cheers

Gary McDonnell-Thomas

p.s did find this site....would a crossover like the one above do the trick

http://www.lalena.com/audio/

Report message to a moderator

Re: crossover help [message #43336 is a reply to message #43334]

Thu, 11 December 2003 11:34

Wayne Parham
Messages: 18688
Registered: January 2001

Illuminati (33rd Degree)

When using an Altec horn atop a direct radiator, you'll want some padding of the horns. The attenuator will serve double-duty as the damper circuit and can provide top-octave compensation as well. I'd put a standard Zobel on the midwoofer. Other than that, the second-order network you've described will work just fine if you cross-connect the tweeter, wiring "+" to "-". The tweeter motor and the woofer motor should be aligned vertically, within four inches front to back. That gives you a pretty wide position tolerance window where performance will be good.

Report message to a moderator

thanks but whats a zobel [message #43338 is a reply to message #43336]

Thu, 11 December 2003 12:38

gazzamongo
Messages: 25
Registered: May 2009

Chancellor

thanks for quick reply...

i am reading through some earlier posts on crossover ..spice "101" etc...but haven't seen a desription of a zobel yet

care to enlighten me

thanks in advance

Gary McDonnell-Thomas

btw are any of the pricier dsp crossovers any good

Report message to a moderator

Re: thanks but whats a zobel [message #43339 is a reply to message #43338]

Thu, 11 December 2003 13:08

GarMan
Messages: 960
Registered: May 2009

Illuminati (2nd Degree)

Hi Gary,

loudspeakers101.com helped me a lot in understanding crossovers. It's also a great online too for calculations too.

gar.

loudspeakers101.com

Report message to a moderator

Zobel dampers [message #43340 is a reply to message #43338]

Thu, 11 December 2003 13:23

Wayne Parham
Messages: 18688
Registered: January 2001

Illuminati (33rd Degree)

Check the π Crossover Document for a description of Zobel dampers. You'll find them on page 37 and then again on pages 48-52, where Zobel's on woofers with second-order filters are shown.

The short version is that a Zobel circuit for a voice-coil driver loudspeaker is an RC damper that is formed with a capacitor and resistor connected in series. The values for each component can be calculated using the formulas on page 37 of the π Crossover Document. The damper is connected directly across the woofer, and it removes a resonant peak that will form due to the interaction between the speaker's voice coil and crossover components. You can see an example of this peak on page 47 of the crossover document. Subsequent pages show the improved response curve resulting from inclusion of the damper in the circuit.

Report message to a moderator

much obliged, ...(nt) [message #43341 is a reply to message #43334]

Thu, 11 December 2003 14:18

gazzamongo
Messages: 25
Registered: May 2009

Chancellor

Report message to a moderator

Re:Hey Gazzamongo, " Getting there is half the fun" [message #43344 is a reply to message #43334]

Fri, 12 December 2003 04:19

BillEpstein
Messages: 886
Registered: May 2009

Illuminati (2nd Degree)

I had you come over here instead of just posting my x-over so you'd meet Wayne. My level of knowledge is best reflected in the referenced post.
But for what it's worth the attenuation circuit I put on the "+" side of the horn is 32 ohm R and .33uF C, with 16 ohms shunt across the "+", "-", ahead of L1. Don't know the sensitivity of the K33 so you'll have to play with the resistance.

Live, Nude Resistors
Creating is more like performing than listening

Report message to a moderator