Weird 2 way Crossover

]|[ GorE · 12th June 2006, 06:44 PM

My Panasonic bookshelves ( with a 5 inch aramide glass fibre cone and a 25mm Semi-dome tweeter) are stated to crossover at 4.5 Khz according to the HTIB manual.
And the only components on the crossover pcb are :

2 caps : 2.2 uf and 4.7 uF metallized polyester 75V
One air core inductor. (forgot the value)

What sorta crossover is this ?? I am asking because i want to upgrade it.

I hope that this thread will get atleast one reply.

RDV · 12th June 2006, 07:23 PM

It's like my Sanyos, it's probably got a 1st order(just a cap) for the tweeter, and 2nd order(cap & inductor) for the woofer.

RDV

RDV · 12th June 2006, 07:25 PM

The inductor is probably a .56mh if the woofer is 8 ohms.

RDV

]|[ GorE · 12th June 2006, 07:28 PM

Any chance of upgrading it or changing it for the better ??

RDV · 12th June 2006, 07:33 PM

I'm trying to do the same thing and what they're telling me is that without measuring equipment I'm just shooting in the dark so to speak.

Do they sound bad as is?

RDV

pwillard · 12th June 2006, 07:49 PM

Quality in an Air Core inductor is harder to achieve than say... upgrading a cap.

It's not like it has a voltage rating. It's not a radio frequency coil, so that doesn't come into play. With Air Core, there is no permeability of the ferrite or other core material to take into account.

If it were me... I'd upgrade the caps and leave the coil alone.

]|[ GorE · 12th June 2006, 08:00 PM

They have oodles of detail.No problem with the bass or midrange.
Its got a shiny treble.Getting rid of it by setting treble to -1 in the tone controls.

RDV · 12th June 2006, 08:07 PM

Quote:

Originally posted by ]|[ GorE
Its got a shiny treble.Getting rid of it by setting treble to -1 in the tone controls.

They probably neglected to pad the tweeter in any way. If you added padding resistors you'd have to change the crossover values then because the impedance would change. It sounds like it would be more trouble than it would be worth IMO.

RDV

]|[ GorE · 12th June 2006, 09:01 PM

What do you mean by change of impedance. Isnt that what the R1,R2 of L-padding are supposed to do ?

RDV · 12th June 2006, 09:13 PM

Quote:

Originally posted by ]|[ GorE
What do you mean by change of impedance. Isnt that what the R1,R2 of L-padding are supposed to do ?

When impedance changes, so does the crossover point.

RDV

12th June 2006, 06:44 PM	#1
]\|[ GorE diyAudio Member Join Date: Jun 2004 Location: Sharjah,UAE	Weird 2 way Crossover My Panasonic bookshelves ( with a 5 inch aramide glass fibre cone and a 25mm Semi-dome tweeter) are stated to crossover at 4.5 Khz according to the HTIB manual. And the only components on the crossover pcb are : 2 caps : 2.2 uf and 4.7 uF metallized polyester 75V One air core inductor. (forgot the value) What sorta crossover is this ?? I am asking because i want to upgrade it. I hope that this thread will get atleast one reply.

12th June 2006, 07:49 PM	#6
pwillard diyAudio Member Join Date: Feb 2006 Location: Atlanta	Quality in an Air Core inductor is harder to achieve than say... upgrading a cap. It's not like it has a voltage rating. It's not a radio frequency coil, so that doesn't come into play. With Air Core, there is no permeability of the ferrite or other core material to take into account. If it were me... I'd upgrade the caps and leave the coil alone. __________________ pw

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12th June 2006, 07:23 PM	#2
RDV diyAudio Member Join Date: Sep 2005	It's like my Sanyos, it's probably got a 1st order(just a cap) for the tweeter, and 2nd order(cap & inductor) for the woofer. RDV

12th June 2006, 07:25 PM	#3
RDV diyAudio Member Join Date: Sep 2005	The inductor is probably a .56mh if the woofer is 8 ohms. RDV

12th June 2006, 07:28 PM	#4
]\|[ GorE diyAudio Member Join Date: Jun 2004 Location: Sharjah,UAE	Any chance of upgrading it or changing it for the better ??

12th June 2006, 07:33 PM	#5
RDV diyAudio Member Join Date: Sep 2005	I'm trying to do the same thing and what they're telling me is that without measuring equipment I'm just shooting in the dark so to speak. Do they sound bad as is? RDV

12th June 2006, 08:00 PM	#7
]\|[ GorE diyAudio Member Join Date: Jun 2004 Location: Sharjah,UAE	They have oodles of detail.No problem with the bass or midrange. Its got a shiny treble.Getting rid of it by setting treble to -1 in the tone controls.

12th June 2006, 09:01 PM	#9
]\|[ GorE diyAudio Member Join Date: Jun 2004 Location: Sharjah,UAE	What do you mean by change of impedance. Isnt that what the R1,R2 of L-padding are supposed to do ?

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