HELP! Crossover for B&W 803s/803d

harrisni · 25th August 2006, 02:19 AM

Hi,

I have been speaking to a couple of B&W dealers and they say that the 803s/803d have 3 crossovers inside the speaker box, is this true?

Crossover High
Crossover Medium
Crossover Low

(Obviously other models may have this aswell, but I am talking just about the 803 range)

How on earth do they connect together? My understanding is that the speaker cable comes in from the amplifier and hits the crossover and then is passed onto the speakers, thats with 1 single crossover, how do they connect 3? without having 3 inputs?

Is there a main crossover that pushes it to the other 3? so there is 4 in total?

noodle_snacks · 25th August 2006, 04:09 AM

harrisni, I think you definately still have a long way to go if you want to emulate the performance of the 800 series with your own designs. I would strongly you go for a kit or published design first.

What the B&W dealer ment by three crossovers is that the speaker has a three way crossover. The "Crossover High" rolls the tweeter off at the bottom end, The "Crossover Medium" rolls off the Kevlar midrange at the top end (to corrispond to the tweeters roll off) and again in the bass region. The "Crossover Low" rolls off the midrange and treble of the bass drivers.

Salas · 25th August 2006, 04:18 AM

harrisni · 25th August 2006, 04:28 AM

HI,

Thanks for the reply,

He said there are actually 3 crossover boards in the speaker box.
HI/MED/LO

noodle_snacks · 25th August 2006, 04:34 AM

the sections for the networks were simply on seperate boards then, functionality is the same

noodle_snacks · 25th August 2006, 04:34 AM

the sections for the networks were simply on seperate boards then, functionality is the same

angsuman · 25th August 2006, 05:33 PM

Yea I find seperating the boards really helps with organization and prevents mis wiring.

preiter · 25th August 2006, 10:09 PM

Are there 3 sets of inputs on the back?

They could be separated for multiple amplifiers.

tktran303 · 25th August 2006, 11:50 PM

Hi Nick,

Some fundamental knowledge is required before you build loudspeakers. If you are interested in speakerbuilding, I strongly recommend you pickup a book like Vance Dickason's LoudSpeaker Design Cookbook, or Speakerbuilding 201 and learn some basic speaker terminology and the basics of electrical circuit theory.

As noodle snacks alluded to, the 3-way crossover are connected in parallel. That means that internally, the single input wire is split into 3, and run into each of high, bandpass and low pass filters. Whether the layout of these filters are implemented as 1, 2 or 3 physical boards is entirely up to the designer, and electrically, makes no difference.

regards,
Thanh.

bambadoo · 26th August 2006, 04:50 PM

Not sure about this, but here is a picture of the crossover for the B&W 802D

25th August 2006, 02:19 AM	#1
harrisni diyAudio Member Join Date: Aug 2006	HELP! Crossover for B&W 803s/803d Hi, I have been speaking to a couple of B&W dealers and they say that the 803s/803d have 3 crossovers inside the speaker box, is this true? Crossover High Crossover Medium Crossover Low (Obviously other models may have this aswell, but I am talking just about the 803 range) How on earth do they connect together? My understanding is that the speaker cable comes in from the amplifier and hits the crossover and then is passed onto the speakers, thats with 1 single crossover, how do they connect 3? without having 3 inputs? Is there a main crossover that pushes it to the other 3? so there is 4 in total?

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25th August 2006, 04:09 AM	#2
noodle_snacks diyAudio Member Join Date: Mar 2004 Location: Hobart, Tasmania	harrisni, I think you definately still have a long way to go if you want to emulate the performance of the 800 series with your own designs. I would strongly you go for a kit or published design first. What the B&W dealer ment by three crossovers is that the speaker has a three way crossover. The "Crossover High" rolls the tweeter off at the bottom end, The "Crossover Medium" rolls off the Kevlar midrange at the top end (to corrispond to the tweeters roll off) and again in the bass region. The "Crossover Low" rolls off the midrange and treble of the bass drivers.

25th August 2006, 04:18 AM	#3
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece

25th August 2006, 04:28 AM	#4
harrisni diyAudio Member Join Date: Aug 2006	HI, Thanks for the reply, He said there are actually 3 crossover boards in the speaker box. HI/MED/LO

25th August 2006, 04:34 AM	#5
noodle_snacks diyAudio Member Join Date: Mar 2004 Location: Hobart, Tasmania	the sections for the networks were simply on seperate boards then, functionality is the same

25th August 2006, 05:33 PM	#7
angsuman diyAudio Member Join Date: Mar 2005 Location: Las Vegas NV	Yea I find seperating the boards really helps with organization and prevents mis wiring.

25th August 2006, 10:09 PM	#8
preiter diyAudio Member Join Date: May 2006	Are there 3 sets of inputs on the back? They could be separated for multiple amplifiers.

25th August 2006, 11:50 PM	#9
tktran303 diyAudio Member Join Date: Dec 2005 Location: Perth, WA	Hi Nick, Some fundamental knowledge is required before you build loudspeakers. If you are interested in speakerbuilding, I strongly recommend you pickup a book like Vance Dickason's LoudSpeaker Design Cookbook, or Speakerbuilding 201 and learn some basic speaker terminology and the basics of electrical circuit theory. As noodle snacks alluded to, the 3-way crossover are connected in parallel. That means that internally, the single input wire is split into 3, and run into each of high, bandpass and low pass filters. Whether the layout of these filters are implemented as 1, 2 or 3 physical boards is entirely up to the designer, and electrically, makes no difference. regards, Thanh.

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