Is this a crossover board?

mtoc

Banned
2015-12-28 4:57 pm
Hi guys, what's this board? (click the pics for better pixel.)

sx_main_pcb.jpg

The board shows in this setup (a setup installed in the powered speaker), those other four boards are all icepower class d power amps.

adam_s5xv_amplifier.jpg
 
Linkwitz Riley is just one of many types of active crossover. Although the 4th order is by far the one that is used most frequently, there is theoretically no restriction when it comes to filter order apart form the fact that they can only be done in even number orders. But you may run into problems of component accuracy when it comes to analog implementations of high orders.

But the crossover type has nothing to do with my remark regading the quality of the capacitors used. Usually, SMD caps can't be had as high quality foil caps.

Regarding a pre-made crossover board: You can't just use a given board like that and use your favourite set of drivers, because the properties of the drivers have to be considered as well for the crossover design.

I can't remember who, but some British member of this forum once made a PCB layout for an active crossover that includes some EQ sections as well to make it more flexible.

Regards

Charles
 
Linkwitz Riley is just one of many types of active crossover. Although the 4th order is by far the one that is used most frequently, there is theoretically no restriction when it comes to filter order apart form the fact that they can only be done in even number orders. But you may run into problems of component accuracy when it comes to analog implementations of high orders.

But the crossover type has nothing to do with my remark regading the quality of the capacitors used. Usually, SMD caps can't be had as high quality foil caps.

Regarding a pre-made crossover board: You can't just use a given board like that and use your favourite set of drivers, because the properties of the drivers have to be considered as well for the crossover design.

I can't remember who, but some British member of this forum once made a PCB layout for an active crossover that includes some EQ sections as well to make it more flexible.

Regards

Charles
Are you sure? I built this 30 years ago (I still have it, updated), and he says you can make it 3rd order. Although I have never done so.
http://www.saturn-sound.com/images ...e crossover - hi-fi news - march 1981 - 5.jpg
 
A Linkwitz-Riley crossover is a special case of an in-phase crossover. These are derived by subtracting the output of either a highpass or a lowpass of order 2*N from the output of an allpass of the order N. In the case, where the allpass has Butterworth characteristic and the other branch is consisting of two equal Butterworth secions with the same pole frequency(ies) as the allpass we arrive at a Linkwitz-Riley crossover.
Since there is no allpass of order 1.5 there is no real LR3. But maybe there are approximations around.
I don't know what 3rd order characteristic Ben Duncan intended to use for this project. I guess most probably Butterworth.
There are other 3rd order crossovers possible than just Butterworth. Some of them have interesting properties like low group-delay distortion but their use does often only make sense for very special topologies (like direct radiator woofer combined with horn tweeter).

Regards

Charles
 

mtoc

Banned
2015-12-28 4:57 pm
Usually, SMD caps can't be had as high quality foil caps.

Hello, you've mentioned several times about caps, did you mean the crappy caps on the Icepower amp on the right side of the second picture? Didn't see any caps in the first pic which is the crossover board itself... (oh sorry, that xos board indeed has some little caps, they look no good, somebody has to replace them with some decent ones.)
 
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