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crossover advice

M

mart43

Member
Hi,

Just finishing off the boxes of my first speaker project. I am using jx150 and jxr6 drivers in a sealed 50L cabinet.

My question involves the the wiring of the 2nd order crossover i will be using.

Due to the size of the components and for conveniece the x over will sit on a draw that can slide into an integrated stand. Only the bass inductor will be inside the speaker.

What is the best way to join the wiring and components to the binding posts?

I thought to run everything to and from the posts themselves, directly soldering everything together at the respective post.

Or should i use a common ground wire and connect everthing at a point away from the - ve post.

I hope that all makes sense and thanks in advance.
 
It won't make much (any?) difference to the sound, so whatever you find easiest to wire up, as long as you get the overall circuit right.

I would be tempted to build a wooden box that can sit vertically behind the stand, have it nice and big, with the input cables at the bottom and the output cables at the top. Have all the components in there, so they are readily accessed and you don't have anything in the box at all. Seems neater to me. You can then paint/finish it to match the stand.
 
If you try to solder lots of wires to binding posts with Lead-free modern solder you might find your soldering iron just cannot give enough heat for a quick joint. If it takes 1 min of heating then plastic stuff melts and everything is a real headache.
 
Thanks for your replies,

I thought about a seperate enclosure for the x over but given the size of the speakers already i think my better half may have somthing to say on the matter.

The stands are fully enclosed, 5 inches high and made from the same wood as the speakers. They will be fixed permanently to the speakers and finish things off rather well. So quite happy there.

I will bare in mind the heat required to solder everything. Good point.
 
What about a piece of hardboard that fits horizontally into the back of the stands, like the tray in an oven? The components of the crossover can be fixed (cable ties?) to the hardboard. The wires from the speakers can come down through the bottom of the speakers, with enough play (3-4 inches?) so you can slide the tray out enough to tinker with it. And if you fix a vertical piece of hardboard or thin MDF along the rear of the tray you can put the binding posts there.
When its IN it is invisible, but when you want to try different components it will slide out and allow you to solder from the top or from the bottom.
 
Hi, yes, thats exactly what i've done.

My problem was with the actual wiring of the crossover and where to join it all.
Is it best to -

1. Run everything to and from the posts themselves, directly soldering everything together at the respective post.

Or

2.Use a common ground wire and connect everthing at a point away from the - ve post.

Thanks
 
I suggest a better option. Connect drivers to a four-pole Neutrik Speakon terminal. Then run a cable to your external XO that is connect to your input terminals.

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Yes, that's even better, James. I'm always extremely impressed by the quality, rationality and beauty of your work.
 
Very impressed, unfortunatly I have gone to far with my original idea. And to be honest it looks fine to me.

Can i take it then, that as long as all the crossover components make the correct circuit it doesn't matter where you make the connections?
 
mart43 said:
Very impressed, unfortunatly I have gone to far with my original idea. And to be honest it looks fine to me.

Can i take it then, that as long as all the crossover components make the correct circuit it doesn't matter where you make the connections?
Click to expand...

It is best to use a "star earth" arrangement for all the parts going to the - terminal and to follow the same idea for the + also. This will avoid any large currents driving the bass driver from causing a signal voltage to appear across the tweeter..... well any more so than would be due to the speaker cable resistance.... unless you want to go for bi-wiring...
 
If its of any interest, for my last 3 speakers I've used small separate plastic boards for the tweeter and woofer. This, I've found, makes it more manageable to work on one or the other, but above all prevents me getting confused as to which component is which.
Then the positive and negative inputs from each board are soldered in pairs to the + and - binding posts. It would also make it easire, in the future, to add another couple of binding posts for bi-wiring.
 
Thanks everyone for your help and advice. I am very much a novice at this.

With regards the 'star grounding' mentioned,

Am I wrong in thinking that soldering all connections at the posts achieves this?
 
I don't know if this can be considered "star grounding" but in any case I don't see the point. Assuming you have the various crossover components on some kind of board or PCB, you would have several wires trailing (unnecessarily) from the board to the Ground post. Why not simply join them together on the crossover board itself?
In general, the shorter and the simpler wiring is, the better.
Ah, and remember that the tweeter is often connected in "counter-phase" to the woofer to smooth out a volume peak at the crossover point. But this depends on the type of crossover, the speakers, etc. You could try it both ways.
 
mart43 said:
With regards the 'star grounding' mentioned,

Am I wrong in thinking that soldering all connections at the posts achieves this?
Click to expand...
This is precisely what I have done. You will see the brown and orange wires (from the drivers) are connected to the same point as all the XO components shunted to ground, which is then connected to the input ground via the grey wire.

3769832-md.jpg
 
Im only trying to learn about this stuff as well so I’m no expert but I will offer my Views on your question
Think you would only need to think about star grounding if you used a series cross over where the 2 or more drivers are in a combined circuit Xover if you separate the xover for say the woofer and the tweeter producing 2 parallel xovers with 4 terminal posts then there is only one wire needed from each terminal post and its best to hard wire each component together, you can fit bridge links to join them together at the back of the speaker which would act as a star ground between the 2 Xovers, or you can bi wire to them which would make the star ground back at the amp. http://www.jantzen-audio.com/html/Crossover Network.html#
Note how the xover here it built on ply wood with each component glued down and tag board is used to help with hard wiring everything together.
Note trolls warning that coils should wherever possible be placed at 90 deg to each other so you have to be careful about placement of caps and inductors or they can interact with each other. see this experiment by Trolls http://www.troelsgravesen.dk/coils.htm

Alan
 
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