external crossovers

[VantheMan]

Hi,
I will be attempting to make some very simple crossovers for a single coaxial Seas driver design now that I have "finished" the boxes themselves. Having read, without understanding much, the virtues of external crossovers I have decided to go for this option and was wondering if anyone could make useful mechanical suggestions to enable me, a veritable chimpanzee in terms of soldering skills and comprehension of things electronic, to make a reasonable job. I believe a wooden or plastic box is required and that the components can de glued to and then hard-wired on a piece of wood ? Any tips ? Should I hard wire the speaker cable to the crossover and thence to the driver - if so, how might the cable be "anchored" or is it better to use sockets and bananas. etc. etc. Would be very grateful for any tips that anyone might suggest.
Thanks,
Chris

[Ianm2]

a reasonable tip is to lay the xover out on the board as it is drawn out on paper.

check out " solen" website for more info on that, xover section

[pre65]

Hi Chris-when i built my Adires i made the crossovers external in a "really useful box" from Martins.

I followed the Adire instructions and built them on a piece of thin ply,with the components held in place with thin cable ties and all the soldering underneath.

I covered one piece of ply with white fablon and made all the marking out on that.After drilling all the holes i peeled the fablon off and restuck it on piece 2 as a template.

Philip

[john & Jake the dog]

Hi Van,
Best to use plugs and sockets at least to start with any way, it is less permanent.
It gets to be a bit of a pain unsoldering speaker cable if you need to.
If you assemble the parts onto multi holed board from Maplins etc(veroboard I think) then you can hard wire on the reverse.
This can then be screwed into the case and hard wired to the sockets.
cheers

[VantheMan]

Cheers all, it´s all coming together now (in my head, at least, which presumably is a good place to start).
Thanks.

[A Stuart]

As a very first step, lay out card cut-outs drawn & cut to the size of each component. As a veritable chimpanzee you need not even put down your banana while soldering with your feet .
As Ian suggested, start with them arranged as per circuit diagram, although they need not end up remotely resembling this, as long as the correct bits remain wired to each other.

My understanding of the benefits of an external crossover is that removal of the crossover from vibration inside the cabinet prevents mechanical vibration being converted (loosely speaking, like as microphone) into electrical changes in time with the vibration.
It also allows ready access if you wish to alter components.
I am sure I have also read, though I am not at all convinced I could hear any change from bi-wiring, that if you place the crossover near the amp, rather than the speakers, then it stops the currents supplying each of the drivers from interfering with each other while passing along a long speaker cable.

As for how to physically fix the cable, make sure it is robust and as near fail-safe as you can devise. You or someone else is bound to trip over the cable sooner or later or drop a screwdriver into it, and a short-circuit could destroy some amplifiers.
Alastair.

[john & Jake the dog]

Hi van,
as regards plugs and sockets.
The best and most convenient are the professional ones used by Linn amongst others. XLR three pin sockets and three hole plugs, only a couple of quid each.

bw91y.jpg

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cheers

[Scottmoose]

I suspect the difference would be slight, unless the box pressures / resonances are high but YMMV as ever. Just so long as the box is non-magnetic you should be OK & it does allow you to optimise the cable-runs for the LF & HF (whatever that means as there's little likelihood of there ever being any agreement on the subject of wire). A couple of attractive cigar boxes would be ideal IMO.

If you do decide to go down the external XO route, I'd hard-wire to the driver. Connections probably cause more problems and losses than any speaker-cable has ever done. Apart from a high-capacitance Goertz in a Naim or NVA setup of course...

[Greg.]

Hi Chris,

This is what I did on a three way system.


Here is the bass filter.


Here is the combined mid range and treble filters.


I hope that helps. Happy to answer questions thereafter. Be assured that applying this option will bring a megga improvement to your sound, per se.

Best wishes,

Greg

[VantheMan]

Cheers Greg,
Couldn´t be clearer. Will post pictures when I finish them.
Chris