Crossover placement and bi-wiring?

focal7C

Member
2008-01-22 2:43 am
What are the advantages/disadvantages of placing the external crossovers near the amplifier?

I will be running four pairs of cables direct to the elements (tweeter and woofer) of a pair of 2-way speakers. I.e there will probably not be any binding posts on the speakers.

If placed near the amp I assume the setup may have the same benefits as bi-wiring from the amp to a bi-wire capable cross-over near/inside the speaker?

The alternatives for closer to the element placement are to:
1. Place the crossovers on the floor under the tower speaker cabinets. OR
2. Glued/dampened inside the bottom hollow of the speaker.
 

BlueWizard

Member
2007-06-29 8:49 pm
One of the draw back to external crossovers is that some idiot will try and hook them up without the crossovers and with disastrous results. I'm not saying your an idiot, certainly not. But I will say the only time in many years of high volume partying that I ever blew a speaker is when I let one of my idiot friend touch the volume control. You can't always be there to protect your equipment from the idiots of the world.

Also, you have an exceptionally long run of wire with the passive crossovers at the amp. Though, external crossovers might be handy for testing and modifying the crossovers until you get them right.

In the bad old days, crossovers were simply screwed into the back of the cabinet some place, and not always placed with wisdom. You need to keep the crossovers away from magnets and magnetic fields to prevent interference. Today, people feel it is best to isolate the crossovers from vibration too. So, they will typically build a small cabinet within a cabinet to house the crossovers. The crossovers are sometime places in a false bottom accessible from the outside of the cabinet, or in a small chamber in the bottom of the cabinet. Or in a small enclosed chamber on the back of the cabinet away from heavy magnets.

I think it would be better, just from an practical point of view, if you intend to place the crossovers outside the cabinet, that you place them in a box close to the cabinet using standard connections between the amp and the crossover, and non-standard connections between the crossover and the speakers. That way, no one can connect an amp directly to the speakers.

That probably wasn't much help but... there it is.

Steve/bluewizard
 
Steve is right to a point. The inductors should not be any closer than about 3 inches from a ceramic/ferrous type magnet just to avoid the possibility of an interaction between them. Other magnet types don't seem to be affected.

The layout of the XO is more important than the placement. ie: the inductors should be placed at right angles to one another rather than just flat stacked beside each other. But again, this is not at the top of the list and only really applies to coils right next to one another.

I've never made any sense of the bi-wiring aspect. I've not ever seen (graphs) or heard a difference. Besides, the speaker itself, the placement in and treatment of the room along with the source are going to have a much greater effect than any bi-wiring ever could.

It's all about getting your house of cards in order. Do the important things right and tinker to your hearts content after.
 

BlueWizard

Member
2007-06-29 8:49 pm
Well, no point in arguing with Cal, he knows his stuff.

But I thought there might be some confusion with placing what are essentially circles are right angles to each other.

What Cal means by that is, if your coils are close to each other, you should lay one down flat like a tire laying on the ground, and place the other one upright like a tire mounted to a car; one on it's side, and the other on it's edge.

I have seen speaker systems that use external passive crossovers, so it's not that uncommon, you just have to go about it with a common sense approach. And, I think the first level of the common sense approach is to ask yourself whether the passive crossovers are part of the Speaker System, or whether they are part of the Amp System. Then whatever you decide, place them close to that answer.

Steve/bluewizard