Hello Everyone,
I’m about to embark on my first speaker project and needed some help with the placement of crossover components.
Most commercial and DIY speakers have all the crossover components on a board fixed right behind the binding posts; but there are also small number of speakers (eg. Epos ES14) have very simple components (usually just caps and resistors) fixed right behind the drivers.
There are some discussions about keeping a decent distance (~15cm) between the inductor and the nearest driver, not I’ve not read anything about the “safe distance” for capacitors and resistors, nor if there should be a recommended “maximum distance” between the inductor and capacitors / resistors.
As I have quite limited space behind the binding posts where it is the furthest point from the Drivers, I’m just thinking if it is wrong mechanically / electronically / sonically if I place only the inductor behind the binding posts while the capacitors and resistors right behind the driver?
Many thanks.
I’m about to embark on my first speaker project and needed some help with the placement of crossover components.
Most commercial and DIY speakers have all the crossover components on a board fixed right behind the binding posts; but there are also small number of speakers (eg. Epos ES14) have very simple components (usually just caps and resistors) fixed right behind the drivers.
There are some discussions about keeping a decent distance (~15cm) between the inductor and the nearest driver, not I’ve not read anything about the “safe distance” for capacitors and resistors, nor if there should be a recommended “maximum distance” between the inductor and capacitors / resistors.
As I have quite limited space behind the binding posts where it is the furthest point from the Drivers, I’m just thinking if it is wrong mechanically / electronically / sonically if I place only the inductor behind the binding posts while the capacitors and resistors right behind the driver?
Many thanks.
This recommendation probably has to do with magnetic field of the inductor and the driver voice coils interacting with each other, whereas the magnetic coupling to the capacitor or resistor may not be as severe (although one would thing there will be some coupling to the capacitor and resistors).
If you have room inside the cabinet, then it's probably not a bad idea to place all the xover components as far away from the driver (woofer, tweeter...) as much as possible and run a wire a bit longer from the xover to the driver. If you're using some decent wires, the IR drop and phase change in the wire won't be as much of a problem since I would think the distance inside the cabinet is very short. Some high end speakers actually have the xover a separate box outside of the speakers.
On a side note but related, please use some decent cables as they do make quite a bit of a difference. I personally use Supra wire from Madisound, and they sound nigh and day compared to some cheap wires I got from Fry's Electronics.
Hi Allen,
For inductor, I'm looking at the Mundorf ribbon ones.
Hi Andy,
Yes, I've been reading up quite a bit on the internal cables and so far I have either Cardas Chassis, or the Neotech solid core OCC.
Thank you both
When I re-do a crossover, I generally build a point to point board that mounts either on the back or bottom of the cabinet.
My layout is generally determined by the minimum number of wires crossing each other and the larger inductors are kept on separate planes... some vertical, some horizontal, even some north-south and east-west when necessary. I don't tend to worry too much about interaction between parts, other than the inductors; while I'm sure there is some it is so trivial as to not really matter.
For internal wiring, 16ga copper is just fine in most cases. Even on tall towers this will ad only tiny fractions of an ohm to the overall wire loss. Certainly it's easy to route and easy to solder. I always solder all my connections.
Whenever possible try to think about serviceability... What happens if you need to adjust or fix your crossover? Do you have to tear the whole speaker down to get at it? Can you take parts out and put parts in conveniently? ... In a few cases this has lead me to mount the crossover outside the speaker cabinet, on the back, in it's own plastic enclosure.
But, as I advise most people... don't get lost in the minutia and hair splitting that is so common in this hobby ... stay with sound, common sense design principles and you'll do just fine.
My layout is generally determined by the minimum number of wires crossing each other and the larger inductors are kept on separate planes... some vertical, some horizontal, even some north-south and east-west when necessary. I don't tend to worry too much about interaction between parts, other than the inductors; while I'm sure there is some it is so trivial as to not really matter.
For internal wiring, 16ga copper is just fine in most cases. Even on tall towers this will ad only tiny fractions of an ohm to the overall wire loss. Certainly it's easy to route and easy to solder. I always solder all my connections.
Whenever possible try to think about serviceability... What happens if you need to adjust or fix your crossover? Do you have to tear the whole speaker down to get at it? Can you take parts out and put parts in conveniently? ... In a few cases this has lead me to mount the crossover outside the speaker cabinet, on the back, in it's own plastic enclosure.
But, as I advise most people... don't get lost in the minutia and hair splitting that is so common in this hobby ... stay with sound, common sense design principles and you'll do just fine.
No. A crossover is not very sensitive to placement in the way some other electronics is.
Although I agree that among all the things that affect the sound, xover component placement is probably close to last on the list, but if you want to optimize to the nth degree then I suppose it makes sense to be careful on the xover layout. And as I said, if possible, place the xover board as far away from the drivers as practical given the confine of the cabinet.
Thanks Andy, what I just said may have been ambiguous. I was thinking in terms of instability, loop areas, EMI. These tend to be active, and/or higher impedance type issues.
With regard to the coil interacting with the driver I would speculate on the driver back plate conditionally increasing the inductance. Your (andy2) idea would be worth testing, maybe run a signal through the inductor and look for it on the voice coil, and vice versa under the right conditions. I otherwise suspect the fixed field of the magnet would have no effect on the inductor.
With regard to the coil interacting with the driver I would speculate on the driver back plate conditionally increasing the inductance. Your (andy2) idea would be worth testing, maybe run a signal through the inductor and look for it on the voice coil, and vice versa under the right conditions. I otherwise suspect the fixed field of the magnet would have no effect on the inductor.
I guess this should not be too difficult to perform if one has a signal generator and an oscilloscope. The signal generator would generate sinewave signal to run through the inductor, then using the oscilloscope to measure the induced noise on the driver voice coil.
Yes, the fix field of the magnet should not affect the inductor, but the varying current on the driver voice coil can still generate a magnetic field that can affect the inductor.
I agree. I also implied vice-versa, because I'd want to know the nature of the influence. The first challenge then, would be creating functional impedance conditions for the tested elements, and factoring in the specific interactions that a particular coil in a crossover would produce.
First thoughts, maybe wire a sample crossover. Put the inductor on the pole plate and connect the crossover to the driving amp. Run the crossover into a dummy load and measure the open voice coil.
Then, swap the amp to drive the voice coil, short the input to the crossover and measure across the dummy load.
IF there is any significant interaction it will be because of INDUCTION ... just like in a transformer. One coil induces current into another coil close by.
Fortunately that is a very short range effect, usually measured in fractions of an inch.
I wish I could still have access to the lab of my previous job. It should be a pretty quick setup to make a measurement like this.
I just did it on my side table... A small amp playing music through a 2mh coil, place coil on back of speaker ... silence. Check the voltage on the voice coil... less than 2mv.
Big expensive lab setup not needed.