A coil is basically a wound up antenna. It’s the length of wire in the coil that determines it’s resonant frequency. When ever you have two coils that are in perfect ratio to each other in length, such as 1:1/4 you will have coupling of the coils and they will resonate with each other. So if your goal is to minimize their coupling capacity, then you want to make sure the length of each coil wire is not in a perfect ratio length relationship and you want to keep them outside of their magnetic field area, which is largely voltage dependent - the higher the voltage, the larger the field strength. The best way to test this is with a magnometer. You don’t want overlapping magnetic fields between coils.
Hello Gabster. What about internal vs external crossover network as some very high end speakers have? Is there any measureable negative microphonic effect with crossover networks mounted inside the speaker enclosure?
Thank you, this is Very informative. i was wondering if any shielding between the two coils would be of any benefit. like a piece of metal placed between them would prevent any cross talk
I did not try to be honest but it is rarely done spacing and orientation is the way to go. The influence of conductive metals being placed in close proximity to an inductor can have detrimental effects on their performance and could affect their inductance. One thing I would do if you have a lot of space and don't mind 3 separate boards is to separate the Woofer, Mid, and tweeter circuits.
I would imagine inductors with a metal or ferrite core would be even more sensitive to distance but possibly more directional. Another reason to use an electronic crossover maybe?
Hi! Exceptionally interesting and useful! I wonder , do you conduct these test only with pairs of inductors, and swap signal genrator back and forth tileach mutual pair is problem free, or do you later on interconnect all inductors except one to get "the system situation" ?
Thank you I conduct these test with pairs of inductors, and swap signal generator back and forth til I cover all possible permutations. If you have the space best is to also separate Woofer Mid and high on separate boards if they can be a foot apart that will make it easier to have them all get along with no interference.
@@Gabster1 OK, thank for info! I am planning to make external crossover boards to my XO-wise upgraded Wharfedale Lintons, and will most likely use your method when deciding on the layout of that. So far only resistors and caps have been upgraded, but inductors left alone. Is your experience that inductor upgrades may have benefits in same magnitude as say capacitors? If , yes, any rules of thumb how to choose wire diameter and coil diameter of air core inductors? BR Magnus
@@vespass225 I'd like to know inductors gauge size.i have read on a diy forum that 14awg is decent gauge! he did comparison against foil and a group of diyers choice the 14 awg wire
@@markclancy5371 Hi Mark. I could try to measure gauge sizes next time I open up my Lintons. I have noticed so far, that the different inductors, for tweeter, midrange and woofer, have different gauge sizes, with heavier gauges for lower register.
Thank you Start with something simple and work your way up I will post how to build simple yet effective streamer/Dac in the future when I get some time
Hello @Gabster love this video watch it like 10 x . I'm building a crossover and I'm stuck on how to place the third inductor.. It ask for three inductors. Now how would I place them so they will not interfere. I have a 1.3 inductor, a 0.2 inductor, and a 0.8 inductor. Now I know that the 0.2, and the 1.3 are the bigger ones I know I will put them on the far ends. But in between how would I place the third inductor so there won't be any interference? Thanks .
3 inductors are easy as you can put them in a X, Y, Z, axis if you look at the video around 3:50 just ignore one of the laying flat ones. the more distance the better 2 to 3 inches or more are ideal. hope that helps :)
I did not try to be honest but it is rarely done spacing and orientation is the way to go. The influence of conductive metals being placed in close proximity to an inductor can have detrimental effects on their performance and could affect their inductance. One thing I would do if you have a lot of space and don't mind 3 separate boards is to separate the Woofer, Mid, and tweeter circuits.
I usually bring a piece of metal close to a inductor to increase its inductance then measure it till I get the level I need when at the testing stage to find the right inductor do that all the time it is a easy way so you don’t have to stock a large number of inductors. Imagine iron inductors they are 10 times stronger. So you want to avoid any metal close by. The closer you get the higher it goes.
I will concur that ferrous metal will interact. However, copper should not as readily interact, changing the inductance values much. Capacitance of the inductor moreso with copper shielding. I have seen capacitors, resistors, and inductors wrapped in copper foil acting as shielding. Strong fields would require grounding the shield, while weaker ones will not require it, as the shield does not get saturated.
The dielectric constant of air is 1.00059, and the dielectric constant of hot glue is about 2,3, so you should get a measurable effect on the electrical characteristics, but I doubt it will be a problem. You may perturb the electrical response slightly, but the glue is likely to suppress vibration of the coil caused by field forces.
I was struggling to find inductor orientation and this helped a lot. Thanks :)
Excellent presentation sir, God bless you. ❤
A coil is basically a wound up antenna. It’s the length of wire in the coil that determines it’s resonant frequency. When ever you have two coils that are in perfect ratio to each other in length, such as 1:1/4 you will have coupling of the coils and they will resonate with each other. So if your goal is to minimize their coupling capacity, then you want to make sure the length of each coil wire is not in a perfect ratio length relationship and you want to keep them outside of their magnetic field area, which is largely voltage dependent - the higher the voltage, the larger the field strength. The best way to test this is with a magnometer. You don’t want overlapping magnetic fields between coils.
Hello Gabster. What about internal vs external crossover network as some very high end speakers have? Is there any measureable negative microphonic effect with crossover networks mounted inside the speaker enclosure?
Thank you, this is Very informative.
i was wondering if any shielding between the two coils would be of any benefit. like a piece of metal placed between them would prevent any cross talk
I did not try to be honest but it is rarely done spacing and orientation is the way to go. The influence of conductive metals being placed in close proximity to an inductor can have detrimental effects on their performance and could affect their inductance.
One thing I would do if you have a lot of space and don't mind 3 separate boards is to separate the Woofer, Mid, and tweeter circuits.
I would imagine inductors with a metal or ferrite core would be even more sensitive to distance but possibly more directional.
Another reason to use an electronic crossover maybe?
Hi!
Exceptionally interesting and useful!
I wonder , do you conduct these test only with pairs of inductors, and swap signal genrator back and forth tileach mutual pair is problem free, or do you later on interconnect all inductors except one to get "the system situation" ?
Thank you
I conduct these test with pairs of inductors, and swap signal generator back and forth til I cover all possible permutations.
If you have the space best is to also separate Woofer Mid and high on separate boards if they can be a foot apart that will make it easier to have them all get along with no interference.
@@Gabster1 OK, thank for info! I am planning to make external crossover boards to my XO-wise upgraded Wharfedale Lintons, and will most likely use your method when deciding on the layout of that. So far only resistors and caps have been upgraded, but inductors left alone. Is your experience that inductor upgrades may have benefits in same magnitude as say capacitors? If , yes, any rules of thumb how to choose wire diameter and coil diameter of air core inductors? BR Magnus
@@vespass225 I'd like to know inductors gauge size.i have read on a diy forum that 14awg is decent gauge! he did comparison against foil and a group of diyers choice the 14 awg wire
@@markclancy5371 Hi Mark. I could try to measure gauge sizes next time I open up my Lintons. I have noticed so far, that the different inductors, for tweeter, midrange and woofer, have different gauge sizes, with heavier gauges for lower register.
Very interesting I like your videos love to do your dac but I'm not that skilled just learning diy.
Thank you
Start with something simple and work your way up I will post how to build simple yet effective streamer/Dac in the future when I get some time
Hello @Gabster love this video watch it like 10 x . I'm building a crossover and I'm stuck on how to place the third inductor.. It ask for three inductors. Now how would I place them so they will not interfere. I have a 1.3 inductor, a 0.2 inductor, and a 0.8 inductor. Now I know that the 0.2, and the 1.3 are the bigger ones I know I will put them on the far ends. But in between how would I place the third inductor so there won't be any interference? Thanks .
3 inductors are easy as you can put them in a X, Y, Z, axis if you look at the video around 3:50 just ignore one of the laying flat ones. the more distance the better 2 to 3 inches or more are ideal.
hope that helps :)
My question is the same as what The Gum has asked. What about shielding, have you tried any form whatsoever?
I did not try to be honest but it is rarely done spacing and orientation is the way to go. The influence of conductive metals being placed in close proximity to an inductor can have detrimental effects on their performance and could affect their inductance.
One thing I would do if you have a lot of space and don't mind 3 separate boards is to separate the Woofer, Mid, and tweeter circuits.
@@Gabster1 how can you say that when you haven’t tried? This is not how discoveries are made.
I usually bring a piece of metal close to a inductor to increase its inductance then measure it till I get the level I need when at the testing stage to find the right inductor do that all the time it is a easy way so you don’t have to stock a large number of inductors. Imagine iron inductors they are 10 times stronger. So you want to avoid any metal close by. The closer you get the higher it goes.
I will concur that ferrous metal will interact. However, copper should not as readily interact, changing the inductance values much. Capacitance of the inductor moreso with copper shielding. I have seen capacitors, resistors, and inductors wrapped in copper foil acting as shielding. Strong fields would require grounding the shield, while weaker ones will not require it, as the shield does not get saturated.
Do you really think the same plane is going to be enough distance from the one diagonal to it in the same plane?
Maybe a stupid question but, is there a problem if I accidentally put quite a lot of hot glue in the center of an air core inductor?
Stops an audible high frequency ringing
The dielectric constant of air is 1.00059, and the dielectric constant of hot glue is about 2,3, so you should get a measurable effect on the electrical characteristics, but I doubt it will be a problem. You may perturb the electrical response slightly, but the glue is likely to suppress vibration of the coil caused by field forces.
When you find that it takes more copper to build a crossover than an amplifier.........its time to consider DSP.