posted
I am building a 3rd order crossover and the design requires a .19 mh inductor paralleled with the speaker. This is a HP xover for an 8 ohm tweet @ 5khz. The closest I can get is .2 so I was gonna series a .15 and a .25 and then pallel two sets of those but that is such a waste!
Can I connect the terminal that is supposed to go to the inductors from each of the tweeter crossovers and then use a .4 mh inductor instead of having to do all that to get .2?
this means I would need 8 inductors for just two HP xovers (both tweeters are on the same channel) but right now I must do it with 8 inductors since i have no other values.
Will this work okay?
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Posts: 138 | From: London Ontario Canada | Registered: Feb 2000
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posted
I personally don’t recommend a 3rd order filter. The q necessary for those is higher than your going be able to get with the parts it will require. You’ll never get a good butterworth roll off. Even a second order (which requires a lower q) would be difficult to get a decent response. Smaller parts are much closer to their specs and can produce a much higher q filter. At one point I figured out how high of order a crossover (active not passive) could be built using the smallest and highest quality parts, and if I remember correctly after 3rd order it was useless because the filter wouldn’t work good enough. For a passive I would never go over two. I never figured out what kind of q you could get with a passive though. So to answer your question I would just use the .2mh if you must use a passive crossover. The tolerance on those is probably like 10-20% if they’re good. Same with the caps. If you want to try to be perfect just unwind some of the windings on the 0.2mh ind. that will lower the .20mh to .19 if you unwind the correct amount.
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Posts: 1259 | From: Fullerton. CA ,USA | Registered: Oct 1999
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posted
umm no offense dude but ya totally overshot my question.
My questions was is I havn't got a problem using a .2 mh inductor, but with the parts I have I have to use 8 inductors total to acheive that value. But, if I combine the lead going to negative from both of the crossovers for the tweets, then I might only need 2 parts to acheive .4 mh, but I wasn't sure if u could do this or not.
I realise the advantages and disadvantagse of 3rd order crossovers and chose to build one anyway.
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Posts: 138 | From: London Ontario Canada | Registered: Feb 2000
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8 inductors for a single pair of circuits is WAY overkill.. Accept a small margin of error in your crossover and handmatch the parts as CLOSE to .19 as possible.. If thats off by .01, remember, that is only a 5% tolerance, which isn't bad at ALL. Either way, if you are using quality parts, that .01mh difference won't bother you THAT much :-)
If you're a stickler or purist on your crossover, see if you can coerce madisound into getting you some handwound .19mh inductors!
ShadowStar
------------------ Computers are a lot like air conditioners.. Open Windows and they become useless..
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Posts: 2578 | From: Somewhere In the Northeast | Registered: May 1999
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posted
Duke- there are two tweets per channel, so they would be both runnhing the exact same signal. Would it still work or should i just go find some .2 mh inductors?
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Posts: 138 | From: London Ontario Canada | Registered: Feb 2000
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posted
Either run the tweets in parrallel and design a 2 ohm xover or keep them totally separate. I'm surprised Madisound does not offer a .19, Solen does. All in all, using a .20 is not the end of the world. It would change the xover characteristics very little.
Again, who the heck is DUKE???
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And that's the bottom line, cuz: LORD DUKK SAYS SO!
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posted
Totally with Dukk on this... and SS... keep your x-over design simple. If the coil you buy is too big, get a hold of an inductance meter and remove a couple of wraps of wire until you get it where you want it. Or, you could wind your own coils...
------------------ STILL waiting to hear a GOOD pair of HLCD's!!
If it dont fit, force it... if it breaks, it needed to be replaced anyway...
posted
I agree with all of yas. I don't care about the .1 mh difference. It was just a quicky because I have several inductors but nothing close to what i need... closest i have is .15 and .25 ON HAND...
So I decided to whip on here and ask if i could add the two tweeter routes together and slap a .4 mh inductor on there which would be just a .15 and a .25 in series, easy stuff.
I don't wanna screw around with the impediance because the other two parts have been wired and placed on the board. I will just order a .19mh inductor for each.
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Posts: 138 | From: London Ontario Canada | Registered: Feb 2000
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