Capacitors and Inductors for passive filters

dgoodhue · Post by **dgoodhue** » Mon Apr 16, 2007 8:24 am

What type of capacitors and inductors would you use for passive filters. I assume axial lead, but I am not sure about what type. (I am making an order from digikey for my input caps.)

Also if I want to use resistor to attentuate a speaker, what type would you use? Obviously I would need some to handle power dissapated.

Post by **VW337** » Mon Apr 16, 2007 8:45 am

Well a Mylar type cap is going to be the best for an audio application without going nuts on price. (Wima brand)

Aircore inductors are the best musically however they have their downside and that is they are far larger than a comparable Iron core inductor to accomplish the same thing.

As for a resistor, well a good tombstone or sandstone type will work.

I can't really give you brand names as to what is best, but if you can figure most people making these specific types of components are well within quality ranges.

1moreamp · Post by **1moreamp** » Mon Apr 16, 2007 8:51 am

You can find a good selection of FILM type capacitors on E-bay or all places.

Resistors should be NON inductive or wire wound type, I like air core inductors.
Flat ribbon inductors are over the top expensive, but nice. I believe you can Goggle the net for crossover design and come up with some really good ideas and sources.

Best of luck on the project. C

eyesofra · Post by **eyesofra** » Mon Apr 16, 2007 9:42 am

i used ansar super sound PPE type film caps and kiwame carbonized silicone resistors for my home stereo loudpseakers...

they were a pair of aging mission flooerstanders, and these simple mod just brought it back to life.
They are a little costly and the caps are larger then the regular metalized PPE caps but they sing....

If not mistaken ProAc uses these caps in their premium loudspeakers.

just google for them.

dgoodhue · Post by **dgoodhue** » Mon Apr 16, 2007 10:13 am

I coming to realization that it would be just easier to buy an external crossover for my M25...

Post by **Bfowler** » Mon Apr 16, 2007 10:21 am

dgoodhue wrote:I coming to realization that it would be just easier to buy an external crossover for my M25...

http://phoenixphorum.com/phoenix-gold-m ... t1378.html

dgoodhue · Post by **dgoodhue** » Mon Apr 16, 2007 10:39 am

Bfowler wrote:
dgoodhue wrote:I coming to realization that it would be just easier to buy an external crossover for my M25...
http://phoenixphorum.com/phoenix-gold-m ... t1378.html

Advice taken

Post by **Bfowler** » Mon Apr 16, 2007 10:44 am

45 is an awesome price for the amount of sanity those will save you over designing one!

Post by **bdubs767** » Mon Apr 16, 2007 11:49 am

for passive xover I've been told by many places and different people who i consider very knowledgable that the difference between say the high end cap and a poly grade cap will simply never be heard.

Post by **VW337** » Mon Apr 16, 2007 1:53 pm

There is a subtle difference, but you are correct most ears will not hear it.

eyesofra · Post by **eyesofra** » Mon Apr 16, 2007 9:41 pm

especially in a car .... i have now come to believe that proper driver placing makes tonnes of difference compared to upgrading the xovers with audiophile components....

GaryJ · Post by **GaryJ** » Sun Jun 29, 2008 8:52 am

Rather than start a new thread, I figured I could just add to this one.

I have a set of Quart speakers and I would like to take a little of the edge off of the tweeters. They are an older coax pair and have a crossover, but its not adjustable in any way. Is there an easy way to make my own tweeter level control using resistors or something else? How do adjustable crossovers do that job? Obviously another amp would be an ideal solution, but not practical for me for cost and space reasons. Keep in mind that I am pretty much a know-nothing when it comes to electronics and the design of such things.

I searched here and on google and found some limited info at partsexpress.com and read elsewhere about l-pads, etc. but I haven't really gotten a good explanation of how this can be done easily or cheaply. Someone here mentioned running them out of phase, which may be a good thing to try and another person mentioned covering the tweeter with some kind of cloth or something. I just figured an electronic solution would be best. Can anyone help?

dgoodhue · Post by **dgoodhue** » Mon Jun 30, 2008 5:12 am

Resistor would take knock down some of the power to your tweeter. I imagine 1 Ohm or 2 Ohm would ve all you need, but I have no real world experience playing with them in an audio enviorment.

Post by **stipud** » Mon Jun 30, 2008 8:58 am

dgoodhue wrote:Resistor would take knock down some of the power to your tweeter. I imagine 1 Ohm or 2 Ohm would ve all you need, but I have no real world experience playing with them in an audio enviorment.

I've always wondered if that would affect the crossover frequency or not. I know when you vary the driver impedance, you change the crossover frequency... so I thought if you added a resistor, it would change as well.

I know PG made the LPAD, which was basically a big ceramic variable resistor, that you could use to attenuate certain speakers. I don't recall if that worked on just tweeters or if you had to use it before the crossover to attenuate the whole set.

GaryJ · Post by **GaryJ** » Tue Jul 01, 2008 8:54 pm

OK, I have answered my own question having thought of some better search terms for google. Better yet, I found something to help anyone trying to do the same thing. This page has a calculator that tells you how to basically make your own l-pad. 2 resistors is all it takes- it even tells you what to use.

http://www.webervst.com/lpad.htm