View Full Version : Which crossover parts to begin with passives?
07-14-2006, 06:42 PM
The last two speaker projects I've built have been active, and the only other one I've built I copied a design. With that, I've never designed a passive speaker on my own, but really, really want to. I've messed with Speaker Workshop just a little bit, and like many newbies to it, it's confusing as heck. I was considering purchasing Soundeasy at the Tent Sale and fiddling with that, if you guys think it's worth my time?
Also, to begin creating passive speakers I'd like to have a repository of passive components to test with. What would you guys recommend I do to get a bunch of components that I can fiddle with? Purchase a couple hundred dollars worth at the Tent Sale? If so, should I stick with some of the lower values so I can run them in parallel to achieve my desired values? Then, if I like my outcome purchase the correct valued component?
Any info is greatly appreciated!
07-14-2006, 06:50 PM
There's good news and bad news. For caps and resistors, buy pairs of a range of values, using NPE caps and PE's ultra-cheap 19 cent 5 watt resistors. The bad news is inductors. You can try to hold down the cost by buying 20 gauge, but then on projects that could be DCR senstive you will not be getting a true picture. You can also series inductors to add values, but I have always heard folks in the know say that is not really recommended. Bottom line: buying a range of inductors to test with will be pricey, unfortuately.
07-15-2006, 05:49 PM
I keep on hand a pair of all cap sizes under 10uF down to 1uF - the Jantzen or Solens are fine. The Dayton film & foil caps are nice and cheap for bypass use - I bought 10 of the 0.1uF, but I'll get the 0.22 next time. There are some good, discount caps at Madisound:
5uF: <A HREF="http://www.madisound.com/cgi-bin/index.cgi?cart_id=9178120.23227&pid=386">http://www.madisound.com/cgi-bin/index.cgi?cart_id=9178120.23227&pid=386</A>
10uF: <A HREF="http://www.madisound.com/cgi-bin/index.cgi?cart_id=9178120.23227&pid=380">http://www.madisound.com/cgi-bin/index.cgi?cart_id=9178120.23227&pid=380</A>
You can make any larger cap sizes by combining.
For inductors, I recommend having a LCR meter so that you can buy a few sizes like 0.5mH, 1.0mH & 1.5mH and then unwind them to the needed inductance. The LCR meter is also very handy when buying electrolytics since they do not have tight tolerances and should be measured and matched - I always buy 4 of the PE NPEs to get 2 that are somewhat close - it would be nice to know if the Bennic NPEs available at Madisound have better tolerances. Since the inductor's DCR generally does not matter for use on the tweeter side, I will buy 18 or 20ga. I do not buy the 14, 15 or 16ga inductors for woofers until I have the project designed since they will be the most expensive items. If you stick with 2-ways, you will probably not need inductors larger than 2.0mH. Three ways will generally need large (5 to 10mH) inductors and iron or steel laminate cored inductors will be the best value. The Erse inductors are nice and will save a little SPL, especially when using a 4 ohm woofer.
I buy the resistors after I have the design worked out also. I buy the Dayton resistors and will always buy 4 instead of 2 to get the price break. Having some 0.3 ohm resistors on hand is a good idea when working out the final padding on the tweeter.
Hope this is helpful, Brad
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