how do you measure the coil in the crossover?


I am in the process of tweeking my rather inexpensive speakers, and I want to update the crossover componants. I would appreciate any help someone could give me on finding the value of the inductor coil for the low pass filter. I want to buy the alpha core equivilant.
Thanks in advance!
128x128chez
Thanks Sean, I have already written down all the values of the current capacitors used, and I plan on purchasing a higher quality (such as hovland musicap) capacitor to put in its place. The current caps are Hanlan, and I am unfamilar with these. There are four different values of these in each speaker, and my estimated costs to upgrade to the musicaps will be almost 150.00. The current wire is a light weight stranded wire that is clipped to the drivers (not solderd). If you could reccomend what guage of solid wire would be best I would consider checking to that.
Thanks again,
Mike
Strictly ballpark suggestions here on wire:

18 - 20 gauge for the tweeter

12 - 16 gauge for the two mid-woofers

You can start off by using some simple solid core copper wire from your hardware store and see what gauge gives you good results for just a few bucks each. Most stores will allow you to buy this from a spool for pennies per foot. Once you find the right combo, you can then experiment with different brands / types of cable that come in those specific gauges. Who knows, you might be happy with the "generic" wire and leave it at that.

As to the caps, i would look at using Auricaps if possible. Don't know if they come in the values that you need, but it's worth checking into.

If you have large resistors in the circuit, try replacing them with some non-inductive Mills . As mentioned, keep the leads on the components ( resistors & caps ) as short as possible and make secure connections prior to soldering.

While you're doing all of this, you should take steps to "damp" both the crossover AND the actual baskets of the drivers themselves from external vibration. You might be amazed at how much sound a ringing speaker basket contributes to the overall output of a speaker. Many different approaches to this, so have at it. If you want suggestions, email me directly. Sean
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Sean, good advice there!

I agree that I have just about never come across a crossover upgrade that didn't yield very nice dividends. Bigtee, you must be speaking to paranoid loudspeaker manufacturers. Anyone telling you that you are changing the design of the loudspeaker is fearful that you will find happiness in the upgrade, and therefore will delay the purchase of your next pair of speakers.

Based on a recent thread, the Mills resistors were suggested to me over the Ohmite or North Creek I have always went with. I did give them a try this past fall, and I could not feel more strongly. The Mills resistors, while certainly superior to the norm which one comes across, were much flatter and more lifeless.

The Ohmite resistors are the best I have worked with. I consider them the single biggest, cost effective improvement one can make to a loudspeaker. Almost always a less than $10 upgrade. They get rid of so much harshness, grain, and glare from the high frequencies, without dulling detail or the music itself, that it almost(yes, almost) feels like a better tweeter was installed.

Also, while I normally go too far in parts upgrades(guess it's the hobby), I think we should scale back capacitor/coil recommendations for this project. Reason being chez stated this was an inexpensive pair of speakers. I think that Axon or SCR caps will provide a great improvement, at very low cost. Instead of the $150 he quoted for the Musicaps, he would be looking at less than $25. And, I would go with 14 gauge coils as opposed to 8, from either North Creek or Alpha Core Goertz.

I think that for an inexpensive pair of loudspeakers, one will find the limiting factors to be the cabinet and drivers. In my opinion, even if these two areas are improved down the road, the limits of the Ohmite resistor/SCR cap/North Creek 14 gauge coil will still not be exceeded. While I am a huge fan of MIT and REL film and foil caps and coils as big as a dinner plate, in order to see their improvements, the rest of the speaker must be on quite a high level themselves. This should keep the price of the upgrade at probably $60 - $75, while taking the speaker's crossovers farther than one would expect, including a sizable cushion for down the road tweaks.
Where can I find the ohmite resistor? also the rosistor in my crossover says 10 W 3 R 3 on it, Is it a 10 watt 3.3 ohm?
Thanks Trelja for you imput.
Mike
Chez, when I used to buy Ohmite resistors, Mouser was normally my source. I understand that North Creek sells their own version now, although the price will be a bit higher. On the plus side, North Creek could be your source for caps and coils as well, so you would get a break on shipping by buying from a single merchant.

I think they have a very reasonably priced capacitor you could look at in lieu of Axon/SCR. Basically, everything they sell is at least very good, so I wouldn't hesitate to buy from them. I would highly recommend you go with their 14 gauge coils for your little project here.

As far as the values of your resistor, your logic seems good, but you should measure them anyway.

GOOD LUCK!