Author Topic: Resistors for speakers...  (Read 1171 times)

medium_grade

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Resistors for speakers...
« on: April 30, 2016, 02:24:02 AM »
Folks,

Thought some of you guys might be able to help. Advanced warning: if anything I say seems silly or simply doesn't make sense, please know that I am very new to all this.

I was doing some upgrades to a set of 80s-era Fisher 3-way speakers (nothing special, I'm more just trying to learn). They didn't sound half bad on their own when I plugged them into my Bogen tube amp, so I thought I'd play around.

Speakers had filtering capacitors and not a true crossover. I found an Infinity crossover for (I believe) a good price on eBay. Took out the capacitors and installed the crossover instead. Speakers now had much better articulation and a much larger sound stage, but the highs and mids were way too bright. I looked at the old components and noticed that both the tweeter and midrange previously had a resistor right after the filtering capacitor. The tweeter was 3.0 ohms/5W with a 10% tolerance and the midrange resistor was 2.7 ohms/5W with a 10% tolerance. I put the resisters back into the path and it certainly helped, but it seems that at least the highs are still too bright. I was simply going to buy a few resistors with different levels of resistance and see what sounds best. Is that a good approach? Also, what resistors do you recommend? I heard that Mundorf resistors are good, but I don't know myself. Any suggestions? Am I just a baboon tinkering in the dark here?
« Last Edit: April 30, 2016, 02:27:55 PM by Larry H »

Consoleman

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Re: Resisters for speakers...
« Reply #1 on: April 30, 2016, 06:56:45 AM »
I'd put it back to the original design with some Dayton caps.
Mark

medium_grade

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Re: Resisters for speakers...
« Reply #2 on: April 30, 2016, 11:19:11 AM »
I'd put it back to the original design with some Dayton caps.

Hmm... already cut a big hole in the back for the crossover. But, perhaps I could upgrade another 3-way pair of Sony speakers I was planning on gifting a friend :-) Dayton caps, you say?

Consoleman

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Mark

Larry H

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Re: Resistors for speakers...
« Reply #4 on: April 30, 2016, 07:16:07 PM »
Dayton crossovers are okay, but they won't give you near the fidelity that Solens will.  Buy Solen crossovers if Parts Express has them in the uF value you need.
--Larry

medium_grade

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Re: Resistors for speakers...
« Reply #5 on: April 30, 2016, 08:52:47 PM »
Dayton crossovers are okay, but they won't give you near the fidelity that Solens will.  Buy Solen crossovers if Parts Express has them in the uF value you need.

So, we're all agreed that trying to put a proper crossover in these speakers was a mistake?

Larry H

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Re: Resistors for speakers...
« Reply #6 on: April 30, 2016, 09:12:36 PM »
You should replace the original crossover cap with an exact mfd. replacement... or very close to the original.  If the original is an 8 uF, replace it with one close to that value.... usually 8.2 uF.  Never try to install a crossover network that's not intended for a particular set of speakers.
--Larry

medium_grade

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Re: Resistors for speakers...
« Reply #7 on: May 01, 2016, 09:28:00 PM »
You should replace the original crossover cap with an exact mfd. replacement... or very close to the original.  If the original is an 8 uF, replace it with one close to that value.... usually 8.2 uF.  Never try to install a crossover network that's not intended for a particular set of speakers.

Is it bad for the speakers or just impractical? I'm okay with the latter as this is more to try and learn something and have fun than to actually build an awesome set of speakers.

AMP82-01-00

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Re: Resistors for speakers...
« Reply #8 on: May 01, 2016, 10:30:02 PM »
In general the OEMs made them to the correct specs of drivers and enclosure. That's a great practice to follow however what sounds good is very subjective. People mod high end speakers all the time.  I like to tinker so usually I leave whatever inductor they have on the woofer but mids and highs I'd look up the specs of them. You have 2 things to not exceed obviously wattage of amplifier and you need to know the lowest frequency a driver is designed to produce. Never go lower than specs say otherwise it will sound nasty and blow. You can play with resistors and caps to tune the response to your liking. I had a set of Klipsch Cornwall's. They sounded very good. But I started playing around with random components and and built a set that blew them away. And they were cheap to build. I've used different fostex tweeters with great success. In general I don't like paper cone tweeters. I prefer dome tweeters. Again all sound is subjective. If it's not some rare set don't be scared to play around with them.
David        "If it ain't interesting, its really just boring"

AlexanderMartin

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Re: Resistors for speakers...
« Reply #9 on: May 02, 2016, 01:36:10 AM »
If you can hear the difference between Dayton 1% poly caps and Solen's on old console tweeters, you must be one EXPERT audiophile!  ;D

But seriously, just change the caps out with either Daytons or Solens, your choice.