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Do Crossovers Get Hot?

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  • craigk
    replied
    Re: Do Crossovers Get Hot?

    Dave,

    everything you do is just outstanding. most impressive crossover i have ever seen.

    Leave a comment:


  • Wolf
    replied
    Re: Do Crossovers Get Hot?

    Originally posted by PEB View Post
    For example a 40ohm resistor across the woofer's series inductor is no problem. It is A) close to the amp, and B) sees low frequency, but C) is a high value.
    Agreed.

    Originally posted by PEB View Post
    A 1ohm resistor in series with the first cap in a tweeter circuit is A) close to the amp, B) sees low(ish) frequency, and C) is low resistance. So it is a problem.
    I'm sorry, Phil- but since signal is AC, the cap will prevent low frequncies from being seen by that resistor. If this is your standard fare HP for a 2-way, I think it'll be fine as I've done this before.
    If this is on a midrange circuit, and either across the driver or in series with a large capacitor, things can indeed change for the worse.

    Another ROF (ask Chris Roemer) I use is if it's above 25 ohms, I can usually use a 5W resistor.
    Later,
    Wolf

    Leave a comment:


  • Baby Huey
    replied
    Re: Do Crossovers Get Hot?

    Unbelievable.

    Looks like I'll be playing the speakers really loud on those cold winter nights...

    Leave a comment:


  • davepellegrene
    replied
    Re: Do Crossovers Get Hot?

    Originally posted by djkest View Post
    This thread delivers! Nice pic of the toasty crossover. Was the other speaker just fine?
    No, it wasn't as bad but probably one more song and maybe one more notch and it would have been there.
    Surprisingly the music was clean. I pay close attention when I play my system that hard.


    My wife was sitting outside the room on the deck and motioned for me to come out. She says there is smoke coming out of the speaker. I just laughed and went back in. She wasn't kidding. Smoke was rolling out of the ribbin. I thought I fried it but it was fine that's just where the smoke finally escaped. Talk about a buzz kill.

    Dave

    Leave a comment:


  • djkest
    replied
    Re: Do Crossovers Get Hot?

    Originally posted by davepellegrene View Post
    Ok, since I've been provoked.

    This was the first crossover I had ever built and went a little nuts with the hot glue as well.




    Dave
    This thread delivers! Nice pic of the toasty crossover. Was the other speaker just fine?

    Leave a comment:


  • greywarden
    replied
    Re: Do Crossovers Get Hot?

    That's B@D@SS Dave

    Leave a comment:


  • theLinks
    replied
    Re: Do Crossovers Get Hot?

    Queen was rocking the whole neighborhood! :D Sorry Dave, lol

    Originally posted by davepellegrene View Post
    Ok, since I've been provoked.



    This was the first crossover I had ever built and went a little nuts with the hot glue as well.



    Dave

    Leave a comment:


  • davepellegrene
    replied
    Re: Do Crossovers Get Hot?

    Ok, since I've been provoked.

    This was the first crossover I had ever built and went a little nuts with the hot glue as well.



    Dave

    Leave a comment:


  • Soundslike
    replied
    Re: Do Crossovers Get Hot?

    I have a set of speakers that were thought to be leading edge in their price range back in the late 70's, that belonged to my neighbor. He managed to run into them with a golf cart, splitting one of the cabinets so he gave them to me. He had three boys when the speakers were new and later in life they admitted to playing them as loud as they could get them for hours at a time. When I took the speakers apart this is what I found. It's a crappy looking crossover I know, but the lesson is that resistors can and do get hot. Hot enough to toast wood. I'd be reluctant to use plastic.

    Leave a comment:


  • Flacjunky
    replied
    Re: Do Crossovers Get Hot?

    I think about that every time I watch Queen in Montreal. :eek:

    Leave a comment:


  • martyh
    replied
    Re: Do Crossovers Get Hot?

    Originally posted by davepellegrene View Post
    My claim to fame!
    The resistor Pete is referring to was a 4 ohm parallel resistor on the mid of the Mini Statements. It was a 10 watt resistor that I had buried in the damping material and was pushing the speakers with a 300 watt pro amp. Once I melted the damping material, burn't a hole through the crossover board and almost caught the speaker on fire I replaced it with 4 Parallel 16 ohm 10 watt resistors and all is good. I also put the crossover out on top of the damping material and lifted the resistors off the board. Jim Holtz called it the perfect storm.
    I've gotten other resistors hot during testing crossovers and it always seems to be in the mid that does it. Never got one hot in a two way.

    Dave
    It was a beautiful thing!

    Leave a comment:


  • davepellegrene
    replied
    Re: Do Crossovers Get Hot?

    My claim to fame!
    The resistor Pete is referring to was a 4 ohm parallel resistor on the mid of the Mini Statements. It was a 10 watt resistor that I had buried in the damping material and was pushing the speakers with a 300 watt pro amp. Once I melted the damping material, burn't a hole through the crossover board and almost caught the speaker on fire I replaced it with 4 Parallel 16 ohm 10 watt resistors and all is good. I also put the crossover out on top of the damping material and lifted the resistors off the board. Jim Holtz called it the perfect storm.
    I've gotten other resistors hot during testing crossovers and it always seems to be in the mid that does it. Never got one hot in a two way.

    Dave

    Leave a comment:


  • Pete Schumacher
    replied
    Re: Do Crossovers Get Hot?

    Ask Dave Pellegrene about that . . . :eek:

    Where in the crossover is important as well.

    Music is not like white noise with equal energy across the spectrum.

    It's more like pink noise, or brown noise, with diminishing energy as you move up in frequency.

    If you break up the spectrum into three decades, 20-200, 200-2000, 2000-20000, you'll have about half the total energy in the first decade, and about 2/3 of what's left in the middle decade.

    If your amp is 100W, and you're running it without clipping, you can deliver about 30WRMS long term under music conditions; 15W to the woofer, 10W to the mid and 5W to the tweeter. In a two way, you'll have 75% or more going to the woofer.

    Leave a comment:


  • PEB
    replied
    Re: Do Crossovers Get Hot?

    Here is a rough rule of thumb. Generally, the closer a resistor is to the amp in the circuit, and/or the lower its value, and/or the lower in frequency it sees, the greater the chance for it running hot.

    There are a couple spots in some of my topologies that I know to spec a 25W resistor. 125F is no problem, but 175F implies changing to 25W.

    For example a 40ohm resistor across the woofer's series inductor is no problem. It is A) close to the amp, and B) sees low frequency, but C) is a high value.

    A 1ohm resistor in series with the first cap in a tweeter circuit is A) close to the amp, B) sees low(ish) frequency, and C) is low resistance. So it is a problem.

    Leave a comment:


  • john trials
    replied
    Re: Do Crossovers Get Hot?

    You could always mount the resistors elevated up off the crossover board if you are concerned about too much heat. Inductors and capacitors shouldn't be a problem.

    Leave a comment:

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