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Lynx4

Crossover help

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Hello all.

  Need some help figuring out my crossover for a set of bookshelfs I'm doing. So I am using a dayton nd105-4ohm for the woofer and dayton nd25fa-4ohm per bookshelf. I have built my crossover and it sounds great but the issue arises when the woofer is under a decent amount of load and the resistor in its filter begins to heat up to the point of burning my finger. Just wondering if there is a solution or a reasoning why this would be happening, everything else on the crossover is cool to the touch. I have a photo of it built and will upload a photo of the design when i can. 

Thanks 

20191109_062950.jpg

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16 minutes ago, Lynx4 said:

Hello all.

  Need some help figuring out my crossover for a set of bookshelfs I'm doing. So I am using a dayton nd105-4ohm for the woofer and dayton nd25fa-4ohm per bookshelf. I have built my crossover and it sounds great but the issue arises when the woofer is under a decent amount of load and the resistor in its filter begins to heat up to the point of burning my finger. Just wondering if there is a solution or a reasoning why this would be happening, everything else on the crossover is cool to the touch. I have a photo of it built and will upload a photo of the design when i can. 

Thanks 

20191109_062950.jpg

Post a schematic and highlight the hot to touch resistor. 10W resistors will burn your finger when only carrying 3W. It maybe OK. But does sound a little odd. 

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You could replace that resistor with multiple resistors in parallel, and/or with resistance rated for a higher wattage.

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1 minute ago, mwhouston said:

Post a schematic

He did?!   It's the woofer resistor.

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1 hour ago, mwhouston said:

Post a schematic and highlight the hot to touch resistor. 10W resistors will burn your finger when only carrying 3W. It maybe OK. But does sound a little odd. 

Hey so its this resitor 3ohm 10watt. I was thinking about putting two 6ohms in parallel to spread the load. But I wasn't sure if it was my wiring or not. 

20191109_173751.jpg

20191109_173645.jpg

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1 hour ago, davewantsmoore said:

You could replace that resistor with multiple resistors in parallel, and/or with resistance rated for a higher wattage.

Yes that was what I was thinking. Just didn't know if it was my wiring, if I did something wrong or not. 

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14 minutes ago, Lynx4 said:

Yes that was what I was thinking. Just didn't know if it was my wiring, if I did something wrong or not. 

 

And have the multiple resistors:

  1. lifted off your board, and
  2. spaced apart

... so you get airflow round them.

 

Andy

 

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Not uncommon. Resistors turn current to heat..


Doing two in parallel will help with power handling

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In the diagram there are 4x resistors total, 2 resistors used in the tweeter section and 2 used in the woofer section. 1 in series and 1 parallel in each section.

 

In the actual crossover you have built you have 2 resistors only total, one in on the tweeter side in series, and one on the woofer side parallel?

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9 minutes ago, Muon N' said:

In the diagram there are 4x resistors total, 2 resistors used in the tweeter section and 2 used in the woofer section. 1 in series and 1 parallel in each section.

 

In the actual crossover you have built you have 2 resistors only total, one in on the tweeter side in series, and one on the woofer side parallel?

No the small resistors is the distance from the inductors. 

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Deleted

 

Never mind, there is a reason I don't build speakers :blush:

Edited by Muon N'

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Who designed this crossover?

 

3 Ohms parallel to the woofer is just wrong. It should not be there. Maybe it should be in series with the cap?

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29 minutes ago, BioBrian said:

Who designed this crossover?

 

3 Ohms parallel to the woofer is just wrong. It should not be there. Maybe it should be in series with the cap?

Agreed, that's really odd as it will guarantee a resistance of less than 3 ohms, and even with the tiny 0.29 ohms in series, it still wouldn't be more than 3 ohms. That's a very low forced impedance for a woofer, the woofer itself will likely bring it down to 2 ohms in real world.

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The series inductor for the woofer is of very low value, which would be pretty ineffective. . Who decided upon that?

 

In your built crossover, the smaller gauge inductor looks to be on the woofer side. Are you sure you got them the right way around?

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1 hour ago, BioBrian said:

Who designed this crossover?

 

3 Ohms parallel to the woofer is just wrong. It should not be there. Maybe it should be in series with the cap?

Design was done through vituix. The 3ohm resistor in parallel eliminated a spike at the higher end of the woofer crossover point. I tried taking out the resistor completely but it resulted in this spike being way to harsh. I can try putting it in series with the capacitor and see what it sounds like. This is why I decided to ask on the forum as this is my first attempt. 

Thanks

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8 minutes ago, BioBrian said:

The series inductor for the woofer is of very low value, which would be pretty ineffective. . Who decided upon that?

 

In your built crossover, the smaller gauge inductor looks to be on the woofer side. Are you sure you got them the right way around?

Fairly certain I can upload the spl graph to show yous. I could have just completely fudged it all up maybe I need to start from scratch. 😥

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