Question About Crossover circuit building?

[FSTP]

I'm thinking of changing out the crossovers on my Old JBL l100 Century's. I was looking at the Dennis Murphy crossover schematic. I've never made a circuit with this many components. So I was just wondering once I have all the parts, to construct the circuit can I just lay everything out like for like how it is arranged in the schematic? or is there something I'm missing?

Thanks,
Jess

[Mr. Widget]

You can layout capacitors and resistors in any layout or orientation you choose. Care needs to be taken with inductors. Inductors need to be away from any ferrous metals and oriented at 90° to each other.


Widget

[Odd]

Placement of coils in crossover networks
Troels Gravesen

[FSTP]

Thank you Odd, that was actually VERY helpful. I will definitely take into account the information provided in that link when laying out the crossover components.

[Swerd]

I'm thinking of changing out the crossovers on my Old JBL l100 Century's. I was looking at the Dennis Murphy crossover schematic. I've never made a circuit with this many components. So I was just wondering once I have all the parts, to construct the circuit can I just lay everything out like for like how it is arranged in the schematic? or is there something I'm missing?

Here's a photo of the Murphy L100 crossover I built back in 2008. I used 7×10" pegboard.

[Swerd]

And here's a labeled drawing of that same photo:

Xover layout.pdf

[FSTP]

That looks great Swerd! How did you like them?

[Swerd]

That looks great Swerd! How did you like them?

After I built them, I spent about a week listening to one speaker with the new crossover, comparing it to the other speaker with the old crossover, adjusting for the change in volume. Both my wife and I agreed that the new crossover was a clear winner.

I tried a wide variety of music that I knew well, including some music where I actually liked the effect that the bright JBL upper-midrange had. The new crossovers eliminate the glare and brightness that I thought I had gotten used to after all these years. The listener fatigue is gone, but the JBL excitement was still there. I remembered that years ago, I used to play with the bass and treble controls, and fiddle with the variable L-pads on the speakers, adjusting midrange and tweeter levels, trying without success to control that ear-fatigue-inducing brightness. The new crossover does it much better. It really amazes me how much better speakers sound when the frequency response curve is flat. You haven't really heard one of these old book-shelf JBL speakers until you have heard it with a proper crossover.

The measured frequency response goes from this (with the original crossover):


To this:


See this thread

[FSTP]

That's very encouraging. Thanks for posting that great frequency data. I'm quite excited to get this crossover project underway.

[FSTP]

Hi Swerd,

I had another question, I was looking at your layout drawing, and I can see where all the drivers Positive side connects to each section of the cross over but where does the negative of each driver connect to?

Thanks again,
Jess

[Swerd]

And here's a labeled drawing of that same photo:

Xover layout.pdf

I had another question, I was looking at your layout drawing, and I can see where all the drivers Positive side connects to each section of the cross over but where does the negative of each driver connect to?

I took that photo before I attached all the wires. Look at the attached PDF of a drawing showing the crossover parts in the same layout as the photo. It shows the wiring.