It has come to my attention that not everyone in the world can read a filter network schematic as easily as a newspaper
and some have some difficulties visualizing the schematic as components physically laid out on a board. The following is a
discussion of a method that I hope will dispel most of the mystery, and provide a means to easily build crossover networks
from a schematic. The method is not new, as I pirated the concept from electrical nodal analysis. For crossover network
purposes, a node is a point where the various crossover components, drivers, and sources are connected, ie. Soldered
Looking at the schematic below, the most obvious example of a node is the 'ground' or the input that is attached to the
negative output of the amplifier. This output from the amplifier is attached to one lead of C1021, one lead of C1041, and
both negative tabs on the woofers. I have arbitrarily designated this node '0'. I have placed a 0 next to each connection
between another component and the source ground. Counting the 0's indicates we will have five connections (counting the
wiring) at this node.
|CORRECTLY TRANSLATING CROSSOVER NETWORK SCHEMATICS FROM GREEK TO REALITY
The + output from the amplifier only goes to L1011, so at node 1 there is only 2 connections: the wire and one end of
L1011. Node 2 has the other lead from L1011, the other lead from C1021, and one lead from L1031 for a total of three.
Likewise, node 3 has 4 connections, and node 4 has only 2.
Now refer to the crossover pictorial. Circles where the wiring or components are connected together designate the nodes. I
generally start with the + input and lay out my components such that all the nodes have the proper number of connections.
By counting the number of connections, you also have a double check as to the accuracy of your layout.
Node 1 only has 2 components connected together, so I placed it in the corner.
Node 2 has 3 connections, so I grouped the components such that they will all easily reach each other. Note that L1031 is
orientated 90 degrees from L1011.
Continue to lay out the rest of the components making sure that they go to the correct node and the correct number of
connections are made at each node. I generally draw it out with pencil on a piece of paper first then transfer the plan over to
the crossover board. My board shows holes at the nodes where the wiring is pushed through, tightly twisted together, then
soldered, and bent over flush with the board. This will provide some security for the connections.
Sanity check: Referring to the schematic, verify that the correct components and the correct number of components are
connected to each node. By performing this 'Nodal Analysis' I hope converting a crossover network schematic into a finished
crossover will be easily and accurately accomplished.