crossovers

[grim]

I am just beginning to build my first speaker project, a small two way bookshelf, and I am wondering what is the best way to construct the crossover. I have selected all of the components but I am unsure of how to assemble them correctly, and I have never seen any step by step instuctions on the process. I have heard of point-to-point soldering, perf board mounting, and pc-board mounting but I am unsure of how do do any of these. Any help would be greatly appreciated, especially with some visual resources.

cheers

 

[vdi_nenna]

X-Overs

What's up Grim!

It would be easier to say that there is no trick to building a crossover, let alone selecting parts & design, but there are some techniques.

I think the easiest thing for you right now is point to point wiring on a pref board. You need to get an understanding of schematics first. You can do that by just looking at other people's designs and placement if they have pictures.

Second, if you don't have soldering experience, you need to get some. You can probably get tips all over the internet by doing searches on Google, Yahoo, ect...
If you have never used a soldering iron, be careful!! Touching the tip is extremely unforgiving. It is a guarenteed burn if you touch anything other than the handle.

You may get away with not having to solder by twisting the leads of the parts, but I don't highly recommend it.

The only problem I can think of off the top of my head is when placing coils on a board with limited space, you need to orient them so that there is little or no interference between them. If you are looking at a coil that's laying flat and need to place another right next to it, you'll need to place the second coil sitting on it's end like a wheel crashing into the 1st coil. This has shown to produce the least interference.

You can build a crossover basically how it's drawn. You just need to know what the symbols mean. Look up 6db slop, 12db slop, 18db slop, 24 db slop crossovers, ect.

Also, you need to consider how close you place resistors to other elements on your board. e.g., I had a friend who has a set of Infinity RS-5's. He noticed smoke coming out of a port. What happened was a resistor was too close to a coil and the coils covering began to burn. He took them back to get repaired and it happened again. Finally he wised up and called me. I put in new resistors, but lifted them off the board some and away from anything. I had never heard of anything like that before but it's true.


Check out these sites

http://w1.864.telia.com/~u86404449/

http://www.speakerbuilding.com/

Good Luck!!

Vince

[Edited by vdi_nenna on 02-21-2001 at 05:16 PM]

 

[grim]

Thanks Vince

I appreciate the help

G

 

[vdi_nenna]

No problem Grim.

There is one more thing, but you may know about this already.

You can by-pass (parallel) large value, good quality capacitors with smaller value, high quality caps. For example, use a polypropolyne cap with the value of 10mF, and use a teflon and tin foil (or another combo of materials) with a .1mF value. Teflon and tin is extremely expensive. About $25 for one .1mF 200v by Reliable. But there are others like polystyrene & tin foil for about $4 from Reliable.

Good qualty would be:
Solen, Axon, Dayton by Parts Express

Better Quality would be:
Reliable, Hovland MusiCaps, MIT and InfiniCaps is another one I think.

These are expensive, but by using a smaller units in parallel, you can achieve some of the benefits. It all depends on what you are trying to achieve.


Vince