Crossover schematic help

[runninkyle17]

Hello everyone-

I have the final design for the crossover I am going to build for my center channel, but I want to make sure that I get the "real-world" layout of the parts correct.

If anyone has the time could you help me out by telling me how exactly would be the best way to lay these parts out on the crossover board? Thanks.

-Kyle

 

[t3031999]

I don't have enough time to do a full layout but I will suggest that you make sure that 3 of the inductors are on 3 separate planes (i.e. at right angles to each other) and that the 4th is either at a 45 degree angle to the others (between to planes) or is as far away as possible from the one in the same plane as it.

 

[runninkyle17]

I will keep that in mind. I am making them seperate crossovers on seperate boards, so hopefully I can place them in positions where they will not mess with each other. Thanks again.

 

[Swerd]

Read this article written by Darren Kuzma titled "Building a Crossover from Scratch". It should answer all your questions about laying out parts for a crossover board.

It is available at the Parts Express website. Because of a conflict between them and AH, URL links to their web site are blocked here.

Get around it by doing this:

http://www.parts express dot com

Remove spaces and convert the dot, then add this:

/projectshowcase/xover/xover.html

and you should get there.

If not, PM me with your email address, and I'll sent it to that way.

 

[Swerd]

Here is an easier way

Google on these exact words: Building a Crossover from Scratch

Also, have a look at this:
http://www.troelsgravesen.dk/diy_loudspeaker/coils.pdf
It includes chart at the end that outlines good and bad ways to arrange coils. I printed a copy and keep it at my workbench.

 

[runninkyle17]

Thanks for that info, it was really helpful.

I am planning to have three pairs of binding posts since it is a three way system. I know that this is not normal, but I am doing it all the same.

My real question is about the midrange driver. I have the midrange setup with its polarity reversed. Do I just reverse the leads on the mid?

Here is a rough sketch of what I have so far...

I have also attached the same image in case this one doesn't show up very well.

 

[Swerd]

My real question is about the midrange driver. I have the midrange setup with its polarity reversed. Do I just reverse the leads on the mid?

That's what I would do. Keep everything on the board with normal looking polarity until you attach the leads to the midrange driver. Reverse them at that point.

Just to be certain of avoiding a mistake, use a dab of red nail polish or paint on the minus terminal of the driver, so you can't forget and make normal connections when you are doing all the soldering. You'd be surprised how easy it is to get it wrong despite your best efforts. I speak from direct experience here . I also work in my basement and the lighting is never the best.

Good luck & keep us posted about your results.

 

[MBauer]

Couple of Questions

Why are you using three binding posts? If you have a moment please let me know. Also, why three separate mounting boards? All you really need is some perf board or even some plywood.

Have you figured out the values for your components? All a crossover network does is filter frequencies, i.e., send the higher frequencies to the tweeter, middle frequencies to the mid range and lower frequencies to the woofer. It is much easier and more economical to have 1 set of binding posts. The output from your reciever/amplifier will contain all the frequencies. The crossover network just filters them.

You should know all the driver characterisitcs before designing your crossover network

 

[runninkyle17]

I have already figured out all the information you are asking for.

I have three different sets of binding posts b/c it is s 3-way system. One set for the tweeters, one for the midrange, and one for the woofers. I know that normally people do not do this, but if I ever want to tri-amp or bi-amp my system, this way I can.

 

[MBauer]

Ok

Even if in the future you want to use up to three binding posts, you can still have one board. It is very easy to just insert a connection into a properly designed board. Even if economics isn't an issue and the cost of additional components is a nit to you, design principles tell us that it is best to simplify any circuits and reduce them to the minimun number of components, thereby reducing the possibility of errors, and unnecessary variables.

 

[j_garcia]

Even if in the future you want to use up to three binding posts, you can still have one board. It is very easy to just insert a connection into a properly designed board. Even if economics isn't an issue and the cost of additional components is a nit to you, design principles tell us that it is best to simplify any circuits and reduce them to the minimun number of components, thereby reducing the possibility of errors, and unnecessary variables.

I have to agree with MBauer on this one. I'd put it all on one board and possibly try to centrally locate it or drop it all the way onto the bottom and just run wires to the desired drivers. There's no board in my speakers - the x-over components are all inline and the inductor is mounted directly to the enclosure.

 

[runninkyle17]

I may not use a board at all like j_garcia suggested.

The only problem I have with using only one board and putting all the components on it is the arrangement of the inductors. With the design of the enclosure, I have made the front baffle removable so I am not too worried about messing up the first time because I can easily correct the problem.

However, I will definately consider everyone's info. Thanks for all the help. I will keep everyone updated on my progress. I plan on posting some pics soon.

-Kyle