Help building a crossover

[tuato]

Hello, i need some help about a crossover for my hi-fi speakers. I've got a Beyma 12ga50 and a Tweeter inside a Marshall Cabinet and i wanted them to play guitar with a POD XT fx modeler through an HH head amplifier. Well, I've been reading out there about the need of a crossover to get the full range of frequencies for my speakers, and i'd like to build one by myself.

The problem is that i don't know what kind of components i must use, i mean , the Farads, the kind of coils etc....

If anyone here could help me with these things it would be great, thanks in advance.

 

[hevans1944]

The Beyma 12ga50 is a "full musical range" loudspeaker and doesn't require a crossover network. But you didn't specify what Tweeter you are using with this speaker. To protect the Tweeter from low frequencies you can install a small capacitor in series with the Tweeter leads. Try a one microfarad plastic (non-polarized) capacitor rated at 16 V or more. If the sound isn't "bright" enough on the high end of the frequency spectrum, you can increase the capacitance. If it is too "bright" you can use a smaller valued capacitor.

There is plenty of DIY information on the Internet to allow you to build a crossover network, but most of it requires you to know a lot of electrical information about the speakers. You might want to start with this page for the big speaker and find a similar one for the Tweeter before embarking on your quest.

 

[tuato]

Thanks for your reply, it looks very easy to get the tweeter works. I send you the specs of the Tweeter, it's a Beyma T-2030, i hope it's useful.

 

[hevans1944]

Great! Now go to this page, plug in the speaker impedance (8 ohms, both speakers), and select whichever type of crossover network you want. I would start with the simple Butterworth filter at 2000 Hz (as recommend by the Tweeter datasheet you posted). This uses one capacitor and one inductor.

 

[Sunnysky]

There are a few more critical details.
The cap needs to be a high quality non-polarized cap. A non-polar electrolytic may work, but polypropylene is much better (PP) http://www.digikey.ca/product-detail/en/nichicon/EXH2E705HRPT/493-13830-ND/4694507

The inductor should not saturate with a couple Amps and must have a low DCR value. In this case pro's use only large diameter air core magnet wire coils.

Also use the lowest impedance, not 8 Ω, which is nominal.