You’re probably aware that there are different kinds of speakers that are suited to certain “parts” of music. For example, your car’s subwoofer is ideal for very low frequency notes. Tweeters are designed for high frequencies, and midrange speakers handle everything in-between. But how does the single audio signal get split up between those speakers? How do you avoid sending the low subwoofer frequencies to the tweeters? That’s what an audio crossover does, and in YouTuber GreatScott!’s newest video he examines whether it is feasible to make your own.
Splitting up an audio signal like this can be done with digital signal processing (DSP) these days, which is usually how modern multi-channel stereos handle things before amplification, but that requires a relatively high amount of processing power. Fortunately, it can also be done using passive components. If you buy a set of speaker cabinets with multiple speakers in each cabinet, there should be a passive audio crossover already built in. But what about if you want to make your own speaker cabinet, or need to replace the speakers with models that have different specs? In that case, you may want to make your own passive audio crossover.
Making a passive audio crossover only requires simple, inexpensive components like capacitors, resistors, and inductors. The tricky part is calculating the values of the various components in order to filter the signal into the proper frequency ranges. The speaker driver being used also affects that circuit, further complicating the math. Those calculations can be done by hand, but it’s far easier to use software, like the free VituixCAD, to model the audio crossover circuit and tune it to your driver. None of that is necessary if you’re just buying a set of speakers that are pre-built, but it’s useful to know that you can make your own audio crossover for custom-built speaker cabinets.