In any system of quality audio, type and tuning crossovers can have a tremendous impact on how the system will sound. Crossovers are used mainly to separate sub-bass, midbass, midrange and frequency of accurate, submit the appropriate frequency range for each speaker in the system (click here for a basic understanding of the topic). As with other system design and tweaking parameters, good-quality crossovers, when adjusted properly, will not attract attention to themselves and, ideally, a crossover effect would only be considered as a listener to enjoy high quality audio experience. However, use a crossover one or set one good and can be clearly heard that something was not right as the system will only sound bad.

Passive crossovers
A passive crossover can be much larger because it works between the amplifier and speakers. So it must be able to withstand any level of power amp can produce. Most of the medium is available / tweeter speaker system includes a passive crossover. This crossover allows the use of a single amplifier to power the midrange and high frequency speakers. The net result could be very good, with the assumption that manufacturers design the crossover to work properly with the speakers, and speakers are placed and installed properly.

In general, connecting the speakers and passive crossovers as recommended will result in good performance. However, do not be afraid to try to reverse the polarity on individual speakers, especially if the mid and tweeter is not mounted very close together. Try different configurations and determind what sounds best.

Designing a passive network itself or modifying an existing task is far beyond what can be discussed here because many variables involved. Without a good computer program to model a crossover design, you can spend a lot of time and large sums of money to design and build different crossovers to achieve best performance.

Passive crossover usually not used in lower frequency region in car audio for several reasons. Low frequency passive network must use large, compoennts more expensive to make them perform better. Also, we usually incorporate a dedicated low-frequency and high frequency amplifier uses an active crossover between them. Likewise, a good quality amp often uses an internal active crossovers that makes this job much easier.

Active crossovers
Active crossover mismatch in the system right before the low-level signals are sent to the amplification stage in the system. So they can be much smaller than the passive crossover and also have the ability to make changes in the selection of frequencies and other parameters more easily than their passive counterparts.

Active crossover is the norm to separate sub-bass, midbass and midrange / high-frequency parts. These crossovers are often used to divide the middle and high frequencies with more precision and adjustments in the application of high-end systems.

Many high quality active crossovers available that allows users to make adjustments to the amount of variation. In addition, many have digital storage capabilities, allowing an instantaneous switch between different settings, so they can be compared easily.

Amp Much better quality crossover combine multiple technologies in power input section, sometimes eliminating the need for outboard crossover special.

Tools to Use
Several tools can be used to help set the crossover. The speaker owner’s manual is one that should provide the recommmended frequency range in which each speaker will perform best. An RTA or other acoustical analyzer can provide a good visual indicaiton of what’s going on; however, it isn’t a required tool. Your ears are, of course, the no. 1 tool and, for the final setting, are the tools of choice—regarless of the other tools you have available.

Other tools can also be helpful, but these are ones that are more often available in installation bays. We’ll cover more about how to use tools as we get into the article.

Crossover Tweaking and Tuning
Now, let’s take a look at setting the crossovers. Start by looking at the speaker manual (or the manufacturer’s website) and find the recoemmended useable frequency range for each driver. Write these down so you can reference them as we go.

For tweeter and other sensitive drivers, like dome midranges or compression drivers, make sure that your crossover settings never go below that driver’s lowest recommended useable frequency.

After writing down the useable ranges for each speaker, determine the useable overlap range between the drivers. For example, the subwoofer may have a good response up to 250Hz, and the midbass or midrange driver may have a lower frequency cutoff of 55Hz. This means, you could choose your crossover frequency anywhere between 55hz and 250Hz. Determine the exact crossover frequency that will provide the best sound performance.

As far as crossover slopes go, often a steeper slope works better than a shallow slope, so it’s a good idea to start steep, if this is an option with the particular components you’re using. You may end up with the same high and lowpass slopes or one steeper than the other. Set them according to what makes the system sound the best.

It’s a good idea to begin by adjusting only one channel at a time. Start with the left channel and adjust the crossover settings to achieve a relatively smooth repsonse. Then adjust the right channel, center channel and each of the rear channels if they’re used.

If you have an analyzer like an RTA, use it for these initial adjustments. With the pink noise playing on only the left or right channel at a time, move the microphone around in an area about the size of your head above the driver’s seat. This lets the RTA display an average response for a larger space than just the pea-sized space at the tip of a stationary microphone. Watch closely for what each change you make shows on the display. When you get the frequency response looking smooth on the display, put in some music and listen to the system. Switch between different settings that look good on the RTA and see what sounds best.

If you don’t have an RTA handy, don’t sweat it. It may take a little longer using only your ears, but in the end it can be just as accurate.

When tweaking by ear, simply listen closely to some well-recorded music that you are very familiar with while making adjustments. When the final crossover settings are done, the frequency response in the transition from one speaker to the other should be as smooth as possible, you shouldn’t be able to sense any annoying peaks, holes in the response or determine exactly when the sound transitions from one speaker to the other. Remember, “smooth” is the key.

For the subwoofer to midbass crossover, I recommend starting with a crossover frequency around 70Hz and work up and down from there. If possible, vary the subwoofer highpass and midbass lowpass slopes and each of the crossover channel’s relative output levels.

For tweeters and compression drivers, start with the steepest highpass filter slope possible and at as high a crossover frequency possible to blend with the midrange driver, and work down from there. Be careful if approaching the lowest recommended frequency for the smaller drivers so as not to burn them up.

For everything else, just work within the available overlap frequency range until it sounds the best. I know that my sound over-simplified, but it really is that simple.

Crossovers as Equalizers?
By setting the highpass and lowpass filters at different frequencies, the crossover can be used to control the overall system frequency and phase response (equalization) to some extent. In fact, I prefer to use the crossover settings to the maximum extent possible for frequency response contouring and use a dedicated equalizer as little as possible beyond that.

In order to do this, if you find a peak or dip in the response in the crossover region when tuning the system, the highpass and lowpass crossover frequencies and slopes can be varied to help correct the problem. For example, to correct a peak in the subwoofer/midbass crossover frequency range, turn the subwoofer lowpass frequency lower and/or turn the midbass highpass frequency higher. You can also change the slope of each and try reversing the polarity of one of the speakers. This can be very effective at smoothing the response.

If you’re using a passive crossover, check to see if it has some adjustment capability. Many have a tweeter level adjustment, and some more advanced ones have a midrange level or “presence” adjustment capability. Don’t assume that setting the midrange and tweeter as loud as they’ll go is where they should be set. Listen to the system and change the settings to see which one actually sounds the best. With a passive crossover system, theese features can be very effective for system tuning.

Final Points
Remember to listen to the changes you make to the system after each adjustment or short series of adjustments. If the changes aren’t improving the sound quality, don’t be afraid to back up and try something different. Don’t be afraid to experiment: Keep the speakers working within their recommended frequency ranges and try as many different crossover setting combinations as possible.

Make sure to write down the settings you have tried, as well as general impressions of each. Then when you have several settings that sound pretty good, you can switch between them and choose the best one. If you don’t document the settings, you will likely be trying the same ones over and over again, or may not be able to get back to one that you really liked after you change from it.

As your audio system develops and as you learn more, you’ll likely continue to make changes to the crossover settings. Adjusting crossovers really isn’t that difficult. With a little thought and a consistent technique, it can go quickly. Keep in mind that a crossover should help make the system sound good and when you get done tweaking it, you shouldn’t even know it’s there. It simply lets the music play without getting in the way.

That’s pretty much it for basic crossover setting. At some point in the future, we will get into more advanced system tuning using different techniques with the crossovers. But we’ve got a lot of other system tweak and tune techniques to cover before then.