Going Active - Worth It?
Passive crossovers that are supplied with your car audio components, are often nicely packaged in a fancy box including a series of capacitors and inductors that the speaker manufacturer designed. You end up having to dedicate a place somewhere up and out of the way, free of moisture, to safely and securely install them.
So what would we gain by ditching these chunky passive crossover networks?
Adjustable Crossover Points
The crossover points in a car audio system are more important than any other audio format. This is because we often have limited real-estate to work with thus a fixed set of speaker sizes & placement options.
For example, a typical set of bookshelf speakers in a home stereo setup, has a similar tweeter and woofer combo as in a common car audio component set, except the tweeter and woofer are mounted at fixed distances from each other, never to be placed otherwise. This is not the case in an automobile. Also in home stereo, the listening position is often much farther away from the speakers, so having the ability to adjust your crossover points isn’t nearly as crucial.
When you use the supplied passive crossover included in the box, you’re using crossover points that were chosen for you, based on ‘average car audio speaker placement & distances’. This is limiting because all cars come in different shapes and sizes, and you want to be able to fine tune a crossover point that's tailored to your specific automotive environment.
Going active, gives you the ability to change your crossover points and slopes to better suit your speakers and their specific placements. Most car audio setups have a crossover 'sweet spot' that just cannot be attained without the adjustability of actively crossing over your speakers.
Precise Level Adjustment
In that passive crossover box we were talking about, you’ll often see switches or jumpers with db adjustments of +2, 0 and -2 when it comes to changing the level of the tweeter. It’s nice that they include any sort of adjustment, but we find this simply won’t do.
When it comes to the higher end of the frequency spectrum 2db increments is too big of a step when it comes to dialing in your system. Especially in a car where you have reflective surfaces galore. Our ears are the most sensitive to higher frequencies. Having the ability to precisely level each of your components individually is essential to getting your stereo imaging right on the money.
Obtaining Time Alignment
Using your supplied passive crossovers, ties (at the least) your mid and tweeter to a shared amplifier output. This means you can’t delay the tweeter and mid individually. This knocks you out of the running for any sort of true time alignment.
Unless you have your all of your speakers on dedicated channels, time alignment cannot be achieved. End of story. This is definitely one of the lesser talked about benefits of going active.
Time alignment fixes issues with phase and imaging that are extremely important for making your music sound great.
Get the Power You Paid for!
Active systems with the same equipment will be louder than the same system using a passive crossover. This is because amplification is happening before the crossover that then burns the filtered frequencies off as heat before it gets to the speaker.
At the end of the day, passive crossover networks waste your amplifier's output. On average 60% of that amplified power makes it to the speaker through a passive crossover network. By crossing over before amplification, none of that power is wasted or burned off as heat. This way you’re only amplifying the frequencies you specify instead of filtering them out after the fact.
Active crossovers are where it's at!
If you’ve heard a well-tuned, fully active system, you know there’s no comparison to its passively crossed over counterpart.
When talking about active systems we’re namely pointing to the use of a DSP (Digital Signal Processor) which has the capability to even further dial in a system with the use of the oh so powerful EQ. If your amps don’t have a bandpass crossover built in, adding a DSP to your system is the best way to accomplish this.