# Active vs Passive - What's the difference



## Mahna Mahna (Mar 2, 2008)

Just wondering what the difference is between active and passive cross-overs...

Which one is best?

How do I tell what I have or need?


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## jp88 (Jun 25, 2007)

http://www.bcae1.com/

They have a section for both of them and it would be a good read to start off with

ps this probably should be in general rather than technical


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## Porsche (Jun 29, 2008)

Active will give you more flexibility, they will be more analytical and digital in sound. Active is a piece of gear and will go between the deck and amp.

Passive, analog and when done properly more neutral/natural in sound. Passive will between the amp and speakers.

I will take a properly designed passive anyday over an active

Christian


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## jp88 (Jun 25, 2007)

Porsche said:


> Active will give you more flexibility, they will be more analytical and digital in sound. Active is a piece of gear and will go between the deck and amp.
> 
> Passive, analog and when done properly more neutral/natural in sound. Passive will between the amp and speakers.
> 
> ...


So you are saying capacitors, inductors and resistors sound different when they are before the amplifier?


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## t3sn4f2 (Jan 3, 2007)

jp88 said:


> So you are saying capacitors, inductors and resistors sound different when they are before the amplifier?


Nope, he's saying that sound better


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## Porsche (Jun 29, 2008)

What I am saying is that a properly designed passive will be more natural than a active. If you design it correctly and use high grade parts a passive is very hard to beat.

Christian


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## Itamar (May 31, 2008)

On the other hand, it is very hard to make a perfect passive crossover. It's true that there is the basic math and calculations, but not always what the eye see is the same as the ear sees.

Besides, electronic adjustments are most of the times much more accurate then passive ones, and there is no "electrical obsticals" (such as coils or resistors) between the speaker and the amp, which let you use the full power of the amp.

Itamar.


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## Bluto Blutarsky (Apr 1, 2007)

You can hear all this with the human ear in a moving car.


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## Porsche (Jun 29, 2008)

Yes, I sure can

Christian



Bluto Blutarsky said:


> You can hear all this with the human ear in a moving car.


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## Jopop (Jun 23, 2008)

Porsche said:


> Yes, I sure can
> 
> Christian


You do know psychoacoustics right? You probably hear a marked difference between different brands of 12awg speaker cable too right? 


Some people believe they can hear a huge difference when they attach a 1" strip of electical tape somewhere on the speaker cable. They DO hear a difference though, but not because the sound changes, but because the brain convinces the ears that it sounds better. You can say the brain tunes the ears..

OT but is your '95 air cooled? My old man has a project going on mating a RUF 3.2 turbo to the rear of a '77 911 (old engine burnt out).. gonna be interesting.

I do think an active crossover has noticably more control over the woofers than a passive, but i might be biased since i *expected* the active XO to sound better. 

An active crossover will beat the included crossover in the component set every time. Unless you're ordering a custom built set and the MFG tunes the crossover to your car then..


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## Porsche (Jun 29, 2008)

noted



Jopop said:


> You do know psychoacoustics right? You probably hear a marked difference between different brands of 12awg speaker cable too right? *i am not going to bother arguing with you on this one*
> 
> 
> Some people believe they can hear a huge difference when they attach a 1" strip of electical tape somewhere on the speaker cable. They DO hear a difference though, but not because the sound changes, but because the brain convinces the ears that it sounds better. You can say the brain tunes the ears..
> ...


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## weng (Jun 7, 2006)

Porsche said:


> What I am saying is that a properly designed passive will be more natural than a active. If you design it correctly and use high grade parts a passive is very hard to beat.
> 
> Christian


x2

It is impossible to explain in words to someone who has never used both active and passive in their own system  And I dont mean those passive crossover that comes with component speaker, but those DIY's with higher grade caps, coils and resistors


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## Bluto Blutarsky (Apr 1, 2007)

Porsche said:


> Yes, I sure can
> 
> Christian


 Now that's amazing!


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## chad (Jun 30, 2005)

weng said:


> x2
> 
> It is impossible to explain in words to someone who has never used both active and passive in their own system  And I dont mean those passive crossover that comes with component speaker, but those DIY's with higher grade caps, coils and resistors


No matter the grade of the cap or coil they still don't take into the account that the speaker is a VERY dynamic load in terms of inductance, capacitance, and impedance, whereas the ass end of an amplifier could care less since it's output impedance is so low. I honestly feel, that in terms of people claiming the passive sounds better, it is due to the phase relationship and the passive components failing at actually doing the job, I certainly agree that a passive crossover adds "character" Good or bad, I can see how some like it. I just prefer active,a nd that does not necessarily mean a DSP controlled active either  I think it's a matter of preference, and in the car I feel that many are biased to active BECAUSE OF DSP and the ability to time allign, EQ individually, etc, that drastic of time alignment in a passive crossover is impossible. you ain't gonna get full milliseconds of delay out of a passive without some considerable loss and phase shift.


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## Porsche (Jun 29, 2008)

Thanks, I do try, it's an art

Christian



Bluto Blutarsky said:


> Now that's amazing!


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## jp88 (Jun 25, 2007)

Porsche said:


> What I am saying is that a properly designed passive will be more natural than a active. If you design it correctly and use high grade parts a passive is very hard to beat.
> 
> Christian





Porsche said:


> Active will give you more flexibility,* they will be more analytical and digital in sound.* Active is a piece of gear and will go between the deck and amp.
> 
> 
> > Please explain the bold statement when referenced to a ANALOG active crossover. I do realize there are some digital active crossovers but this is a bold sweeping statement.
> ...


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## weng (Jun 7, 2006)

chad said:


> No matter the grade of the cap or coil they still don't take into the account that the speaker is a VERY dynamic load in terms of inductance, capacitance, and impedance, whereas the ass end of an amplifier could care less since it's output impedance is so low. I honestly feel, that in terms of people claiming the passive sounds better, it is due to the phase relationship and the passive components failing at actually doing the job, I certainly agree that a passive crossover adds "character" Good or bad, I can see how some like it. I just prefer active,a nd that does not necessarily mean a DSP controlled active either  I think it's a matter of preference, and in the car I feel that many are biased to active BECAUSE OF DSP and the ability to time allign, EQ individually, etc, that drastic of time alignment in a passive crossover is impossible. you ain't gonna get full milliseconds of delay out of a passive without some considerable loss and phase shift.


Couldn't agree more on personal preference. It does apply to almost everything under the sun 

As for using DSP in passive crossover, there is still 1 last possibility - bi-amping. Eg. using the HU built-in pairs of pre-outs setting full range and feed thru the passive components. You could still do TA and EQ the signals which pass thru the passive crossover for its "character".


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## FG79 (Jun 30, 2008)

In a home environment, active vs. passive is a tradeoff at the highest end. 

Do you want a bit more dynamics, headroom, spatial separation? Go active.

Do you want a sound that is most coherent? Go passive.

You can come very close with an active setup for coherency, but will always be slightly off. This is not a big deal of course; nitpicking at the highest levels.

And with the amps that I use, you do not need to go active just to get great dynamics. Going active is a form of going "all out", for a 10% gain perhaps and much added expense.

In a car, if the passive crossover points are reasonable and I have access to the finer tube and solid state amps, I don't mind using the passive route. If I have all of the speakers grouped together, even more of a reason to go passive. Even with the standard passive crossovers that come with speaker sets. 

Active in a car is necessary for the highest level of tweaking, even tonality wise due to the nature of the car environment. And since I have a different philosophy on crossing woofers to tweeters, it's nice to have this level of control.

Obviously a huge advantage also in crossover point flexibility for staging and imaging purposes.

So in summary, there are advantages and disadvantages to both. If I wanted to build the most refined setup at home, I'd go passive; if I wanted to build a nightclub type system, active.

In a car it's really a tradeoff of your time/$/space/alternator capacity for 50 amps, versus a straightforward install that can still sound very good.


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