Active vs. Passive: An attempt by me to explain

[troytag 10+ year member]

ive been out of the stereo scene for a very long time.at least 20 yrs......soo i need some help...

im just about done with a 60 impala..been working on it for 5 yrs now..

im just about ready to buy a head unit,speakers,processor/crossovers?

it sounds like active is the best sq?

can someone give me some tips on a good deck/processor that handles the active process?

i was leaning tword an eclipse 7200?

6 pre outs..no power...8 volts..and i think it has built in crossovers?

not sure if this is the right direction..

i hate to spend over 500.00 on a hu

focal k2 or morels ..or maybe dls...for speakers???

like i said i just dont have the exp or knowledge to buy the right combination of speakres,deck,?

anyone avail in the bayarea that does quality installs?

p.m. me

heres what ive got for amps..

1 studio 500

1 z600c2-sl

1 z400c4-sl

3 z300c2-slx

1 z300c2

1 sx-lx eq/crossover

1 sp-4

all older stuff... but pretty good in its day..

troytag@comcast.net

thanks..

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[seankurz 10+ year member]

Nice work Pete! Now please explain why the differential harmonic relay module circumvents the capacitor limitation on the network reponse curve //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

the what goes where now?//content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

 

[22mountaineer 10+ year member]

Found this in a search and I'm going to pull this from the dead due to the picture in post #1 . So when raising the octave, are you making it to where the speakers initially respond at a higher frequency? Do you change this for the speaker specs in general or do you change it for what you hear? What's the difference in what you are going to hear from a sharper curve (higher octave)? If any.

It's been awhile guys! Started a family, just bought a suburban and I need to replace all of the speakers so I'm refreshing my memory. Thanks

 

[JohnKuthe]

Very correct, and I'm an Electrical Engineer by Bachelor's degree! The pic is good because it shows the rolloff curves of the different frequencies!

John Kuthe...

 

[The_Quiet_One 10+ year member]

[quote name='JohnKuthe']Very correct, and I'm an Electrical Engineer by Bachelor's degree! The pic is good because it shows the rolloff curves of the different frequencies!

John Kuthe...[/QUOTE]

Would you please quit raising dead threads?

Also @papermaker

Is this one of your many illegitimate children?

 

[Papermaker85 5,000+ posts]

[quote name='Souldrop']Would you please quit raising dead threads?

Also @papermaker

Is this one of your many illegitimate children?[/QUOTE]i work nearly 14 hours a day. seriously?

 

[The_Quiet_One 10+ year member]

i work nearly 14 hours a day. seriously?

Apparently you're working between the sheets.//content.invisioncic.com/y282845/emoticons/suave.gif.858fc102f7646e678ee8af7e1fbc41d1.gif Granted this guy is likely the offspring of that one time you stole a chimp from the zoo.

 

[Papermaker85 5,000+ posts]

Apparently you're working between the sheets.//content.invisioncic.com/y282845/emoticons/suave.gif.858fc102f7646e678ee8af7e1fbc41d1.gif Granted this guy is likely the offspring of that one time you stole a chimp from the zoo.

KMSL might be the kid judy had and wont let me see.. lol

FYI that proto is a BEST and i love it.. to bad your old hick *** is in Tennessee..

 

[The_Quiet_One 10+ year member]

KMSL might be the kid judy had and wont let me see.. lolFYI that proto is a BEST and i love it.. to bad your old hick *** is in Tennessee..

How did you know my last name! Are you stalking me?!

I would be curious to hear it. I have my reservations about how amazing it supposedly sounds, but I'm sure it at least sounds decent with the right enclosure. Get some scores up and see about getting some klippel parameters. Who knows I may be looking for a low QES 15 (pending other parameters line up with my goals) in a year or so once I'm ready to really tear into my car.

 

[Water Bear]

bessel filters are filters that have coefficients based upon bessel polynomials.

Speaking as a guy with a math PhD: Holy hell, an application for Bessel polynomials!

I took one class on E+M physics about oh...8 or 9 years ago, and I remember almost nothing. But orthogonal polynomial basis...there are people that build their career studying that stuff.

 

[ihossain6898]

Active crossovers

A key ingredient to an active crossover is that the filtering now occurs before amplification and now hence needs an external power source. This is a basic diagram of what it is:

Head Unit --> Crossover --> Amplifier --> Speakers

This is compared to a passive crossover in which the diagram is:

Head Unit --> Amplifier --> Passive Crossover --> Speakers.

Now basically what an active crossover gives you the ability to do is choose the crossover points and slopes for your speakers rather than a predetermined crossover slope and points determined by a passive crossover. This is a huge advantage because we all know that each car has different characteristics that can alter a speaker’s response. An active crossover can be used to make up for these discrepancies in a car. Here’s an example.

On my first set of components I bought the Rainbow SLCs that came with its own set of passive crossovers. According to their specification sheet the passive crossover is designed to have a crossover point of 4.5 kHz with a 12db/octave slope. I can’t change this at all to adapt to the car environment. But with my Eclipse 8455, which has a built in 3 way crossover I now can choose a crossover point of 4khz for the tweeters at 12db/oct and a bandpass filter for the mids at 3khz @ 12db/oct and 80khz @ 12db/oct. Not to mention I low passed my sub at 80 Hz @ 12db/oct.

I can change these points at any time I want. If I feel now that the mid performs better when low passed 2.5 kHz @ 6db/oct then I will change it to that slope and point. A huge advantage is that you can change these points and slopes to your liking instead of having some company telling the speakers where it sounds best.

Another thing about active crossovers is that each speaker will need its own independent channel so you can't go active by going off of a two channel amp. in order to run a two way active frontstage you must use a 4 channel amplifier or a combination of two 2 channel amps. Why? well if you have your mids and tweets running off a two channel and trying to go active then you can't cross the mids and tweets correctly. So its important to have a channel per speaker to run active.

One thing about going active is that it takes a ton of time to tune. If you are a type that likes to set it and forget it (using passive crossovers), going active isn’t for you. Going active takes a lot of time and effort because you are constantly changing crossover points and slopes to fit your needs and takes a lot of time to find that right combination. Not only that but it takes forever to get your staging and imaging exactly the way you want. Staging and imaging is a totally different animal as well.

Just a quick note on how to choose crossover points and slopes, just simply look at a speaker’s frequency response graph and it can give you a rough idea where to cross everything. Every manufacture has these graphs, so look at them and it can give you a rough idea on where to choose your points and slopes.

So that’s my explanation. Kinda half assed because I’m doing this at school, lol. So if you knowledgeable people who know more about going active please feel free to correct my mistakes. Any questions you noobs //content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif ?

 

[Popwarhomie 5,000+ posts]

 

[marc2112 10+ year member]