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View Full Version : Active vs. Passive: An attempt by me to explain

alphakenny1
03-07-2006, 03:19 PM
I’ve noticed there have been a lot of questions regarding the differences between active and passive crossovers. I am going to attempt to explain the differences between the two and also the advantages and disadvantages of both. I’m not going into a very detailed technical explanation, I just want a basic explanation for the people out there who don’t know the difference between the two.

Just some terms to know before reading:

Low pass filter

A low-pass filter is a filter that passes low frequencies well, but attenuates (or reduces) frequencies higher than the cutoff frequency.

High Pass filter

Exactly the same as a low pass filter but passes high frequencies.

Bandpass Filter

Is a combination of a low pass filter and high pass filter.

Octave

An octave is doubling the frequency. For example going from 50 Hz to 100 Hz is one octave. Going from 50 Hz to 200 Hz is two octaves, ect…

Crossover slope or roll off (reference www.bcae1.com)

Crossover rolloff (or slope) describes the rate which the audio level increases/decreases per octave as the frequency increases/decreases. Usually a crossover slope is given as 6db/octave, 12db/octave, 18db/octave, 24db/octave, etc. If you want to see a visual of this here is a great picture:

Cyan = 6dB/octave
Red = 12dB/octave
Green = 18dB/octave
Violet = 24dB/octave
http://i15.photobucket.com/albums/a356/misterassman52/xover.gif

As you can see the different types of slopes and also notice that the crossover point is 1k.

Crossover Point

This is where frequency where the roll off or slopes starts to begin. As with the picture from above the crossover point is 1 kHz roll off begins at that frequency.

2 way crossovers

These crossover have two difference types of crossovers: Low pass filter and high pass filter.

3 way crossovers

These crossovers have three different sets of crossovers: Low pass filter, bandpass filter and high pass filter.

alphakenny1
03-07-2006, 03:19 PM
I’m going to do a copy and paste of an explanation of what a passive crossover is that squeak9798 wrote in the sticky “Speaker FAQ.”

Passive Crossovers

Ok, passive crossover networks are unpowered crossovers (i.e. no external power source) that split the frequencies between the speakers in a component set. They send the higher frequencies to the tweeter and the lower frequencies to the mid(s). They accomplish this by using a combination of capacitors and coils to create certain crossover points and slopes. They are wired in line with the speakers, between the speakers and the amplifier. The amplifier's output is connected to the passive's input, then the mid(s) and tweeter are connected to the passive's output.

Now, when two speakers (a mid and a tweeter) are on a passive crossover, the mid and tweeter are not wired in series or parallel. Two 4ohm speakers (a mid and a tweet) do not make a 2ohm load or an 8ohm load. Two 4ohm speakers on a passive crossover network create a 4ohm load on the amplifier. Two 8ohm speakers on a passive xover create an 8ohm load. A 4ohm mid and 8ohm tweeter on a passive xover creates a 4ohm load for the mid's frequencies and an 8ohm load for the tweeter frequencies. Reason for this has to do with the fact that passive's are based on frequency distribution and not power distribution.

When you have components sets with passive crossovers, the power from the amp is not split between the speakers. If you have a 70 watt amp, then each speaker is going to receive 70 watts (assuming all speakers are the same impedance). If you are sending 70 watts @ 4ohm to the component set, and the mid is 4ohm and the tweeter is 8ohm, then the mid will receive 70 watts but the tweeter will only receive 35 watts.

This probably isn't a very technical explanation….but it gets the point across none-the-less Let's pretend theoretically that we are running a 70 watt @ 4ohm amp full range. That amp (theoretically) puts out 70 watts at all frequencies at 4ohms, correct?? Now, pretend that we are running that amp to a component set (with all 4ohm speakers) through a passive crossover with a crossover point of 3500hz. So, we are taking that full range signal from the amp and splitting up the frequencies between the mid and tweet at 3500hz. Now, since we are splitting the frequencies and nothing else, there is still going to be 70 watts worth of power at all frequencies below the crossover point and at all frequencies above the crossover point, just the same as there was before we split the signal (since it was putting out 70w at all frequencies).

Just a summary basically a passive crossover built by a certain company has a set high pass filter for the tweeters and a set low pass filter for the mids. It’s set in stone. You can’t change it. Another key thing is the passives crossovers occur after amplification.

Passive crossovers are for a person who likes to plug and play and that’s it.

alphakenny1
03-07-2006, 03:21 PM
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 :p: ?

jujumantb
03-07-2006, 03:23 PM
Crossover Point

This is where frequency where the roll off or slopes starts to begin. As with the picture from above the crossover point is 1 kHz roll off begins at that frequency.

BEEP! The crossover point is actually where the rolloff reaches -3dB ;)

alphakenny1
03-07-2006, 04:25 PM
BEEP! The crossover point is actually where the rolloff reaches -3dB ;)

like i said, some of my material might be a lil off but thanx.

AcidicDreams
03-07-2006, 04:30 PM
how hard is it to make a passive xover for yourself?

squeak9798
03-07-2006, 04:42 PM
how hard is it to make a passive xover for yourself?

Depends.

Construction wise; not hard at all.

Design wise....depends on how much work, effort, research and time you want to put into it.

Doesn't take long or much time/effort to whip together a generic 2nd order filter.

To really do it right, and build a great crossover optimized for the speakers you are using, where you are mounting them, etc....it really takes some time, knowledge and measurement equipment that not everyone has access to.

Eugenics
03-07-2006, 04:43 PM

FoxPro5
03-07-2006, 06:24 PM
Nice work Pete! Now please explain why the differential harmonic relay module circumvents the capacitor limitation on the network reponse curve ;)

alphakenny1
03-07-2006, 06:33 PM
Nice work Pete! Now please explain why the differential harmonic relay module circumvents the capacitor limitation on the network reponse curve ;)

:crazy: :crap:

FoxPro5
03-07-2006, 07:15 PM
:crazy: :crap:

:laugh: Sorry that made no sense and I totally made it up...just wanted to keep you on your toes. Good write up though. We need to sticky that!

helotaxi
03-07-2006, 08:01 PM
Or explain how a Besel filter is needed to account for impedance rise at resonance to allow for a smooth crossover frequency responce...

AcidicDreams
03-07-2006, 08:05 PM
Depends.

Construction wise; not hard at all.

Design wise....depends on how much work, effort, research and time you want to put into it.

Doesn't take long or much time/effort to whip together a generic 2nd order filter.

To really do it right, and build a great crossover optimized for the speakers you are using, where you are mounting them, etc....it really takes some time, knowledge and measurement equipment that not everyone has access to.

hmmm I think active would be easier.... maybe down the road when I have more free time...

thch
03-07-2006, 08:06 PM
BEEP! The crossover point is actually where the rolloff reaches -3dB ;)

well, its really application specific. when you design generalized filters you assign goals. you can define a filter by an arbitrary cutoff point, but for most things, its assumed to be -3dB. The biggest example is the Linkwitz Riley crossover which has a -6dB cutoff.

@OP -- please add info regarding the dB scale. you have information about octaves, but not dB.

a nice guide, not cumbersome. at this point i like to classify crossovers into categories:
1.) preamplifier, active analog. (like amplifier crossovers)
2.) preamplifier, passive analog. (fmods)
3.) preamplifier, digital (HU filters using DSP)
4.) postamplifier, electrical (passive crossover)
5.) postamplifier, acoustic (using acoustics to give a desired response).

maybe i'll add some generalized filter stuff, because it comes up ALL the time:
most filters are defined by a combination of 1st (-6dB/oct) and 2nd (-12dB/oct) networks. 1st order filters are not resonant and cannot really favor one specific frequency more then other. 2nd order filters can either be two 1st order filters (Q < 0.5) or can be resonant (Q > 0.5). a high Q* filter is highly resonant, favoring one frequency more then others -- possibly even more then other frequencies in the passband.

4th order networks (-24dB/oct) can thusly be made from 2 2nd order filters. typically it will be a filter with a higher Q (maybe 1.6) and a filter with a lower Q (maybe 0.6). this ends up not favoring any specific frequencies, but also gives a sharp cutoff.

--------------- main point ---------------
This is important becuase EVERYONE asks if you can combine filters. YES you can. BUT not with the intended results. The final filter will be the product of all the filters. thus if filter A is -10dB at 80hz, and filter B is -0.1dB at 80hz, the final result will be -10.1dB @ 80hz. if both filters A and B are -3dB at 80hz, the result will be -6dB @ 80hz. if you were defining a cutoff at -3dB, then the resulting filter's cutoff is not 80hz.

further, just because you have maybe a 4th order filters (made from 4 1st order stages) doesn't mean it will be good. the slope WILL eventually make it to -24dB/oct, but it may not change from -0dB/oct to -24dB/oct in a small bandwidth. i assume this is why some concider fmods to be -6dB/oct filters.

New developments in crossovers are there in digital filters as well as combining bandstop filters with normal filters. the bandstop creates a high slope but only in a small band. the argument is that you can get a filter that is -60dB/oct, and always at or below -30dB in the stopband. CDT and NTM use these filters. NTM has a patent on applying the hourglass filter to audio systems. I also had this same idea, but never finished working on it.

* -- Q refers to the "quality" of a resonator. basically how well it favors a single frequency. a high Q filter may not be desired if the filter is to affect a wide bandwith.

thch
03-07-2006, 08:17 PM
Or explain how a Besel filter is needed to account for impedance rise at resonance to allow for a smooth crossover frequency responce...

actually, i've never heard that term used.

bessel filters are filters that have coefficients based upon bessel polynomials. the result is a filter where the phase response is fairly linear -- giving a simple delay that is constant for all frequencies. (actually not true, but the bessel filter is the best for constant delay).

the speaker has an impedance that can affect the passive crossover. there exists a few solutions to the common problems.

the easy solution is to place a resistance in parallel with the speaker. if you place a 4ohm resistor in parallel with a 4ohm speaker, the impedance will be between 2 and 4ohms. but this uses a lot of power (the resistor gets equal or more power then the speaker).

the other solution is to use a resonantor to effectively place a resistor in parallel with the speaker, but only at one frequency. the idea is to place the resistor in parallel with the speaker only when the speaker has a high impedance and thus to remove the speaker's high impedance, at least as far as the amp/crossover is concerned.

speakers also have an inductance. so a "zobel" network is sometimes added in parallel with the speaker to basically place a lower and lower value resistor in parallel such that the parallel combination of the inductive speaker and capactive zobel ends up with a constant impedance.

FoxPro5
03-07-2006, 08:20 PM
well, its really application specific. when you design generalized filters you assign goals. you can define a filter by an arbitrary cutoff point, but for most things, its assumed to be -3dB. The biggest example is the Linkwitz Riley crossover which has a -6dB cutoff.

@OP -- please add info regarding the dB scale. you have information about octaves, but not dB.

a nice guide, not cumbersome. at this point i like to classify crossovers into categories:
1.) preamplifier, active analog. (like amplifier crossovers)
2.) preamplifier, passive analog. (fmods)
3.) preamplifier, digital (HU filters using DSP)
4.) postamplifier, electrical (passive crossover)
5.) postamplifier, acoustic (using acoustics to give a desired response).

maybe i'll add some generalized filter stuff, because it comes up ALL the time:
most filters are defined by a combination of 1st (-6dB/oct) and 2nd (-12dB/oct) networks. 1st order filters are not resonant and cannot really favor one specific frequency more then other. 2nd order filters can either be two 1st order filters (Q < 0.5) or can be resonant (Q > 0.5). a high Q* filter is highly resonant, favoring one frequency more then others -- possibly even more then other frequencies in the passband.

4th order networks (-24dB/oct) can thusly be made from 2 2nd order filters. typically it will be a filter with a higher Q (maybe 1.6) and a filter with a lower Q (maybe 0.6). this ends up not favoring any specific frequencies, but also gives a sharp cutoff.

--------------- main point ---------------
This is important becuase EVERYONE asks if you can combine filters. YES you can. BUT not with the intended results. The final filter will be the product of all the filters. thus if filter A is -10dB at 80hz, and filter B is -0.1dB at 80hz, the final result will be -10.1dB @ 80hz. if both filters A and B are -3dB at 80hz, the result will be -6dB @ 80hz. if you were defining a cutoff at -3dB, then the resulting filter's cutoff is not 80hz.

further, just because you have maybe a 4th order filters (made from 4 1st order stages) doesn't mean it will be good. the slope WILL eventually make it to -24dB/oct, but it may not change from -0dB/oct to -24dB/oct in a small bandwidth. i assume this is why some concider fmods to be -6dB/oct filters.

New developments in crossovers are there in digital filters as well as combining bandstop filters with normal filters. the bandstop creates a high slope but only in a small band. the argument is that you can get a filter that is -60dB/oct, and always at or below -30dB in the stopband. CDT and NTM use these filters. NTM has a patent on applying the hourglass filter to audio systems. I also had this same idea, but never finished working on it.

* -- Q refers to the "quality" of a resonator. basically how well it favors a single frequency. a high Q filter may not be desired if the filter is to affect a wide bandwith.

Brilliant! Thanks for the info Chris. We need more guys with BSEE's around here :cool:

helotaxi
03-07-2006, 08:29 PM
speakers also have an inductance. so a "zobel" network is sometimes added in parallel with the speaker to basically place a lower and lower value resistor in parallel such that the parallel combination of the inductive speaker and capactive zobel ends up with a constant impedance.
Dammit. That is the term I was looking for. Zobel. Resonates opposite the driver to cancel out the impedance rise and smooth the crossover rolloff. I don't deal with this stuff enough and get my terms confused sometimes...

ngsm13
03-07-2006, 08:34 PM
****.

Simple. Nice.

nG

03-07-2006, 08:43 PM
www.bcae1.com
Might want to fix that

alphakenny1
03-07-2006, 08:46 PM
great! i jus wanted to explain a very basic defination distinguishing the two. I appreciate the very detailed information and doing all the work for me guys ;).

rocky 59
03-07-2006, 09:08 PM
very very nice kenny.

squeak9798
03-07-2006, 11:18 PM
Dammit. That is the term I was looking for. Zobel. Resonates opposite the driver to cancel out the impedance rise and smooth the crossover rolloff. I don't deal with this stuff enough and get my terms confused sometimes...

Just an off-the-wall observation....but I remember reading a thread back when I first joined where you did the exact same thing :D You and zobel networks just don't get along very well.

jujumantb
03-08-2006, 12:05 AM
Just an off-the-wall observation....but I remember reading a thread back when I first joined where you did the exact same thing :D You and zobel networks just don't get along very well.
haha, good memory! :p:

helotaxi
03-08-2006, 02:35 AM
We get along fine, we just aren't on a first name basis...

ngsm13
03-08-2006, 02:36 AM
Brilliant! Thanks for the info Chris. We need more guys with BSEE's around here :cool:

Talk to me in a little over 3years ;)...

nG

alphakenny1
12-20-2006, 11:11 PM
woot! i made it to sticky status :D.

Team Hammer
12-25-2006, 11:34 PM
You might add that there are two types of "Q" Constant and Variable.

If you use Parametric EQ or Graphic you need a Constant Q to control the bandwidth of channels close to it.

Varable Q is just too hard to know what is really going on when you make changes.

It was one reason I got a H701 and a C701 to get the best sound out of those exspensive speakers.

squeak9798
12-29-2006, 06:55 PM
You might add that there are two types of "Q" Constant and Variable.

If you use Parametric EQ or Graphic you need a Constant Q to control the bandwidth of channels close to it.

Varable Q is just too hard to know what is really going on when you make changes.

That would be great if it wasn't for the fact this thread is about crossovers and not equalizers.

Team Hammer
01-02-2007, 12:12 AM
* -- Q refers to the "quality" of a resonator. basically how well it favors a single frequency. a high Q filter may not be desired if the filter is to affect a wide bandwith.

I was under the impression that "Q" along with a Parametric EQ was used to bring the DB up where the Crossover has been set. This Negative DB Region.

Given that you do have a -Db in this region and also has a Phase **** to some degree, Which can be corrected. I know some that just change the speaker wiring to correct this. But I would rather use some sort of Time Correction to fix this.

I seen so many missed matched speakers with as much as a 7db differance its a wonder they sound good at all and no crossover in the world is going to overcome this problem.

If you know of any books that cover this let me know. I do have have most of Chinn's along with others that cover this subject.

yusufsa
01-04-2007, 04:15 AM
Hi

I have MB Quarts DFD 6" split components for front and rear of G5 gti. Jl audio 13w3v3 and a RF p800.4 sunning entire car. Pushing 400RMS into sub, running mids of remainder on amp. The crossover on the amp is not doing the job for my mids, not sounding good at all, very sharp at high volumes. I have the crossovers that came with my mids, would that help my problem or would i require a 3way for this problem. OR, is it that these mids are just crap coz i know they are entry level.

Angry Negro
05-09-2007, 06:49 PM
This might be a really dumb question to you guys, but how does one go "active"? Is there a separate crossover unit like an equalizer that you buy or is this a feature that needs to be built into the headunit? Or can you go "active" by adjusting crossover points on the amplifier if it is capable?

///M5
05-09-2007, 06:57 PM
This might be a really dumb question to you guys, but how does one go "active"? Is there a separate crossover unit like an equalizer that you buy or is this a feature that needs to be built into the headunit? Or can you go "active" by adjusting crossover points on the amplifier if it is capable?

All three options are possible. Some headunits are capable, you can use an offboard processor, and some amplifiers also have crossovers.

Angry Negro
05-09-2007, 08:05 PM
which would be the most desireable solution of the three mentioned?

nismos14
05-09-2007, 08:25 PM
Easiest is HU, no extra interconnects, tuning from your front seat.

alphakenny1
05-10-2007, 07:08 PM
if you are going with a 2 way front stage + sub, the most practical and easier solution is getting an HU with a built in 3 way crossover. also going active is not using passive crossovers and using external crossovers either via processor, amps or hu. here's a list off the top of my head that has at last a 3 way xover:

clarion drz9255 (has a 4 way xover)
pioneer 860, 880prs
alpine 7998, 9813,9815,9833,9835,9855,9853
eclipse 8053, 8443,8455,cd7000, cd7100

nismos14
05-10-2007, 07:22 PM
CD5000 and CD5100 too, IIRC.

alphakenny1
05-10-2007, 07:25 PM
not sure on the 5100 but i know for sure the cd5000 doesn't have it. and just going by eclipse's history, the 5100 shouldn't have it either. each year they have only one hu that has a 3 way xover. the 8445 didn't have it, neither did the cd5000.

nismos14
05-10-2007, 07:30 PM
not sure on the 5100 but i know for sure the cd5000 doesn't have it. and just going by eclipse's history, the 5100 shouldn't have it either. each year they have only one hu that has a 3 way xover. the 8445 didn't have it, neither did the cd5000.

Makes sense, I wonder why I thought it did, man I'm dumb lawl :)

alphakenny1
05-10-2007, 07:40 PM
hahah. all good! even the best make mistakes every once in a while ;).

FoxPro5
09-04-2007, 11:52 PM
Bump for my homeslice laying down the truth!

Lotus FTW! :)

alphakenny1
09-10-2007, 03:12 AM
haha nice john

audiobahnuser18
11-30-2007, 03:09 AM
Good information im really trying to follow this. im like a newbie at component's sad i know but this would be my first set of component's of me installing. i do have a couple questions if someone could post up here pm me bout it i would really appericate it.

1.) you take out the stock speaker but what do you do with the stock wiring do you use it or not?

2.) how do you hide the wiring for the crossovers

3.) how do you hide the wires for the tweeters

4.) how do you actually wire everything up .

Here is what im working with would really really appericate the help guy's sry i know im a newbie in this part of audio but i gotta learn some how:D. Most of the music i listen is rap once i have my system in that is but i do listen to techno , rock and metal also and i will be running for now a deh pioneer 4800mp.

http://i153.photobucket.com/albums/s226/ngugraphics/IMG_1709.jpg
http://i153.photobucket.com/albums/s226/ngugraphics/IMG_1710.jpg
http://i153.photobucket.com/albums/s226/ngugraphics/IMG_1712.jpg
http://i153.photobucket.com/albums/s226/ngugraphics/IMG_1713.jpg

nismos14
11-30-2007, 07:52 AM
Why would you post that in THIS thread???

Eugenics
01-14-2008, 01:48 AM
two years later and still such a great tutorial. the ideas outlined in this thread are just now fitting together in my head.

this does not mean that the ideas take this long to understand, only that my venture has taken me on a 2 year path to reach the level of understanding that is presented in these outlines.

nismos14
01-14-2008, 08:19 AM
two years later and still such a great tutorial. the ideas outlined in this thread are just now fitting together in my head.

this does not mean that the ideas take this long to understand, only that my venture has taken me on a 2 year path to reach the level of understanding that is presented in these outlines.

20k post and it took you 2 years?!.... :rolleyes: :D

CRXBMPN
05-08-2008, 02:22 PM
two years later and still such a great tutorial. the ideas outlined in this thread are just now fitting together in my head.

this does not mean that the ideas take this long to understand, only that my venture has taken me on a 2 year path to reach the level of understanding that is presented in these outlines.

i agree... i've been an SPL head for about 7 years and this is the first time i've actually looked in this section :) and I have always wanted to know the legit and somewhat technical terms and differences... very good read!

macq32
10-12-2008, 01:21 AM
wow... great thread, I feel that I actually have a decent basic understanding

de8212
11-18-2008, 08:33 PM
I'm looking into this but not sure if my headunit will work.

it's an alpine 7894. Looking at the manual it says it has a built in crossover

HPF (Setting the High Pass Filter):
FLAT (OFF) ↔ 80Hz ↔ 120Hz ↔160Hz
Outputs all frequencies higher than that selected

and

LPF(Setting the Low Pass Filter):
FLAT (OFF) ↔ 80Hz ↔ 120Hz ↔160Hz
Outputs all frequencies lower than that selected
(Only available when using the subwoofer output from
this unit.)

Since I am not running a sub that would make the LPF option not applicable.

So, that leaves me with only HPF. But I have a 4 channel amp and would need seperate settings for the front two and rear two, right????

Also, I though I read somewhere (maybe earlier in this thread) where the settings were changed in db's? but mine are settings for Hz????

I'm assuming my Alpine just won't do it. Anyone know for sure?

http://akamaipix.crutchfield.com/Manuals/500/500CDA7894.PDF

eggyhustles
03-30-2009, 02:35 PM
can you go active with a dnx8120 or avic n5?

nismos14
03-30-2009, 02:38 PM
No, neither one.

TurdFergueson2
03-30-2009, 02:47 PM
can you go active with a dnx8120 or avic n5?

Pioneer makes one DVD HU that can, but it doesn't have Navi. And it's expensive as hell

Pioneer
AVH-P7950DVD

eggyhustles
03-30-2009, 05:06 PM
Hmm..so what what be needed go active with either, an external processor?

TurdFergueson2
03-30-2009, 05:10 PM
Hmm..so what what be needed go active with either, an external processor?

I would say a capable HU and a 4 channel amp. Also some mids and tweets without the crossover. That's pretty much it. There are some other alternatives, but I feel this is the easiest way.

Not sure if there is a way with either of those. I believe you can hook an external processor up to the Alpine screens.

eggyhustles
03-30-2009, 05:30 PM
I wanna go active..but i also need nav :crap:

DidUHearThat?
03-30-2009, 05:35 PM
Then just get an external crossover or an amp that has a built in crossover that's flexible enough to hit your crossover points.

eggyhustles
03-30-2009, 05:54 PM
seems like a shitload of work lol

passive it is..

DidUHearThat?
03-30-2009, 06:16 PM
seems like a shitload of work lol

passive it is..

:confused:

It is?

James Bang
03-30-2009, 08:00 PM
basic 3-way setup:

highpass tweets
bandpass mids
low pass subs

4-way (3-way fronts):
highpass tweets
bandpass mids
bandpass midbass
low pass subs

joeboxer5876
03-30-2009, 08:14 PM
seems like a shitload of work lol

passive it is..

first thing i did when i started learning of this site was buy and alpine 9835 with the crossovers built in the hu and got rid of my passive crossovers. it is nice and one of the reason why i wouldn't buy and dvd unit. only units i would want cost over 2 grand! its very easy to do with and external crossover but it is really nice when the crossover is built into the HU.

JimJ
03-30-2009, 08:18 PM
I wanna go active..but i also need nav :crap:

Alpine W205/505, Blackbird, H701 processor...

JJDH
05-09-2009, 10:24 PM
premier f90bt can be active, right?

nismos14
05-10-2009, 12:35 AM
premier f90bt can be active, right?

nope.

ejschultz
05-16-2009, 10:29 PM
Pioneer Premier p800prs can also go active. Only the p880prs was mentioned. I haven't gone active yet, but it's something I've been thinking about. Only thing is (I know it defeats the purpose to an extent) I'd like to keep my rears. My car is rather large and I do like having a rear fill.

Sarthos
05-20-2009, 08:07 PM
Stupid question I suppose, but when going active how much power can you put to the tweeters and the mids? Since they need separate channels I know you can't put the max RMS to each channel can you? If I have 6.5" Type Rs with 110 RMS, would I put 55 to the mids and 55 to the tweets or something else?

JimJ
05-20-2009, 08:15 PM
but when going active how much power can you put to the tweeters and the mids?

As much as you'd like, under the mechanical and thermal ratings of the drivers...

Sarthos
05-20-2009, 08:40 PM
How can you find that out? Its not something simple like half their combined power each? I only know the Kicker components had a pair where each part was 100 RMS so half power each.

ejschultz
05-20-2009, 11:35 PM
Stupid question I suppose, but when going active how much power can you put to the tweeters and the mids? Since they need separate channels I know you can't put the max RMS to each channel can you? If I have 6.5" Type Rs with 110 RMS, would I put 55 to the mids and 55 to the tweets or something else?

i don't know much about the type r components, but i'm assuming they're 4 ohm. being 4 ohm and according to this thread, both the tweeter and the woofer would each be 4 ohm. the crossover divides the frequency so if you're putting 110 watts rms into them, both the tweeter and the woofer would be getting 110 watts rms. the woofers are going to be getting 110 watts of their frequency range determined by the crossover and likewise with the tweeter. in that case i'd assume you can put 110 rms into both the woofer and the tweeter as long as you have your active crossover set properly. if you lower the high pass for the tweeter, you're going to be lowering the power handling capabilities of it. if it's going to be set at the same frequency, you can give it the 110 watts rms, but this would defeat the purpose of going active. by changing the crossover points and changing the levels and time alignment of the seperate components, you can tune the speakers to better, hopefully perfectly build the sound stage of your car. going active isn't easy and it takes time, knowledge, and a good ear.

Sarthos
05-21-2009, 01:48 AM
That makes sense. Of course that also requires twice the power to put out the same sound. Dang.

Or, now that I think about it, if I were using a 2 channel amp which does 2x100 @ 4 ohms to the speakers or 2x200 @ 2 ohms couldn't I run the speakers together in parallel (or is it a series, I can't remember) so they would present a 2 ohm load on the channel and do the same with the tweeters so my amp would put out 200 watts to the pair of speakers and 200 to the pair of tweeters off the same amp? Sounds like a lot of extra power and wear on the amp though :(

ejschultz
05-21-2009, 11:02 AM
That makes sense. Of course that also requires twice the power to put out the same sound. Dang.

Or, now that I think about it, if I were using a 2 channel amp which does 2x100 @ 4 ohms to the speakers or 2x200 @ 2 ohms couldn't I run the speakers together in parallel (or is it a series, I can't remember) so they would present a 2 ohm load on the channel and do the same with the tweeters so my amp would put out 200 watts to the pair of speakers and 200 to the pair of tweeters off the same amp? Sounds like a lot of extra power and wear on the amp though :(

sure you could run them in parallel to get a 2 ohm load at the amp, it's no more wear on the amp. 2 ohm is only making the amp run more efficiently. as far as crossovers go at that point, there's no way to implement an active crossover and hook up tweeters and woofers in parallel to get more power. you could at that point use the capacitor bass blocker filters for the tweeter, but as far as i've seen, there isn't any low pass or trebel blocker filters. these also, from what i've seen, handle 50 watts rms. also, these are considered passive, not active. the only way to go active would be use 2 2 channel amps or a 4 channel amp for the fronts along with the active crossovers (hu, external processor). i guess it does require more power than using the passive crossovers that come with the components. for example, with the passive crossovers (my focal 136v) the woofers is getting everything below 3500hz is getting at 70 watts rms. the crossover splits the power for the frequencies so the tweeter is getting everything above 3500hz at 70 watts rms. my rear speakers are 2 ohm so they're getting probably around 110 rms (alpine rates the amp at 70x4 @ 4 ohms and 100 x 4 @ 2 ohms, i figured it's probably a little higher than that for the 2 ohms, 140 rms would make sense but i've got it turned down as to not overpower my front stage, which it still does:( ). if i were to run my front as active, the rears would no longer get power from my 4 channel amp, and actually probably not even get used. because the focals are 4 ohm, the woofer and the tweeter are both 4 ohm. this means that each component, when hooked up to my amp would be pulling 70 watts rms, give or take a little for minor adjustments. before the fronts were only requiring 2 of the 4 channels of my amp for a total of 140 combined watts rms. now they're taking up the entire 4 channel for a total of 280 combined watts rms. technically it's twice the power to get the flexibility of an active setup. however, the tweeters are still getting 70 watts in their frequency range as are the woofers. it's not going to sound like twice the power, but with proper tuning, it will sound a lot better. i hope this is a good explanation as to how this works.

as before, if you can correct it or say it better, please do.

Sarthos
05-21-2009, 12:59 PM
*brain explodes*

magliteman
07-01-2009, 01:13 AM
Question......

Looking at going active. One amp I'm looking at (DLS A5 & A2) have high and low pass. Can I go active with these?

Aso looking at the Arc KS300.4 which has hi,low and full along with the KS500.1. Can I go active with this as well?

Starting my first DIY install and need to know before I go foreard.

Thanks

James Bang
07-01-2009, 01:37 AM
No!

ejschultz
07-01-2009, 10:06 AM
Question......

Looking at going active. One amp I'm looking at (DLS A5 & A2) have high and low pass. Can I go active with these?

Aso looking at the Arc KS300.4 which has hi,low and full along with the KS500.1. Can I go active with this as well?

Starting my first DIY install and need to know before I go foreard.

Thanks

The DLS A5 is a 2+1 channel amp so not with that one. The A2 is a 2 channel amp so no with that one either. The Arc KS500.1 is a mono amp so no luck with that one either. Now, the KS 300.4 is a 4 channel, so yes, you could potentially do it with that one. You would either need 2 2 channel amps or a single 4 channel amp with an active capable head unit or sound processor.

G.W.Kush
07-01-2009, 10:10 AM
The DLS A5 is a 2+1 channel amp so not with that one. The A2 is a 2 channel amp so no with that one either. The Arc KS500.1 is a mono amp so no luck with that one either. Now, the KS 300.4 is a 4 channel, so yes, you could potentially do it with that one. You would either need 2 2 channel amps or a single 4 channel amp with an active capable head unit or sound processor.

say in this case your tweeters where lower power than your mid-woofers would it technically be better to get two two chanel amps so you could adjust the gain correctly for each set (the tweets and the mid-woofs)?

ejschultz
07-01-2009, 10:32 AM
say in this case your tweeters where lower power than your mid-woofers would it technically be better to get two two chanel amps so you could adjust the gain correctly for each set (the tweets and the mid-woofs)?

You could do that. It would be a slightly easier install to use a single 4 channel amp and then set the gains on the amp or levels on the hu lower than what you have for the mids. Tweeters are also usually a higher impedance; they won't pull as much power as the mids.

ngsm13
07-01-2009, 11:07 AM
I use two 2channels.

:fyi:

nG

James Bang
07-01-2009, 11:09 AM
The DLS A5 is a 2+1 channel amp so not with that one. The A2 is a 2 channel amp so no with that one either. The Arc KS500.1 is a mono amp so no luck with that one either. Now, the KS 300.4 is a 4 channel, so yes, you could potentially do it with that one. You would either need 2 2 channel amps or a single 4 channel amp with an active capable head unit or sound processor.

For a 2-way front, generally, yes. If you need more powa, bridging is always nice, but will need more channels of amplification to do so. Bridging will also give the benefit to balance L/R separately if you don't already have the processing to do so.

For a simple 2-way front + sub, you will need a 3-way xover (2-way front + sub = 3!). and no, the quantity of highs, mids or lows will not cause you to need more than a 3-way xover. ie. tweet, mids, and two or mor subs will still just need a 3-way xover.

1--High pass for highs/tweets (HP)
2--Bandpass for mids (HP+LP)
3--Lowpass for sub(s)
=1,2,3-way

soooo, for a 3-way ''system'' you'll need a minimum of 5 channels of amplification. 2 tweets + 2 mids + 1 sub = 5

3-way front + sub, will call for a 4-way xover

1--High pass for highs/tweets
2--Bandpass for midrange
3--Bandpass for midbass
4--Lowpass for sub
=4-way

a minimum of 7 channels of amplification is need for a 4-way "system"

James Bang
07-01-2009, 11:10 AM
I use two 2channels.

:fyi:

nG

1 for each speaker would be pimp.

ejschultz
07-01-2009, 11:18 AM
1 for each speaker would be pimp.

Aren't most mono amps designed specifically for subs? Their frequency range are from about 10 hz to about 400 hz or somewhere in there for most mono amps.

krainium
07-01-2009, 11:26 AM
Aren't most mono amps designed specifically for subs? Their frequency range are from about 10 hz to about 400 hz or somewhere in there for most mono amps.

Where does he say mono amp. I think he means one 2 channel amp bridged per speaker.

James Bang
07-01-2009, 11:27 AM
Where does he say mono amp. I think he means one 2 channel amp bridged per speaker.

indeederoonie

GAM3OVR
07-01-2009, 11:28 AM
Talk to me in a little over 3years ;)...

nG

NG, you there yet?

ejschultz
07-01-2009, 11:31 AM
Where does he say mono amp. I think he means one 2 channel amp bridged per speaker.

For some reason one amp per speaker made me conclude he was referring to a mono amp, probably because I saw one and my mind turned that into mono. Bridging a 2 channel amp for each speaker would definitely work, as long as the speakers could take the power. You could also use a head unit that will let you take full control of each speaker seperately. This could potentially give you the same controls with a single 4 channel amp that four 2 channel amps would provide.

James Bang
07-01-2009, 11:35 AM
For some reason one amp per speaker made me conclude he was referring to a mono amp, probably because I saw one and my mind turned that into mono. Bridging a 2 channel amp for each speaker would definitely work, as long as the speakers could take the power. You could also use a head unit that will let you take full control of each speaker seperately. This could potentially give you the same controls with a single 4 channel amp that four 2 channel amps would provide.

noooo sheeeeeat

4 two channels will always > 1 4 channel on matter what processing you have, but it won't have anything to do with active xovers, which this thread is about.

ejschultz
07-01-2009, 11:40 AM
noooo sheeeeeat

4 two channels will always > 1 4 channel on matter what processing you have, but it won't have anything to do with active xovers, which this thread is about.

I would think the only reason they would be better is because you'd be able to get more power out of them. As far as processing goes, with my hu I'm able to fully tailor each speaker independently. I can use my 16 band graphic eq for left and right, in network mode (3 way active) I can control time alignment, level, and crossover point and slope for each individual speaker. What more could using four 2 channel amps do other than provide more power?

James Bang
07-01-2009, 02:26 PM
stereo separation for the fancy folks.

ejschultz
07-01-2009, 02:34 PM
stereo separation for the fancy folks.

Stereo separation seems very possible just by using the time alignment correctly to place yourself directly in the "middle" of the speakers. I don't see how stereo separation can be better just by using four 2 channel amps. As long as you're in the middle or have the time alignment set correctly, you should get proper stereo separation.

magliteman
07-01-2009, 02:38 PM
The DLS A5 is a 2+1 channel amp so not with that one. The A2 is a 2 channel amp so no with that one either. The Arc KS500.1 is a mono amp so no luck with that one either. Now, the KS 300.4 is a 4 channel, so yes, you could potentially do it with that one. You would either need 2 2 channel amps or a single 4 channel amp with an active capable head unit or sound processor.

OK....so I'll go with the KS300.4 for the front. My HU has a high pass and low pass (sub) xover built in.

Since my HU only has high and low, will I require an external xover that is 3-way compatible (like the Arc IDX Xover)?
http://www.woofersetc.com/p7201/IDX--ARC-IDX-Digital-Crossover.htm

Thanks

nismos14
07-01-2009, 02:40 PM
2 channel and 4 channel amps have "crosstalk." It's near impossible for those amps to have channels that are 100&#37; purely separated. Some amps, like the old Eclipse amps had separated their channels 100% which is why they are still popular these days.

troytag
08-11-2009, 06:56 PM
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..
ive got several older zapco amps..studios and compititions..
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..

[email protected]
thanks..

troytag
08-11-2009, 07:01 PM
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..

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..

[email protected]
thanks..

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seankurz
02-13-2013, 02:17 AM
Nice work Pete! Now please explain why the differential harmonic relay module circumvents the capacitor limitation on the network reponse curve ;)

the what goes where now?:laugh: