hi everyone.

after chatting and listening with my mates and their sytems today and i am confusing passive crossover and active crossover.it seem like passive crossover system sound better than active crossover system (play same cd track and same Focal K2P speakers and PPI DCX 600.4) what is passive crossover and what is active crossover?
is it good to use passive crossover rather than active crossover? can speakers work with passive crossover and active crossover at the same time? should passive crossover be custom made? any passive crossover is selling in the market?


thanks for your opinions and helps

PHD

Glad that you are asking. I just switched my crossover from passive to active and was going to start my own thread to report the results

A passive crossover has the crossover network between the amplifier and the speakers. Because the crossover has to work on an already amplified signal, the components have to handle higher current loads and some amplifier power will be wasted as a result.

An active crossover has the crossover network between the head unit and the amplifier. This means that the signal is split into tweeter/mid/woofer/subwoofer before the amplifier, so seperate amplifier channels are needed for each. The cost will add up because you have to buy the active crossover unit, then buy enough amps to drive each speaker independently.

Advantages of active crossovers over passive crossovers:

1. No insertion loss. Amplifier power is not wasted by the crossover.

2. Improved damping. Imagine a speaker which has been told to accelerate forward by the amplifier. When the amplifier cuts the signal, the cone will continue to move forward under its own inertia. However it will produce current of its own which the amplifier will "see" (known as back electromotive force or back EMF). In an active system there is no x-over between the amp and the speaker, so the speaker can control cone movement much more precisely.

3. Constant resistive load. Speakers vary in resistance according to the frequency. Passive crossovers are designed for a certain resistive load. When the speaker resistance changes, the response of the crossover changes and falls away from specification. With active crossovers, the only load that is seen is the amplifier - and that is constant.

From my reading I knew that active crossovers are theoretically better so I asked my installer to switch my crossover network from passive to active. In my case, this simply involved removing the passive crossovers and rewiring some cables. System: Pioneer DEX-P9R + DEQ-P9R (has a built-in active crossover), Butler TDB 475, and Dynaudio MW160 + MD130 speakers with a modified Dynaudio X280 crossover.

First things first: I lost power by going active. This is because in passive mode, the Butler amp was bridged giving me 2 x 200W. By going active, I now have 4 x 75W. But this was offset by the lack of the power-wasting X280 crossover.

The X280 crosses over at 2300 Hz with a crossover slope of 12 dB/octave. My installer set me a crossover point of 2500 Hz with a slope of 18 dB/octave. My first impression was that I lost a big chunk of mids - voices became hard and shrill, instruments lost a lot of "body". It is as dramatic as turning a violin from a warm comforting instrument to a hard shrill screaming instrument. However I noticed a dramatic improvement in bass and stereo imaging. The system lost some of its boominess and control of the bass is tightened. I can now hear echos of the drum around the room and I can precisely pick where the percussionist is sitting. Incredible. This might sound a bit boastful, but it this is the BEST imaging I have heard in a car. Anybody's car. It is comparable to my high-end home setup.

The next thing I did when I got home was to reduce the slope from 18 dB/octave to 12 dB/octave. This gave back a large chunk of my missing mids and made singers and instruments sound fuller bodied. The difference was very pleasing but still sounded nowhere as good as my previous passive setup.

I am thinking of moving the crossover point down to 2300 Hz with a 12 dB/octave slope but I am wary of exposing my MD130 tweeter to bass frequencies.

So now I have a slight dilemma. I love the bass and the stereo imaging of my active setup. But I miss the warmth and body of my previous passive setup. My installer points out that I will be getting a sub very soon (which will be run active) but that will only provide bass control and not give me the imaging. In the end I value sound quality over imaging. Voices have to sound like voices. Being able to place the singer in the room is secondary. So I will probably go back to a passive setup.

Personal prefferance (at this stage i might add) is to go with passive x/overs.
Active cross overs are nice and allow for different setups and easily enable you to use slightly miss matched components (impedance wise) together where using a passive would require alot of custom work.

No you cannot use passive and active setup together on the same speakers.

You can get custom passive x/overs but they are pricey for quality.
Can i ask what components your thinking of running active? all splits "component sets" come with passive crossovers set at normally a good setting.

Any how the passive setup would have been reciving more power than the active setup (320 perside as opposed to 80 per driver) so naturally would have sounded "better" as focal speakers love power.

And amphibius beat me to it ^^^ and i like his answer

how much did you spend in your passive crossover. what parts did you use in your passive crossover? is that x280 crossover active or passive? i am considering to buy a standard passive crossover which made by mundorf. but i don't know it is worth or not. if i use passive crossover, would i lost any imaging but sound better with good bass or gain the imaging and lost the bass and sound quality? is more power meaning sound better? as far af i know, passive crossover won't use any power. am i right? it is a hard task for me.

PHD

What speakers are you using with it?

You cant just use any off the shelf item . . .

PHD I have never heard of the Mundorf passive x-over. But that shouldn't surprise you as I'm a bit of a newbie to car audio myself

My experience with the passive is limited. What my installer did was to modify my STANDARD Dynaudio X-280 crossover with upgraded capacitors. He left the coils alone. The difference was noticable - I had more detail, more body, and the gap between the woofer and tweeter seemed to close. It did not cost me anything as he was kind enough to modify my crossover for free until I finalized my plans. He was very attentive and paid attention to my listening impressions and changed components until I was happy with the sound. Then, he changed to the active setup.

Also, you are wrong - passive crossovers consume power. This is because the amplifier presents the crossover with a full-frequency amplified signal. The passive crossover then removes signal and transmits what is left to the speaker.

Your car is different to mine, and you will be using different components. So your experience may be different. All I can say is this: in MY situation, a mildly modified passive x-over sounds better than an active setup. People with more experience in car audio may well report differently

i am planning to use focal k2p since i have listened my mates's system.

Mundorf make crossover componets, the brand is highly regarded. If i'm not mistaken, Eton use Mundorf in one of the passive component.
http://www.mundorf.com/english/

Oh yes you can. You can set the low pass filter on a set of splits on the headunit, and let the crossover and natural rolloff take care of the rest.

This is called semi-active, no?

I dont see how you can make a direct comparision between active and passive if your not using the same crossover cut-off/slopes on each.

I get how active can sound better with adjustment, but you could also modify your passive crossover for the same effect.

So, tell us if theres any difference between active and passive when all values are equal.

I would think you'd have a much better indication if you were comparing egges to eggs also. If you change the crossover points you are gonig to affect the sound without a doubt. You may also find that the passives have offset or equal crossover points also?

If you used the same cross over freq and slopes would there be any audible difference between the passiver and active set-up's???

Can anyone confirm or deny this?

i agree with you here, i prefer mine to be tonaly accurate than the imaging to be spot on.

Make me think twice of going active, I'm using Dyn as well and right now the vocal is superb, warm and full body, the only thing that lacking is the midbass snappiness and the imaging. Maybe modifying the passive will yield a better result.

Now lets think about the CONTEXT of my post. The question was can he use passive and active on the same speakers. IE from headunit signal split passed through an active xover on one side then pumped through effectively 3 amplifiers on to the speakers on side via the passive the other direct to the speakers like so
Click to view attachment
click to enlarge

While your post is correct I dont know of too many in car setups that you full passive for every thing from sub to tweeters. But thats not to say it hasnt been down - it is something that I have toyed with the idea of but I dont have enough power to waste

But in a 3 way setup, you could have the passive crossover taking care of the splits, and run a midbass active. Very easy, only two amp channels taken up then. You could set the LPF for the splits on the amp, run them passive, and then bandpass a mid.

You'd still only be using two amp channels then. For one side.

This is also called semi-active, right?

But in the context of splits, and the context of your diagram, your right, it shouldnt be done like that. Not *couldnt*

Yeah in a 3 way you can have semi active but to me that seems like a half arsed attempt - why bother

yes you are right - should not, not can not - the human mind and its ability to make absolute stupid decisions still entertains me

passive and active have their place. i consider active to be advantageous if you're mixing and matching brands/models of drivers (ie: not a matched set with supplied passive xover) and you have the $$ to do it properly.

if you're going as far as a 3-way active setup, then you are probably someone to have a comprehensive EQ as well. a competely tunable system is fantastic and can yield awesome results if done properly.

much of the disappointment some people face no doubt relates to a lack of experience or lack of tunability. and also the lack of appropriate reference tools (ie: RTA) to help tune the system.

i find nothing wrong with passive setups if the set of splits are a matched set, and it sounds good. again, a quality EQ will help and the ability to tune it correctly.

so i wouldn't do an active setup half-heartedly. do it properly, with enough high quality amps, fully tunable xovers, a good EQ, and experienced ears and reference tools.

meh!

who needs an RTA or an EQ to do a awesome sounding active setup

all i need is a tribe called quest album and 10min

Main advantages of going active is nothing to do with crossover slopes or the like, its simply a matter of control :

1) Passive crossovers lower damping to effective zero at resonance. Now i dont know about you, but i didnt pay mega bucks for a high end amp with good damping control, only to have it wiped out by using a passive crossover.

2) Time alignment : wanna try using it on passives?

3) What happens if i decide i want to increase the frequency range going to my dome midrange and lower those going to the tweeter, to help the ambience? With active, i spend 2 minutes twiddling with knobs on the Drive 30, press a button, and voila, perfect. With passives, i pay some speaker guru $500 to rebuild me an entire passive network.

4) What happens if, due to install, i want to lower the level of the tweeter by a specific amount? Or increase the level of the mid relative to the rest of the system? No-can-do with passives.

There is one bonus, and one bonus only to passives : cost. They're cheaper, because active requires processors, extra amps, and so forth. They're also generally easier to install.

There isnt ONE thing that passives can give to/take from the sound that cant be exactly and easily matched by an active setup with the right unit. Problem is, people dont spend enough on buying a decent processor and amps, and too much worrying about whether they have 99.999999999% OFC cable and a capacitor the size of a small house

as a question
If you use a pure class A amplifier do you still have the problem with the "back" EMF (I think if i was naming that sh!t i would have called it captive EMF but that me and i didnt find it so I lose) cause u have a constant?

Back EMF is a function of the speaker, not the amp. Its generated by the suspension of the speaker causing a back current to generate to the amp by electro mechanical means... i.e, its functioning as a microphone

Blackrazor, what crossover points and slopes have you set for your speakers?

I dropped the x-over point to 2300 Hz and 12 dB/oct today. Sounds much more acceptable but still not as good as the passive I had before.

yeah i understand that but with a constant the emf would be drawn out straight away rather than going and being stored in the caps in the xover?

sorry guys im still a newbie, and wen i had my system installed, i auditioned my speakers and my amp, and i bought them for there seemingly warm sound, wen installed, they played loud clear and were ok, i guess, but there was a extrreme lack of mid bass, they were run active. i have my suspicions that the crossover points are fkd. would goin passive make them any warmer, or can any body suggest how to improve them now, ie. crossover points etc. i dont want to muck around wit the h/u EQ cos i got no idea, i run mbq pce216's off a rf p4004 any help would be appreciated

All right, i've had the weekend to muck about with crossover and EQ settings on my newly configured active setup. I am not able to set the same x-over point as my previous passive setup (2300 Hz, 12 dB/oct) because my HU only allows x-over points in 500Hz steps. So I set it at 2000 Hz 12 dB/oct and 2500 Hz with the same slope and listened to both.

I prefer the 2500 Hz x-over over 2000 Hz, but I have to report that in my case the stock Dynaudio passive is superior. I will be going back to a passive setup.

don't go to low with dyn, last time i damage my md100 tweeter, cos cut the crossover to low (1.8k) , anyway c u next week at the party, u coming rite?

Why on earth wouldn't you take your speakers to a shop with a number of different (and preferably adjustable) Xovers and let them work their magic? Or actually buy an adjustable Xover and do it yourself?

Because my active x-over setup doesn't sound that good. I have tried a number of settings and it simply doesn't sound as good. I can't even approach the quality of my stock passive setup, let alone the same passive setup modified with a few components. Believe me, I don't know why! I know that the active setup is theoretically better, but I just can't get good results with it.

it took me 4 years before i finaly had a active setup i liked. but i did take that lest amout of time on setting this one up.

Your mids need more power.. why dont you go 3-way and add in another amp and midrange? 120wattsx2 for the midbass..75x4 for the tweeters and mids. You should appreciate your system better then. This is what im planning to do soon.

what components did you try? :huh: as far as i know, dynaudio xover is using axon cap. what is your set up now and what xover components are you using? can you take some pictures for your xover? someone told me that active xover sound is worse than passive xover but much easier tuning than passive xover.

cheers
PHD B)

bahahahaha.

passives worse than active?? depends on who is doin the processing. if its all electronicly driven by the proper processors rather than physical components. y shouldnt it be better? the signal is getting sent to the right spot at the right time.

Hello guys, I just joined this forum and was interested in your discussions. I used to design High End home loudspeakers many years ago and can comment on your topic.

It does not surprise me that passive crossovers can sound better than the active crossovers used in car head units. There is a reason for this.

With Passive Crossovers you are able to control 3 things:- 1) The Crossover Frequency 2) The Slope and importantly, 3) The Damping (or the Q) at the crossover frequency.
By controlling these three factors it is possible to better match the characteristics of the crossover to those of the driver to produce the desired ideal acoustic response.

The problem with most Active Crossovers I have seen built into car head units is that they only allow you to control 2 of the 3 required crossover parameters , namely, 1) Crossover Freq and 2) Slope. They do not allow you to adjust the Damping (or the Q) around the crossover frequency.

Because of this, the end result may not be as good a match acoustically as with a passive crossover that has been designed to perfectly match the driver characteristics.

What dictates this is the raw response of the drivers being used. If the raw response of the drivers is perfectly flat (perfectly behaved) and not requiring any damping or equalisation modification at the crossover frequency then in theory the active crossover should work just as well as the passive one.

This however is rarely the case and you always have to "tune" the crossover to the driver which is much harder with standard electronic crossovers that assume the driver response is perfectly behaved.

I joined this forum because I myself was looking to build a quality sound system for my car using Focals and was hoping for any feedback from anyone who has used the Focal Utopias with active vs passive crossovers. I would welcome your feedback and any other questions on the above. Have a great weekend guys..

If you wanted the slight shift of Q at the crossover point, you could use the EQ to do that. Although it would affect both speakers, not just the one you wanted. Also you can either overlap or gap the crossover between 2 speakers to help get a smooth response.

You are correct, using the EQ is not the answer to get perfect crossover performance because it does not act on each driver separately which what it takes to perfectly match the drivers to each other. Once that is done, with whatever crossover method used, one can then use the EQ to correct any response anomalies in the car.

Does anyone out there have any feedback on whether the old Nakamichi SP50 woofer and SP10 tweeter with the matched Nakamichi passive crossover would sound better or worse than the Focal K2s or the Focal Utopias ??

I have the above Nakamichis brand new in a box unopened from 10 years ago and now I want to install a nice system in my car. I don't know whether to just install the Nakas or sell them and get the Focals instead.

When I bought the Nakas all these years ago they were considered among the best you could buy - I think they were made ny ADS for Nakamichi. However, I know the world moves on and what sounded excellent 10 years ago may just be average by today's standards.

I would apprciate any advice or feedback from anyone out there who has heard these speakers and can tell me what they think of each.

Thanks and best regards..

Gab are you wanting to use the Utopias with the Nak passives? if thats the case, just try them.. well on the Utopia passives, there is major power loss, compared to when i swapped to DLS iridium crossovers. Just a simple swap out of crossovers, the DLS gave me approx 5 notches louder on an alpine deck than the utopia crossover with identical gain setting, also SQ increase was quite noticable. If this was proving how good the DLS iridium crossovers are, or how bad the Utopia crossovers are, its your call

i dont believe that manipulating the electricity after the signal is given is good enough. like i believe in do it once do it right. the signal should be controlled electronically. thats why we use DSP's like the PXA H701. that way we can use the damping factor on the amp like we paid for. however im not sure now that i think of it wether u can adjust the Q at the xover freq with the DSPs. i havent used my H701 yet. nebody else know? besides it isnt that crucial neway.

I like my active system.
I can change the slope, filter model, frequency, time-alignment, phase, and level of each driver independently.
I still don't know how to tune it properly, but I am learning.
with passive crossovers, I had no option of fiddling with things and it sounded ok, but the active certainly sounds better.

One thing I read, not sure if it's true (open to comments here), but at 12dB/oct high pass, with a constant input the driver excursion remains the same as frequency drops due to energy/frequency distribution. this would say to me that I should get better performance, and be able to drive my speakers harder if I choose a steeper slope. and with a 24dB Linkwitz-Riley I also minimise phase errors between drivers.
I have heard some awesome passive crossovers, but know that the owner spent many hours in measuring and calculating the exact values required for each driver individually.
With only a CD player source, it is hard to get the best sound possible due to the limitations of the medium.
My opinion, if you have the time and the patience, go active and have fun.
in my experience, even if you lower the x-over frequency on your tweeter to below recommended, at normal listening levels it won't blow up unless you hear it complain first.
I was surprised that my 5kHz crossed-over tweets actually sound quite nice at 3.5kHz, although the power needed to be dropped by 40%.

Hello Hype, thanks for your feedback.
I was not planning to swap Xovers. I was wondering which speaker sounded better with its own factory Xrover, the Nakas or the Focal K2 or the Focal Utopias. I don't want to go and buy the Focals if the Nakas I already have sound just as good or almost as good. I have never heard my Nakas, I bought them all these years ago and they are still in the box, unused....

Re your DLS iridiums, who distributes them in Australia? Where would I go if I wanted to hear them or find out more about them?


Thanks again Hype..

Hello PULSE-R, thanks for your feedback, I am really impressed the trophies you won..
I am also really encouraged with your feedback on active crossovers. Many people have had the opposite experience where their original passive xover sounded better than the active one.

I think you are right though, actives do give more flexibility but they will require more fine tuning to give best sound. That is true for any Xover.
I myself used to design passive crossovers and have all the measurement and design gear to do so, so fiddling with passives is not a problem for me.

Re your comment on the 12db/oct slopes relative to the 24db/oct slopes, you are right, the higher the slope you choose the harder you can push your drivers especially the tweeter. the 24dB Linkwitz-Riley is a great xover slope because it also has good phase characteristics. Many home audiophile speakers use the 24dB Linkwitz-Riley crossover alignment for this reason.

Talking of steep slopes, have you heard of elliptic slopes? These are almost infinite slopes of around 100db/octave or more. Their phase response is not as good as that of the 24dB Linkwitz-Riley but their slope is so steep that some peopel say they sound better for cars because they minimise lobing effects due to the tweeter and the woofers being so far apart in a car. Also with these infinite slopes you can cross your tweeter over very low (very close to its resonant frequesncy) without risking damage to it.

I am dying to try one of these out once I have installed some system into my car. I just don't know which speakers to go with. My old Nakamichis, the Focal K2s or the Focal Utopias ??

Over and out for tonight guys, good night.

GABSTER interesing comments

ive only seen lobing graphs for passive x-overs

would the lobing be associtate with linear phase active digital x-overs???

now you talk about different qs for different alignment passive x-overs used. as we know each different alignment rolls off differently due to their inherent q (yes guys even alignemnt types of same order slope). NOt only this but thye also have different phase and frequency characteristics due to their qs. Interesting to note that buttorworth is one of the more popular 12db/oct alignments due to its better frequency characteristics. NOte also 6db/oct doesnt have a alignment characteristic due to the fact that it only has one component (however this would change if you were to add a impedence compensation with a reactive component like a cap in parallel with the speaker load).

if you wanted a knee at a certain active digital point (i could never imagine why you would even need one) some of the more expensive car audio equipment use separate eqs per channel. this would allow you to add a gain right at the x-over point with variable q settings.

it would be ince if the dsp engineers did give us more control of the x-over slope and point. ITs not hard to be more adjustable for either of these, 100db/oct slope in dsp, no problems but you will have more linear phase due to the fact that you have more sampled points in a FIR setup.

Mate cartoys,com,au sell DLS Australiawide i believe

Hello again Jas. Thanks for the valuable feedback and sorry for the late response.

From what I know, I am pritty sure lobing will occur with any type of Xover, passive or active. linear phase and non linear phase types.

Lobing is the interaction of any two drivers producing the same frequency range at the same time. Just like the wave interaction of two stones thrown in a lake.

From what I know, the greater the distance between the two drivers (tweeter & woofer) the more pronounced the lobing. This is the challenge for car set ups.

Shallow slope xovers will produce more lobing because the two drivers "interact" over a greater frequency range than with steep xovers. With steep slope xovers the drivers interact over a much narrower frequency range and hence there is less lobing. Some people argue that this sounds better for cars where the tweeter and woofer are so far from each other.

Lobing only occurs at the xover region between any two drivers. Outside the xover region there is no lobing because only one driver is producing the frequency. (waves from only one stone in the water)

Like you I wish head units were available with more functionality and more xover slope options. I am interested in getting a Clarion HXD2 but it bugs me that it only offers 6, 12 and 18 db slopes.

That is why I would like to experiment with my own infinite slope passives to see how they sound like.

I will be more than happy to share thougths and ideas with you. You sound like you have a lot of experience with car sound systems.

Thanks again and best regards Jas..

THANKS Hype, I'll check them out. regards..

would be nice if they answred emails..

OK first off not all passives are created equal. Dyns (that I use) are phase correct and so avoid phase shifts/reversals at crossover point. As most xovers are crossing over at a point in the middle of female vocals, being phase correct at this point will effect the overall result. we can discuss the pro's and con's all day but if a good passive is workin for you then jobs done.

Until I started using dyns I was a huge fan of active as to be honest with most cheaper speakers you can get better results this way, but when you are using very high end speakers, you may just be chasing your tail

those Naks wont be worth much less if used, as most ppl wont know what they are(ie you wont get a lot either way), so Id give em a run and see what you think as they may be awesome and if you sell them you will never know
peace
Cyberpunky

God bless you Cyberpunky, thanks for your feedback.

Your comments on the Dyns are most interesting. The Dyns sound good because they are excellent and well engineered drivers.

DO NOT believe what they tell you about their speakers being phase correct. Speakers can only be phase correct if you use certain types of xover AND provided the drivers are time aligned relative to each other.

Dynaudio can design their xover to be of the "type" that is phase correct BUT they have no control over the time alignment between the drivers once they go in a car because they drivers can be placed in any one of a million locations.

To give you an example, if you design a phase correct speaker system and then change the position of any of the two drivers relative to each other, it is no longer phase correct amd in fact may become 180 degrees out of phase, requiring you to invert the phase to one of the drivers to bring them pack into phase.

In most cases though, the position of the drivers is such that the phase difference between them is not exactly 180degrees but somewhere between 0 and 180, meaning you will never get them to sum perfectly irrespective of whether you invert the phase on them or not. This is why it is SO hard to fine tune xovers for cars and why every set up is so unique.

For home speakers you can do phase correct designs because the drivers are fixed in their position relative to each other and then the xover is designed to be phase correct WITH RESPECT to the position of the drivers to each other.

I would be very interested to know how Dynaudio can claim their speakes/xover combinations are phase correct when this actually depends on where the drivers are placed relative to each other and they would have no control over that at the design stage.

Don't get me wrong, Dyns sound great because they are excellent speakers that are very well engineered and very well behaved, but I know too much about xover design to believe the hype they are promoting about their speakers being phase correct. May be in their lab with convienient driver positioning, but not in a car with all the placement variables..

The moral of the story, try the sound with the phase reversed and you may like it better even with Dyns.

Thanks again Cyberpunky and best regards.

peace to you too my friend..

Yeah tell me about it!

correct but I didnt mean speakers were phase correct just x/overs. No one can design an x/over and then work out all possible speaker physical alignments, but when a company gets the x/over correct phase wise if TA is correct at least you have a level playing field.

This why installation is the governing factor and not passive or active. If you physically time align your drivers then electrical TA etc is of little regard and why a good install with lesser equipment kicks great gear installed poorly's butt.

anyway phase issues, as well as TA issues, in physcal sense are more a factor than what type of Xover or wether passive etc is better. Install stuff right and you dont need active period. My car is proof of this...EQs set flat, no TA and it images ...OK lol
peace
Cyberpunky

Without getting into the debate because I haven't got a chance ( ) I would just like to point out that passive X-overs are meant to be built with the speakers installed in their final locations. One does not build it on a test bench then ship it to the car. Factory X-overs are a compromise....

Thus you shouldn't be moving your speakers all around or fiddling with attenuation... do it right first time

And because of the intensive process of building passives for a car they are definitely not cheap, perhaps cheaper but considering that you only need maybe 20W/side for your tweeters you're hardly looking at a mega-$$$ amp!