Outboard crossover? Why not?

What do you think?  Any disadvantages?
I am aware of only one brand that used to use it - Michael Green Audio free resonance two way reference speakers.
Nola uses them or did when they were Alon  and so does or did  Tannoy on some speakers. No disadvantage performance-wise in fact most would say the opposite. But it's obviously more expensive and for many people I would guess aesthetically less pleasing.
Those 'many people' could go buy nice furniture that would also happen to play some music. Audiophiles are interested in performance. Outboard crossover would take up more space, this can be a problem for some, just like big monoblocks.
LOL well some of those many people are audiophiles with significant others says a former Alon Lotus SE owner.
Well, those significant others could try and accept their fate and enjoy extra Cartier piece presented in an elegant manner.
But it can be tough, I know.
Hello inna,

The loudspeakers I use, Dali MegaLine III, must employ an active electronic crossover. 


I’m assuming you are discussing having a passive crossover, that is outside of the speaker cabinet, right?

There are no disadvantages at all, but several possible advantages. I should point out there’s a hybrid approach. In this, there is a separate enclosure just for the crossover components but the enclosure itself appears part of the speaker. I personally like this solution the best.

Advantages include:

  • Reduced effects of microphonic interactions with the speaker or the amp
  • More physical space is available for the crossover, allowing for the use of massive coils and caps which may not have fit otherwise
  • Less space is needed for the speaker cabinet
  • Better crossover cooling, which keeps the crossover’s behavior stable
  • Since the heat generated by the crossover stays outside the cabinet, the temperature inside the cabinet are reduced which keeps the drivers cooler and are therefore less prone to thermal compression

If you were talking about active vs. passive, it’s more complicated. :)


Erik, that's quite a detailed post. I guess, I was talking about passive crossover. Pardon my ignorance, what are passive and active crossovers? In simple terms, please, I mean in English.
So, maybe we should lobby speaker designers and ask them to stop fooling around with designs that by definition cannot yield best results.

I didnt say all inner crossovers were bad, but that ther could be benefits of externals.  an active crossover is before the amplifier.  its called active because it needs a power supply.  the subwoofer output of a dvd player is a type of active crossover.

I see. Sure, I was talking about passive crossover.
Magnepan eliminated the external Xover box on the 3.7 and 3.7i, only because they felt it was an eye sore.

It eliminated the  bi-amping option, which I liked.
Living Voice use external crossovers.
back then Apogee Diva ribbon speakers used to have an external passive x-over. I agree with erik_squires re. the adv of external passive (& active) x-overs.
i also agree that not all passive internal x-overs are bad or compromised. There are several speaker manuf that take a lot of trouble to get the correct & optimum internal passive x-over into their speaker cabinet. 
The Apogee's had no real speaker cabinet though, did they? :) I mean, it was one giant magnet frame.

I did not write anything about advantages of active vs. passive, by the way, at least not here. :) It's more complicated than one or the other being better. Depends on your values and needs.

My preference is a fully digital crossover feeding reference grade DAC's and a multi-channel preamp, but I can't afford that at all. :) After that it's passive.


I agree with the advantages mentioned and think it's worth emphasizing Erik's comment "Reduced effects of microphonic interactions with the speaker". That translates to blacker background and lower distortions. 
It's a shame that perceived visual issues have resulted in fewer external crossovers, especially since most of them sit right behind the speaker which is pulled out from the wall anyway. Usually they can't be seen from the listening area and even if they are it's less visually imposing than making the cabinet twice as deep for the extra room some require to include the electronics.
The cost of another pair of extra chassis especially with upscale veneers adds significantly to to production cost. So do multiple strands of high quality jumpers like the silver ones that Nola uses. Cheers,
erik_squires504 posts08-25-2016 11:14am@bombaywalla 
The Apogee's had no real speaker cabinet though, did they? :) I mean, it was one giant magnet frame.
yes, essentially correct. The cabinet was very wide & about 3 inches thick. And it was very easy to hide the xternal x-over behind that wide frame @  essentially no visual cost. A standard metal box which kept out RFI & EMI did the trick for holding the passive x-over components.
My preference is a fully digital crossover feeding reference grade DAC's and a multi-channel preamp, but I can't afford that at all. :) After that it's passive.
you know I doubt that you will need a preamp as you can find several DACs in the market that have built in digital volume control  that dont compromise sound quality (one such example is DEQX) OR several that have an analog volume control so that you can go straight into an amplifier.
NO Advantage at all , Just raise the price
Active x-overs certainly offer theoretical advantages and (generally speaking) I'm a big believer.  Digital, active x-overs offer even more theoretical advantages and (generally speaking) I'm an even bigger believer.

All passive x-overs (internal or external) present certain issues that demand trade-offs.  Hence the great debate about low order vs high order x-overs.  An active, digital x-over doesn't demand the compromise.  Although (obviously) many here find digital sources (or ADC) a compromise in, and of, itself.  Be that as it may...

My main system is now fed almost exclusively digital program material that's crossed in the digital domain.  There are too many variables at play to say that the x-over scheme is the reason that I prefer the results to any of the many analog based (program material and crossovers) systems I've used in the past, but I prefer the results.

As an aside, several systems use active external x-overs (models from Linkwitz and Salk) come quickly to mind.  Going all the way back to the 80s or early 90s, I think Hales had an external passive x-over option available.
Overall, I find Erik's comments to be right on.  I did not see an easy answer to Inna's question of the difference between an active vs electronic vs passive. could be helpful to others... So,  when a signal from your source comes from your amplifier,  all frequencies hit your speaker.... for now, lets just say 20 to 20,000 hz.  A passive crossover is a filter network... One filter will block low frequencies to a tweeter, another filter will block upper and lower frequencies so a midrange will only see the frequencies meant for the middle region and a low pass then blocks high frequencies and allows the low frequencies or bass only to go to the woofer. 
On an active crossover,  the Filter is put in Front of the amplifier... so you typically need more than one amp.  The filter blocks the signal before the amp,  so 1 amp will be fed only high frequencies, so that amp will be used to play a tweeter... on a 2 way speaker, another amp would only be sent mid and lower frequencies which would go to the woofer.  So on an active crossover,  the dividing network is in front of the amp,  the amp channel plays highs mids or lows and you need 4 channels for a 2 way or 6 channels for a 3 way.  I hope this helps... Erik mentioned a lot of the advantages of an external crossover... I really like having the room to lay out coils to keep electromagnetic field to a minimum.  You can hear it. Erik and Bombaywalla both mentioned the advantages of a digital filter in front of the amps with variable slopes.... There is no substitute here.  Electronic/active crossovers sound better, period.

 We discuss just about passive Crossovers, Inna get question about this,
Active crossover totally different story , The assume amplification  with
different amplifiers and normally working outboard  
Tim, thank you, I have a general understanding of the differences.
We can and perhaps should expand the thread to cover active crossover too, and various implementations. Why not? I think, it will be interesting to many readers.
One thing appears to be very clear - external crossover, either passive or active, has only advantages. I always suspected that.
At the risk of annoying purists....

I'm running a Behringer active xover, but I play about with diy speakers and odd 'hybrid' mixes...albeit not in the 'audiophile sphere' of units available and/or favored.  It does allow a wide range of types, slopes, and points that, with active eq and a calibrated mic on an RTA allows me to amuse myself.  And bi- or tri-amping is another factor in the mix as well.  But one's amusement can be another's horror, so to each his/her own....

Ultimately, let your ears be your guide and let the rest follow....;)
And let's not forget open baffle designs which practically demand active crossovers. You can read lots about those on Linkwitz' site.

Although I have read the thread here re crossovers, I am still bemused by my own situation. I bought for my third system 2 Audiovector (Mi5s I think) speakers that the seller said were not jumpable but needed a 6 channel amp. The Mi5s have 3 sets of inputs and I have since bought more Mi5s of "similar 3 input sets" to have a consistent surround set up. The more recent purchased speakers I saw had been jumped by the previous owners, so now  I wonder about the first set I bought. With the first set the seller included an external crossover box and suggested I bought a Rotel 1066 which he said would be very suitable. I bought a 1066 as they are not expensive and so I now am confused as to how to progress. The external crossover situation seems daft as I would surely need 6 speaker cables for the 2 speakers - best presumably all the same - and that would just look silly going into the rear of the speakers. I do have many speaker cables which I would be pleased to find a use for!
@tatyana69   Internal Crossover,  Correct?  3 pairs of teminals... Bass, mid, treble,  Correct?  For the life of me, I can't see any reason that you couldn't jumper these.... I would assume that the seller just thought they were better being tri-amped, but being passive crossovers, that is not always the case,  You should be able to jump these without issue.... To be fair, I've never laid my hands on a AudioVector speaker,  but I've been in more speakers than I care to think of,  Should be no risk involved at all to jump these.  I hope this helps,  Tim
You have to be SURE that you have an internal crossover! :)

If so, then sure, jumper away.

The tweeter, for instance, needs at least 1 cap to keep it from blowing.

My current reference pair, there's no internal crossover at all, but you can't tell by looking at the outside.


Many thanks for all that. It is a price of not really paying attention on a purchase!
As Erik says, the non existence of an internal crossover may not be stated on the back, so what indications can I look for that I have or have not?
Surely jumping can do less damage (Tim thinks so whatever internals??) in any circumstances than triamping, if that is what it is called.? For those who do triamp do they really prefer all those speaker cables?
I am a BIG fan of not using speakers with crossovers inside them.  I use an active crossover (DBX) and it is between my preamp and amps, so my amps actually see my speakers, directly, not my crossover.  When you use internal crossovers, your amps never see the drivers, just the crossover.  

You run the risk of very easily blowing your tweeter and watching it turn ballistic unless you know what's going on for sure. There's no "less" damage here, either is as risky.

If you have a multi-meter, connect it to the tweeter section. It should, over time, read infinite resistance.

If you get a number between 3 and 10, and it doesn't change after a minute, you don't have a crossover. :)

Of course, you could just take a driver or the panel off and look.
@tatyan69    If you don't have a separate box from the speaker,  the speaker has internal crossovers... You would know if your amp had an electronic crossover to adjust frequency... Jump away,  you will be fine....
The seller included an external crossover box (with instructions - good grief!) so  I suppose all the indications are that I do not have internals. It seems I will have to put these as rears unless I invest in a superior multichanel amp, which makes the whole thing so heavy going + all the extra speaker cables. They seem to however be very pleasant indeed speakers from listening to the ones with internal crossovers, It just makes listening so much more complicated having to sit down and read a manual first. I though those days were over! I am taking them all one at a time (odd shaped luggage at 23kg) to my home in Ukraine so I will have time to read up there, as there is not much to do in Ukraine!

I thought Ukraine was a lot of fun, certainly looks like that from across the ocean. A number of interesting cross-overs over there.
Early Meadowlark Audio models had the crossover located outside the speaker proper. You can remove a little panel under the speaker and get to the xover if you want to mod it. 
Here is an example of an internal crossover being turned external, check out the pic with the coffee cup and caps. You'll see what I mean when I say enormous caps.



Here is a photo of Naim SBL x-over, original (L) and with upgraded parts (R):
now, the same original (R) with more serious upgrade (L):
and my final choice, an external x-over for both SBLs:
Built for me by Steven Foote of Audio-42
Nothing can beat electronic crossover: NAXO2-4 with Hi-Cap but for now this is what I am listening to. Naxo/HiCap kept in safe storage.
Active vs. passive is not as easy as saying one is better. There's always trade offs.

Passive crossovers have no power supply noise to add, and no new op amps or transistors to put in series with your high end gear.

DSP solutions require more DAC channels.

So, I personally feel I can beat a lot of active crossovers with a passive.  Not always though. :)

@sevs great looking pics!

Easy - just the two outputs - high and low
As in my earlier post - more complicated , how to work a three input high middle and low on my audiovectors?
Wires everywhere, I don't have the energy to attack it yet.
Has anyone any pictures of a 3 input set up? Showing wires into the crossover and coming out into the speaker?

@tatyana69 You may have better luck on the DIYAudio forums.  Also, there you can post pics of your external crossover, which makes this discussion a lot easier.


@erik_squires   Active vs. passive is not as easy as saying one is better. There's always trade offs.

Hi Erik, I agree that a competent crossover designer can come up with a very good speaker and yes better than a crappy electronic crossover and amps or better than someone that doesn't know how to use the active crossover properly,  but give me "or You"  any good crossover and amps and the crossover designer doesn't stand a chance. The improvement is always audible.

Thanks for the vote of confidence, I’m sure you can do a better job than I could. I still see it as trading off. For instance, if I go all DSP happy, I need to find multiple DAC’s as good as I’m listening to right now and multiple amps with an ongoing explosion of cables. Also, DSP’s tend to be bandwidth limited. Getting a DSP that can do all your tweaks at 384/32 is no mean feat. Of course, this assumes we CAN take a digital signal and DSP it. I don’t know of any libraries for doing this with DSD on the fly.

If I do this in the purely active and analog domain, I’m forced to deal with power supply noise, and the addition of even more gain stages (op amps) than there was before.

To do the same phase and amplitude matching in DSP as in passive is still a challenge, though you can iterate a lot faster. In some ways I have an easier time with passive, I can tweak the filter Q’s up or down to trade phase and amplitude issues across the drivers in funny (and very useful) ways by altering values of caps, coils and resistors.

Maybe I need to look at the DSP manuals more closely to find this.

Still, I love being able to delay the tweeter in the purely digital domain. You can do some crazy work with that. Maybe this is my alternative to half-order slopes. :)

My message is just, there’s absolutely no free lunch with any option. Integrating any two drivers in the real world is no easy feat to do well, whether it’s in a single cabinet, or a subwoofer plus main speakers.

As for off-the-shelf units, I think pro gear is designed for a very different set of expectations. Of course, some is top notch, but a lot of it is for engineers putting together megawatt systems and close-enough is all they need. Any problems with the drivers and they'll hammer it right with EQ. Gaah!! I mean, I used to do this in theaters and it was fine, especially since you have such a variation in seating position, trying to get any spot with great phase alignment was nearly impossible.

So, could I take a "generic" crossover off the shelf and get to "working" with the speakers I"m listening to now? Yeah, in minutes, but no, I could not get the same quality of alignment and integration between the drivers.



Thanks Eric,  if you ever get the chance to play with a mini dsp hd,  give it a try. experiment with frequency, slopes, time delay, all of it...

Appreciate you brother, Tim