External vs. internal

January 14, 2023
 by Paul McGowan

I was recently asked an interesting question.

Is it better to have the loudspeaker crossover inside or outside the loudspeaker?

At first, the answer seemed rather simple. Inside, of course. Shorter wires, fewer binding posts, etc.

Yet, in thinking about it, I can see at least one advantage to an external box filled with speaker crossover parts (like we did on the IRSV). I would imagine there would be benefits from lowering internal vibrations. When external in their enclosure, the crossover parts are not vibrated by the loudspeaker’s output.

We know that anything one can do to dampen or isolate sensitive parts from the speaker’s outputs is almost always a benefit.

The problem with any of these ideas is the simple matter of trade-offs. What are you giving up, and what is it you hope to gain?

My guess would be that a slight overall advantage would be gained with an external crossover enclosure. And with that in mind, one would have to ask the second question.

Would it be worth the hassle?

As in any noble experiment, one must always ask the right questions: cost vs. gain and hassle vs. ease of use.

My vote would be to keep your speakers build as the designer intended.

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53 comments on “External vs. internal”

  1. I really wonder if the designers at Devialet or Cabasse ever put this question when designing their most innovative active loudspeakers with digital inputs and a most unique cabinet design? These Devialet Phantoms let rattle the drywall in my listening room in contrast to my much bigger conventional loudspeakers.

  2. If microphonics can affect the sound of electronics such that it is readily heard, how much more is it likely to affect the s cross over inside of a vibrating speaker? Then there is the question the affect of the magnetic force inside a speaker caused by the driver magnets.

    1. I know, let’s put amplifiers, DACs & streamers inside loudspeaker cabinets & just shake the crap out of every piece of electronics that we possibly can 😀

  3. Ok, so we understand microphonics, however, solid state components are
    less susceptible to vibrations than say vacuum tubes & reputable loudspeaker manufacturers will try to ‘cushion’ an internal crossover as much as they can with some sort of isolation plate & yes, I know that it’s going to be very limited in is ability
    to isolate or ‘cushion’.
    I think what’s more important to be considered, where crossovers are concerned, is whether they should be passive or active.

    Vale Robbie Bachman (1953 – 2023)
    “Jeff Beck must need a drummer” – Randy Bachman.

    1. FR, I spent the day on Friday listening to Jeff Beck. I had picked up Emotion and Commotion a while back – what an amazing talent gone. He is “one of one”.

    1. There are some speakers that are designed with only a single capacitor on the tweeter, which is pretty close to what you’re asking for, Yorkie.
      Reference 3A from Canada comes to mind. Excellent sounding speakers.

  4. Leave it to the designer? Same as leaving it to the manufacturer and the business who also look at a little thing called profit margin. That profit margin and ease of assembly have a major say it the development process.

    Internal versus external crossover I don’t know. External can be more flexible for upgrades, multiple amps, and even tighter fine tuned crossover points especially when done in the preamp realm.

    But like was stated there are compromises / plusses and minuses which ever way one decides to go.

    If the majority of audiophiles believe in certain design characteristics, regardless of the component, then that’s what they should demand and purchase.

    1. Yes exactly, “leaving it to the designer” in this case only means sound quality compromises for the sake of convenience, cost and less clutter.

      I think in most cases the decision against something like external crossover housings was even taken for such reasons without having tried out the positive effect at all. From Paul’s wording I got, it was so also in case of the FR line. But maybe Chris or Paul know the possible extent of the effect from historic experience…but it didn’t sound like that.

      One of my or probably my favorite small speakers, the Living Voice OBX-RW4, use an external crossover. Admittedly the benefit of it probably is not only the avoided resonances, but also the fact, that the crossover makes nearly 1/4th of the main speaker cabinets size.

      https://www.borderpatrol.net/loudspeakers/

  5. Anything involving more cables and more boxes? No thanks.

    P.s. typing on a bus, just remembered I used to take this bus route to school when I was 8 years old. Can still visualise. Time flies.

      1. Elektor, in spite of having lived on five continents and many countries i know many people who have lived their entire lives within a 50 mile radius. And most of them feel their lives have been enriched by truly being part of a community. So I do not think it unusual at all.

        1. My family ( except for me ) and my two closest friends have lived their entire lives with a 50 mile radius of St. Louis. I envy them. Not because St. Louis is anything special ( compared to NYC it is a small town ), but because they have true roots.

          1. Everyone was born and grew up, lived and married and died within less than fifty miles. Until just recently in history, (the Industrisl Revolution, off to the big city factory)

            Also, it’s handy for Family History researchers to have a limited area to search.

            1. Peter i think you are not taking into consideration historical migrations and conquests that distributed sapient all over our planet well before the industrial revolution

              1. A bit of both don’t you think? Groups migrate. Then settle down. Far closer than the fifty miles— the next village.

                Another view of “their mileages vary”

      2. I don’t. I live at least 2 miles from where I grew up.

        London is often described as a collection of villages and there is tremendous variety like any international city. The only thing you won’t find here are external crossovers.

        1. Steven prior to being aided by GPS the only way I could ever navigate in London when driving was from village to village. Else I would get totally lost

  6. An associated question might be, “Are you a manufacturer, or, are you a DIY’er with the goal of attaining the Nth degree? If *yes* to the second part, you would not be using a passive speaker-level crossover anyway.

  7. If we’re concerned about the vibrations in the speaker cabinet affecting the crossover what are we to make of them affecting the amplifiers in active loudspeakers. Of course if active speakers were the norm someone would have the great idea to site the amplifiers externally.

    Sure it’s best to follow what the designer intended but what about when the designer offers both options. Living Voice a U.K. maker of high efficiency speakers (94dB) has for about 15 years offered a model with exactly that choice. Over those years it’s basically been a development of the same model, the current versions being the IBX-RW4, inboard crossover and OBX-RW4, outboard crossover. The manufacturer clearly thinks it’s worth it and so must the buyers paying a $3000 premium for the outboard version. Reviews are also favourable but does that surprise anyone. The external crossover is housed in a cabinet beautifully finished to the same standard as the main speakers, is about the size of a stand mounter and weighs 5kg. Placement and the extra cables are obvious issues.

    1. Hi.
      Thanks for the information about the reference A3 loudspeaker design with one capacitor on the tweeter, the pearl acoustics sibelius is a single driver speaker with no crossover.
      If I ever go to a HiFi show again I would like to hear them.
      The speakers I use have three drive units with only one component in the signal path of each, which makes me wonder about a crossover-less design.

      1. Hi Yorkie,
        From what I’ve be able to glean, if you can design loudspeaker drivers that will roll-off naturally exactly where they need to along the frequency range then the fewer components you will need in the cross-over.

  8. I often wish we could post photos with our replies.

    A few years ago I was restoring some vintage “Frazier of Dallas” speakers, and had a friend build me some custom crossovers. Prior to installing them in the cabinets I asked him about the long term impact of vibration on the cross over components. I was more concerned with reliability than microphonics, since the crossovers were point to point wired.

    My friend recommended I just get an aerosol can of spray insulation foam and pot all the components together. Which I is what I did. Simple fix 😉

    1. Invalid,

      Realize that a circuit board populated with large heavy components like capacitors or inductors, when exposed to vibrational loads does not react as a single monolith mass. Parts that are not rigidly bonded or potted together will see an amplification factor applied to vibration levels due to their cantilever mounting. Component resonate frequencies will also be higher without being potted, and more likely in the range of the speaker frequencies. This is why potting and surfacing mounting of components is essential in high vibration environments.

  9. Well, that ‘designer’ has accountants to answer to. As was m Ed ruined pit the XO in dense material. (even wax), do
    Like many other ambitious “engineers” do build and install them in. Separate compartment any use s nice metal plate to attach the parts to snd security bolt it to tgif cabinet. Wilson audio(?)?amongst many other top end/ hi-end /high performance speakers. And as has been mentioned active or semi active.

    And can we really trust that careful A/B single blind listening tests were done? (snicker).

    The latest issue of Stereophile has a product that needed some shipping damage repaired. The balance control was wired in reverse. Nice QA or QC.

  10. I had TANNOY Professional’s with 15 monitor gold’s dual concentrics and the crossovers were outside the big boxes with all those internal baffles. They sounded great, we’re super efficient and we’re powered by solid state Mac’s ……..ah…wishing for the old days!

  11. So there’s no vibration hitting a crossover if its outside the box, only onside of it? At least inside the box there is damping material surrounding the crossover. I agree with your final conclusion Paul and that is leave it as it is.

  12. I’ve had bi-amped systems since the 70s.
    One had electronic XOs in the speakers, another had an external passive electronic XO

    I currently have most of the bass in my 3-ways “bunged” off and an active sub.

    Considering a potential tri-amped setup..

    They say it never ends, but budget does.

  13. I have been moving the cross over out of the speaker box for years! The speaker always sounds clearer and smoother. Doesn’t matter what speaker! Speaker designers make the device as heavy as possible to limit vibration! Cross over mid and high speakers must always be disconnected from low frequency vibration. It is amazing that designers haven’t done it.

  14. Some weeks ago, Paul posted something about M&K speakers. Memories flooded. M&K’s were the first non DIY speakers I got. They came with a subwoofer (volkswoofer?). I bought them with a Carver C4000 preamp. The one with sonic hologram and autocorrelator. Also the M-400 little cube amp. I remember my dad was absolutely delighted with them. They were small and the sound was magnificent. He would invite his friends home to listen to it. But there was one specific record he always wanted me to play for them. It was the Telarc 1812. There was something about this particular record. I had a ReVox 790 with a Sure V-XV Type 4, that could play it well. His friends had been in WW-II with him. When I visited my mom last month in Oz, I saw a lot of pictures of my dad with record players. There’s one of him in uniform, others before meeting my mom and also soon after. He always loved music and passively encouraged my “affair” with music and equipment.

    Those memories triggered by the M&K and the pictures, made me download that specific record from Qobuz, the Telar 1812. And I just played it in my speakers that not only have crossovers inside, they have amps inside too. Even though I have two subwoofers in my office, I was concerned about the cannons and the excursion. So I played it a little less loud.

    I can’t have dad back. But I can get the feelings while listening to that music that he shared. It is raining in SoCA, no biking today. Not inside either. But reminiscing of dad with gorgeous music through amazing (objective) equipment is incredible. I have no idea if the sound is “better” or not. Sound memories are fleeting. I do know that the music moved me, even if it is not a great piece.

    Those M&Ks had this control that you could change the sound to “British” or “American” sound (brightness). You could also overload the subwoofer if you played it loud enough. Those cannons again…

  15. Random thoughts and mutterings from the deep.
    Crossovers inside the power amplifier stage and tri-wiring the speakers….. Capacitor dialectics warming up and expanding vs coils being vibrated in an already moving magnetic field… Oh my….
    The curiosities, the experimentation, the potential!!

  16. I’m amazed only one person has so far reported doing this. I have taken the XO outside the boxes several times and friends commented on the improved sound. But moving them around is a major drag, especially if they’re hard-wired 😉

    Nowdays I have external electronic crossovers and muti-amp setup which is a whole other story. One amp channel per driver has a lot of benefits. The main downside is more cables but they can be braided together for neatness.

    I remember Naim speakers used to have removable crossovers (so you could use an external active crossover). I never heard of any other manufacturer who did this and I’m sure consumers would complain if it was forced on them. I’m convinced it’s worth it in the pursuit of great sound.

  17. My home theater front left & right speakers (also used for music) are VMPS RM40s, which I bought perhaps 15 years ago or so (40″ ribbon midrange, ribbon super tweeter, custom-damped treated paper cone woofers). I opted for the external crossover boxes. Advantages besides the vibration factor discussed here: External controls for the midrange and tweeter levels, and easy access to the crossover components if any repair or upgrade should ever be necessary.

  18. I found that the poor connectors and wires leading to and from my external cross-over boxes were ruining my sound. I raised my towers 4 inches, mounted the cross-overs on the bottom of the cabinets and hard-wired them in using a pricey Dueland 4 nines silver ribbon cable with a natural silk dielectric embedded with oil at high pressure.
    It was a big audible improvement to my
    Green Mountain Audio Imagos.

  19. Paul,
    As a builder of speakers you’re in a position to actually compare the two methods. Instead of speculating as to the trade-offs, modify a pair of your flagship FR-30s and let us know the results.

    1. Pikpen the same happened with my Tympani T1-Cs, which were sold under an Audio Research label rather than Magnepan. My later T1-ds retained, and still do their internal crossover even though I have been tempted to go external a few times

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