I have converted my ms20i pearls to active drive and as davedotco said easy to do with this speaker.
Very simple crossovers, inductor on bass feed to roll off the high frequencies and bypassed capacitors on the tweeter feed to roll off the low frequencies.
Sound between active and passive drive is not that different to be honest, The active speaker is a bit more tighter through the bass but not as good as the passive through the mid and treble.
I suppose this could be due to the extra electronics of the electronic crossover in the signal path so adding some 'character' to the active speakers sound.
maybe active drive using digital dsp crossovers would sound cleaner,
I dont think its worth going active unless you have big 3 way speakers, and then i think i would leave the passive network to the mid and treble and just run the bass driver active.
To be honest, it is morelikely to be the (non) effect of the inductor which may well tame the inband response of he bass unit by reducing the output around the point the cone srarts to break up.
The more expensive ES14 had a better behaved bass driver and needed no inductor to modify it's inband response, an even better subject for activation if you can find a pair.
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Given that the epos es11 and 14 have no crossover components on the bass drivers they are actively driven. Only a single capacitor is used on the tweeter to protect it from low frquencies.
I have heard them sounding great on naim and exposure amps.
I think drive units have come along way in the last 10 to 15 years and the newer metal and ceramic drivers just dig up so much more detail than the old polypro drivers from then.
I really want to build a nice 2 way floorstander using accuton drivers, but man they are pricey.
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the only problem I encountered with the ES14 was a slight harshness in the midrange, I put this down to the fact that the tweeter still had considerable output in the mid due to the slow roll of of the simple 1st order capacitive filter.
Similarly the bass driver was putting out more high mid than would be ideal, hence the thought that an active crossover would be of considerable benefit.
FWIIW, the Onix OA 21 amplifier was a particularly fine match with these speakers, much better than the more expensive options you mention, sadly they disapeared sometime in the early/mid 90s.
On another thread someone mentioned that his Onkyo TX818 A/V amplifier has built in electronic crossovers and plenty of power amplifiers to properly bi-amp suitable speakers.
Clearly the relatively simple crossover can not equalise driver irregularities but a speaker such as those you mention or, my favourite Epos ES14, which have purpose made drivers and minimal crossovers would be ideal.
Ok, so my Mordaunt Short MS20i Pearl speakers have removable bridges to allow bi-wiring or bi-amping.
I go out and score myself an Onkyo TX-NR818 with all this DSP & electronic x-over gubbins and enough seperate amp modules to have one dedicated to each of the four drivers.
Do I rip out the speaker's own crossovers (and have a true active set-up with seperate amps and electronic crossovers built into the Onkyo receiver) or leave them in place and have some kind of conventional bi-amped system with a bit of DSP thrown in?
How would this work?
[EDIT] It's ok. They explain both approaches here...
...missed that bit.
Hmmm. So it seems a true active topology is just one of the available modes (so long as the old crossovers are removed and the drivers are directly wired to their respective terminals).
I think I ought to do a bit more research on this and drop Onkyo a line or two on whether any old - modified - two-way (like my MS20i Pearls sans crossovers) would be ok or whether a specific brand/type of 'crossover-less' loudspeakers have to be used in order to be compatible.
Chebby, I think I would want a speaker for which I had accurate measurements for each drive unit (think Scanspeak etc) before I'd start to convert to active. I dont know if these are available for the MS but I have not seen any.
I am not sure how much help accurate measurements would be in this instance, you would need to be able to design your own crossover with all the requisite eq for the drive units or at the vey least fing an electronic crossover with user programmable dsp to do the job.
This is why the MS speakers are ideal for experiments of this kind. As you point out the drive units are specific to that particular speaker and already have a response that is flat across their operating range. The drive units need no eq and minimal crossover, in many of Robin Marshal's designs the bass driver is driven full range, the upper frequency roll off being dictated by the design of the unit itself.
Both tweeter and mid/bass driver will still have a break-up mode, no matter how beningn no?
The fixed phase plug is a good thing though as it prevents the usual phase cap/dome acting like an ad-hoc tweeter.
Pretty ... and pretty proud of it
Absolutely, as mentioned in my last post.
The point is not that they do not have breakup modes but what specifically you are going to do about it, even with acurate response graphs.
But then I could be selling you short, maybe under that fine dress lurks a highly competent electronic/audio engineer, I think you should come clean DM.
How will a TX-NR818 'know' what active crossover/DSP parameters to apply when presented with a crossover-less pair of speakers? Will it analyse them in some way? Or does the human have to enter information from driver manufacturer's data-sheets and other info like cabinet dimensions and cabinet type?
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You have to set the crossover frequency from one of the dozen or more available and set the levels for each band along with any correction for baffle alignments, the Onkyo websight says you can do all of this though it does not show how.
Equalising each drive unit is not offered, unsurprisingly at this level, though I believe some pro crossovers use programmable dsp to do just that.
So would you say - from your expert point of view - that this is just a worthless gimmick or that Onkyo are on to something?
I think it is pointless for all but a handfull of diy enthuiast.
Any crossover, passive or active, really needs to be specifically taylored for individual speakers and I think this is essential for critical use.
I thought deep down it might be b#####s. You've confirmed it. A pity because it's an interesting concept for a mass market AV receiver.
It certainly is and it is easy to just circumnavigate the crossover. Whether buying the Onkyo for just this feature makes sense is another question but it is commendable to include it.
At least you have a 'near active' with your Pearls ...
I haven't bought an Onkyo 818 so the present tense is redundant regarding it or any speaker mods.
It seems, from what Dave has confirmed, that the electronic crossover/DSP in the TX-NR818 is worthless without either specifically designed speakers (to match the limited settings), or professional electronic crossovers where every variable can be programmed..
In other words.. a gimmick with no real world value slapped into a mass market AV receiver.
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