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In Reply to: RE: there is one very good reason series xo's are used posted by Story on November 26, 2021 at 07:22:46
Total speculation. They are not inherently more phase coherent.
And, series crossovers are not limited to 6db/octave.
The reason Magnepan has switched is for practical concerns vice performance.
The component values required are smaller (relatively speaking) and allow a crossover physically much smaller than previous ones. This allows (among other things) to dispense with the large external crossover box on the larger models.
Dave.
Follow Ups:
and that's too bad for you. I know what I hear succinctly. Do what you want to
My opinion is based on decades of experience working with speaker systems.There are trade-offs in all speaker systems, but let's not be making statements about series crossovers being "superior."
Clearly, they have a use case in some designs, but (generally) they are not the best option.As usual with most things audio, Rod Elliot has an excellent write-up on the trade-offs with high-level crossovers.
https://sound-au.com/parallel-series.htmDave.
Edits: 11/26/21
decades, yes decades. Anyone who views this can take my advice if they wish and build 2 xo's and verify this for themselves.
It's interesting that before the X.7 series Magnepan was using parallel crossovers on most of the their models for 40+ years. Why do you think they did that??
Dave.
because they discovered the superiority of series in sound Q
It took them forty years to discover that? :)
What do you think of the sound Q of bi/tri-amped systems using line-level crossovers with no high-level crossover??
Dave.
I think the SMGa also had a series crossover, and it has been often regarded as a particularly outstanding and sweet sounding model.
Also the main driver properties themselves changed to QR from round wire, and of course electronic design tools and measurement equipment is notably superior to years past.
That's why I said "most of their models" a couple of posts back. :)
I'm well aware the SMG had a series crossover.Dave.
Edits: 12/02/21
I'm now a fan of simplification and do passive from one amp. I've tried biamping as I've had many amps at any one time but it was too bothersome and just complicated things too much so I stopped doing it. I have Quad ESL 57's and they are my lifelong reference since 1975. I use them from 100hz up and have regular speaker cloth covering them instead of the metal grills which opens them up and extends the top end considerably. My hearing limit is still 16khz. The quads sit on Morel 9" woofers and I also have 2-16" Altec's in the corners. I use a simple parallel network, coils on the woofers wound myself on laminated cores to the frequency necessary, and caps on the 57's which have a rather complex impedance curve. It took me research and trial & error to figure out the points etc but they integrate into my particular room very well. I've witnessed and been thru measurement rigors but I still use my ears in my room to integrate everything all together. I've done all this to the point that I am not compelled to screw with things and just sit back and listen to the sweetness in the music and not obsess.
BTW for anybody, many years ago I had an xover program (I forget the name) that would allow plugging in all the info and variations you want including a built in database and it had all different kinds of speaker xovers including series. If it's not around anymore I'm sure there is something else.
Very nice.
What amp do you have driving them, S?
A mate of mine has a pair, driven by some lovely Italian tube monoblocs (a mere 18w, I believe).
I understand they are a pretty wicked load - so very few ss amps can handle them?
Andy
A real good amp for the QUAD ESL ("57") is the Music Reference RM-10 (Mk.1 or 2). Roger Modjeski used the ESL as his load when developing the RM-10. Roger passed away a few years back, but his assistant (who still runs Roger's business) may have one left to sell, and they occasionally turn up for sale used.
I've had quite a few over the years but I'm down to a pair of Dynaco III's not stock per se, a Quad 405 that has a thorough updated rebuild, and my favorite a relatively unknown Kinergetics pure class A KBA75. I had a Levinson class A at one time but the 75 was just....better, what can I say, it has an effortless authority and clarity and I don't speak a lot of reviewer speak, I just listen.
Very nice! :-))
Andy
Nice setup. ESL-57's are on my bucket-list for a listen. I had a short opportunity with ESL-63's many many years ago.
Dave.
Dave, aren't the components of a series and equivalent parallel XO the same, just the wiring is changed? The elimination of the external box is a result of using a 1st order XO rather than the higher order XOs seen on the earlier models.
"Our head is round in order to allow our thougths to change direction." Francis Picabia
That would be true if you were talking about textbook alignments. But start skewing the curves around to tailor the acoustic responses and you will see what I mean. The inherent interaction of the series crossover limits what you can do in this regard.
The classic example is the Magnestand MMG crossover. It's designing for a textbook electrical (and impedance) response, vice an optimized acoustical result.You are correct that shallowing of the electrical slopes in the newer models resulted in simpler networks. But, I maintain, the reason for doing so is practical and not performance.
Dave.
Edits: 11/26/21
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