Can Thiel CS1.2s be upgraded?

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I have a pair of Thiel CS1.2's that I love but I'm always looking for ways to make what I have better.

They seem to have Vifa P17 woofers, 25mm Seas Aluminum dome tweeters, and complex crossovers that has polypropylenes at least paralleled anyplace there is an electrolytic cap. The cabinets are amazing and I seriously doubt they could be improved.

Would changing the crossover to polypropylene only give a noticible benefit? Is there a better woofer or tweeter I could use? Googling for modified CS1.2s comes up with nothing.

Thanks

EDIT: I talked to Thiel and got the layout!

452769d1418051388-can-thiel-cs1-2s-upgraded-cs1.2.png
 
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I'd need to see the crossover schematic to actually suggest anything. But that Vifa P17WJ-00-08 is a lovely flat polycone woofer. And a SEAS Metal Tweeter is not too shabby.

It's time aligned, you see. Which is good. Probably hard to improve if the designer has got it right. Losing ferrite core coils, and using polypropylene capacitors with some added resistance if electrolytic aged non-polars were originally fitted remains a possibility.
 

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Hi,

The short answer is no, leave them well alone,
you will be basically simply wasting your money.

The long answer is with a thorough understanding
of the x/o, the speaker and your system, tweaking
is possible, preferably entirely reversably.

Sadly :
Thiel CS1.2 loudspeaker | Stereophile.com

Has a lot more hot air than any facts that you can use,
i.e. a decent set of full proper measurements to go on.

rgds, sreten.
 
I have a pair of Theil speakers. For their size, you would have a lot of trouble finding better speakers. I have not taken mine apart, but to get phase coherence, they must have a rather complex crossover. I would not mess with it. Chance of improving it seems remote to me.

If you are skilled enough to improve your Theils, you would be better off building you own speaker system from scratch.
 
I wouldn't look for miracles here. But a time-aligned 6" low inductance polycone with copper rings two way is potentially a very nice speaker, albeit with some bass limitations.

You must draw up the schematic. I really couldn't guess beyond saying the flat impedance suggests copious use of Zobel impedance correction. It could be a series or parallel circuit.

See, you must do some work here yourself. It takes about 6 months to fine tune a speaker from concept to final run.
 
OK, so you seem to be saying a lack of bass is an issue? :)

Well, that's the nature of a small bass drivered 6" two way. Any other beefs?

It's a speaker for a small room really. If you have a big room, 3 ways are better.

Now stop waffling and trace the schematic. Otherwise you and we are blind men walking without a white stick. I'm pretty good at loudspeakers, but am I psychic? NO. :D
 
No the bass wasn't the issue for me, but with everyone saying they really can't be improved I thought I would focus elsewhere in the system.

I'll try and take a picture of the crossover for you

A picture would be good, but some values and a schematic and the polarities of the drivers would help a lot more. This is evidently one of those 6dB/octave Mickey Mouse designs: Thiel CS1.2 loudspeaker Phase Coherence | Stereophile.com

A one-trick pony with good phase alignment and good impulse response, and not much else going for it, unless you like cone breakup and tweeter distortion! It has simplistic series crossover written all over it. Those can be improved a lot IMO. Most of these types of design were based on the "Acoustic Reality" crossover, which led a lot of people up the garden path! :eek:

BTW, don't read too much into the sim on frequency response. A paper bass is a different animal from a polycone.
 

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Thiel employ 1st order filters, but I've never seen a simplistic example from them, let alone an AR type. To the best of my knowledge, they're parallel designs with extensive impedance correction & multiple notches where appropriate to ensure a decently flat response. The attached image for instance shows the 1st order filter for the CS6 -not exactly a minimalist cap & coil. ;) In the measurements page of the Stereophile review of you link to, John Atkinson provides the following remarks:

-'it is noteworthy how little change there is for each speaker... I would conjecture that Jim Thiel has used some form of conjugate load system in his crossover designs to give such a flat curve with frequency.' No news there, standard practice for Thiel.

-'the in-room response is one of the flattest I have measured'. It's not half bad.

So they are evidently doing a fair bit right. Granted, 1st order means limited power-handling & off-axis response -that's the trade off. Not to all tastes to be sure, but it's not without merit either. They're one of the few places where you can 'see' a 1st order filter implemented 'properly'.
 

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Flat room response is a characteristic of any odd order crossover, so no big deal there. :)

I suppose it could be a parallel crossover with impedance correction. It can be done.

But first order always says "Little Girl with a Guitar" or "Kabuki" speaker to me. Something that can't go loud with big program material.

Which is all to say, we (well, most of us) all understand how this stuff works.

Anyway, I'm STILL just waiting for Mr. bmw to come back with some detailed info. I waste a lot of time waiting, and waiting, at this forum. :mad:

Meanwhile I have far more interesting projects occupying my time. :D
 
It will be (parallel). Thiel don't use series filters ('can't say I blame them for that ;) ).

I'm not saying I disagree -I prefer high order filters myself for the improved power handling &c. But some, especially the big (as in 'big') Dunlavy's etc. can do it. Variable slope works too of course, if implemented well.

True -forums can = waiting. Still, nobody obliges any us to be here, or to try to help others, so it's not like we're in a position to complain! ;)

Interesting projects? Do tell. Always good to see something different. :)
 
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snip...Interesting projects? Do tell. Always good to see something different. :)

I have no beef with series filters whatsoever, except they need time alignment to work well. But, you know me. I'm always interested in the two ways with decently performing 8" bass.

TQWT-

You know those old classic speakers with BIG boxes and baffles? What is special about them? Mainly that you can get away with low value bass coils. Which has the knock-on effect that you can use nearer Zobel value shunt circuits.

So what I am finding is that to get a 8" bass to perform well, you need a big baffle. Which allows you to use some serious shunt capacitance, which sounds better.

And something odd then happens, which is that you then need a bass driver with lower Le inductance to work well. So in general, I am moving away from narrow baffles. You did ask, and I've obliged you with a serious answer. :cool:
 
Dear System 7

Quote:

Flat room response is a characteristic of any odd order crossover, so no big deal there.

Would you care to explain why any driver/odd order x/o combination produces a "flat room response" whatever that is may be?

regards,

Eelco
It's not often I get called "Dear" system7 by the "friendly" folks at this forum, so I thank you. :)

How it works, is even order (LR2 and LR4) filters give a very flat frequency response on the horizontal axis. Unfortunately it all goes "tits up" above and below axis. What this means is if you are listening down the hallway or in the back of the room is there is a spooky loss of energy at crossover. It sounds a bit odd.

When you use a odd order crossover correctly, with all the oddities of their 90 degree phase alignment, it actually sounds quite realistic. In general, I am more interested in the 18dB slopes of third order Butterworth. Perhaps this leads to third order MTTM designs. Time will tell. :)
 

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