After been doing a bit research into "DSP option", it just happens that I may have found a mis-understanding, or may have been a false claim, with respect to time-coherent design. I certain did make that myself in this thread. Apparently, I myself did say a few times in this thread that "time-coherent" design is only possible with first order filter. But after doing some research into "DSP", it seems that a time-coherent design is possible for filter different type of filter, with different order such as 2nd, 3rd, or 4th and so on, NOT JUST with first order. Now it's also a matter of definition as well. If you want the strictest definition as possible, that is the only speaker that is qualified for "time-coherent" is first order filter then I guess there is nothing I can do about it, then if that is the definition, then only and only first order filter speaker can be called "time-coherent". But my definition of "time-coherent" is a bit broader. That is any speaker that have 0 phase shift and can perform a proper step response is qualified for "time-coherent" or "time-coincident". If this is the case, then there are other classes of filter designs that are qualified as "time-coherent". One example is "Bang and Olufsen" design, which uses LR2 (second order), that can perform a proper step response and has zero phase shift. Here is a picture of it:
https://www.beoworld.org/prod_details.asp?pid=868Not only that, but if you employ "DSP", then you can actually have higher order filter, which normally won't be able to achieve a proper step response, but you can introduce a "correction" factor in "DSP", that will make the overall speaker response to have 0 phase shift, proper step response and all. So now you can see that you have a situation where you have different types of speaker with different types of filtering topologies, 1st, 2nd, 3rd, 4th and so on, but all will have zero phase shift, proper step response, and and hence can be qualified as "time-coherent", which definitely will make things a bit complicated. So the question to ask is: is there any advantage of using "first order filter" at all? Because we have seen that any filter order will be qualified for "time-coherent" and able to perform a proper step response. Also another question to ask is: Are all "time-coherent" created equal? Is one better than another? |
they close forever on 12/21
It seems like I've made lots of mistakes using that word "forever". |
By the way, has anyone had a chance to listen to the "B&O" MS150? https://www.beoworld.org/prod_details.asp?pid=868 It is a time-coherent design, or at least that is the claim made by B&O. I think B&O uses the term "Uni Phase" design, or basically it means to have zero phase shift and able to perform a proper step response, just like Thiel speakers. But instead of using first order filter as the Thiel’s, it uses LR2, or second order filters. |
Andy2, glad to see that more people are getting familiar with options to have linear phase. The steepness of the slope had an impact on the pre ringing, as has the frequency of the filter. Although I've always believed in first order filters, I was somewhat skeptical of the "time-phase coherence" part and was not sure if it does make a difference. After converting two of my speakers xovers and making them "time-phase coherence", I am starting to become a firm believer in the advantage of "coherence". I am not sure what my mind is saying, but my ears definitely are hearing a difference. There is something in the sound that just more "natural". I guess that's the best adjective I could use. I would hesitate to use the word "better" though because people will have their own "belief", but I am comfortable with the word "natural". In my previous speaker design, although they also sound "natural", with "time-phase coherence", there is an extra "ease" as if the music "flows" better. Since I work on my own speakers, I was able to compare two identical speakers (same cabinets, same drivers ...), one with and one is without "coherence", and I prefer the "coherence" version. |
Something funny ...
I was having a few beers late last night then I found myself listening to a pair of beautiful CS7.2 in a large mansion no less ... then I woke up, no speakers, no mansion, no beef :-) Maybe I should stop working on speakers for awhile. |
Bud, Coors, Heineken, Corona, Draft?
It's not the beers that made the man. |
With the CS2.4, when I listened to Pink Floyd Welcome to the Machine track on Wish You Were Here album, the initial sound affects of the track comes practically from the right wall right on my right side at my listening position. With my own speakers or from other brands, the affect comes also from the right wall but further up close to the speakers so it is not quite as spooky as with the CS. I also listened to them at a dealer with a more proper room treatment and the soundstage was even more real. |
I think different frequency range presents its own difficulty. The upper mid/treble region does have its own issues. On the opposite pole, the lower bass has its own unique issues as well. I've designed speakers with both ported and seal designs, and the ported has more "bass", although the seal bass theoretically can extend lower freq., it has a less perceived bass vs. the ported design. On the flip side, the ported has a higher order high pass slope, so it has more group delay vs. the more shallow slop of the seal bass design. For monitor design with smaller woofer, a ported design makes more sense since it has "more bass", at the same time, it is small enough that does not load up the room and may cause room issues. I've used seal bass design for monitor and they just do not have enough bass to justify the more "bass quality".
For three way design, with a larger 8in woofer for example, you could afford to use seal design, but given the same 8in woofer, I could clearly hear the less bass output from the seal design. I think if you have a good cabinet design, a ported 8in woofer will sound just as good and a 8in. woofer is still small enough that will not load up the room and cause issues and that is if the cabinet is well designed.
Most Thiel designs use Passive Radiator. In theory, it has a higher cut-off vs ported, but lower cut-off vs the seal design, so it is somewhat in between, with respect to efficiency and transient response. The ported design has the most bass efficiency but poor transient response, the seal design on the other hands has the least efficiency but the best transient response, and of course the Passive Radiator is somewhat in between.
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The story of the CS1.7 from Tom is very interesting since it told a story of what is superior - the fourth order xover that allows for better power handling and "smoother" treble response, but of course it is not time-phase coherent which some view as having technical superiority. I was wondering whether the reason it was not well-received by the Thiel loyalists because it was not a time-coherent design or of some other reason? Is it possible that even if the CS1.7 is "better", it would not have been embraced by Thiel loyalists
no matter what
because it was not time-phase coherent?
I guess it could be viewed under the lens of a philosophical debate between first order vs higher order, and not based on the technical merits? I am just asking since I don't know the details, but it seems like a perfect example of what has been arguing within the audiophile communities: first order vs. higher order.
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Jim’s approach was that everything matters. First thanks for your insights and I don't mean to play the "monday quarterback" game, since that could offend others, but it would be interesting to see "what if?" without being too negative. Is it possible that if Thiel as a company was not so strong in its insistence on first-order coherence, that is if Thiel product portfolio was a bit more inclusive, was more open to other point of view, it could be more financially viable even after Thiel? I think some of the speaker companies who are more currently successful have a wide range of products - if for nothing, it is to stay financially viable since one product can be used to support others and so on. Having only one product or having only one philosophical point of view may restrict oneself to the potential buyers, who whether we like it or not, will determine the success of a company. Had Thiel had been more flexible, it is possible that Thiel would still be in business, and that means not only more people would have access to Thiel time-phase coherent products, but Thiel other products will be made available to the a larger group of buyers, and ironically, it would serve to what you stated as "everything matters". I don't know ... I guess I am more flexible as opposed to your point of view. If it was possible to go back to the past, if you had known the road Thiel was going would eventually lead to the current situation today, would you still? Anyway, this post makes me want more beers ... something I guess most people would agree :-) |
To Andy's point: New Thiel demonstrated quite clearly how a marketplace responds to non-focused strategies. New Thiel spent $10Million trying to do the standard job really well. Their tower speaker got 5 stars from Brent Butterworth and did the standard thing at least as well as X,Y and Z. But who would buy a Thiel Standard, when you could buy the real X,Y or Z Standard from PSB, B&W or anyone else in the field. Primary among the reasons we chose first order slopes is the uncanny rightness of sound, which I have previously addressed in this forum. I am not arguing about the technical merits of time-phase coherent. I am only arguing about Thiel business model as if it is financially viable. I would not criticize PSB or B&W as they are able to find a way to be viable even if using a different design strategy. To me it seems like Thiel had put themselves a bit into a corner with such a singular mindset - that is first order time-phase coherent or all else which may be correct technically, but financially, it did not have a way out. For those who "get it", there is often no going back. Count me in that camp in company with many of you. Again, I am not arguing about that either, but financially, since there are very few who actually "get it", and it seems to limit the potential pool of buyers. A senior executive at Dynaudio relieved our angst by saying: "What you are doing is impossible, expensive and invisible. Don't worry about others trying it." He was right, and we changed stragegy from patenting innovations to running as fast as we could on our own course.
What you said was a bit of an irony. I could interpret what you said as a "put down" of Dynaudio, but then Dynaudio is one of the largest speaker maker in the world so they definitely know what they are doing.
That seemed worth doing, and still feels good.
I think it was Plato (or Socrates I don't remember) who said that if it feels good, then it probably is not good. I've been drinking too much beers so I probably agree with that :-)
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I'll probably see if the KEF R series can come close to the magic that is Thiel, but I'm not counting on it.
The magic is in the beers :-) |
When the world turns dark
And the heart turns cold
And beauty turns to me
That's when I turn cold.
OK, what's the hell is that? I think I just need more beers :-) |
There currently a pair of CS3.6 at Audiogon. Quite tempting.
Could anyone compared the CS3.6 to CS3.7? I've heard the earlier Thiel tends to sound a little bright.
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What Gear is in your current set-up?
DAC: Ayre QB9
Pre: Pass Labs X10
Amp: Sim Audio W7
Speakers: Home made
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^^^You have to zoon in the pictures to see.
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I am back :-).
I sold my CS2.4 a few years ago, and after that I regretted ever since. And I’ve been waiting for a pair showing up here at Audiogon for a few months. Just a week ago, one pair came up for $1500 and I wasted no time getting them.
Their is also a pair of CS3.7 here locally in Socal but the asking price is $5500 which is a bit more than I am willing to spend. I think the CS2.4 is good enough for me.
Now it’s all good.
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What other gear and cabling are you planning for the system?
Not in the near future. I currently have a Pass XP-10 preamp. If I have to change one thing, it would be the preamp for a tube unit. My system is all SS so the midrange is a bit on the lean side. A tube preamp would add a bit of bloom to the midrange.
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Has anyone had any experiences with rebuilt coax driver for the CS2.4. One of my coax driver stopped working. I need to send it to Rob for rebuild. Rob told me in the email that the rebuilt unit should have the same spec as the original one and should sound the same.
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Hi Tom,
Thanks for your reply. I feel good now with your info,
Thanks,-Andy
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Hi Tom,
I was wondering if you know that CSS is open this week. I have Fedex tracking that said they couldn't deliver the package because the business is closed.
Thanks,
-Andy
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Hi Tom,
Thanks. I hope things will be OK with Rob and his mom.
-Andy
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Thanks to Rob, I got my CS2.4 coax driver fixed. After a month of waiting, I finally got the driver back today.
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Raise your hands if both of your CS2.4 coax drivers went out? It happened to me but thanks to Rob at CSS, both got rebuilt. :-)
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One thing I don't know is how durable the 8in. woofers are - whether they can withstand the abuse from long term usage.
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For the CS2.4 owners, are your vocal reproduction holographic? Mine is a bit recess. I am not sure what is the root cause? Could be from my upstream components.
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Hi jafant,
My upstream components are Ayre QB9 DAC, Pass XP10, Simaudio W7 amp. Cables are Acoustic Zen Hologram II.
It could be my hearing. I am in my mid 50’s and my high frequency hearing is pretty bad.
The W7 could be a bit laid back so that could contribute some factors.
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AZ on the warm side of neutral? : Corrected.
I can try another cable but I don't think it's the cable though.
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I tried to pull the speakers out a bit from the wall. I got a little bit better vocal definition but the mid bass leans out a bit which I did not like.
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To Thiels owners, do you value time coherent above other aspects of sound reproduction?
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more complete sound, from the harmonic structures, dynamics, and a natural sound balance between all the sounds, so most things don't stick out as not fitting into the picture.
I think you could find these qualities in other speakers too. Not just the Thiels.
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Thanks for Tom as usual for your insights.
I think the CS5 is an example where time coherent was achieved at the expense of a speaker that sounds a bit reticent. I've read the Stereophile review that the xover consists of a total of 114 components. That is just too many in the signal path, and it probably contributes to the "reticent" sounding.
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I say that neither Jim nor Thiel Audio would espouse valuing ’"time coherence above other aspects of sound reproduction"
I think all speakers design is a compromise. If one aimed to achieve time coherence design, one compromise other aspects of the sound reproduction.
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For CS 2.4 owners, do you notice the soundstage lacking a bit of image height?
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What does is it mean for CSS? Will it be viable for a long while?
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