Hey @vair68robert
Given the cap sizes you are talking about I'm assuming these are in low pass sections, and going to ground. The Solens, or their cheap brand, Axon, will be great choices, BUT, you must maintain the original ESR + R of that portion of the circuit or you may suffer unexpected impedance issues, which causes your amp to suffer, along with changing the crossover points.
Save the top-end caps for caps that are in series with the drivers.
Best,
E
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Let me chime in as some one with relatively recent experience with Clarity and CMR in particular, but not with Thiel rebuilds.
The CMRs are excellent caps. I honestly don’t know if they are better than the previous generation. I’ve swapped them out in my application and they sounded equally excellent.
What I have found in both cases (CMR and MR) is that Clarity caps above 5uF benefit from a small bypass copper cap. This was a suggestion passed onto me at DIYaudio by Speakerdoctor before he passed (RIP). Though he did not suggest it above a certain uF value, I have found this to be about the break point. Below this value, a bypass cap did not help, but above it certainly did.
Based on his suggestion I’ve used Audyn 0.1uF TrueCopper bypass caps, and they worked really well. Anyone who wants to ship me Jupiter caps instead please do so! :) I wish I could afford them.
Best,
E
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Question can you run a cap and resistor in series to equate the the esr of the original ? @theaudiotweak Yes,
you can, though ESR is not exactly a constant at all frequencies, you
can definitely compensate with a little eye balling of the relevant
graphs. :) 0.1 Ohm difference isn't as important as going from 1.5 Ohms to 0.3. That in shunt can really drop the impedance of the next range. Not as fancy, but I love Mills. Small, very high power, extremely accurate and thermally stable. Remember the same thing with inductors. Keep the DCR the same, or you are changing the speaker. There are a number of designs (including my own) which use the DCR as part of the baffle step compensation. Best, E |
Jafant, erik_squires has gone on record here at Audiogon of not being a fan of Thiel’s. I'm afraid this is true, but I'm always surprised anyone remembers what I like or don't. The tonal balance of the Thiels was not for me, though I have not heard them in many years, and it was never a complaint about the quality of the product, just not suitable for me. The MRA case is quite a bit smaller for a lower dissipation factor. So
put the MRAs on little balls of Mortite or BluTac for 360° radiation and
airflow.
Really good advice, especially if planning to ship them, but otherwise, for a home project just lifting them off the board works. Thanks but the Mundorf does not have the value needed
Consider the difference in age alone. In the 1980's/1990s electrolytic caps were generally crap compared to even budget bipolars of today. Best, E |
Erik - what is your target frequency response, either outdoors / anechoic, or in a room? Thanks for asking, @tomthiel , honestly I’m a little chagrined sharing what I do with some one who actually has been so successful in the industry. I should explain that the last time I heard a Thiel speaker was before I returned to my electronics background. Mid 1990s perhaps? I wasn’t really measuring anything then, so I have no way of knowing what I was hearing or what struck me then. Long after I decided to take some of what I stole from Dr. Leach at Georgia Tech together with modern inexpensive tools and get into speaker design, so I don’t want to say anything as being definitive of how I would hear things now, or what I might be able to ascribe to what I heard in the 90s. But to answer your question, my target ends up being the old B&K curve at 1 M, but, measured in-room. Of course, these are cheats I can only get away with for a 2-way speaker. However I recently took in-room at listening location measurements and posted here: https://speakermakersjourney.blogspot.com/2020/01/the-snr-1-room-response-and-roon.htmlThe mic was at couch seat level, so probably much closer to mid-woofer axis. now to Eric’s credit, while his opinion of Thiel high frequency performance is dated Extremely dated, I wish people would remember that caveat when they post about my comments. he does have IMO an acute and appropriate focus on room treatments:-) Ty for the kind words, @tomic601 , but for me it is necessity. I am unusually susceptible to room acoustics, and wish I was not. I run into so many audiophiles at shows who can shrug it off. Wish I was more like that. |
Of huge importance to Jim was that of balanced design. He worked toward
a performance plateau where all elements worked equally hard and
efficiently to perform at maximum cost efficiency as a whole system. It's really easy, especially as hobbyists, to focus on some particular component like capacitors or the tweeter, at the expense of everything else. It's like putting the most expensive tires on the market on a Honda Civic. Best, E |
@Unsound While I apologize for the confusion, I didn’t think I needed to make a caveat when the OP clearly established the boundaries of the conversation in the thread you posted as being about the Thiel CS2, which was reviewed at least as early as 1985: https://www.stereophile.com/floorloudspeakers/1085thiel/index.htmland the Vandersteen 2c which was reviewed at least by 1989: https://www.stereophile.com/floorloudspeakers/914/index.htmlIf you wanted to know if I meant to review all Vandersteen and all Thiel speakers forever, then you should have asked the question as such and I would have said "no, no I do not." If you wish to hold me to an editorial standard of writing complete monologues each time I post on this hobby site then we can discuss an appropriate salary. Best, E |
I haven't spent much time listening to carbon drivers per se, but I have to say that overall I've always ended up preferring composite cones, anything from the Focal W construction to the ScanSpeak sliced paper to simple fiberglass/resin construction from Peerless.
Certainly I can say that I like composites a great deal more than I do the top ceramics.
Still, there's a lot more to a speaker than a driver material and it's' focusing on these single items which leads to out of proportion spending and myths about specific speakers. The system is what matters, but the drivers are always fun to talk about.
Best,
E
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Hi @tomthiel
Sounds like you have a lot of work but all of it is engaging and creative so I am sure you are well motivated.
I did some experimenting a while ago with coils and conductors and discovered how easy it was to have a coil couple via capacitance to traces underneath it. Wonder if you are running into that as well.
Best of luck,
Erik
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Eric - you are most welcome to share your turbulent / laminar flow ideas if you wish, either here or via PM. @tomthiel Um, was this for me, or is there another Eric in this thread? I don't remember saying anything remotely related to fluid dynamics. :) Best, E |
Hi @unsound,
All multi-way speakers employ crossovers, and the phase must align correctly or there will be frequency response anomalies and lobing effects.
What I suggest you do is look at the Stereophile reviews for Thiel and Vandersteen speakers and compare them to say Monitor Audio or Wilson. your answer is there.
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One area in phase that you is always left out is the phase of the midrange cone during playback. If you look at the Wilson midrange it’s out of phase as it’s not a true pistonic driver. I’m sorry but this is misinformed. The correct polarity of the driver (which terminal is attached to + or - wires) has nothing to do with "true pistonic" motion. We assume they’re all pistonic in their operating range. The reason a speaker designer may flip a driver is to phase match the driver above or below it. The output’s phase angle is related to the rolloff. This flip ensures optimum frequency response across the crossover region. In fact, using positive polarity would create a deep null. With traditional (non time-aligned) 2-way speakers, flipping the tweeter relative to the woofer is quite common. With three, having the mid-range flipped relative to the woofer and tweeter is. The angle of the speaker’s baffle, the acoustic center of a driver and the crossover slopes all contribute to these choices. "Pistonic motion" does not. Lastly, if we are talking about the sliced paper cone drivers Wilson uses, those are some of the very best sounding mid and mid-woofers in the world. I have them in my own speakers and many high end manufacturers have turned to them as well. They are amazing. |
"Pistonic motion" does not.
To be fully accurate: at a high enough frequency most cone drivers eventually have break up modes where the driver no longer functions as a piston. It is the speaker designer's job to account for this in picking the driver and low pass filter. There is no "true piston" vs. not designation in traditional drivers, just what range and what output levels they remain pistonic in. The exception that proves the rule though are the Ohm type drivers, which are decidedly NOT pistonic. I believe they are fixed at one end, and driven at the other. |
@unsound
I could find nothing in that post which supports your statement that flipping polarity of a driver is in any way related to it behaving like a pistonic driver.
I suggest you quote any relevant sections.
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Getting good, deep bass in a room is always complicated.
A smaller (higher -3 dB) speaker can often sound much better in many rooms. 20-40 Hz are possible from even 6.5" drivers, but of course, not at concert levels.
Room treatments should always be considered among your first choices in getting good bass. Lowering the mid-treble energy in the room plus controlling room modes can transform speakers into sounding much larger.
Best,
E
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Just FYI - Looks like Madisound has started carrying replacement drivers from Seas.
Only saw two there, but worth checking out. A titanium tweeter and a mid-woofer.
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