Hi Tom, To the point of Seas, Vifa etc. could do "it". We tried for years without success working with the best. It’s not so easy as it might appear. That is very interesting. Seas and Vifa were some of the very best at the time indeed. I have no doubt at all that is not easy, but I just thought if someone like Seas or ScanSpeak (since Vifa was taken over by SS) were serious enough about it, maybe they could make some very good concentric drivers. The challenge is in the motor design as well as doppler affect of each driver modulating each other. Based on what I read online and what are available off the shelf parts, it seems like the speaker design industry more or less has given up on time-coherent design. With exception for some very few drivers, most drivers has to be designed with at least 12db roll off. For example, Accuton is a very reputable driver makers, but if you use their drivers, you almost have to go with 12db or 24 db roll off. As for Seas and ScanSpeak, with their portfolio of products, only a few drivers can be implemented with first order. Another things I found interesting is that almost all of Thiel designs use aluminum drivers. To the best of my knowledge, there is no off the shelf aluminum drivers on the market today can be implemented using first order filter because of their inherent break up at high frequency. So you pretty much have to use higher order filter to suppress the break up. So how Thiel did it with first order using their aluminum drivers must require some unique engineering. I think the "wavy mid range" driver of the CS2.7 is one way to minimize the break up. As for the CS2.4, I am just guessing but the mechanical of the rubber surround was meant to solve the break up problem, and whatever it is, it really works. Hm..., this whole big planet that there is nothing like Thiel? To borrow a phrase from the movie "Contact" which was based on Carl Sagan book, "this whole big universe and our planet is the only source of life? What a waste of space." |
I was able to obtain the CS2.4 oxver upgrade information from the other thread. Doesn't seem that difficult and I can't see why there would be any problem. I think I'll give it a try next week. |
but what about the resistors in series on the tweeter/mid crossovers?
They are not part of the 6db crossover but the signal is going true them, confused!!??
There are two possibilities: 1. The resistor is in series with cap that eventual leads to the mid/tweeter. In this case, it is worth upgrading them to better spec resistors. 2. The resistor is in shunt to the mid/tweeter network then it is not in the critical path which means it is not critical so upgrading will not yield any meaningful improvement. But resistors are mostly less expensive so since you're already in there, might as well upgrading then as well. I have not seen the xover network in person yet so I am not sure if the resistor is either #1 or #2. Also, in my experience, caps make a lot more differences vs. inductors so upgrading the inductors may not yield a lot of improvement. That said, there is sonic difference between foil and wire type inductor. Having seen the xover in picture, the inductor coil in the bass xover is of wire wound coil inductor so it may be better to replace it with another wire wound type inductor. The original inductor looks like having a 16 AWG, so upgrading to something like 12AWG inductor may give you slightly more bass. Also looking at some of the xover pictures, the wiring may deserve some upgrading as well. I guess it won't be much work to upgrade to something like Supra wire from Madisound.com. |
First I don't mean to take this thread off topic. Maybe just slightly side way. But has anyone heard a speaker with concentric midrange/tweeter? I can think of Kef but I personally have not heard it myself.
The reason I asked is that I am trying to narrow down the unique sound signature of the Thiel? Would you say is it because of its time-coherent design or is it because of its concentric drivers? |
I think the new owners may not have understood the nature of the speaker market. In speaker designs, there are a lot of good brands. If you want something, most likely there are ten brands will compete to offer you that "something". So it's not like there is a shortage of speakers out there. And each brand already has its own loyal customer base.
The new Thiel attempts to build speakers that may be good in themselves, but they are no more special than what already available out there which themselves already has its own followings. Why would the existing customers have to take a chance to purchase the new Thiel speakers while they already know their current preferred brand fairly well?
It's hard to build up a brand image that people can identify with, especially in the speaker industry where most stuffs are more or less a commodity especially at the price point the new Thiel was trying to compete. It's tough to compete in that segment. Someone once told me that if want to go into doing business, target either the very high end or the very low end. The middle end is very tough. It seems like the new Thiel strategy was going for something in the middle in both price and technology - just another headwind for them. The old Thiel although in term of pricing, it is somewhat in the middle but it's technology was at the very high end of the market.
I've seen some very successful brands such as Dynaudio, B&W, Spendor, Sonus Faber and so on ... I think part of their success are as much on life style as their sound. People buy them for decorative purpose as much as the music. Seems like the new Thiel was trying to position themselves into this market but I guess it didn't work out for them. |
Just curious, has anyOne received either Tom or beetlemania xover mod? |
Anyway, in a parallel universe where Thiel still exists with the sound that we have come to love. But what if just for fun ...
I would partition Thiel into three distinct product lines that can leverage the driver technology from the time-coherent designs. There needs to be a Thiel house sound which is based on its magnesium/aluminum concentric drivers so people know what to expect. I assume the cost of designing the drivers is pretty high so it makes sense to spread the cost to more product line. Also having more products will improve growth and revenue.
Here is how I would position three product lines that buyers can easily identify with.
1. Home Theater
2. Luxury
3. Time - Coherent
For Home Theater, sound quality is not as critical so first order is not needed. This will shorten the design cycle but still use some variance of Thiel magnesium/aluminum or even existing drivers but matching drivers are not as critical due to the use of high order (which also should lower cost). The product will include a two way, three way, four way with the fourth being a self power subwoofer with some type of room correction. The styling language will be similar to that of the time-coherent product line. The sound should have the same musical clarity that is known of Thiel. You can use 2nd 12db roll off which is not bad. It has the clarity of the higher order filter but can retain most of the musicality of the first order design.
For Luxury, this is where Thiel can lavishly throw everything at it. The price will be in the 30 - 50K range. It does not have to have first order so that you can have a freedom of selecting different driver configuration. Think of this as Thiel own version of Dynaudio Confidence. You can have two midrange drivers, multiple bass drivers. I can think of having the concentric driver cross over at around 1000hz to a pair of midrange then cross over at around 200hz to a pair of bass drivers. Higher order can be employed. The drivers and styling should have some unity with the time-coherent product line. This is where Thiel can showcase its aristocratic side for the rich. I think this is where the new Thiel was trying to do but the problem is they abandoned all previous Thiel signature thus having absolutely no brand recognition. This would only work if you can tie in with the rest of Thiel products. Not only it will save cost from sharing the drivers and styling, but buyers will recognize them as Thiel products.
And last but not least, the Time-Coherent will remain the same as before, but it will also serve as a corner stone for other product lines in term of designing the driver and developing a styling language.
|
Not yet, pretty soon you'll be getting some early reports.
Thank you Tom for the update. For some reason, I thought some of the Mod's have been available. But good luck with your works. |
Our upgrades are considerably more extensive and expensive and not yet finalized.
Hopefully we'll see your final product soon. |
We working on upgrading the whole crossovers with better parts.
Are you also planning to upgrade the xover wiring? Based on what you've seen, is it easy to replace the wires? |
Don't know what you specific mean with listening experience, but I am a audio lover for many years and have build up a nice audio setup.
I think he meant if you could share your impressions of the CS2.4 sound with the cap upgrade. Thanks. |
Ok, lots more air (very impressive!!)
I feel that the stock CS2.4 does lack a bit of air or I call it "treble glow". In my previous post I said it probably because the stock caps may be the the culprit. I can't wait to get mine upgraded. Thanks for the picture. |
I might also compare foil and wire coils.
Hi beetlemania, In my experience, wire coils sound slightly more lively and forward vs. foil coils. Foil coils sound a bit warmer and slightly over-damped on the bass. Everything considered, I may actually prefer wire coils. But I think ultimately it will be implementation and system dependent. Certain system may sound best with wire coils, but others may sound best with foil coils. |
"density of sound" I keep hearing this phrase coming up when describing the sound of Thiel speakers. Is this a special characteristic of first order filter? Or is it a matter of speaker voicing? For example, if I were to design my speakers using 4th order filters, can I still achieve this aspect of sound? |
It depends on the size of your listening room. As good as the CS2.4, as far as the bass is concerned, it cannot compete with other speakers with 10in. or 2x10in bass drivers. |
There seems to be some talks of what if you want to upgrade the CS2.4? Overall I still think its only real weakness is the lack of low bass. For clarity and detail and natural integration, it's probably still some of the best even for today. Some newer speakers now are using fancier tweeters such as be dome, ceramic which may offer better treble detail but I am not sure it's necessarily better. For speakers using higher order filter, they can afford to add like a 10in. driver such as the Wilson or Dynaudio and so on, but for the CS2.4 being first order time coherent, it's not that trivial and given the constraints I am not sure if it's even possible. So with larger bass driver such as 10in, you get a more fuller sounstage abeit with higher order type of sound. I guess it's all a compromise. You choose the CS2.4 for all its strengths, but have to accept its lack of low end grunt.
But can we add an active subwoofer with some type of room correction DSP? Probably - just like what Vadersteen did with their top of the line offerings that costing even above $50K, which is why I am a bit surprise why none of the Thiel speakers follow this strategy which would not only solve the low impedance issue but still retains the time coherent characteristics.
So the best upgrade for the CS2.4 would probably be some of the Vandersteen top of the line speakers (although a lot more expensive) with a built-in subwoofer. |
Thanks to Tom for recapturing all the works went into the measurement phase. That seems like a lot of works. I supposed that was before the proliferation of personal computers?
I think today speaker designers probably have a lot easier time with speaker design with the advance of software and inexpensive access to computation. Some of the software are actually free and can be downloaded into your personal computers. I personally only spent about $270.00 and able to purchased a set of hardware that can perform all the measurements needed to speaker design. All the softwares that I am using are completely free and available on the internet. The rest is up to my own imagination.
As for measurement distant, I think the problem with making measuring at 8ft distant is that by the time the sound arrives at the microphone, you have a lot of sound reflection from the floor, the side walls of the measurement room. You could put a time bracket so you can only capture the sound at a very narrow time window before the reflections but that would compromise the low frequency portion. The longer the measurement distant, the narrower the time window, and hence the lower frequency response compromise. You could correct for that by measuring at closer distant such as 1 meter which is industrial standard. The problem is with first order speakers, at that distant, the mid and tweeter may not fully integrated so that is another challenge. Or you could build a large chamber so the floor and side walls distant is a lot longer than 8ft. Another problem is at low frequency, the wavelength is so long that you need a very large chamber so that you can accurately capture the one wavelength of low bass frequency before reflection. Tom mentioned that Thiel was trying to measure the speakers outdoor with the speakers mounted on a tree to eliminate reflection from the ground so I guess it had to be a pretty high tree :-). Eventually it may not be practical to build such a large chamber so there are a few methods of trying to merge the high frequency and low frequency response. There are software that could do this but they seem to have their own limitation.
But I think you could make it as complicated as you want, or you could simplify as much as you could to get a finish product.
|
All the technical discussions not withstanding, it's all about the music albeit first order, higher order, ... as long as you enjoy the music, it's all that matters. |
Also besides the complex architecture of DSP, you can’t do the following:
1. Use vinyl as your source
2. Use your favorite tube amplifier
3. Use your favorite DAC as your source
4. If you have a set of favorite speakers cable such as Crystal Cable Absolute Dream, you can’t use it either because the DSP setup has its own dedicate built-in cables to the drivers. So if the DSP design uses low end cable, you’re more or less stuck with it. |
Just curious how do you position your CS2.4?
Mine are 7ft apart center to center.
I sit about 9ft measured from the front facial.
The back of the speakers are about 19in from the front wall. |
Does anyone know of an active, dsp, phase correct/coherent speaker?
I have seen one claim from the DIY community that was able to produce a perfect step response but I can't personally vouch for it. He claims that he uses DSP to delay the tweeter so that it matches with the mid range (the equivalent of tilting the cabinet as in Thiel design), but other than that, I don't know anything else. I think using active DSP has its own drawback. It's not all that it claims to be. In someway, it's even more complicated than passive cross over. For example, for a three way, you need six different amplifiers and six different DAC's. I mean one amplifier is expensive enough. In order to have six, you have to use inexpensive amplifier such as digital amplifier, so the quality of the sound is heavily compromised. Likewise, with six DAC, you have to compromise as well. So everything considered, using active DSP is a compromise approach. |
As others have mentioned, integrating the sub to the main speakers is not easy. For time-phase coherent speakers, it's even more difficult. I think that is why Vandersteen chose to integrate the sub into the main speakers so at least you have some control over how the sub will be integrated to the main with your own DSP algorithm.
I personally think deep bass is important. Now I don't mean earth shattering bass that vibrates your windows, but I mean the speakers able to reproduce the low frequency portion of the recording such as capturing the recording spaces to make the listening experience more authentic. |
Hi beetlemania,
I was wondering if you had to remove the xover boards from the cabinet then swapped out the components, or do you solder the components while the xover boards were inside the cabinets?
Thanks. |
I'm planning to replace the 7bst with a higher quality amp of up to 30 watt, class A, tubes or SS. What would you recommend. Been looking at pass labs and luxman.
I have a pair of Cary Six Pac Monoblocks rated at 50W in triode mode, but they just cannot drive the CS2.4 effectively. They dynamic is clearly lacking and the music just does not have any life. If you are looking for tubes, I think you really need some really high power tubes. |
Hi Tom,
I was wondering if you would be willing to share the xover design of the CS2.7 or CS3.7. I believe the mid+tweeter unit has separate xovers (vs. the 2.4 which is mechanical). For the tweeter xover design, do you know if it has an electrical delay network to align the phase of the tweeter to the mid driver? Or the phase alignment is done acoustically?
Thanks. |
There is no time compensation in those crossovers. The coincident alignment is achieved geometrically via the position of the coaxial midrange and tweeter.
Hi Tom, Actually you have answered my question. Thanks. |
yesterday's HiFi Chats via YouTube featured Dave Gordon of ARC.
Fast forward to around 30:15 where Dave said "not all USB cables sound the same". I am sure a lot of people will have issues with that :-) |
I have been through tons of speaker cables and I can tell you that you do not need expensive cables to enhance characteristics of the 3.6. There are several sub 1K cables that have worked better for me than many low to mid 5 figure cables. All depends on your tastes and your amp. Enjoy those great speakers!
I am thinking whether it is a good thing or a bad thing. It could mean the bottleneck could be in the internal cables used for the particular speakers. So the overall improvement by the external cables is held back by the quality of internal speaker cables. I have used various cables in my speaker designs. I have used some cheap cables from Fry's electronics and Supra cables from Madisound and the Supra cables significantly improve the sound. I have seen various pictures of the CS2.4 xovers and although I don't have any information on the cables used, something tells me the CS2.4 could use some improvement on the cables used in the xover wiring. |
internal wire is definitely a factor. It carries a slightly different set of requirements from external cable, which must cope with many unknowns of run length, electromagnetic environment, speaker impedance fluctuation, and more. The internal wire is engineerable to the known requirements of the speaker where it is installed.
I agree. For most cases, the internal wirings are much shorter than the external speaker cables, therefore I think it is less likely to modify the signal phase and amplitude vs. the external cables. Some of the expensive speaker cables nowaday I have seen have rather sophisticated geometry and dielectric core material and grounding that together act like a transmission line to deliver the signal as uniformly as possible across all frequencies. Some people think that audio frequencies are too low to be affected by transmission line but I do not think so. Some lesser cables may have resonance issues and the effect is exacerbated as the length increased. Some believe that the only difference between cables is the resistance. I think it's more than that. You also have the effect of inductance and capacitance - the longer the cable the worse the effect. A perfect cable should deliver the signal from the amp to the speaker input with a constant phase and constant amplitude losses across all frequencies, but since there is no perfect cable (or is there?) by the time the signal arrives at the speaker inputs, the phase and amplitude will be affected differently vs. frequencies. This affect materializes itself as a form of jitter (although there is more than just jitter) A good cable has better phase and amplitude uniformity compared to a bad cable. Some speaker cables are engineered to intentionally have a transmission line affect so the signal phase and amplitude can be better controlled by the designer. With twisted pair, the number of variables is somewhat limited by the wire gauge size and number of winding per in. therefore it may not be able to optimize signal transmission. In some speakers, the xover boards are located at the bottom so the wire to the tweeter could be as long as 3ft. At that length, there could a transmission line like effect that may modify the signal phase and amplitude non-uniformly vs. frequencies therefore the quality of the cable is more important. But I have personally seen that something as short as 1.5ft length could make significant difference with quality cables. Anyway, I don't mean to make this into a cable thread (I don't want prof to loose his sleep :-). |
But there is this other dimension. In my acoustic guitar design and archival recording I have identified an accumulation factor. Recording engineers and piano techs and other technical artists also experience this phenomenon. When on a particular path of exploration, guided by both cognition and intuition, there are many choices which are not provable or even discernible. But a conglomerate effect becomes identifiable / meaningful over time. There are so many subtle factors contributing to the overall result, that each of them could be ignored or over-ruled, but they can matter in their aggregate.
I think it may have to do with how our brain processes signal and the threshold that it will register a response. For example, our brain could identify a certain amount of echo given the delay after the initial sound arrival. Theoretically, there is echo everywhere, but our brain will only trigger a response only if above a certain delay. If our brain is perfectly analog, then the brain should be able to tell use the exact amount of echo from small to large. But I am glad because we would be driven to crazy if we are constantly bothered by all sort of echo around us. So in a sense, our brain will only let us know if an echo is worth our attention. I think this is our own built-in "hysteresis" not unlike the hysteresis in for example a thermostat. Let's say you program your thermostat at 70deg with 1deg of hysteresis, then the thermostat would turn on when the temperature is below 69deg and will turn back on at 71deg. Without hysteresis, the thermostat would oscillate constantly at 70deg. In the same sense, our brain would oscillate constantly without a built-in threshold. So given a small change may not make a difference but as the amount of changes built-up in the aggregate, our brain will trigger a response as if a switch has been turned on. A lot of people have reported a certain "burn-in" phenomenon in which the changes happened abruptly that lends to a certain mystery only adds to the whole "burn-in" controversy. |
Hi beetlemania and Tom,
I am wondering if you could comment on the sound improvement of the CS2.4 given various xover upgrades? I think you have said there was improvement but could you elaborate a bit more? I understand it's hard to describe sound quality in verbal language but if you could give some impression on the improvement over the stock xovers?
Thanks. |
While a heavier gauge in a single conductor may allow a higher capacity, I am curious how signal response across the contemplated frequency range through such increased conductor cross section would be impacted. Perhaps a multiple optimum conductor scheme would be a more desirable arrangement under such circumstances, or over longer distances where such frequency distortions are compounded.
I think the trick is to design a cable that does not really favor any particular frequency. It is easy said than done though. You don't want to for example emphasize high frequency but not at low frequency - you then end up with a cable that sound bright and edgy. And you don't want a cable that has resonance issue at some specific frequencies either(I suspect some low end Monster cables suffer from this condition). As far as having gauge size of 18AWG as optimal, that's an interesting observation. 18AWG itself may be too small to drive a speaker as it may not be able to carry a lot of current without experiencing a lot of phase shift. One way is to bunch together a lot of 18AWG wire then run them on a dielectric substrate so you can have the best of both world - low distortion of 18AWG but able to carry a lot of current. A lot of cables use this strategy especially at the high end spectrum. I looked at StraightWire website and it seems like the as the cable cost gets higher, the construction becomes more complicated in term of number of wire strands and dielectric arrangement. It's interesting that high end cables is only a recent phenomenon. I was not around back then but in the 70's or 80's it was not an area where people were paying that much attention. Personally cables in my system have made the most prominent differences given their modest cost compared overall to my system. Anyway, cables is an interest area of mine but as I said I don't mean to discuss too much on cables as this is mainly a Thiel thread. |
Have you guys (Andy, Beetle, Holco or Tom) found this problematic for your personal system power amps to drive? As I understand it, this is correlated in drops between 4 Ohms down to 2 Ohms across much of the speakers' frequencies. 3 Ohm nominal.
The impedance of a speaker can be a bit complicated (but it doesn't have to be). The other side is how the amp drives the speakers if the amp is a no-feedback or feedback design. In general, the higher the impedance is the better but that statement is a bit overly simplified since higher at some frequencies may not be good. In most speakers, the impedance is lowest at low freq. around 100 - 200 hz and rises toward the higher freq. The low freq is where most amp will have issue if it stays too low. I think the impedance of 3ohm or above is probably OK, but below 3ohm, some low power amp probably will have problem. At high frequencies, low impedance is usually not an issue since high frequencies do not demand as much current vs. low freq. As the freq. rises higher, you probably don't want impedance to get too high (due to inductance rising) which will result in treble harshness. In some speakers, there is an "impedance correction network" to reduce the rising impedance so that it won't be a problem for tube amplifiers. So this is where high impedance is not good either. As for impedance angle, it is mostly negative (capacitive) at low freq. and gets more positive (inductance) at higher frequencies. As long as there is not excessive swing from negative to positive, it should be fine. In general, you don't want the phase angle excessive negative at low frequencies and excessively positive at high frequencies. Too negative angle at low freq. will be hard to amp to drive. Too positive at high frequencies may result in treble harshness. In general, capacitive load demands more current and reduces dynamic, whereas inductive load causes high frequencies issue. The other side is the amp design. Some amp are design with no feedback and some with feedback. Most people agree that no feedback is better sounding vs. feedback. But amp with no feedback are more sensitive to speaker impedance swing so it is a trade off. Interestingly enough, most low cost amplifiers are designed with relatively high feedback because it costs a lot more to design a good amp with no feedback. Tube amps tend to be most sensitive to impedance since most of them are designed with very little feedback or no feedback at all and exacerbated because tubes usually don't have a lot of drive current. For those who are interested in feedback vs. no feedback argument, there is a good article from PASS lab that I included the link below: http://www.firstwatt.com/pdf/art_dist_fdbk.pdf |
have you compared Clarity, Mundorf, and Jantzen (or others)? Which ones?
I have used the Clarity CSA (the older version, not the latest one with their newer Copper Technology), Mundorf Supreme cap, and Jantzen Z-Silver. The CSA is OK I think but compared to the Mundorf supreme cap, it has a bit of a haze and the soundstage is a bit constricted and lacking three dimensionality. When I used the Mundorf Supreme, I was actually a bit surprised at the amount of improvement. There is additional soundstage bloom, more palpable, and a marked improvement in detail retrieval. For example, in Cowboy Junkies Trinity Session, the background noise of the recordings is quite a bit more apparent with the Mundorf vs. the Clarity. The Jantzen Supreme Z silver has everything of the Mundorf Supreme but adds a subtle layer of extra detail in the treble. It is very detail and may be just a bit too much detail on the treble but in a good way though. It also needs a longer break in time. If you have a high end setup, I would recommend the Jantzen over the Mundorf but both are very good and the difference is minimal. |
@tomthiel This thread
https://forum.audiogon.com/discussions/thiel-cs2-4-upgrade-to-cs-2-4-se
Thanks beetlemania for the pic. Based on the pic, I drew up the schematic and I would like to make a few comments. Since this forum does not allow posting picture, I had to create a thread at DIYaudio.com so that I could post the schematic. Please see the link below. You could download the schematic in .png format. https://www.diyaudio.com/forums/multi-way/332679-thiel-cs2-4-xover-schematics.htmlHere are my comments on the xover upgrade: Mid+Tweeter xover: Since there are a lot of caps and resistors, it would cost a lot of money to upgrade them all. Here is the order in which I would prioritize: 1. Cap C1 & C2: these are the most significant since all the current will flow through these so I would upgrade these first. I would use some high end cap such as Mundorf supreme or Jantzen silver or equivalent. 2. Cap C8 has a 16ohm resistor in front of it, so the current through these will be very little so you probably won't need any expensive caps. I would use some basic audiophile grade quality cap such as Clarity. 3. Cap C6 & C7 may not be critical. They along with inductor L2 form a notch filter at around 2.5KHz and most of the time, there is no current through them. R4 is actuall more critical (see below) so again, use some basic audiophile grade cap such as Clarity. 4. Resistor R4 is next most critical since all the current will flow through these so I would use the best one you could afford. 5. Next up is resistor R1 and R2 which have relatively very large value, so they are not as critical as R4, but resistors are relatively inexpensive so I would replace them. 6. Cap C3, C4, inductor L1, and R3 are not very critical since they form a notch filter at around 150Hz, but since these electrolytic caps may be old so you may want to replace C3 and C4 due to age concern. These should be electrolytic since they are not very critical. Base xover: In general, at low frequency, the caps are not too critical, but since the CS2.4 crosses the bass and mid at relatively high freq. at around 1kHz, it may make a difference. Also, both caps C9 & C10 both are being formed with respective inductors so there is no point of buying expensive caps. I would keep the existing caps. But I would change the resistor R5 to something decent since there is still some current flowing through them. Although most of the current will flow through L3, it may be worth it to upgrade R5. |
I would like to make a correction from my post above.
3. Cap C6 & C7 may not be critical. They along with inductor L2 form a notch filter at around 2.5KHz and most of the time, there is no current through them. R4 is actuall more critical (see below) so again, use some basic audiophile grade cap such as Clarity. C6 & and C7 are critical so you should use high end cap such as Mundorf or Jatnzen silver or equivalent. |
Hi andy2, what is your opinion on the 1uF foil caps (C2 and C7), why JT omitted it in the SE crossover? Before answering your question, let me just take a moment discussing the physics behind capacitor and inductor. Think of them as the ying and yang of circuit design. I am not sure if you're technically inclined but they act opposite of each other. The capacitor acts to slow down a current whereas the inductor acts as to speed up a current. Mathematically a capacitor is an integrator (a process of averaging) and an inductor is a differentiator (a process of diffrentiation which emphasizing the extreme). To make thing a bit more complicated, the larger the capacitor, it carries extra parasitic that is not part of the capacitor. The lower quality of the capacitor, the higher amount of parasitic. Therefore, there is a need to have a smaller capacitor in parallel for the higher frequency to get through bypassing all the parasitic of the large capacitor. If you have a really good capacitor, it would have less parasitic so it will not degrade the treble frequency so bypass capacitor may not be needed. So the purpose of C2 and C7 are meant to provide an extra path for the higher frequency signal therefore to improve the transient of the treble frequency. Now it's a matter of implementation. If you think your main capacitor is good enough, then C2 and C7 may not be needed. So it's your call. Although C2 and C7 improves the treble transient, the problem with running a large capacitor and a much smaller capacitor together is it may introduce jitter since the signal path is now unequal. Another way to implement it is to equally split the capacitance value in half. For example, if you want 14uf, it might be better to have two 7uf vs. one 13uf and one 1uf. Both implementation both adds up to 14uf, but the physics will be different hence the difference effect in treble. At the end, it'a a matter of fine tuning. For comparison purpose, most speakers have separate tweeter and midrange driver, therefor the tweeter xover on those speakers have very small capacitor in the signal path which is around 4.7uf to 6.8uf. For the CS2.4, if you count up all the cap in the signal path (14uf + 28uf = 42uf), that is quite a bit so the bypass cap is probably more important. Listening to the CS2.4 and my own design, I do feel my speakers have that extra treble details that is hard to describe but it's there. Some have mentioned that after the cap upgrade on the CS2.4, there is extra air and transparency so it may have something to do with that, |
Andy - would you please clarify which ClarityCap you are referencing? The CSA has the copper ends.
Hi Tom, Sorry, I got confused with all the acronym. The Clarity cap I used was "SA" and not "CSA". So I the Clarity cap that I used did not have the Copper Technology. Again, sorry for the confusion. |
Andy - thanks for the clarification. The C is for Copper in CSA and the CSA is reported to be a big step better than the SA. One day I will directly compare the SAs from the 2.4SE with the new CSAs. Hi Tom, It will be interesting as what is the difference between the "SA" and "CSA". I personally am a bit doubtful as to how much the difference between the copper technology vs. the older "SA". Sometimes I think the marketing is getting ahead of the technology itself. I think for the most part, it’s the dielectric material of the capacitor that determines the quality of the capacitor and not the "copper contact". Without knowing more, I still would prefer capacitor that has the reputation such as the Mundorf Supreme or various Jantzen capacitors. |
In term of low frequency measurement, please be careful with room affect. Based on the plot above, it shows that at 30Hz, the energy is the same as at 1KHz which does not seem to be right. The energy of the speaker should be down quite a bit at that low frequency. |
Maybe CS2.4TB for Tom’s Bliss
How about CS2.5? |
For the passive radiator, how solid are the threads on the screws? How many times do you think they can be removed? Ideally I guess you only need to remove only once but it would be nice to have a bit of margin in case of errors. |
Good thing. Between early reconnaissance, replacing the resistors, and the more recent work I’ve probably taken the radiators off 20+ times. There is a trick to it. Elsewhere I posted instructions from Rob Gillum.
Thanks. That makes me feel much better trying to work on the xovers. |
I've gone thru a few really good amps over the years and felt something was always lacking
I am not sure there is a perfect component. You could spend a lot of money on something but it won't be perfect. Every design is a compromise. I like the CS2.4 very much but I always feel like there's something it could do better, but of course this is also true for any speakers in the world regardless of cost. |
As we speak, I am now working on the internal Supra wirering with grounding, hopefully with a positive result.
I am curious what type of Supra cables you plan to use? I bought them from Madisound which has reasonably good price. They are available in various gauge size, but the larger gauge such as 9AWG has an odd resonance issue, but I had good experience with the smaller gauge wires. |
Hi holco,
Very nice job. I am curious that if you had to remove the woofer and mid/tweeter from the front baffle in order to connect the new wire? |
How did you seal the new wire at the hole where it enters the coax chamber?
That would be a challenge since I assume the coax chamber has to be sealed from the bass compartment. If there is any leakage, it will affect the sound of the coax driver. My guess is you have to cut the existing wire, then run your own wire through the existing opening, then seal it with some type of weather sealant from Home Depot. |
|
gasman117,
It seems that you have the CS2.4? I do not find them "hot" at all. Actually I think they are just a touch on the warm side although they are very transparent so it could be the electronics.
My front end equipment are Ayre QB9 DSD, Pass Lab XP10, SimAudio W7 amp, Acoustic Zen Hologram II cables. |
The 2.7 has a huge electrolytic cap bank to roll off the bottom of the midrange where the 8" woofer wants to cross in.
Hi Tom, Out of curiosity, since the 3.7 and 2.7 share the same midrange/tweeter driver, wouldn't the 3.7 should also has a large capacitor bank as well? My guess is the need for a large cap bank because the xover freq. is rather low - probably aroud 200 - 300Hz to the bass driver on both speakers. In a typical speaker if crossing over at 200Hz is required, the amount of cap is probably around 80uF to 100uF depending on various parameters. I could see the use of electrolytic since using poly cap could be expensive if 100uF is needed. |
