Why would lower numbers be any nicer than higher numbers during the Jim Thiel era?
Showing 50 responses by unsound
@Pwhinson, a first order cross-over might be the only cross-over capable of time and phase coherence. The single driver Quad ESL 63’s and the quasi-multi driver Ohm Walsh, etc., did it without an electrical cross-over. Even with a first order cross-over a multi driver loudspeaker will need physically staggered drivers, and as you pointed out wide bandwidth drivers, that will in all probablility need compensating components added to the first order cross-overs to behave as as a time and phase coherent loudspeaker system. |
@thielrules, The 3.5's midrange is much sturdier than you might be suggesting. Thiel recommended (depending on model year) between 40 or 50 and 250 Watts per channel for the 3.5's. That's for an 8 Ohm amplifier. Into the Thiel 3.5's 4 Ohm load with a quality amp that can double down, that would be 500 Watts per channel. Jim Thiel even suggested that 300 Watts per channel (8 Ohm rating) might be appropriate in some cases. I've been using a 250 Watt per channel amp capable of doubling down without incident for years with my Thiel 3.5's. Look at the magnet assembly on those midranges, they could embarrass some woofers. The paper surrounds can need maintenance from time to time but, I'd hazard a guess that Thiel received more damaged drivers due to under powered amps than from over powered ones. The 3.5's eq with it's 12 dB boost at 20 Hz can put additional demands on the amplification, though the impedance bump at the that very frequency range mitigates the extra power demands some what. |
@dinopau, I haven't actually tried this, but you might be able to work around the Thiel 3.5's eq with a Roon Core, though I think you'll need one with an i7 processor chip in order to take advantage of the eq capabilities. I'd strongly recommend taking tomthiels's recommendation to reverse the cable leads first, to rule out other considerations first. |
For their CS models Thiel suggested a minimum of 8’ from speaker to listener for proper driver intergration and time alignment, with a minimum of 1’ and ideally 3’-3.5’ and preferably even more from back of cabinet to wall and a minimum 3’ and preferable 5’ or more from sidewalls/corners in a forward firing equilateal triangle as a starting point for most of their loudspeakers. Thiel measured their speakers from a distance of 3 meters (just shy of 10’). The single co-axial driver models have some different placement reccomendations. |
@JTHIFI, those Thresholds were over engineered and built to the most conservative and highest standards, i.e. the transistors are operating at only 20% of rated output. BTW, I seem to notice the price of these old Thresholds not trending down, but instead up. |
At the risk of appearing redundant; I still wonder if the 3.5's baffle could be modified to accept the co-axial midrange/tweeter from the 3.7's. Then we would have a genuine Thiel replacement and the advantages of a lobing fix. Sort of a time reversal of what Jim did when he took drivers from previous higher end models to use on newer lower cost models. |
@thielrules, Thanks again. Excellent information. The price of the drivers doesn’t seem unreasonable. The required cabinet work might be more than I bargained for. Not to mention the crossover tweaking. @sljhigb, the original 3.5’s mid’s 50 Watt rating was an 8 Ohm minimum recommendation. It was capable of handling 500-600 Watts into it’s 4 Ohm load. |
Perhaps things have changed, but when a dear friend had Thiel CS 2 driver repaired, there were no such caveats. Only prompt, courteous, professional service. Needless to say, he was very pleased with the transaction. The current websites packing instructions seem to suggest mailing as a viable course of action. |
@tomthiel, While I can see how the grill cloth frame on the 3.5's fits on to the top and side edges so that they avoid flat reflective edge surfaces, I have often wondered about the supporting frame extensions which seem to be in near and direct reflective path of the drivers. Any thoughts? BTW, Those graceful curved baffles sure are pretty. |
If I may be so bold as to add to TomThiel's commentary on baffle size. Years ago I asked Jim Thiel why he didn't use a more tapered pyramid shaped cabinet to avoid baffle deflection. At that time he explained that only market considerations kept him from using more preferable to him even wider baffles. He added that the wider baffle area would provide more consistent sound for the end user, as a narrower baffle would then put more emphasis on the listening room, which would in turn make the sound output that much more unpredictable. |
With all due (and sincere) respect for tomthiel, see my thoughts on removing the eq from the 3.5's here: https://forum.audiogon.com/discussions/thiel-owners-2?page=12 |
ronkent is right on! The 3.5’s recommended power was 40-50* (depending on vintage) to 250 (and even 300 in some circumstances) Watts per channel. Those recommendations were based upon standard 8 Ohm amplifier ratings, with the understanding that with quality ss amplifiers those power numbers would double with the halving of speaker impedances. So with the Thiel 3.5’s 4 Ohm nominal/ 4 Ohm minimum rating, you’d be well within Thiel’s recommendations for the 3.5’s. With the extra demands the 3.5’s eq makes on amplifiers, I think the extra power would be more welcome with the 3.5’s than with most other speakers with similar sensitivity and impedance loads. *Interestingly enough the early models had a sensitivity rating of 88 dB and a minimum recommended power of 40 Watts per channel, and with later models Thiel spec’d the sensitivity to 89 dB but also increased the recommended minimum power to 50 Watts per channel. |
I've been using my 3.5's with eq on full boost in a moderately large room (15' ceiling peak) and play music at the volumes which were intended, scaled back for domestic room size, in other words; fairly loud on peaks, with an amp capable of 500 Watts (and double that for a couple of minutes at a time) per channel into their 4 Ohm load for many years now, without a hint of problems. Though, I do wish they could play even louder on dynamic peaks with less strain. My 3.5 midranges drivers were rebuilt by Thiel shortly after I purchased them. The previous owner used what IMHO was an underpowered receiver to drive them. Again, no problems since. Not using the eq would be an anathema for me. Even on steadily loud rock music, I would use the eq at least on the 40 Hz setting. With more lowered tuned 5 string basses and synthesizers being used, there's too much music below 70 Hz where the eq kicks in to compromise without it . That coherent sealed box deep bass is part of the reason I like the 3.5's so much. Without it, I might have kept my old CS 2's. I still prefer the 3.5's to the later Thiel offerings, except of course for the only other sealed box Thiel's; the CS 5i's. The amplifier requirements for which are the only obstacle towards my ownership. That up to 12 dB eq boost might seem a bit extreme, but it is mitigated somewhat but the concurrent rise in impedance. |
@thielrules, while I agree with what you've posted, I think there are few things to consider. The 3.5's as supplied only have single amplifier inputs. What you are suggesting is not possible without modifications to the speakers, which could depreciate their resale value. Sending a separate signal to the eq and then to the woofers, and a separate signal to the rest of the drivers could present a time lag to the woofers compared to the other drivers. Time is after all really what makes speakers like Thiel different and special. Of course in the digital domain it could be compensated for fairly easily, but in the analog domain, well that might take someone like Jim Thiel to figure that out. Also, 6 dB may not be much compared to say what a port rolls off, but it still is rather significant. That 6 dB is per octave, and there are two octaves to cover. |
@tomthiel, as usual an excellent response. I do think that 40 Hz is not too much to ask of a 10" woofer. Of course, as has been discussed before these suggestions could double one’s amplifier budget. And, with 1st order crossovers there would be quite a bit of overlap, suggesting that even more so than with other configurations, using identical amps would be preferable. It might be more palatable if there was an upgrade path from 2 channels to 4. Or more? It’s quite a testament to all at Thiel Audio that a 30+year old speaker is still so relevant today! Other than the huge amplifier requirements and depending on perhaps too complicated a crossover when a more thought out baffle arrangement might have sufficed, I don’t consider the CS5’s to be unsuccessful. When properly powered, in the right room, they are still amongst the best I’ve heard. Perhaps you mean from a marketing perspective? Could your suggestions applied to an updated 3.7 with a sealed box and woofer drivers from the smart subs might be a consideration? As I understand it, as is common with so many integral self powered subs with Class D amps, the amps are often problematic. Would the sub drivers have huge power requirements? Too much to be practical with Class AB amps? @jafant , I don’t believe eq parts would be a concern. |
@Thieliste, it depends on the model Thiels, room, desired volume levels and the particular amplifiers in question. While Class A has advantages with regard to cross-over distortions over Class AB, there’s more to good sound than that alone. Furthermore, many so called "Class A" amps lose Class A output in proportion to increased power output into lower impedances. It's not uncommon for some Class A amps to halve Class A output with each doubling of power output into halving of impedance load. For example, one might have an amp rated as providing 55 Watts per channel of Class A power into 8 Ohms and be able to double down into 2 Ohms to provide 220 Watts of power. If we put such an amplifier on a speaker say with a sensitivity rating of 90 dB @ 2.87V with a minimum load of 2 Ohms, the Class A output of that amp into this speaker at 2 Ohms might be less than 14 Watts and that would be at a 2 Ohm sensitivity of about 84 dB. One can see that it might be quite easy to power out of Class A output and into Class AB power output. The advantages of low output Class A amp might be better appreciated with a speaker with a higher impedance load. On the other hand there are other considerations that might demonstrate that a lower impedance might be more beneficial, just perhaps not as much as with many low powered Class A amps. |
@tomthiel, Sorry, I don't have much to add. I've never heard them, though I would welcome the opportunity. The company has managed to last despite having a limited number of retailers, which I think are all out west without any in the east. They don't seem to have much presence at the shows. Though the shows don't seem to garner much attention either, at least here in the east. They had unusual aesthetics, that might have discouraged some? Most of the attention they garnered was in regard to their time capabilities, rather than their dispersion characteristics. There are a few reviews on the web. Stereophile has a couple I think. The reviews though not negative weren't especially enthusiastic. I'm not aware of any reviewer's that properly measure the time prowess of such speakers. Which is a shame. As you know things like step response and square waves illuminate so much about a loudspeaker. The rest is just opinion (at best, at worst it might be crooked). Their longevity suggests some market viability, but I'm not sure how. The small "monitor" model was garnering some positive talk here on Audiogon, with the exception of one poster who seems to have an axe to grind, in that he takes any and every opportunity to take shots at them (some of those shots were obviously without merit). As for dispersion etc., you may recall, I have been toying with the ideal of as close to flush wall/corner mounted drivers and room correction DSP for a while now, and am now trying to figure out if there would be a preference for point source or line array. The funny part of it was prior to this notion, I was considering mid room placed omnis . A little knowledge can be dangerous, and the math for some of this goes way beyond my middle school physics.:-) |
rwmeditz, It would appear that your unusually flexible integrated (kudos to Linn) might allow you to insert the 3.5's eq between the Intek's pre out and the Intek's amp in. Caveat: the manual does suggest dealer support when using the Intek's amp input! https://www.manualslib.com/manual/619667/Linn-Intek.html?page=4#manual This would free up all your inputs and tape loops. As your using the minimum suggested power output into your 3.5's, you might want to consider the 20/40 Hz button on the 3.5's eq when playing tracks with loud deep bass. Damage is more likely with under powered rather than over powered amplification. |
@obglny, FWIW, I have next to no confidence in the meters commonly found on consumer grade gear, regardless of the price and/or reputation of the manufacturer. They are almost never calibrated and often mislead consumers to erroneous conclusions. They are, IMHO, more often than not just extraneous light shows adding just another expensive part to wear out, break and need replacement. |
@oblgny, Sounds like you have a nice quiet and dark listening environment. I could say the same, except the wildlife trips the spot lights from time to time. The meters can be worse than just annoying. I can't tell you how many times I've seen new amps with stereo meters being fed mono sources (yes, we swapped cables and components to be sure) where the different channel meters varied wildly. I remember someone posting here on Audiogon about 10 years ago, re: Pass Labs quoting an above $400 cost for one new meter on an X250. Back then X250's were about $6K new. That's quite a $% for a superfluous part. I can only imagine what it might cost today. Good luck with your new (for you) Thiel's! |