Rob - Thiel's wire was developed in the late 70s through our contact with an aerospace avionics engineer (cousin Ted). For many reasons we settled on OFHC polished solid copper in teflon jackets with a tight 3/inch) twist. Wire carries competing parameters, but that configuration does more right and less wrong than most other options - and we landed there.
In developing the CS7 / 6 (after my time) Jim reportedly revisited wire and kept the original configuration, although the 5-9s aerospace ware was no longer available. Best of form is CDA101 @ There are differing opinions, and I am looking closely at options. There is justification for not going to thicker gauges in the lower frequencies due to varying skin effects. Also, many of his networks see a series coil as the first element and it might present hundreds of feet of wire and were rarely larger than 18 gauge, sometimes smaller, which would make larger wire meaningless. My present study suggests that larger gauge coils in some of those elements would be desirable - because there is more going on in wire than plain resistance. 99.99%, etc. Ours is slow extraction, high polish, etc. Straightwire supplied that from the mid 80s to the end.
I am moving toward star quad for noise suppression. Tweeter is double twisted (star quad) 18 gauge as described here before. Midrange might be the same unless I insert a 16 gauge foil coil in the first midrange element, then it will be star quad 16s. Woofer might end up being star quad 14. But that's unsettled and dependent of crossover variables. But all remain solid, not stranded, and that opinion is well corroborated in the technical field.
Anyone who says that only the big three: resistance, capacitance and inductance matter just hasn't looked deeply enough.
As a historical aside, I've mentioned here before that I did some work with John Dunlavy when he was moving to Colorado from Down Under. John's specialty and multiple patents were in the field of antennae, especially deep space low signal communications antennae. He played his cards pretty close to the vest, but he paid extensive attention to wire and wire routing within his speakers with knowledge of propagation interference and conjugation. I wish I knew a fraction of what that guy knew; but I am asking more questions in that realm than Jim did. And I hope to (dare I say expect to) reap some benefits.
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Is the Straight Wire used by Thiel of Kentucky 18 guage solid wire
or is it straned ?
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tomthiel
Thank You for weighing in on CS7 vs. 7.2 models.
Hope you are well and enjoying Summer.
Happy Listening! |
Fitter - I got the chance to compare CS7s with 7.2s when I visited Rob G at CSS last Thanksgiving. What a treat! I judge the 7.2 to be more concise / articulate, but he and I both liked the 7s better, as more easily listenable on more material. The main and possibly only difference is the mid drivers. The 7 has flat-front cast styrene pistons and the 7.2 has cones (of unknown to me technology). The flat launch plane eliminates whatever cavity effect the conical pistons might produce. They are both extraordinary speakers that I wouldn't mind owning with the proper room to do them justice.
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Gs5556 I owned 3.6s for 27 yrs I purchased cs7s last October my has a hairline crack by the woofer. When I contacted rob Gillum it didn’t seem like an issue. FWIW I use a Bryston 4 b which did a great job of driving the 3.6s but is now on the weak side of driving the 7s.ive never heard the 7.2s but the 7s are definitely an upgrade over the 3.6s!I can’t wait to get a bigger amp I feel they expose your equipment upstream and are going to get better as I upgrade my equipment! I agree with Tom as far contacting Rob just to make sure.
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Tom
I agree with you on the " B " , I believe that is why different wire
manufactures and configurations create sonic differences .
The only measurement that I can go by is resistance ,
stating my opinion about wiring or what I am hearing has little
quantitative value .
Rob
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Rob - I’ll get some measurements on my various wires. However, the resistance is not the whole story. In fact, audibility is a result of many factors and many of those are phase related. Two parallel tracks. A: lower resistance will change the frequency balance where it is operative, and B: all the other reflectances, skin effect, eddy currents, differential dialectic absorption, etc. will change many subtle things that audiophiles hear, but the engineering field ignores as insignificant. I suspect that more of interest is going on in B than in A. But changes in A must be corrected to maintain proper frequency balance.
As a historic note, Jim’s working rule was that focused listeners can hear 1/10 dB at an octave bandwidth. Lots of effort went into determining 1/10dB octave to octave frequency balance - anechoic flat. So he was bothered when "people" judged his speakers as having too much or too little of whatever frequency range. The intent was to be flat. Our fans tended to agree. Our detractors often criticized too little mid-bass and too much mid-treble.
My present experiments with wire and components and layout and baffle launch, etc. tend to rectify those criticisms without changing the measured frequency response. In other words, the criticisms may be caused by factors other than actual measured output. Of course, I don’t have a way to reliably measure differences of 1/10dB, so I’m flying far more blind than Jim was. Nonetheless progress is being made.
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From Cardas
Ten feet of 15.5 AWG measures 0.1411 ohms.
Ten feet of 17.5 AWG measures 0.1638 ohms.
Ten feet of 18.5 AWG measured 0.1883 ohms.
Ten feet of 20.5 AWG measures 0.2279 ohms.
So little differences yet one can hear it .
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Good Morning Tom Thiel and All Thiel owners
Update on the wiring of my 2.7 ,
I replaced the 15.5 with 17.5 awg wiring on the mid range of the coaxial
speaker to equalize the resistance , it sounded like the mid / treble
was louder or more pronounced .
It seems like without modifying the crossovers that whatever wiring
one upgrades to the resistance should be the same for both ,
at the same time it can't be to low .
Measurement on the 15.5 was .2 ohms for 3 feet ,
on the 17.5 it was .3 ohms for 3 feet ,
the JSC 16 that was removed was .5 ohms for the 3 feet to the coaxial speaker .
I've contacted Cardas about their measurements for the
15.5 , 17.7 and 18.5 sizes , I'm sure they have more accurate readings
than my SnapOn multi-meter .
I might consider trying the 18.5 but as of now I couldn't be happier
with everything I'm hearing .
Tom what is the resistance measurement of the 18 guage Straight wire ?
Rob
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Stspur - thanks for your report. I am interested in further sonic developments through time. Let us know what you hear.
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GS - no definitive answer. Check with Rob G at Coherent Source Service. Photos may be required. Generally speaking, the high mass of that baffle precludes much movement in use. Shipping ? If mine, I would consider an expansive hydraulic grout or cementatious epoxy repair.
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gs5556
Welcome! Good to see you here. I believe that there is a 7.2 owner on the Panel. Stay tuned until you receive an answer to your query.
I look forward in reading more about your musical tastes and system.
Happy Listening! |
As a Thiel 3.6 owner for over 25 years, I'm considering replacing them with either the 3.7 or 7.2. Found a pair of CS7's that were converted to the 7.2 but the cement baffle has a horizontal crack from each side of the midrange to the edge. Is this a serious problem with respect to transporting them? Assuming they remain unchanged after transport, is the sound affected?
Any input appreciated. Thanks. |
jazzman7
Nice catch! Hope those speakers find a good home.
Happy Listening! |
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stspur
Thank You for the update and shout-out for Mr. Rob Gillum at CSS.
Your XO project will provide Tom with insight on the 3.6 loudspeaker.
Keep us posted on further tweaking/voiceing. Have fun!\
Happy Listening! |
Hey Thiel Gonners! Just finished my last round of updates for my 3.6 XOs. My midranges came back from Rob a week ago: he replaced the voice coils and surrounds. He was even so thoughtful to included solder samples for me to ensure the proper termination. They sound fantastic by the way with more transparency and balance; just a slight forwardness to the upper midband which I feel is more settled now with this present round of XO updates. For this round I changed out the remaining Solens Caps and started replacing the ERSE 1uf bypass caps with ClarityCap CSAs: the quadruple treble bypass feed stage. Rob also send along some original 18 AWG twisted pair harness wire to extend my leads to the drivers which I was thankful to have. Before, I had to splice my runs (cringe). As an aside: what intersting discussions we're having about different wire runs Rob and Tom. Star quad runs sound like fun some day and always glad to have further insights and history. Anyway, I ran my summed mono A/B comparison tests yesterday and confirmed the results this afternoon In stereo. Over all the sound now has less forward upper midband and more controlled lower/mid bass than before. Threre is also more treble extention and presence. Vocals and solo instrument are more pronounced with greater clarity without being forward or unbalanced in the presentation. Kind of reminds me of a well implimented horn setup rig. Klipsch la Scalas come to mind but with all the attributes of well executed bass authority as well! It's also fun to hear new details, 3d imaging, and air now present. On the down side: the lack of lower and center midband is creating a just the slightest sense of sterility without as much warmth as before. Perhaps further break-in time will reveal more in time. I am to understand that more mid bass will show itself in a day or so hopefully warming things up a bit. I do feel that sound is more balanced and refined than with the original Solens/ERSE caps as I'm sure they must be showing there age with technology advances and such. It's well worth the effort and I'm learning so much along the journey! Many thanks again to all who have supported me thus far! Next up will be to replace the remaining "Thiel" resistors with more Mills MRA-12s and the final round will be replacing the remaining ERSE 1uf caps with CSAs as well. Afterward, I look forward to further tweeking as there'll certainly be voiceing down the line as well. What fun!!
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masi61
Keep us posted on the progress w/ stspur as well.
Have fun!
Happy Listening! |
masi61
stspur is currently upgrading his 3.6s , check page 167 . |
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masi61
Good to see you again. Keep us posted on your experience w/ Mr. Rob Gillum. As for tips on your CS 3.6 loudspeakers, take time to peruse this thread. There is a plethora of information from 3.6 owners and members of The Panel.
Happy Listening!
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Tom
Single 17.5 chassis wire with +/- seperated ,
+ tweeter and midrange running together and - running together up the back and sides of the cabinet .
Rob
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Masi - my suggestion is that you are doing well with sspur. Also, this forum has lots of information going back a few years with answers to lots of your questions - and there are people here with first-hand experience to guide you. I have not formally addressed the 3.6 and would be speculating with anything I would say. SSpur, Beetlemania and others here have solid experience regarding brands and outcomes. I will chip in as I can find time.
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@tomthiel. I have been messaging @stspur about some changes he is making with his CS3.6's. He soldered in some different components into his crossovers which he says have made a big impact on sound quality. Is there any way to get a list of the specs/part numbers/brands of components that would help to freshen the crossovers on my CS3.6's. I am already planning on taking my CS3.6's to Rob at Coherent Audio to have the ferrofluid checks and get the later style speaker binding posts. I have Analysis Plus speaker wires that were quite expensive that are terminated with spade connections. These spades can't be tightened down quite enough, there is some rounding off evident on the plastic nuts. I told Rob that I would like him to do the later style which he said have slightly more durable metal speaker terminals and said he could do this. The cost did not seem that excessive to me compared with the turntable updates I am doing with my LInn LP12 turntable right now. One more question: I am using Sound Anchors stands under my CS3.6s but nothing right now between the bottoms of the CS3.6's and the tops of the Sound Anchors. I could use the factory spikes and just get some cups to put on top of the Sound Anchors or maybe some of those cork/sorbothane squares I have seen would work. What suggestions would you have here. I get a lot of bass from my Bryston 4B2 amp but I get the feeling that I could tighten it up a bit in my second story carpeted listening room with some tweaks. |
Rob,
Is your wire a single twisted pair of 17.5 per leg?
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Tom
I installed the 17.5 guage chassis wire to the tweeters Sunday
and my conclusion is this is the correct size to use .
While the 15.5 guage sounded very good there was a glaring issue ,
on loud higher frequency notes distortion appeared .
This was first noticed when listning to the War album Deliver The Word
when an alto sax hit the high notes , I then checked with the album that I use for testing when changes are made Norah Jones Come Away With Me , some of her piano notes caused the same ear bending distortion as heard on the War album and finally the worst offender of all listening to Freewheelin Bob Dylan album , his harmonica playing convinced me to try changing in wire gauge .
The 17.5 sound smooth and sweet , all the notes that were distorted before now sound detailed and clear , even Bob Dylans harmonica playing or to say at least as good as his playing gets .
If I do any other wire changes it will be to increase the gauge to the bass crossover board but for now it's time to listen to the music for a while before I start installing the Mills the resistors .
Rob
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jazzman7
Nice catch! The Cherry finish is beautiful.
Happy Listening! |
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jon_5912
I concur- 115db is loud indeed. Have fun!
Happy Listening! |
vair68robert
Excellent idea for your guys to post any issue/problem(s) that potentially threaten driver integrity. Stay safe.
Happy Listening! |
@Rob, I definitely think it would be good to document problems and their solutions that we've had with our Thiels. That'd be a good addition to the Thiel models blog actually. I found out about the air chamber when I took my blown midrange into Audio Consultants and they told me that was a potential problem. |
It's probably caulk - I don't know what kind. In my time we used acrylic latex painter's caulk with good results, and sometimes hotmelt adhesive to build a mound. But, sealing was always be a big hassle; hotmelt and caulk are both permanent, which leaves few options when a leak develops. so I am experimenting with something else. Permatex type II non-hardening sealant from the automotive store. It softens with heat for removal and resealing. I'm working the Ptex between the wires, putting a Mortite dam on the bottom / outside, and adding a Ptex mound inboard, then hitting it with hot air to settle it. So far, so good.
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Tom
Will do ,
delivery is expected Monday , I hope to know something by Tuesday or Wednesday .
Can you tell me what the black rubberized coating is ,
it looks like it was painted on and is around the edges where the
bracing attaches to the walls and was used to seal up the
openings where the speaker wires came thru .
Rob |
jon_5912
When I read your post from 2018 you had 3.7s that blew a coaxial
speaker , supposedly because of the cable pass thru not being sealed .
Thanks to your post it would have been awhile before I sealed the
speaker cable pass thru solving the problem .
Lazyness caused my problem .
Distortion was not heard at lower levels until reaching my normal
listening levels and really was bad if I tried to go higher .
Luckily I almost never turn up the volume more than 2 notches
beyond my normal so no damage was done .
I would encourage any Thiel owner to post any problems
so we can all be aware and listen for possible issues before a speaker is damaged.
As jafant would say
Happy Friday
Rob
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I'd guess the overpowering sound was due to distortion when the drivers were pushed outside their normal range. It's an interesting problem to have. I've found it's distortion that hurts the ears. I can crank my ATCs up really high but because they're made to play very loudly without distortion it doesn't create the discomfort just about any other speaker would. 115db continuous is loud! http://atcloudspeakers.co.uk/professional/loudspeakers/scm110asl-pro/ |
Rob - I will be most interested in your 15.5 to 17.5 gauge comparison.
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Tom
Plugging the pass thru holes for the speaker wires solved the mystery
of why when I turned up the volume the mid and upper range frequencies became overpowering .
The magic has returned .
I was focusing and blaiming the sound unbalance on the increase in wire gauge , my electronics backround blinded me I guess .
Using your recommendation I'm still going to reduce the tweeter
wire gauge to 17.5 for a listen ,
I can always go back to 15.5 .
While it can be frustrating and not always fun ,
the end results have been worth it .
I can honestly say that working on an amp in much more
straight forward than on a speaker .
Rob
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tomthiel
Second, Thank You for being our consummate body of knowledge and wisdom here. Hope you are well today and having fun in your hot rod garage/studio.
Happy Listening! |
Rob,,
Sealing between the chambers is important for impulse integrity. If open, the woofer air pressure yanks the midrange around - not good. You can temporarily seal well enough with Mortite or bowl putty.
When I came to New Hampshire in 1996, we had local long-hair wool production in the village. I looked into it for speakers as a venture prospect. I also read the British, etc. opinions which are widespread and respected. But I was never convinced given my own experience. I anecdotally attribute the "British Bloat" partially to the tendency of wool to decouple below about 100 Hz. Changing batting isn't on my radar, but who knows? We never know.
Wire gauge is part of the resistance equation. All design measurements and listening is done with the selected gauge. But there is another element in play. Skin effect / signal penetration depth is frequency dependent. 18 gauge is optimum for tweeter frequencies. Larger gauges are suitable for lower frequencies. Your change from 18 to 15.5 will add a harsh coarseness caused by propagation eddy currents. What I am doing with Straightwire is replacing the 18/2 with 18/4 in a star quad twist. We keep the optimum skin depth while halving the resistance and multiplying common mode noise rejection - these cables are in an electromagnetic soup from the drivers and crossovers. I am assuming that final level tweaking will be required due to resistance changes. I am applying the same star quad regime along with progressively larger gauges to the other drivers, all with promising results.
Carry on and keep us posted.
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Tom
Again I have to say thank you , your knowledge , experience and insight
is valued and appreciated by all Thiel owners .
I remember you telling us that Toyota approached Thiel with the thought of using Thiel speakers in Toyota cars ,
your stories and life experiences are always interesting .
As for batting , I've given up with the idea of changing from fiberglass but still the reading and research was very interesting .
I almost bought some " long haired " sheeps wool after reading about it being the best and used by top British speaker makers ,
but overseas shipping prices prevented me from trying .
I'm back to the wiring because I think I made a mistake when I increased
the gauge to 15.5 reducing the resistance to much ,
the mid tweeter sound is to forceful so I've ordered
17.5 to see if resistance is the problem .
I believe you warned me about that .
I read an old post by @jon_5912 about the holes between the woofer
and the coaxial chamber where the wires pass thru and the possible effect of them not being sealed , I've not sealed mine do to continued work but I'm going to do that this morning to see if the sound is affected.
Luckily no damage like jon experienced .
Try , Listen , Learn
or is it
Learn , Try , Listen
Rob |
tomthiel,
'Just my little peek behind the curtain regarding how everything is hooked to everything, nothing is simple, and no good idea goes unpunished.'
It's a real privilege to have your input and insights here. Cabinets are no doubt fiendishly complicated things and your words do help to ground things back into reality somewhat.
Thankfully for most of us here, we're only on the listening side of the fence!
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Rob - I saw and heard the first pair of 2.7s at the factory in 2012. I believe there was an angled dividing board between the lower (woofer) and upper (midrange) chambers.
I should add a thought to the insulation riddle. Many people assume that wool is best, the other synthetics are next and fiberglas is worst, due mostly to cost, where fiberglas is the least expensive. I've previously mentioned that Thiel's fiberglas is a best of form type. I don't think that I've mentioned my reasons for confidence that it's pretty good, perhaps best for the task.
In the late 80s during development of the CS5, I took on the project of comparing, contrasting, testing and choosing an 'optimum' batting / insulation scheme for the CS5. Such research always trickled down to less expensive products where an as cost-effective. I had some pretty luck help. Toyota was coming to town with their Camry plant. Also IBM keyboard products was down the street and the University of Kentucky had developed a School of Advanced Engineering in support of Toyota's success. I've mentioned the happy quirk that Thiel Audio was a 5th member (of 5) of UK's Advanced Manufacturing Roundtable, to which I was Thiel's representative. Lots of stories there, but today's is that Toyota, of course, was bigtime in the sound deadening business as was IBM. In addition to picking their brains, I brought my cousin Teddy (the GE Jet Engine guy) to the party for his knowledge of aircraft noise abatement. Needless to say, there was horsepower in play. Less likely, is that the scheme we had originally developed in the late 70s won the day.
Many of the reasons for choosing other materials have to do with odor or fungus or handling or airborne particulates. Those issues were all manageable and wool felt and fiberglas is what we kept. There are many new subsequent products and concepts. Thiel never approached constrained layer damping or suspended case in case construction. But we did explore various surface damping schemes. I found nothing to make any appreciable net improvement over what we had. And it seems that future products kept on keeping on. Although I am investigating air movement and panel resonance, I haven't considered re-addressing the original wood felt / fiberglas batt chamber damping. For now at least.
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Thank You Tom Thiel
I wish I had known about the findings by Thiel
before I tried experimenting with wool batting ,
so with the knowledge you have shared I will give up any thought
about trying to use wool , especially since the 2.7 doesn't have
a seperate chamber for the midrange speaker .
Rob
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tomthiel
Thank You for sharing your insight on loudspeaker insulation.
Happy Listening! |
For the record, wool acts quite differently than fiberglas, as does polyester fiberfill or spun mineral wool, especially in transition to the deep bass. Final placement and voicing of damping was always made by results. Listen to it, and if you have the means, measure the output smoothness. Insulation schemes will unload at various frequencies due to complex resonant behavior, especially in reflex systems. Fiberglas behaves more simply and predictably than any other scheme we found.
In my time, and possibly onward, the first reflection of the midrange driver off its rear enclosure wall was absorbed with dense pure wool felt - it worked the best for that purpose and its considerable expense was worthwhile. Our evaluation of wool batting for absorption was not as good as fiberglas.
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beetlemania
Thank You for the confirmation.
Happy Listening! |
@jafant I made no comparison. Just assumed that the previous volume was “optimized”, a dubious assumption given that the volume can easily be modified by compression, ie, there is no one OEM volume that can be discerned. I merely made it as close as possible to how it was when I first removed the radiator to view to boards. |
