Thiel Owners

Congrats on the score! And many hours of sweet, happy listening! A few years ago I had picked up the 3.7s and love them. I often gravitate to vintage and good, and paired these with a Bryston amp, and eBay Tom Evans pre-amp. But some of the greatest advancements came from the cabling which, relative to the system, was actually the most cost effective. I first experimented with, then put broadly, the Anticables, from Paul Speltz. At that time, Tidal was offering a section of their website that tested the "can you hear a difference [with lossless format]?" And before the cables, it was random. After the cables (on the same system) I want to say I picked out five out of six. 

All of this is through Oppo BDP 105D, which is a sweet (but unfortunately discontinued) media server.f

Enjoy!

More good info thanks tom.  Can you elaborate on “kind of problems that plague Thiel users” when using the Adcom amp?  Would other Thiel models benefit from being modified for dual inputs to allow for vertical biamping, and could (should?) this be done as part of a XO modification?  Apologize if this has already been covered in the thread, if so I will go on a search mission, unfortunately withthis format it’s easier to ask than go back and search.

I bought a pair of AHB-2s about a year ago and am thrilled. I specifically want to hear bridged vs stereo and how this amp stacks up against my well-known Classe DR9s (also a pair). They are remarkably similar and grain-free. The Adcom GFA555mkII exhibits the kind of problems that plague Thiel users. The 3 amps provide a good window into what might be going on.

BTW: John Siau (AHB designer) told me the following, based on my speaker schematics and his load analysis:CS7.2 Stereo or mono (bridged)CS5: Stereo onlyCS3.7: Stereo onlyCS3.6: Stereo onlyCS2.4: Stereo onlyCS2.2: Stereo or mono

Believing him, I have nevertheless tried both modes on the 2.2 and 3.6. The 2.2 does fine either way (Its impedance is higher and more benign.) The 3.6 sounds a little sweeter on stereo. When bridged and pushed hard the amp clips with very effective momentary protection. Amidst the thunder the only evidence for me was seeing the red lights flicker. This amp is Class H power feeding a class A output. Very unusual distortion profile. Essentially clean until it's not, which shuts down instantly.

Twoleftears: that single vs dual input scheme is high on my list, but I haven't implemented it yet. I'm wired for vertical bi-wire/bi-amps.

If you try the Benchmark, you could consider a pair for either horizontal or vertical biamping.  Just don't bridge them... (see the parallel thread on bridged stereo amps into lower impedances...)

Good question tomthiel re the Benchmark, I convinced myself a while ago that if I were to spend my audio $$$$s on a ss amp, it would likely be this one, but thus far I have not tired of tubes.  My guess is very few Thiel owners have tried this amp, but for the life of me I don't know why, as on paper it seems a match made in heaven.  Maybe it's a question of distribution?  Maybe the classics (Bryston, Classe, Pass, Ayre, etc) are the no-risk choice of high current amps?

And once again, reading some of these other threads reminds me of why I so much enjoy coming back to this one - the regular posters have a lot to offer newish users like me, and they are generally very open to others' experiences and philosophies.  Rock on Thiel Users!

Thosb & Tomthiel,

I've read the "Class D and 2 ohm load" thread, and there's lots of interesting discussion - but quite a bit of rude argument as well. I don't know if I agree with the poster who claims that Class D amps are a bad match for low impedance speakers because they typically don't double the power output at 2 ohms compared to 4 ohms. There appear to be a number of Class D amps that can provide reasonable wattage at under 4 ohms, but I don't have enough personal experience with those amps to know if they really have the low-ohm current to power hard-to-drive speakers like several of the Thiels.

What I do know, however, is that my PS Audio M700 monoblocks do a great job with my Thiel CS 2.2 speakers. I don't know, though, if the M700s would do as well with some of the Thiels that are harder to drive than the 2.2s. The M700s (Class D) took over for an Adcom 555-II (Class AB) I've had for many years, and the new amps really made the 2.2s come alive, improving both bass control and naturalness/openness across the spectrum.

I don't have any experience with the Benchmark AHB-2, but I would assume that it would power the 2.2s well even if it might have more trouble with some of the Thiels that present lower impedance loads to the amp.

Thosb - Wow, what a ride! The topic of amps driving Thiels is, of course, of great interest and concern to me. Jim did his thing for his reasons, and I disagreed (about impedance mostly), but he was the designer-engineer. The interacting variables are very real. My hope was that by developing our own in-house driver manufacturing we could circumvent some of the hard problems of magnetic gap electrodynamics, etc. that limited the overall system design. Thiel drivers did indeed become quite radical. But to my dismay, the system impedances fell rather than rose, which disappoints me as I re-assess these designs.

I wish that Thiel speakers presented a minimum 4 ohm load! That didn't happen. The nearly magic work-around that a poster mentioned on that thread, is to add a second input for a separate amp for the 3 bass drivers. Most of the problem evaporates, but cost is incurred for 2 more amps.

I find it interesting that in all that discussion and examples, that Benchmark AHB-2 didn't surface. My question about it on this thread also got no response. Is it invisible or somehow inappropriate? Absolute Sound rated it Class A. I find it exceptionally clean, uncolored, versatile and affordable. Am I missing something?

not sure "centered" was a good word choice above, the thread does get way off topic at times.

btw, if you haven't read this thread and don't mind scanning through some atypical (even for audio forums) trolling bs to get to some good info, this is a good discussion centered on class d amps driving Thiels - I learned a lot!

https://forum.audiogon.com/discussions/what-class-d-amps-will-drive-a-2-ohm-load

TGIF for sure, and thanks jafant for the cable info, much appreciated.

Happy Friday! All

Thanks andy2 for the cable recommendation, jafant I imagine you must have some speaker cable opinions, or maybe could share what the expected differences in outcomes would be for using Duelund 12awg based Acoustic BBQ vs Acoustic Zen's Holographic II, which uses 8awg 6N zero crystal copper?  Tube amp driving 2.3s.

@andy2 

The only remaining OEM are the drivers and cabinets. If I had Lexington rather than FST boards, I would have salvaged a few coils and, maybe, bypass caps.

tomthiel

Thank You for the SCD-1 update. Watch eBay weekly for Sony ES parts, especially, the SCD-1 player. Hope you can return health to your spinner.

Happy Listening!

1) connections on XO boards where multiple coils, resistors, and caps come together (especially joining the Litz wire to the bundle), and 2) connection to driver posts, all the more so with the Litz (but even the OEM solid core was pretty much a solder connection there).

Hi beetlemania,

Does it mean you also did swap out the stock internal xover wires?

I’m very happy with the Cardas binding posts even if it’s tough to get a good mechanical connection. Tom had me strive for that standard wherever possible. A couple of other places I had trouble: 1) connections on XO boards where multiple coils, resistors, and caps come together (especially joining the Litz wire to the bundle), and 2) connection to driver posts, all the more so with the Litz (but even the OEM solid core was pretty much a solder connection there). 

Thanks for thinking about it beetlemania

I plan on taking the passive radiator out , play the EBI cd
and feel around inside to see what is vibrating .

since I don't have the outrigger support I go directly into the speaker
like the original rounded spikes , I use the original nuts to level and tighten .

I have been looking into binding posts and it seems that
Cardas might be the only maker of long posts .

@vair68robert 

top nut on my outriggers occasionally gets loose but it’s possible one of your spikes is doing the same, especially if the weight is mostly on three spikes rather than all four as could happen with an uneven floor. Worth a quick check.

Ours would act up at Kathleen Battle.

I would too :-)

andy2  

Ours would act up at Kathleen Battle.

Yes, dogs' hearing goes higher. Don't let your dog or cat near your tweeters!

Horses can "hear" a train more than 5 miles down the track. They sense that 4Hz wave through their hooves.

In that sense, I was wondering if dogs are just opposite?  They can better sense high frequency sound.  That's why my dog tends to act up when I play Diana Krall :-)

Hi Andy,I believe the ear drum maxes out at 20kHz.#1: the cochlear envelope gets inputs in addition to the ear drum.They mostly modify the conversion from sense (electromagnetic energy) to neuron output, but also direct cochlear vibration produces modification. Also, there are other types of auditory input in addition to vibration. Think time-impulse, not tonal-frequency.

#2: False assumption. Brain gets inputs from cochlear cilia (hairs) which can be stimulated various ways. Plus additional inputs (beyond cochlear cilia). It is known that video input affects the ear (dizziness from spinning alters sound perception) and bright lights (strobes affect hearing), and so on. The brain is a parallel processor.
#3: Probably mostly true, but the ear-drum-stirrup system obeys the mass-stiffness-damping physical laws and therefore falls off rapidly above its upper resonance. And I don't know how much importance to assign to the residuals. Psychological damage can be inflicted via super-sonic sound that is not knowingly heard. On the other hand, there are thresholds below which we don't knowingly hear, and there are masks where we become unaware of sound beyond some marker, such as a resonance frequency or FR hump. More questions than answers. 

#4 ( A lot of people). That's a good example. Sound below about 20Hz is sensed via the solar plexus (chest-diaphragm) as well as mastoid process (skull behind ears) and forehead. The head bones directly modify the cochlear response, but the solar plexus couples directly with the right-brain auditory cortex, with speculation about other skin-body involvement.
Historical note: The Germans developed a sub-sonic technology in the 3 to 5 Hz range to play before Hitler took stage. People puked, fainted and became agitated. As he took stage, they stopped the signal for a state of comparative euphoria. These low frequency tones can be lethal, infra-sonic but definitely directly related. Horses can "hear" a train more than 5 miles down the track. They sense that 4Hz wave through their hooves. I mention these things as examples among many to illustrate that hearing is complex beyond 20Hz to 20kHz eardrum vibration.

Beetlemania

No I do not have outriggers that cost $500 ! ,
but I did purchase the outrigger spikes to penitrate the carpet .

Beetle , as in VW beetle ?

Rob

but anybody try Acoustic BBQ speaker cables with their Thiels? I need to get some speaker cables with spade connectors (long story) and leaning towards trying these, unless someone can make a strong case for something different for less than $400. Same old requirements - less harshness in the treble, no loss of resolution or harmonics. Currently have AQ CV-8s which are the only audiophilesque speaker cables I've tried.

For high end speaker such as the Thiels, in order to bring out the best, I think you need some really decent cables.  I am using Acoustic Zen Hologram II and the sound is a lot more sure footed than some low end cables.  These can be found for about $500 here at Audiogon.  

We are barely scraping the surface here. The point is that the inner functioning of the ear mechanism itself is vastly complex, even before the neuronic energy is sent to the brain for processing.

Hi Tom,

I was under the impression that the only part of our body that can "sense" sound is the ear drum, but then what you’re saying is that since our ear drum is only part of a complex network that forms a mechanism to "sense" sound, therefore it’s possible our brain can get sound information from other than our ear drum.

So there are three options to this argument:
1. If what you said is true, then even if our ear drum can only vibrate at 20KHz max, other parts of the ear has the possibility of vibrate at higher then 20KHz. I mean our body works like a machine in that sense. You need something to vibrate at higher than 20KHz for our brain to process signal. Otherwise where would the brain get the information from?

2. But if the ONLY part of our body can vibrate is our ear drum, then I don’t see how we can sense sound at higher than 20KHz.

3. The third argument is this. Considering the equation Y = 1/x.
Y is approaching zero but never gets to absolute zero. Y will get smaller and smaller but never zero. In general that’s the nature of our analog world. Nothing is absolute zero. So our ear drum is like that. Is possible that the ear drum does not get cut off right at 20KHz, but its response after 20KHz gets smaller and smaller but just enough to be able for the brain to obtain information. And when we say "we don’t hear it", it’s our brain that "told" us that we don’t hear it, but that does not mean our brain did not process it. Think about it. If we are constantly being interrupted by supersonic sound, we would be driven to crazy. Trust me. I know. I used to have a girl friend lols.

A lot of people say that truely low bass can only be sensed, and not heard. Our whole body can be thought of as a giant ear drum but for only very low frequency. Our body can actually vibrate but only at very low frequency. So when we "hear" low bass, I guess it’s more like the sensors in our skin telling our brain about the low bass (how else would we know if somebody punched us?). In that respect, not only our ear drum can hear low bass, our entire body can hear it too.

@vair68robert

I was doing my yoga this morning and found my eyes about a foot away from the outriggers on my 2.4s. Do you have outriggers? If any part of the outriggers is not tight, the Ayre tone glide can result in a rattle over portions of the sweep!

Tom, 

Thank you.

George - by tonality I intend to mean the whole perception of tone, which includes the fundamental and all the overtones. Tonal information, as I understand it, is processed differently than time information.

A very interesting, to me, aspect is the interplay between tone and time. I am presently working on a new termination scheme of the piano string at the bridge. Various schemes deliver various temporal envelopes relative to the frequency (tonal) response of the note.
(all related to the impedance variables at the bridge and the length and tuning of the back-scale between the bridge and the string's final termination.) The fascinating aspect is that the fundamental is only required momentarily, for the brain to "get it" (understand the harmonic structure), rather than having to create a phantom fundamental inferred from the upper harmonics (which takes lots of work.) Anyhow, once the real fundamental is there for a instant, the upper harmonics make sense, and then the phantom can drop out and the upper harmonic structure is more intelligible on its own. This harmonic development / sonic motion is related to the phase interactions of the string and bridge, which can be manipulated. Imagine that.

Tom, 

Sorry for an antediluvian question:  When you speak of tonality, are you referring to a pure sinusoid wave form or one containing the harmonics?

In my earlier years, I was taught the beauty of a violin tone came from the addition of the harmonics to the fundamental. 

Umm, I feel like an acolyte interrupting the masters at work, but anybody try Acoustic BBQ speaker cables with their Thiels?  I need to get some speaker cables with spade connectors (long story) and leaning towards trying these, unless someone can make a strong case for something different for less than $400.  Same old requirements - less harshness in the treble, no loss of resolution or harmonics. Currently have AQ CV-8s which are the only audiophilesque speaker cables I've tried.

I was once asked a question " can you hear it " ?
I've discovered that many times I didn't hear it
until I was not hearing it !

Andy - Tonality stays intact far above 20kHz, and plays some role in perception. I have auditioned mics / preamps flat to 50K and 40 and 30 and 20kHz.  I along with most people can hear the difference. Go figure. That fact is not questioned in the recording community.

You brought up limit of eardrum vibration above 20kHz. That is a subtle question about which I know only a little. The eardrum is connected via the ear bones to the cochlea which is a hydraulic-mechanical receptor. The eardrum is an impedance matching device from the low-impedance air to the high-impedance cochlea. The drum (transformer) is locked to its output side (cochlea), which limits its upper frequency response to around 20kHz . . . unless partially decoupled in various ways, but lets call it locked.  

But, that's only part of the story. The cilia - inner hairs in the cochlea which generate the auditory neurons - are embedded in a basilar membrane which changes its own charactristics to bias the cilia for differing functions, which include signal sampling (reading sequenced impulses such as every 100th peak, etc.) Now, the basilar membrane is known to respond to external stimuli including (but not limited to) inputs from the forehead and mastoid process skull bones, the phase relationships of those inputs being important for basillar bias functions. Hmmm.

We are barely scraping the surface here. The point is that the inner functioning of the ear mechanism itself is vastly complex, even before the neuronic energy is sent to the brain for processing. And, by the way, the left ear signal goes to the temporal lobe and on to cerebral processing, whereas the right ear signal goes directly to the auditory cortex to register its primal and emotional content and link to smell, taste, memory and the endocrine system. The multiplexed (left-right) signal begs to be reconciled for complete satisfaction. 

The more I study and make connections, the more I am convinced that everything matters, and that dismissing some aspect is arrogant. Note that the engineering community's dismissal of phase importance is based primarily on ABX testing. Note that such testing may have less to do with the hearing under test than to other brain biases. Note that executive - judgement - choice functions take precedence over more subtle functions. I posit that the test set-up (distinguishing and choosing A or B with consequences to success-failure, professional reputation, etc.) may be usurping the brain-power required for pure auditory absorption of the musical (or just sonic) content. The ABX test is the scientific gold standard, but it is highly suspect to me.

JA - I use the CD-80 either in-toto or as a transport to the PSAudio Stellar DAC-PRE. The performance of the two signal paths is similar. The PS affords the ability to select low-pass filter types and remote selection of inputs and volume control. I use multiple signal paths to 4 speakers under test to learn various performance aspects.

JA - the SCD-1 is sick. After a few discs, it would not play, would not open its lid and showed bogus text . . . It is at the shop, needs a new master control board, which Sony does not support. I'm looking for a used board.
But . . . while it played, it was pretty grand, both on CDs and SACDs. Compared to my reference Philips CD-80, which was SotArt in 1985, the SCD-1 was more relaxed and vibrant. I do hope to get it back someday.

tomthiel

how are you enjoying the Sony SCD-1 player in your hot rod garage or studio?  Do you utilize this player for CD, SACD or both on playback?

Any other spinners in your current possession? Excellent discussion on the whole time/phase front.

Happy Listening!

Hi Tom,

Thanks for your detail feedback.  Something just struck me that could give me a clue.  I keep thinking that music is limited to 20KHz, but that's not true, it's our hearing that is supposedly limited to 20KHz.  BUT musical instrument has no frequency limitation.  For example, when a drum is struck, the energy could be well above 20KHz.  So the speakers whether we are aware of it or not, are required to reproduced music at quite a bit higher than 20KHz.

Anyway, more to come.

Yes - the impulse response contains both time and frequency information which are related in known ways decipherable by Fourier and Hilbert Transforms. But, I am referring to the auditory-brain mechanisms which perceive frequency/tonality differently from impulse/time. This area is much more obscure and unstudied and, I believe, contains they key to understanding why some folks think phase/time coherence is valuable in music reproduction.

I land firmly in that camp - that it matters. But most of the audio engineering community (Toole and others) believe otherwise. My extensive personal experience leads me to value it and therefore try to understand it. I also know how easy it is to demonstrate the false negative premise - to 'prove' anything isn't so.

Over the years there have been many reviews and comments regarding how well details can be heard with Thiel speakers. Recall John Atkinson having to re-master a recording when getting the 2.2 for review, because he could hear edits and punches which had previously gone un-noticed. I recall a commenter stating how 'screwed-up' the Thiel 3.5 was because the orchestral recording sounded like the listener was hanging from the rafters! Guess what? The mics were hanging from the rafters. So, I consider his condemnation as a compliment - the speaker allowed apprehension of spatial presentation masked by even very expensive studio / mastering monitors.

This spatial ability is not related to frequency response. There are many speakers with far flatter frequency response because first order requires very broad range of all overlapping drivers, operating far out of their comfort zones. Thiel went to all that trouble to get flat-enough frequency response because we were and remain convinced of the musical importance of coherence, even if most people don't care and most experts dismiss its validity. That's what specialty companies do, they propose their unique vision. 

Hi Tom,

By tonality I suppose you meant frequency domain.  But time and frequency domain are the same.  You can convert from time domain to frequency domain and vice versa.  

For example, if you have a waveform in time domain, you can perform Fourier analysis into frequency domain, but then later on, if you want, you can convert the frequency domain back to the original time signal with no loss of information.

You probably had in mind steady state frequency response.  But when you convert from time domain to frequency domain, the phase information is still there, so no information is lost and the frequency domain is just as valid as in time domain.  One is no superior than the other.

Andy - in re-reading your question I see that your hypothetical speaker spec is entirely in the frequency domain, requiring playing and measuring sine wave tones. But, I am addressing the time domain. Jim specified some of our speakers in mS rise time. I don't have them at my fingertips. But in the lab during CS5 development I saw the rise-time graphs. Doing the math on those slopes results in 200kHz frequency domain equivalents. I'm saying that time and tonality are different animals and for best understanding should not be confused.

Andy - there's too much to chew on here. But I can comment a little.No I do not think we hear tone above 20kHz. And I know that dogs do, and that Natasha hears bats talk and that fish sense 50kHz signals.
David Blackmer (DBX founder) and others have demonstrated that we can detect the presence or absence of 40kHz tones when riding on audio frequency tones. We also know from auditory research that impulses are processed in the time domain. In other words a crack or snap is perceived directly as a crack or snap with directional and other information that is not tonal. That impulse is further decoded in the brain, to "hear" its component frequencies much like a Fourier Transform,.

I am not claiming that a coherent speaker plays higher tonally than an incoherent speaker, merely that the temporal content is processed and "heard". Some individuals are quite sensitive and others completely insensitive to this temporal / impulse information. My suspicion is that Thiel customers probably fall in the time-sensitive camp more often than normal. 
My upper limit is now 4kHz, dropping at 12dB/ octave. So I'm down more than 24dB at 20K. However, I can hear the artifacts of different digital filters working in the range of 20K and above. My point is that the sonic characteristic of tonality is only one aspect of hearing and does not define the limits of auditory input. In my opinion, which is in good company albeit in the distinct minority.
(A fascinating observation is when playing with the back-firing second speakers a couple weeks ago: I could tell more about the various digital filters when playing the filter changes from the rear-firing speakers than when playing from the front-firing speakers. Also, polarity reverse of the rear-firing speakers did not change my ability to perceive which filter was in use. Go figure!)

Perhaps more to the point in speaker design, we at Thiel systematically discovered the auditory - emotional - holistic importance of accurate phase/time component in the musical signal. In particular, the absence of phase distortion lifts a mental veil which allows the audio brain to see more thoroughly to the essence of the sound. Sound processing is processor (brain) intensive, and removing the big demand of reconstructing time/phase information in a scrambled signal frees the brainpower to perceive other subtleties of the signal (in my considered opinion.) That effect might be called psychoacoustic, but it is nonetheless real given the fact of auditory processing system limitation.

My present work on lifting a veil for the Renaissance revitalizations makes use of this insight. I would not even hear the veil on a higher order system. But I can on this minimum phase system, and I can hear considerable detail and make and test constructive hypothesis, all well below intelligibility on a high order system.

My study of audio and auditory neurology reveals that multiple parallel tracks decode the auditory stimulus, and the whole body is involved including the ears, mastoid process, sinus cavities, solar plexus and skin envelope - all working together to sense, decode and decide on the nature of incoming sound.

Hi Tom,

Do we know if our ear drum can vibrate at much higher frequency than 20KHz?  In order for out brain to process higher frequency, I guess at least mechanically, our ear drum is not the bottleneck which is something that can easily be determined.  We evolve from primitive animals and I am pretty sure they all possess ability to hear at much higher frequencies because is critical for their survival, but as we evolve it is not as critical for us so I guess our ability to process high frequency is no longer there.

One circumstance in play is that the temporal domain is not limited to the 20kHz frequency domain limit. Onset transient form and integrity which we can reliably hear, translate to wave-forms in the 200kHz range

That is an interesting claim.  Theoretically I suppose that's possible but how to prove it I can see it could be problematic.  I am no longer as young as I used to be, but when I play a 15KHz tone, I swear I could not hear it :-)  But music is more than just a single sinewave tone, so I guess it cannot be used as a proof.  Raise your hand if you can hear a 20KHz tone.  God blesses you :-)


But let remove our hearing aside and look at thing objectively.  Let's say if you were to design a speaker that acts purely as a transducer - that is it required to convert an electrical signal to acoustic sound pressure.  Usually you would come up with a spec that say something like:
My transducer can work from 0 - 200KHz or 2MHz or some frequencies with a certain harmonic distortion.  So you would have to be able to show data to prove the spec.  What you would do is playing various sinewave tone from 0 - 200KHz or to 2MHz and measure the sound pressure at various sinewave frequencies including distortion.

My guess is the higher the frequency, the higher the transducer will show distortion and phase shift, and up to a certain frequency, the distortion will get so large that the transducer will no longer able to produce a clean sinewave.  So with this method, you could objectively compare two different transducer.  

The problem with step response is it has such a wide range of frequency bandwidth that it is not easy to be used to compare or to characterize.

Back to speaker design, I would suspect a true time coherent speaker will be able to produce higher frequency tone vs non-coherent speaker with less distortion.  And of course, as we go higher and higher frequency above 20KHz, the distortion on average will get higher and higher for any speakers.

Back to Tom's claim that we can actually process signal as high as 200KHz, and as I have said in my previous post that the higher frequency that human can process, the more likely we can hear the difference in coherent speaker.

Thank You andy2

Great resource , added to my bookmarks .

Rob

Prof, Andy and all - lotta stuff to chew here. We approached these matters a few months ago and got into trouble. I suggested that study was in order, not intending to disparage anyone - it is all quite subtle and worthy of more depth than we can enter here.
Prof: Toole's statement is false, and it carries lots of baggage. A: The basis of his mistake is that Jim candidly stated that it would be foolish for Thiel to approach the market with anything other than phase coherence. Note the difference in Toole's inference. B: It is nonsense. But Toole has a professional investment in the non-importance of phase coherence.
Andy: You state it well "Maybe our hearing is very tolerant". It is. It is more than that: hearing is a synthetic activity, we create the heard experience via very complex mechanisms. In a fiendish twist, the more sophisticated the listener, the less phase coherence matters, because s/he can create the heard experience despite the incoherent content.
As Andy alludes, the non-believers point to bandwidth limitations at 20kHz max to nullify the importance of waveform integrity. My study of audio and auditory neurology reveals that multiple parallel tracks decode the auditory stimulus, and the whole body is involved including the ears, mastoid process, sinus cavities, solar plexus and skin envelope - all working together to sense, decode and decide on the nature of incoming sound. The right and left ears transmit to different parts of the brain for different kinds of processing and the entirety is eventually reconciled into an aural image - what we think we heard. It is all very fascinating and far from completely understood science. I have been blessed to know some outstanding Otorhinolaryngologists as part of my learning. Audio engineers, even the best, barely scratch the surface.

One circumstance in play is that the temporal domain is not limited to the 20kHz frequency domain limit. Onset transient form and integrity which we can reliably hear, translate to wave-forms in the 200kHz range - that's 10x the frequency domain limit. Such variables are routinely ignored or dismissed by many audio scientists and engineers, in great part because they are inconvenient. The effort and knowledge to design and engineer a product (Thiel speaker) which honors time and phase along with the traditional domains, is orders of magnitude more complex than the generally accepted models would require.
Andy, your closing statement is true. "First order filter . . . does not have phase distortion". Again, we got in trouble over phase distortion earlier. First order is correct on all fronts. All other forms, such as 4th order linear phase, possess forms of phase distortion including pre-ringing and other anomalies. Those distortions can all be managed and valid products are designed with such work-arounds, the ear-brain is a magnificent synthetic filter. It has been said here before: the kinds of care required to produce a speaker which honors phase/time is by necessity a very thoroughly engineered speaker. Many subtle problems which can be ignored in non-coherent speakers become very obvious when phase coherence is introduced, because the auditory mind considers those sounds to be real rather than electronic facsimiles.

Andy, I think the step response may be the most useful tool in the kit. With knowledge, it contains the whole envelope, including frequency response.

Some are saying (on that thread) that perhaps somewhere down the line Jim realized it was of no sonic consequence, but kept doing the time/phase coherent design because Thiel had already built a reputation marketing that characteristic. I think that is nonsense.

John Atkinson at Stereophile once said that if everything else being equal, he did notice that speakers with time/phase coherent have and advantage in soundstage presentation. The difficult part is how to determine whether a pair of speakers is superior to another pair of speakers because of its time/phase coherent or something else. For example, the CS2.4 may have better soundstage vs. another pair of speakers but maybe because it is just a better design with better driver integration and not because of the time/phase coherent aspect. How can you 100% sure the CS2.4 is better because of its time/phase or something else? Maybe the CS2.4 superiority comes from its coax driver and the quality of the xover? So you end up comparing apples to oranges.

The proponents of time/phase always point out to the "step response". But then if "step response" is so important, then you would think that non time/phase coherent speakers shouldn’t be able to reproduce music at all period, since in theory, if you can’t replicate the actual input electrical signal, then in theory, the output is all wrong and therefore what you hear should be all garbage. But obviously, non-coherent speakers can reproduce music just fine, therefore it is a contradiction, and therefore the "step response" is not a valid criterion, right?

I’ve been thinking about this but nothing came to fruition. I have a couple of explanations but really it could be anyone’s guess.

First, maybe our hearing is very tolerant. Even with non-coherent speakers, if it comes close to reproducing music, our hearing won’t really care much. But if the speakers happen to be coherent, then it would be icing on the cake. It’s like baking a cake. Anyone can bake a cake and most of the time, any cake would be fine, but if a really nice coherent cake comes a long, it would wake up our taste bud.

Secondly, and this one may be related to the first, is that the step response in theory has infinite frequency bandwidth, but our hearing is only limited to 20KHz. I won’t go into the mathematical details about the infinite bandwidth stuffs but you could look up. So the step response is not a valid "test" for our hearing since our hearing won’t care much for any high frequency content. I would imagine that if we human being has supersonic hearing capability all the way to the MHz range, then I am sure we could clearly hear differences between coherent vs. non-coherent speakers and the step response would be valid. Of course if a pair of speakers are just plain garbage then well anyone can tell :-)

Anyway, I’ll try to capture a step response in the next the post to illustrate the bandwidth limited theory. Looking at a simulation step response from one my design, it is consistent with what I said above with respect to our hearing bandwidth limited.

Regardless of time/phase or not, I DO see an advantage in first order design vs. higher order based on various listening experience. First order filter is the only filter that does not have phase distortion.

vair68robert

I will second playing those test disc(s) no louder than a moderate level. 
In fact, low level playback is preferred for system protection at all times.
Utilizing the frequency sweeps and tones are an excellent evaluation tool.

Happy Listening!

@tomthiel

Over on the AVSforum, there is a thread on the current science of loudspeaker design, essentially touting the "NRC/Harman Kardon" school of speaker design (itself based on lots of prior research).

The eminent Floyd Toole responded to an inquiry about whether he knew Jim Thiel with this comment:

Floyd Toole: I would occasionally see Jim Thiel at audio shows, but I never got to know him personally. We disagreed about the importance of phase, but for him it was a distinguishing feature for marketing, not science. He was always friendly.

As apparently inferred by others, that seems to say that Jim was designing for time/phase coherence for marketing purposes, not for it’s actual sonic properties. In other words "it’s just for marketing."
I have been saying I’m very skeptical of that account, as it seems obvious from what I’ve read of Jim (articles, interviews etc) that Jim certainly did see time/phase coherence as having sonic consequences. He says so explicitly in at least one interview, where he said his own tested demonstrated it to his own satisfaction, if not to skeptics or to a fully scientific level of evidence.


Some are saying (on that thread) that perhaps somewhere down the line Jim realized it was of no sonic consequence, but kept doing the time/phase coherent design because Thiel had already built a reputation marketing that characteristic.   I think that is nonsense.

TomThiel, could you add your comments on this? Thanks.

Yes, really tough to get a solid mechanical connection with the Cardas posts but, if you’re using Litz wire, the tinned ends necessitate a solder interface either way. I couldn’t compare other than the OEM wire and binding posts to the full Cardas but I can tell you the difference put a smile on my face. 

I’m looking forward to reading about your choices, progress and results.  

I have not used any high end binding posts.  The most expensive I've used so far only cost me a few dollars from Madisound.com.

I guess you won't know until you try out, but for those who have used expensive posts before, do they make a difference in the sound?