I have a pair of Stax transformer driven phones, and yes, they are magical for their detail, clarity, lows/highs extension, and their clean outright loudness capability.
There are many here who have not heard this kind of clear and pleasurable reproduced sound...not to ever hear it, is not to never know it.
Ditto loudspeakers....Genesis, Duntech etc.
I have not heard the Watt's, but the above two are seriously impressive, for sheer and clean power delivery if nothing else....their imaging and detail was pretty darn good also, imho.
'Forgiving' loudspeakers can be a good thing, but not long term fully satisfying, and not particularly useful when listening for fine detail.
Interestingly, I find that seriously good electronics gear can be very forgiving in a sense....source distortions that blare and glare loudly on lesser gear, become just 'matter of fact', and don't necessarily detract.
Recording distortions and mastering errors are revealed subtly as such, and with good gear the vibe and the live presence of the performances remain intact, and subjectively dominant.
Just about any old speaker will reveal differences in the source/amplification chain, but it can require really good loudspeakers to reliably discern and 'fingerprint' fine differences in the upstream electronics.
John, you have valuable new tools, please enjoy.
Dan.
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Figure 8 of the paper from Cyril Bateman...
Cables, Amplifiers and Speaker interactions. part 1.
This is the scope photo. He states this is the reflection of a 10 Khz signal, so that makes the reflection 4 microseconds.
He used 4.9 meters of a supra 2.0 cable, 16 feet. The hf transit time for that cable is approximately 50 to 60 nanoseconds, which clearly does not explain a 4 uSec reflection.
jn
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I used my mono AR-1 based system from 1963-1967, in several locations, fairly successfully. Certainly it was better than most other 'student' systems, and I continued to experiment, with phono cartridges and adding a 'tweeter' to the AR-1. I finished college and got my first professional job(s), one in a hi end audio store that specialized in K-horns, triode amps, Mac, and Ortofon, etc., and my first professional job in electronics design (Friden) working under very experienced electronic engineers. I first heard and compared the AR to a K-horn in 1965. Wow! The K-horn just blew it out of the water. I promised myself that in future, I would get a K-horn or two when I could afford them. I also was able to compare the sound of the Ortofon moving coil cartridge with the latest Shure, etc cartridges, and again the Ortofon won hands-down.
So I switched my focus from AR to Paul Klipsch, as far as ultimate speaker quality was concerned, and I even met with and talked to Paul Klipsch, himself on several occasions in that time period. Under many conditions, the K-horns, even today, do pretty well for themselves, especially with large orchestra reproduction. They DO have certain serious problems that effect their stereo imaging, and EVEN the sound of a person's voice due to the rather large path lengths between the drivers. In those days, the ear was presumed to be 'phase deaf' from a mono source, so 2-4 ft path lengths between drivers was considered 'acceptable'. This changed slowly over the next decade by Richard Heyser's papers to the work of Manfred Schroeder that overcame the exasperated complaints by Paul Klipsch that the ear was phase 'deaf' which he was taught from the 1920's and even earlier. (more later)
So I switched my focus from AR to Paul Klipsch, as far as ultimate speaker quality was concerned, and I even met with and talked to Paul Klipsch, himself on several occasions in that time period. Under many conditions, the K-horns, even today, do pretty well for themselves, especially with large orchestra reproduction. They DO have certain serious problems that effect their stereo imaging, and EVEN the sound of a person's voice due to the rather large path lengths between the drivers. In those days, the ear was presumed to be 'phase deaf' from a mono source, so 2-4 ft path lengths between drivers was considered 'acceptable'. This changed slowly over the next decade by Richard Heyser's papers to the work of Manfred Schroeder that overcame the exasperated complaints by Paul Klipsch that the ear was phase 'deaf' which he was taught from the 1920's and even earlier. (more later)
Is the line load purely resistive at 10kHz? Or rather, does it have exactly the same phase angle as the line characteristic impedance at 10kHz? Only then will the reflection have the same/opposite phase as the initial signal. In this sort of thing you need to carefully distinguish between a phase shift and a delay.jneutron said:
To the non-casual listener, phase shift and delay are of no importance. Sound is. My test setup is geared to only measure the time difference between the voltage and the current at the amp as a function of the impedance of the load. The basic measurement problem is trying to get accurate zero crossing numbers at the single digit microsecond level with 500hz to 5khz sines.
At 1Khz, a 1 microhenry cvr generates an inductive reactance of 2pi 10e3 times 10e-6 volts, 60 milliohms. A 1 ampere sine into a 100 milliohm/1uH cvr generates 100 mV at zero phase, plus 60 mV at 90 degrees lagging.. Confounding the absolute precision. Raising the resistance introduces unwanted resistance at the amp, changing the entity being measured. That's why I believe a good cvr is required here.
You'll have to read the article. Here is an excerpt from his article..discussing the scope photo I pasted.
Cables, Amplifiers and Speaker interactions. part 1., Cyril Bateman, page 6:
Cable Reflections.
At much lower frequencies reflections do still occur with mismatched terminations, but produce less dramatic impedance changes. Reflections at 10kHz using the Supra cable driving the ESP_replica load are easily measured using a reflection bridge, the basic tool of all RF measurements. The figure shows some 40% of the incident signal has been reflected, equivalent to a VSWR of 2.2:1 and returned out of phase to the source. For this measurement I used my 50W HP8721A reflection bridges.
jn
edit: Again, as Scott said, Cyril is gearing towards amp stability, whereas I'm concerned with how the variation in the voltage to current timing alters image reconstruction.
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By 1970 I had 2 K-horns, and had made 2 'fairly successful' solid state power amps to drive them, but I went into pro sound reproduction with a company called Alembic. Alembic used JBL mostly, but they were not prejudiced, so I got a pair of Klipsch LaScala full horn speakers sent to the office. After a realistic evaluation, I realized that the Klipsch just was not the same quality for HIGH LEVEL sound reproduction as JBL or Altec, for that matter. I was kind of disappointed, but I learned about DRIVER QUALITY, and some of the 'laws of physics' that made horns both superior and yet sometimes inferior. It just depended on which problem dominated in that situation.
At really high levels, horn throat distortion was DOMINANT, and we found that massed high QUALITY direct radiators, could do better at frequencies 4KHz and lower.
I found that the woofer driver that Klipsch used in his K-horn was a 'dog' compared to a JBL. I was kind of disappointed, but the K-horns still worked OK in the home.
Then I started an acoustics design Lab with John Meyer (later founding Meyersound) in Switzerland, in 1974. John M. also knew Paul Kipsch well, and he never stopped criticizing him. John M. was technically right, but kind of wrong in spirit, but we both made a serious attempt to remove the inherent time delays in most multiple horn systems. We were very successful with this project, and it was EASY with this quality of speaker system to sort out amp quality, and we EVEN found a problem with the very expensive volume control pots in the Levinson JC-2 with our listening tests with this speaker.
For my home system in Switzerland, I bought one of the first Magnepan loudspeakers right from the designer, and had them shipped to Switzerland. John Meyer almost laughed at these speakers, and they did NOT measure very well, yet they did have some sound qualities, like imaging, that was exceptional. They were also very FORGIVING to the electronics, in general. So where the horn system was sensitive to the electronics, the Magnepan was not so much. They did not have very good high frequency response either. I made up for this by using a STAX electrostatic headphone for evaluations.
A few years later, John Meyer went back to the USA, and I stayed in Europe, working for a pro sound design firm. Of course, I was very happy designing electronics, but my boss decided that I should build a monitor speaker system that would go into a Paris recording studio. It would be bi-amped, and I could select just about any drivers that I thought would work best. I did build the prototype, but I should have known better, that I still did not have the natural design abilities in speaker that someone like John Meyer did, and even after a couple of years of working side by side with him, did not give me enough to do a great speaker. This is where I finally decided to give up loudspeaker design for the most part and leave it to others. John Meyer and I commenced working on electronics projects once I returned to the USA a year or two later. (more later)
At really high levels, horn throat distortion was DOMINANT, and we found that massed high QUALITY direct radiators, could do better at frequencies 4KHz and lower.
I found that the woofer driver that Klipsch used in his K-horn was a 'dog' compared to a JBL. I was kind of disappointed, but the K-horns still worked OK in the home.
Then I started an acoustics design Lab with John Meyer (later founding Meyersound) in Switzerland, in 1974. John M. also knew Paul Kipsch well, and he never stopped criticizing him. John M. was technically right, but kind of wrong in spirit, but we both made a serious attempt to remove the inherent time delays in most multiple horn systems. We were very successful with this project, and it was EASY with this quality of speaker system to sort out amp quality, and we EVEN found a problem with the very expensive volume control pots in the Levinson JC-2 with our listening tests with this speaker.
For my home system in Switzerland, I bought one of the first Magnepan loudspeakers right from the designer, and had them shipped to Switzerland. John Meyer almost laughed at these speakers, and they did NOT measure very well, yet they did have some sound qualities, like imaging, that was exceptional. They were also very FORGIVING to the electronics, in general. So where the horn system was sensitive to the electronics, the Magnepan was not so much. They did not have very good high frequency response either. I made up for this by using a STAX electrostatic headphone for evaluations.
A few years later, John Meyer went back to the USA, and I stayed in Europe, working for a pro sound design firm. Of course, I was very happy designing electronics, but my boss decided that I should build a monitor speaker system that would go into a Paris recording studio. It would be bi-amped, and I could select just about any drivers that I thought would work best. I did build the prototype, but I should have known better, that I still did not have the natural design abilities in speaker that someone like John Meyer did, and even after a couple of years of working side by side with him, did not give me enough to do a great speaker. This is where I finally decided to give up loudspeaker design for the most part and leave it to others. John Meyer and I commenced working on electronics projects once I returned to the USA a year or two later. (more later)
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I'll read more tonight but Bateman gives the magnitude and angle of the load for that photo and it would be good to do a lumped R/L/C computation as a sanity check on delay vs simple phase shifts. From what I can tell his bridge works fine down to 0 line length and could also have the same reading with a simple passive lumped substitution for the load.
EDIT - just had an idea, why not use one amp and two speakers in the null test but flip the phase on one speaker and sense the deviation from null in the sweet spot with cable swaps?
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I wasn't listening to the 'scope display. You said 'delay'. I suspect a phase shift. Not the same thing at all.jneutron said:
Just to be clear: the reflection at the end of a line is only at the same phase as the incoming signal (or inverted) if the termination has the same impedance angle as the line characteristic impedance. At audio frequencies this is unlikely, as the line impedance is unlikely to be purely resistive and neither is the load. Which is more likely: a 4us delay in a rather short line or a 14 degree phase shift due to an unmatched termination?
The bridge shows what was reflected, energy returning to the source from the load. The line is about 2000 feet too short for a single transit reflection.
It's closer to standing waves.
jn.
Interesting considerations on what this audio thing is all about ... do we want to be in the path of an 'analytic tool', or do we want to enjoy the musical event that was recorded? I must say that every setup with Wilsons that I've heard is like being in a dentist's chair - moments of quite pleasant relief, intermixed with everything else ...
Personally, I want the system to be 'forgiving' - always ... . Then, I want to hear more and more of what the recorded performance was, without losing the 'forgiving' at any time. If I'm at a concert listening to live music, I don't want to be aware of how precisely comfortable my seat is, nor the fine detail of the colour scheme, or the bits of paint peeling at the edges of the walls while listening - that's not why I came to the show - I came to be lost in the music ...
Hello. I have been following this interesting debate....and thread
Can this, or part of this, be explained by the asymmetric distribution of current, making the mutual inductance complex in nature (M=Ma+jMb). Supra 2.0 probably have severe proximity issues in the audiorange beeing zip and with the conductors quite closely spaced.
Both Ma and Mb vary with frequency in no easy way changing phase and magnitude with frequency.
I am linking this old article on the topic:
http://www3.alcatel-lucent.com/bstj/vol14-1935/articles/bstj14-2-179.pdf
hmm. I post a picture directly out of Cyril's paper, with the word "delay" put in the picture by Cyril, and you ask me why I describe it as a delay?
You do understand I quoted from his paper, right?
It's not me your arguing with. I'm the messenger.
jn
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Audio band reflections of <20kHz waves on 2m of speaker cable are either unimportant or nonsense and rather both. The important thing are reflections at high frequencies (HF interference) and its influence on power amplifier audio band properties. I have done my first measurements of this phenomenon more than 10 years ago. AFAIK NP had published an article on similar theme even earlier.
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