Testing audiophile claims and myths

[maverickronin]

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Just clarified a few things there.
 
Also, I must say that personally I don't really like the "orthodynamic" and "isodynamic" terms...  They're more or less marketing terms used by Yamaha and Peerless (orthodynamic); Wharfdale (isodynamic); Sansui and Aiwa called them "omni-dynamic"; Fostex called them "RP type" for "regular phase"; and so on...
 
While none of those terms are necessarily wrong (or really less accurate in describing the driver than "dynamic" is, respectively), they're not the best terms IMHO.  "Orthodynamic" is a combination of "orthogonal" and "dynamic", more or less meaning "pertaining to, characteristic of, or acted upon by forces at right angles"; and "isodynamic" means, similarly (and I take this from dictionary.com):
 

•  Having equal force or strength.
•  Connecting points of equal magnetic intensity.

 
While both are true, they could be applied to one degree or another to both electrostatic and conventional coil ("dynamic") drivers.  Planar magnetic, however, avoids that entirely, although it doesn't preclude true ribbon drivers (although nor do ortho/iso-dynamic).
 
Anyway, I suppose it doesn't really matter so much, as long as everyone understands what's being talked about.  I'm just picking nits, having come from the speaker world where "planar magnetic" is perhaps the most well-understood term.  "Ribbon" (as refers to true ribbon drivers), however, is often misused for planar magnetic drivers like Infinity's EMIT and Magnepans...  That's actually the first term I knew for such drivers, until I learned about the difference in operating principle.
 
Anyway, let's get back to designing plasma headphones...
 

I don't really think the name matters that much, but I'm not a professional engineer either...
 
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So it's basically only beneficial when forced to use a crap DAP. I haven't seen any measurements of the iPhone 4, but I haven't noticed any audible flaws either. Perhaps I should just relax and enjoy the music then

Well, you've got to pick you poison.  IMO there isn't a single good DAP on the market.  They all have a fatal flaw somewhere.  Using an amp with my D2 is way easier than hacking an SD slot into an iDevice or fixing the UI.  The clip+ even had the "pitch problem" until rockbox fixed it.  It still doesn't support SDXC though.  The Fiio X3 may be the first decent DAP since the venerable Rio Karma if its UI isn't a mess.  I'd prefer not to have to hire a retinue of pixies to help me swap micro SD cards, but even the Karma wasn't perfect.

 

[Heidegger]

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Bringing dark energy into electric and acoustic engineering is so out here that I'm truly at a loss of words, next thing we know, he'll be bringing Special Relativity onto internal combustion engines.
 


 
 

I was trying to understand what an audio null test is, and the closest approximation I had to that was the kind of nulling they do in astronomy. It was merely a point of comparison.
 

 

[Heidegger]

deleted by author

 

[Heidegger]

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The AES paper below seems to confirm the benefits of high-rez, albeit limited to comparisons between 44.1 and 88.2 kHz. I wonder what their findings would be with even higher resolution formats such as DXD (352.8 kHz 24 Bit PCM) and/or DSD...
 
AES E-Library
Sampling Rate Discrimination: 44.1 kHz vs. 88.2 kHz
(http://www.aes.org/e-lib/browse.cfm?elib=15398)
 
"It is currently common practice for sound engineers to record digital music using high-resolution formats, and then down sample the files to 44.1kHz for commercial release. This study aims at investigating whether listeners can perceive differences between musical files recorded at 44.1kHz and 88.2kHz with the same analog chain and type of AD-converter. Sixteen expert listeners were asked to compare 3 versions (44.1kHz, 88.2kHz and the 88.2kHz version down-sampled to 44.1kHz) of 5 musical excerpts in a blind ABX task. Overall, participants were able to discriminate between files recorded at 88.2kHz and their 44.1kHz down-sampled version. Furthermore, for the orchestral excerpt, they were able to discriminate between files recorded at 88.2kHz and files recorded at 44.1kHz."
 
Authors: Pras, Amandine; Guastavino, Catherine
Affiliation: McGill University, Montreal, Quebec, Canada
AES Convention: 128 (May 2010)
Paper Number: 8101
Subject: Audio Coding and Compression

 


 

'The dCS PCM converters were, and still are, considered among the very best in the World, yet switching between the “SA-CD” and “CD” versions showed the clear improvements that DSD could bring to recording.  The rasp on strings was better.  The ORR uses period instruments and the thwacks of the small timpani sounded like wood hitting skin.  There was an ease to the sound that was missing in the “CD” version.  The “CD” image seemed to be two-dimensional in comparison (even when listened to in multi-channel).  The start of the 4th Movement begins with a quiet string section that is joined by the horns as the level begins to build.  It was this 90 second section that demonstrated one of the biggest benefits of high-resolution recording: the sound of horns.  If there is one thing that CD cannot do, it is reproduce a horn playing loudly.  As the sound begins to expand from the bell, something seems to go wrong and it sounds like the notes are being pinched or squeezed.  The DSD version allowed the notes to build naturally.  We were all dumbfounded.
Still, the most telling part of these test recordings was listening to the silences, the pauses between recordings.  Anyone who has stood in an empty concert hall has heard the “room-tone”, the sound of an empty room.  Listening to this in multi-channel DSD was a revelation.  For me, it was the thing that really made you feel like you were back in the Colosseum.  Bizarrely, even the room-tone sounded different between the “SA-CD” and “CD” versions!' Source:
 
http://www.superaudiocenter.com/DemRep.htm
 

 

[Heidegger]

Would the quality of the headphone jack make a difference? I also had a question regarding impedance, but I bundled it into my next post.
Quote:

Someone PM'd me a question for this thread, but I can't get this site's PM to work at all. And I prefer not to use PM anyway. So here's what was asked:
 
I'm wondering if an amp can have any positive effects other than more volume?
 
It depends how you define "positive effects." To me, the most positive thing an amplifier can do is amplify the signal to play as loudly as desired, without affecting the frequency response or adding audible noise and distortion. So in that sense the answer is No. But some people like the sound of certain intentional colorations, such as distortion or maybe a slight "loudness switch" type bass boost. So in that sense anything goes. But if your goal is to hear accurately what the mixing and mastering engineers intended, then we're back to No.

 
--Ethan

 

 

[maverickronin]

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I'm surprised that your explanation does not take impedence into account. Some headphones need to be driven. Isn't it true that not all amps may be able to drive a certain headphone. My Headroom Micro couldn't fully drive my 300 Ohm 650, while my new amp can. The difference is audible. My receiver couldn't fully drive them either. Also, I have heard that a quality headphone jack also makes a difference.

I think your forgetting that things like amps are best measured into actual loads that replicate a voice coil.

 

[Heidegger]

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So we see its effects but is doesn't, "show up on any test or analysis."  Makes perfect sense to me!

No, it doesn't show up on any test or analysis because it has never been detected; they don't know what or even where it is. (To explain it, some theorists have posited other dimensions.) Another theory has to do with the latent energy associated with recently broken symmetry. For example, there is a product called Easy Heat used by campers. The packets contain supercooled water (sodium acetate solution). When you disturb the solution, the symmetry is broken and the solution crystallizes. During the phase shift from liquid to solid, the solution releases latent energy as heat, and the packets get pretty hot. They can be used for warming. Some physicists speculate that dark energy is some kind of force associated with a recently broken symmetry on a cosmological scale.
 

 

[Heidegger]

Quote:

You can use Argument From Authority all day long, but it doesn't make your case. The difference between you and others who disagree with me, and me, is that I can explain the facts clearly and succinctly. I can explain what and also why every single time. They never can, so the result is often anger and then insults.
 
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I still have more questions for Ethan about null tests, questions that were not addressed in his video. For instance, it isn't clear to me how certain phenomena are registered to begin with so that they can, in turn, be nulled by the test. Is "sparkling sound" just a measure of how high the frequency goes? What does depth of soundstage look like when you measure it? How about the air around the strings, how natural their tone is, or whether a recording conveys the "wind" or "fanning" effect that you get when you attend a live classical music concert? How do these things show up as measurements?

 
Not understanding "how certain phenomena are registered" is a big part of the problem. You fail to understand some of the most basic things that define what audio is. In this case, audio is changes in air pressure for acoustic sound, and changes in signal voltages for audio passing through wires and gear. So all sound is "registered" as these changes. Once you understand that, then you understand why a null test shows all (electrical) differences.
 
--Ethan

Well, how specific phenomena such as depth of soundstage and brilliancy are measured and registered is what I'm trying to understand, but I can see that you're not going to explain it in detail here. In any case, areas of compression and rarefaction (air movement) is basically what a sound wave is. But a sound wave is not something on a graph. What you see as a measurement during a test and what you actually perceive when you listen to a recording are not the same thing any more than thinking of the ocean is the same as the electrical processes occuring in my brain when I think about the ocean. Now, you feel when air is being pushed around. When I use my micro amp or when I listen to CDs, I don't feel as much air being pushed around as I do when I use my Lehmann and listen to SACD. My Headroom Micro amp has no problem driving my 650 volume wise; that is, it can make my 650 sound very loud. But it can't reproduce the texture as well as the Lehmann does -- that is, the sensation you get when you feel the air being moved against your ear, say with deep bass. Also my Lehmann, while it doesn't make the soundstage wider, adds depth, not to mention that all the instruments seem to grow in size when I listen via the Lehmann BCL as opposed to the Headroom Micro. Isn't this perhaps a sign that the Micro can't properly drive the 650? In which case, there would be other factors to consider when choosing a headphone amp than just transparency or coloration.
 
In a previous post you mentioned wasted bandwidth. I'm not sure why you would believe that we must conserve bandwidth. Why shouldn't you let a frequency go as high as it wants to, even if you can't hear it. Is there a reason why we should not waste bandwidth? 
 

 

[maverickronin]

Quote:

No, it doesn't show up on any test or analysis because it has never been detected; they don't know what or even where it is. (To explain it, some theorists have posited other dimensions.) Another theory has to do with the latent energy associated with recently broken symmetry. For example, there is a product called Easy Heat used by campers. The packets contain supercooled water (sodium acetate solution). When you disturb the solution, the symmetry is broken and the solution crystallizes. During the phase shift from liquid to solid, the solution releases latent energy as heat, and the packets get pretty hot. They can be used for warming. Some physicists speculate that dark energy is some kind of force associated with a recently broken symmetry on a cosmological scale.
 

You continue to set the bar higher and higher.  Or is that lower and lower?  I can't even tell anymore.
 
Quote:

In a previous post you mentioned wasted bandwidth. I'm not sure why you would believe that we must conserve bandwidth. Why shouldn't you let a frequency go as high as it wants to, even if you can't hear it. Is there a reason why we should not waste bandwidth? 
 

Because it costs money and space.  You might as well collect jars of air...

 

[Prog Rock Man]

Quote:

Would the quality of the headphone jack make a difference?


 

Please remember this is not a speculation thread as they create and further audiophile myths. Please ABX headphone jacks and post your results, OR STOP SPECULATING!!!!!
 

 

[nick_charles]

Quote:

'The dCS PCM converters were, and still are, considered among the very best in the World, yet switching between the “SA-CD” and “CD” versions showed the clear improvements that DSD could bring to recording.  The rasp on strings was better.  The ORR uses period instruments and the thwacks of the small timpani sounded like wood hitting skin.  There was an ease to the sound that was missing in the “CD” version.  The “CD” image seemed to be two-dimensional in comparison (even when listened to in multi-channel).  The start of the 4th Movement begins with a quiet string section that is joined by the horns as the level begins to build.  It was this 90 second section that demonstrated one of the biggest benefits of high-resolution recording: the sound of horns.  If there is one thing that CD cannot do, it is reproduce a horn playing loudly.  As the sound begins to expand from the bell, something seems to go wrong and it sounds like the notes are being pinched or squeezed.  The DSD version allowed the notes to build naturally.  We were all dumbfounded.
Still, the most telling part of these test recordings was listening to the silences, the pauses between recordings.  Anyone who has stood in an empty concert hall has heard the “room-tone”, the sound of an empty room.  Listening to this in multi-channel DSD was a revelation.  For me, it was the thing that really made you feel like you were back in the Colosseum.  Bizarrely, even the room-tone sounded different between the “SA-CD” and “CD” versions!' Source:
 
http://www.superaudiocenter.com/DemRep.htm
 

 
 
It is trivial to detect amazing differences when you know you are listening to different things, there are endlesss sighted comparisons showing the superiirity of X over Y, the above is just one more...

 

[jcx]

multichannel is quite different - not a good basis for reasoning about 2-channel or headphone listening "soundstage" or "imaging" illusions - it was known from the beginning of Stereo that 3 channel with a center speaker gave much better spatial clues - it was just that Stereo was easy to add on to existing modulation schemes and was still a big step up from mono
 
people in general don't seem to appreciate the modern understanding of "Signal Channels" - especially in the electrical domain we can be very certain of the quality/integrity/accuracy of the signal transmission between the microphone, through the recording/playback process to the Volts (and current) at your loudspeaker or headphone
 
"soundstage", "imaging", "realism", "emotion" are all properties evoked in your brain after processing the reproduced sound waves - engineering doesn't know why or how - but we do know the how and why of accurately transferring the signals in the Studio to the headphone drivers on your head 

 

[EthanWiner]

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That does apply to conventional ("dynamic" as they are called in these parts) transducers with a diaphragm and a voice coil surrounding a magnet which are just miniature versions of traditional loudspeakers.  Some speakers and and increasing number of very popular headphones around here are alternatingly called orthodynamic, isodynamic, and planar magnetic and work a bit differently.  They are almost completely mechanically damped (often with precisely tuned layers of felt or other fabric) because they don't put out much (any?) back EMF in the first place and so they have no need of low output impedances to electrically damp them.  Second, they are almost purely resistive loads so the impedance of the driver is almost completely flat over the whole audible spectrum and won't cause the FR to vary due to the output impedance of the amp. That's why AFAIK, amplifier output impedance doesn't matter for those types of drivers.

Excellent thanks.
 
--Ethan

 

[EthanWiner]

Quote:

Would the quality of the headphone jack make a difference? I also had a question regarding impedance, but I bundled it into my next post.

Only if it's broken or intermittent.
 
--Ethan

 

[EthanWiner]

Quote:

Originally Posted by Heidegger /img/forum/go_quote.gif
Well, how specific phenomena such as depth of soundstage and brilliancy are measured and registered is what I'm trying to understand, but I can see that you're not going to explain it in detail here.
 
In a previous post you mentioned wasted bandwidth. I'm not sure why you would believe that we must conserve bandwidth. Why shouldn't you let a frequency go as high as it wants to, even if you can't hear it. Is there a reason why we should not waste bandwidth?

I have explained this many times already in this thread. Depth of sound stage etc is a psychoacoustic phenomenon that is unrelated to "measuring" the fidelity of audio gear. Since the main discussion has been about burn-in, and cables, and other things that affect the performance of gear, how humans perceive depth and width etc is totally unrelated.
 
As for why we don't want to waste bandwidth, that's very simple. If a normal CD can hold up to 80 minutes of music, you'd get only about 30 minutes at 24/96. All your Wave or FLAC files would also be 2.5 times larger, and would take 2.5 times longer to download or email to friends. It seems to me that waste is waste, no matter how low the cost.
 
--Ethan