I'm one of those recording engineers. There are electronics that really are neutral- that don't emphasize the highs while also getting the bass right. The problem areas are in equipment matching, distortions made by equipment that the ear interprets as brightness, speakers that don't have problems of their own, and the media itself.
If you have a recording that you have created, its possible to wade through all the errant examples of hifi and find those that really work. So the answer to this was hidden in the original post.
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Some studio consoles are excellent and others not so good.
I do a lot of listening on Grado headphones; they are trustworthy.
We built up 6 channels of vacuum-tube microphone preamps which are wired directly into the tape machines- no intervening mixer console; no EQ, nothing but the mic. Our monitors are made by High Emotion Audio and are very fast and revealing. I don't think there is any Yamaha gear in the entire recording chain...
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with the induced magnetic field produced by current flowing through all
cables and wiring including those big honking transformers AND the
RFI/EMI generate by the house AC as well as all those cute little
microprocessing chips. You can avoid that by going balanced line. |
EMI **is** magnetic fields! So yes, that is what you are talking about.
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Well you got the first sentence right. The rest of it seems to point to the area of confusion. You might want to think about the fact that radio waves can very much metals.... An example that most of us know about are microwaves. I think maybe where you are having the disconnect is this: Recall the experiment with iron filings and a magnet? The magnetic lines of flux are stationary. What you are talking about is a simple magnet- much like what would happen if you put DC into a field coil. But that does not cause EMI- but if you use AC as a source now it can. IOW a simple magnet does not cause EMI only because it operates at DC. As best I can make out that must be where your confusion lies. An example of an AC source powering what otherwise might be considered a magnet is a tape head degausser. It is an electromagnet; different from a power transformer in that the core is the load rather than a secondary winding. If you get it near the tape head you will see a prodigious signal through the playback electronics if they are on. But you might be surprised to find out that if you take a simple magnet and bring it near the head the same thing will happen- not because the magnet is creating a field so much as the act of moving it is putting the field in motion and inducing something in the head as a result (thus the use of the term V/meter instead of Gauss). RF most definitely follows the inverse square rule BTW. The reason ELF works is that the ground wave can extend around the planet whereas at higher frequencies (FM for example) don't. Take a look at this Wiki page: https://en.wikipedia.org/wiki/Ground_wave_propagationI really recommend you read Wiki pages at the links I have posted!! |
Of course the real point is that EMI is not magnetic field. Which is
what my original post was addressing. I.e., that shielding is effective
for RFI/EMI but not for either external magnetic fields such as those
produced by transformers or induced magnetic fields such as produced by
current running through cables and wires. I used to work on the ELF
program which transmits at 75 Hz so yes, I’m quite familiar with low
frequency radio frequencies. Just because some people might not consider
it a radio frequency it actually IS a radio frequency.
Hi, atmosphere, sorry but no it’s not. EMI is radio frequency
interference just like RFI. It’s an electromagnetic wave. Unlike its
ugly cousin magnetic field which is a stationary field. Both EMI and RFI
are light speed. The other difference obviously is what I'm referring
to is the induced mag field whereas EMI is an external radio frequency
interference. I trust my post doesn’t sound too much like I’m all jacked
up on cafe lattes. Its apparent to me that you did not look at the Wikipedia link I posted earlier for your convenience. EMI really is a magnetic field and one that can occur at almost any frequency. So is RF, as they originate from the same principle of electricity. We usually use 'RFI' to refer to higher frequency phenomena (an example might be an oscillation in a circuit) but its just a polite nomenclature. What is generally different about the two is that for audio purposes, RFI **usually** originates via an antenna (driven by an RF source), whereas EMI generally does not (likely instead radiates from a power transformer or power lines, or any source that is powerful enough to radiate directly without the need for an antenna, although power lines might well be argued to be antennae. I recommend you take a look at the link I posted or ask your colleagues at the ELF station. |
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The shielding in cables protects the cables from external radio
frequencies but does nothing to protect the audio signal from the
induced magnetic field. And the reason is because the induced magnetic
field is a different issue and requires a different solution. It's name
is high permeability. Again your first sentence is correct but what follows is not. One reason balanced lines work is because the system is relatively impervious to induced magnetic fields. This is because the magnetic field is impinged on the shield of the cable and the two conductors within. Since the shield carries no signal current whatsoever there are no worries there- it can't induce noise in the ground plane since ground is ignored. The internal connections carry the signal in two phases, 180 degrees opposed. When it arrives at the input (amplifier) the Common Mode Rejection Ratio (CMRR, https://en.wikipedia.org/wiki/Common-mode_rejection_ratio) of the amplifier then comes into play. If properly designed, the result will be that EMI imposed by the magnetic field cannot get amplified. This is because the input of the amplifier is looking for what is **different** between the two input signals and the EMI is the **same** to both inputs. Because the amp is looking for what is different, EMI gets rejected. The result is that the cable plays little or no role in the overall sound of a system. There are other factors that contribute to why this is so that have not been discussed. I find it quite odd that this technology has existed now for close to 70 years but still gets a lot of resistance (if you will pardon the expression) from audiophiles; eliminating cable interactions is a big part of obtaining neutrality in an audio system. I was designing satellite systems when you were wearing bell bottoms. It could be that you know so much that you have forgotten more than I will ever know. That *could* explain your lapse of basic communications knowledge essential to satellite technology. But Occam's Razor https://en.wikipedia.org/wiki/Occam's_razorsuggests a simpler explanation. |
The human ear is tuned to be the most sensitive at bird-song frequencies. It also uses higher ordered harmonics to calculate how loud a sound is- its not doing that from the fundamental frequencies as such are quite rare in a pure form in nature. So if the system generates these harmonics (5th and above) even in trace amounts our ears are so sensitive to them that they will be heard, even though the distortion of the amp might be 0.005% THD.
The converts distortion into tonality. So the presence of these distortions is heard as both brightness and harshness (the 7th in particular having been known since the 1930s as a source of a metallic coloration), even though on the bench or in the room the system might measure perfectly flat.
In fact the ear has tipping points wherein tonalities created by distortion can be favored over actual frequency response errors. So in some cases its better to have none of these distortions rather than perfectly flat frequency response.
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If it sounds any way all the time, even smooth and relaxing, that is not
a good thing to me. Its not good either if the sound is continuously
irritating and chases me out of the room. Its OK if some recordings
are and come out that way. I agree fully! |
(I happen to think Geoff was in the middle of making a very good and
valid point about magnetic fields here originally before he was so
shrewdly interrupted ;-) He got interrupted because he didn't understand how magnetic fields worked. This was around the issue of balanced line connections, which can be used to eliminate problems of cable construction and colorations as well as the effects of magnetic fields impinging the cable. BTW, this is not to say that EMI/RFI isn't a problem; Geoff was right about that); what I am saying is the if you run balanced lines and the equipment supports the balanced line standard then the cables will have almost no effect on the sound and it will get around the problem of EMI impinging the cable. |
Geoff, its really obvious that you did not read any of the links to basic information about the nature of EMI and RFI. Don't worry about me, you still have to get 'yet on the same page' with some of those basic rules to which those links referred.
FWIW photons are a phenom normally associated with light, not RFI or EMI...
Our gear does not have problems with stray magnetic fields on account of the fact that its fully differential and thus a great deal of shielding is not required. Differential circuits, if laid out correctly, can reject noise from magnetic fields (EMI) just as they can Common Mode noise and for the same reason.
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https://en.wikipedia.org/wiki/Photon-From the page: A photon is massless, [Note 3] has no electric charge, [12] and is stable. However it also states that it is a form of EM radiation. However the signal in a cable is not carried by photons. A better carrier would be the electron, although stated in those terms might be considered a gross oversimplification. Ivan, if you had read the thread through (and I don't blame you for not doing so) you would see that I brought up the balanced line thing specifically with respect to the fact that if properly executed (and quite often in high end audio, the balanced line standard is pretty well ignored) then the cables at least will be immune to EMI (stray magnetic field) problems. If you do not hear that in your system then its likely that it is not supporting the balanced standard. |
Turns out signals in cables don't travel at the speed of light anyway: https://en.wikipedia.org/wiki/Velocity_factorIt would appear that Geoff has opened a new branch of physics. If you can slow down photons to the degree upon which he insists then its not necessary to get something going at the *full* speed of light to actually *go* the speed of light :) Doesn't it sound like that could have some impact on space travel? |
Electrons carry charge, whereas the music signal is an electromagnetic
EM wave so it (the signal) must travel in a conductor at near
lightspeed. In order to travel at that speed the wave must be,
physically, photons, not electrons. The electrons in the conductor only
travel what a meter an hour or something. If the audio signal wasn't
light speed you would hear a pretty big delay for normal phone
conversations, no? Wow. Just wow. So are you saying that there is no current flow in a vacuum tube or a transistor? That its all photons? or does the the photon flow turn into electron flow once it hits the tube? Wow. |
The 'why' is I was simply dealing very directly with the statement you made which I quoted above so the context is very immediate. Here it is again: Electrons carry charge, whereas the music signal is an electromagnetic
EM wave so it (the signal) must travel in a conductor at near
lightspeed. In order to travel at that speed the wave must be,
physically, photons, not electrons. The electrons in the conductor only
travel what a meter an hour or something. If the audio signal wasn't
light speed you would hear a pretty big delay for normal phone
conversations, no? This suggests that you think the audio signal is traveling in the form of photons. Obviously to do that, eventually the signal has to arrive at a tube or a transistor, in order for a stereo amp or preamp to do its job; therefore the **only** logical conclusion one can draw from your statement is that you think the tube or transistor must have photon flow too! I think you know that is not the case; giving you that benefit of the doubt how is it that you square the fact that tubes and transistors have current flow but somehow the wires that attach to them only have photon flow?? IOW, what's wrong with this picture? You are correct that electrons don't flow very quickly in a conductor. The reason that the signal travels much faster is easily seen if you think of a hose filled with marbles- the hose representing the wire and the marbles representing the electrons. If you put a marble in the input of the hose another immediately (at light speed) pops out the other side. In practice not the same electron you put in but it does the same work. IOW, signals do not propagate through any audio cable in the form of photons, unless that cable is a fiber optic. And the signal does indeed move much faster than the electrons. |
I never said they did travel at the speed of light in cables.
Really? Wut up?: As I said previously RFI/EMI is light speed due to the photons involved whilst the other - magnetic field - is stationary. The audio signal moves VERY rapidly. It moves at near light speed in a conductor. Sure looks like you said that to me. I don't think you realize how much you've painted yourself into a corner- on the one hand you seem to get that magnetic fields can impinge themselves onto a cable, OTOH you say that a signal passes through a cable via photons (which won't be influenced by said magnetic fields). Ya can't have it both ways... |
The speed of electromagnetic waves in a vacuum is what 186,000 miles per
second, right? And in a conductor it is a large fraction of c, let’s
say it’s 80% of c or about 150,000 miles per second. That’s close to c,
and that’s why I refer to it as "near light speed." Follow? Well, the funny thing here is that you claim that the signal is in photon form. If so, its going at the speed of light 'cause that's how fast photons go on account of quantum. And if that's so, what can be inferred from that is all you have to do is put the signal through a cable and you can slow it down (on account of the dielectric and quantum). If that is so, it is further inferred that all you need is enough dielectric and you could get a person pedaling a bicycle to go at the speed of light. Then of course you could shed the dielectric and presto! the bicycle made it to Mars in only 30 minutes. Of course, none of this is really possible, because signals **don't** travel in cables in the form of photons (which is of course ridiculous) and also not because of quantum :)! Of course I've been having some fun with this! |
Oh, brother! Are you pulling my leg? Yes, Thought I made that clear! |
^^ of course, there is the issue of what is meant by 'zero distortion'.
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If you kill the phase errors you kill harmonic distortion. Hm. That's good work if you can get it. https://en.wikipedia.org/wiki/Phase_distortionIn a nutshell though such is not the case, you have have harmonic distortion while at the same time having little or no phase distortion. They are not mutually exclusive. |
I've heard speakers that you can pick up and move around and all the while the soundstage is perfectly focused. Not all speakers do that but some do. The first time I head that Mike Maloney was moving his Tesla loudspeakers around while I was in the listening chair during a dealer demo. The soundstage was very focused on that speaker. Since a set of our early amps was playing at the time, must be that we got that focus thing several decades ago. Bottom line - even with perfect bolted down loudspeakers with good
coherency they cannot project a stable image due to the dynamic
modulation of the velocity fed to the speakers by an unstable amplifier. It must be that its all in the setup. I've yet to hear a functioning amplifier than can't project a stable image. |
I think it is a matter of how stable and how focused compared to live.
I recommend that you get a set of really good microphones (I use Neumann U-67s) and go out and make your own recordings. That's what I do (Canto General, which was produced on LP and CD, is one of my first reference disks, produced in 1986). Having been there at the recording site and having heard what the microphone feed did (and having heard many microphone feeds before and since), I can instantly if something is right or not. Having your own reference is really handy; how else are you to know if a recording is really sounding right? Stable and focused is no worries. |
The analogy does not hold up.
Do you have a method of measuring the effect you describe?
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That's just a flip of a switch with our MP-1 or MP-3. Actually the number of inverted recordings is more like 50%.
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The speed of acoustic waves in air is the most important aspect of sound reproduction to get right. Are you suggesting that a circuit can change the speed of sound through air? Or are you meaning something else? |
Atmasphere do you know if the MLP label recordings were "inverted"?
I've
never heard anything about that. My understanding is they have the
"holographic imaging" the best ones do because they were miked very
simply for that (2 or 3 mikes for natural stereo live recordings).
Did they know of and play phasing tricks in the production?
How about more modern champs like Mapleshade or Dorian? I couldn't say. What I do know is that if you want to do a really good recording, you keep things as simple as possible. Al, Here's the link to the polarity database that George Louis compiled. Draw your own conclusions. The conclusion is of course that this is bunk. George would have had absolutely no way to know one way or the other! One time he came into our room, proclaiming that our system was out of phase (it happened at the time that we were playing Canto General which I had recorded). So I flipped the phase inversion switch. At that point, upon not really hearing a difference, George said that you could not hear it on analog recordings. I had the CD on hand so we played that. Same results. So I'm just going on personal experience here- George had and has no way of knowing so you can ignore that database. |
Geoff, you got it wrong: If you go back and look, you will see where; I wrote: At that point, upon not really hearing a difference, George said that you could not hear it on analog recordings. So, I’m going with ’That would be pretty silly’, yes. |
Could this be a major reason why many listeners prefer analog to digital?** Such a Red Herring! We don't even know that such is even true... sheesh. Anyway, we let George hear the CD (so this was not an analog/digital thing at all) but he couldn't make the call on that one, despite telling us initially that the room sounded fine other than being the wrong polarity. Can you see the problem? I'm sure that is why he left so quickly- it must have been as obvious to him as it was to us. |
I should also point out that George’s criterion for determining which is
better N or R for a given recording is that it’s one that sounds more
like "live" music must be N. Roger’s criterion is the same, I.e., "live"
music, for what his amp sounds like compared to amplifier X.
Well it was easy to hear on our system how the LP was better; and since LPs have greater bandwidth than CDs, pretty easy to discount his comment when he said 'you can't hear it on analog recordings'. The fact of the matter is that you can. But to do so, the recording can't have more than 2 or 3 mikes (and the 3rd mike, which will be the one in the middle ala Mercury recordings, had better be phased properly). That is why we have the inversion switch BTW and we've had it since the inception of the preamp in 1989.
"Food for thought...
If you can’t tell the difference when you switch the phase then it [the system] is not clean enough to expose it."
That’s
what I just got through telling Atmasphere is the likely explanation
why George Louis was unable to hear the difference between R and N in
the Atmasphere room at the show. The show is perhaps the worst possible
venue to try to demonstrate anything, including the very speakers and
amps and cables that make up the exhibit; exhibitors shoot themselves in
the foot by not bringing along electonics or speakers that are ALREADY
broken in.
We had broken-in electronics, as well as broken in loudspeakers. In this case I would not use a strawman argument for something, especially when you don't like them used on yourself: George made it quite clear upon entering our room that he could hear the difference. The funny thing is we could hear the difference on both the LP and CD (Canto is a 2-mic recording), and it was correct the first time when he came in. But despite that, George came had his own confidence; we entertained his requests without rancor but he just got up and left as fast as he could. |
No answer to my question yet, I duly note. The industry does not pay attention to absolute phase. As a result, 50% of all recordings might be incorrect phase. The problem you have thought is that about 99.3% of all recordings employ more than two mics, often with tracks recorded in entirely different rooms. Sometimes these tracks are in phase with the rest of the project and sometimes they are not. This can result in out of phase bass which requires in some cases a special processor when mastering LPs. Otherwise the stylus can get knocked out of the groove. This does not happen with digital of course, but the point is that there are a lot of recordings that really are not absolutely in phase or out of phase. Because of these factors inverting the phase is often not audible. You need a purist recording; everything has to be right in order to hear it. We included the phase inversion switch on our preamps on account of the fact that its a real pain in the rear to reverse the phase at the speaker terminals for each recording! |
A total of (0%) manipulation takes place in
the amplifying process. By default it produces sound [objects] that appear to
be in mid-air and are located (placed) back into their relative locations using
the embedded information captured in the original venue. Our stuff does that too! No matter how complex the material is, the soundstage image stays absolutely **locked** in place, perfectly focused. The volume control only changes the overall size. Blumlein developed the concept back in the 1930s. |
