Well that statement sheds some light on some of you guys' expectations. Free yourself indeed! What makes you think you can glean more out of a recording than what's there? It's only "information". Once you've retrieved it, it's all there is and there ain't no more. The secret is knowing when you've gotten it all. And it is possible to know. You poor sods. No wonder you're spending more on wires and cables than gear. |
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Listener fatigue is nearly always a consequence of distortion.
Two distortion sources are IM distortion and odd-ordered harmonic distortion. Both are known to be irritating to the human ear- and this has been known since the early 1950s.
What is less understood is some of the studies of the human ear that have occurred since then that relates directly to listener fatigue.
One of those things is that the ear/brain system uses odd ordered harmonics to sort out how loud a sound is. To do this it is very sensitive to the presence of odd ordered harmonics. Audiophiles have terms for the presence of trace amounts (less than 0.01%): hard, harsh, bright, etc.
This is why two stereo pieces can measure flat on the test bench but one might sound bright while the other does not.
In addition it is useful to know that the ear is tuned to birdsong frequencies. Knowing that makes its easier to understand how the ear can be that sensitive to the presence of the 5th, 7th or 9th harmonics.
The ear translates distortion as tonality. A 2nd harmonic is interpreted as warmth, a 7th as brightness.
IM (Intermodulation Distortion) is a form of harmonic distortion that the ear usually translates as brightness. This is where two more more tones can interact in the stereo system to produce other frequencies, the sums and differences of the tones involved. It is caused by non-linearities in the system, any place where the tones can interact, such as a feedback node in an amplifier, poor power supply design or a breakup in a speaker cone.
There is a special form of IM distortion called inharmonic distortion that only occurs in digital products (good luck looking for the specs on that- most manufacturers don't publish the numbers). These are intermodulations between a fundamental frequency and the scan frequency of the recording rather than harmonics based on the fundamental tone as is encountered in analog recordings. The ear treats these as brightness as well.
There is a tipping point in the human hearing perceptual system where the ear will favor distortion as tonality over actual frequency response errors. As a result is is often more important to have low distortion rather than flat frequency response. For this reason its usually best to reduce the types of distortion that the ear finds most objectionable and noticeable before going after frequency response errors. |
As we have seen recently with the WA Qwantum Chips and some other things, too, like SteinMusic Harmonizer, Schumann Frequency Generators, demagnetizers, ionizers, and - all of this in utter disregard for the textbook view of distortion and noise in audio systems - such things as Silver Rainbow Foil, cream electret, the Red X Pen, things of that nature. If the only wine you've ever drunk is Boones Farm, you probably think it goes down pretty smooth. LOL |
Atmasphere answered my thread :-)
I'm so excited!! |
Again, what are we...chopped liver???
BTW, well said, Ralph. However, harmonics of all sorts exist as you inferred whether they're distorted or not and therefore are included in any recording, are they not? So isn't it the degree of odd ordered harmonic 'distortion' a particular amp exhibits which is the significant factor in determining or confirming how pleasant or irritating the sound may end up being? And therefore whether those harmonics are being produced cleanly. Serious question with respect. |
If you're drinking Boones Farm only, you are probably more likely to try almost anything that might make things better.
Disclaimer: never had Boones Farm. It might be pretty good for all I know. |
I find Ralph's response extremely interesting as I detect a hint of the significance of the subjective experience as a significant part of the musical equation. I don't think engineers like thinking like this, fortuneately for us subjective listeners, although I think he took his oscilloscope and sound meter with him into the netherlands. This poses an interesting question. If Ralph was able to build an amplification system that "trips all the audiophile triggers", dropping us to our knees in tears through manipulating the presentation of the source signals, would the system be considered high fidelity and would he be raped by the audio reviewing and audio engineering community for manufacturing inaccurate equipment? The Shehanian Diopsan/ Stereophile debacle comes to mind. |
Mapman, my gut is you would probably like Boones Farm.
;-) |
Csontos, you are spot on.
The specs an amplifier has on paper don't reflect the whole story though. An amplifier with very low distortion with steady state signals (sine waves, used to test for distortion) can act quite differently when asked to reproduce a waveform that is constantly changing.
The feedback used in the amplifier can have a huge bearing on this phenomena. So it does not follow that the lowest distortion on paper will also be the least fatiguing.
Generally speaking, the use of feedback in an audio circuit will reduce most forms of distortion but will leave audible amounts of odd ordered harmonic distortion caused by the ringing of the signal in the circuit due to propagation delays in that circuit. In a nutshell, the feedback always arrives back at the input of the circuit slightly too late to do its job right.
The higher the frequency, the more pronounced this problem becomes. Since our ears use the odd orders to sort out how loud a sound is, essentially the use of negative feedback in an audio circuit violates one of the most fundamental rules of human hearing. To avoid this you have to avoid the use a negative feedback.
Such amps and preamps that do so will seem to have higher distortion on paper, but quite often will have less listener fatigue on this account. |
"Mapman, my gut is you would probably like Boones Farm."
Probably not. I like wine but am not crazy about most wines out of the bottle. I prefer to add my own "tweaks" as needed in most cases.
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Ralph, I gotta hear you tell me it's possible that odd ordered harmonic distortion in an ss amp can be low enough to render it inaudible with or without NFB. Please tell me it's so. I don't wanna buy a tube amp:) |
"I don't wanna buy a tube amp:)"
I like to look at and listen to other peoples tube amps and have always thought tubes are the coolest thing since sliced bread... but neither do I.
After all if a SS amp starts to glow all pretty, you probably have a problem. :^) |
Csontos, you put your finger on the leading edge of what is possible with transistors.
Here is one of the difficulties you are dealing with. Transistors have a non-linear capacitive aspect inherent in the junctions of the devices. In fact some semiconductors take advantage of this capacitance, as in the example of varactor diodes that are used in the tuning of modern FM radios.
This non-linear capacitance is magnified by the amount of current through the junction. It results in non-linearities in the amplifier that employs such devices. Now if you were reading between the lines, one way to reduce this problem is have the amp drive a higher load impedance. This will reduce the current in the driver transistors and output devices.
There are other advantages to a higher load impedance besides this one, but that is one effective means of reducing harshness in transistor amps. Of course you will get less power, but in high end audio usually we are more concerned about sound quality rather than raw sound pressure.
Now in tubes there is also an inter-element capacitance; the difference is that it is constant and unchanging regardless of signal level rather than non-linear and changing. This makes it a lot easier to build a circuit that is low in odd ordered harmonics.
This seems to me to be one of the things that has to be dealt with in a transistor design before overcoming the apparent advantages of tubes insofar as listener fatigue is concerned. One patented method to get around this problems involves heating the power transistors to a high (+100c) temperature- I have heard one of those amps and its quite impressive- but also very expensive- over $100,000 for a 100-watt/channel amplifier. Plus it made all the heat of a class A tube amp of the same power.
So it seems to me that in more practical terms tubes do have the upper hand in this regard, as its fairly easy to build a zero-feedback tube amplifier. That is hard to do with transistors; but Ayre and the Pass First Watt amps are examples, and IMO these are some of the best transistor amps made today. |
But what about 'bridged' amps? An issue I have just brought up on another thread in an unrelated? issue, 2nd order harmonics being cancelled out. |
Csontos, the 2nd harmonic is considered musical to the human ear (contributes to the coloration known as 'warmth' or 'richness'), and is not used as a loudness cue. Its the 5th, 7th and 9th that are, and they are likely to be in slightly higher numbers in a bridged transistor amp. |
O.K., we have a top notch amp manufacturer giving his expert opionion on how the amplification process can contribute to listener fatigue, is that the whole story? The presence or absence of odd ordered harmonics perceived by the brain as noise explains it all. Do lack of detail or dynamics contribute? Can too much detail cause fatigue? How much does the preconceived notion in our head of good sound contribute? Can complying too much or varying too much from this image cause fatigue? Is complete aversion, like fingernails on a chalkboard, instant fatigue or something else? |
Ralph, I'm wondering if you've come across Susan Parker's 'Zeus' zero feedback impedance amplifier? I'd love to hear your thoughts on her design. She's had a following on DIY since she posted it in 2004. "Straight wire with gain", either tube or ss. |
Petepappp, people often associate brightness with more detail. They are not the same. Detail is that which tells you more about the music. Brightness can allow you to do that, but at a price of listener fatigue. What works better is when you get more detail coupled with a relaxed presentation.
BTW, you might be interested to know that in most audiophile conversations, the word 'dynamics' can be safely replaced by 'distortion' without changing the meaning of the sentence. IOW, many audiophiles don't pick up on the fact that distortion can masquerade as 'dynamics'.
Csontos, I've seen the amp before. Its nice and simple, and I don't mind being called a purist when I say that I don't like transformers. But with the right transformers this amp might perform quite well, although it might not double power as you cut impedance of the load in half. However IMO that particular trait in an amplifier is way overrated. |
Ralph,Dynamic swings are heard continously in live music, this natural ebb and flow gives music the emotion I love. This dynamic character occurs at low, moderate and louder levels. This is so apparent when listening to musicians live.I can easily control dynamics when I play my trumpet. Are the dynamics that exist in nature a form of distortion? How is an audio component to reproduce dynamics without this distortion as you call it? How would a component convey dynamics without this identified distortion?
Regards |
I believe the ceiling is around 150 watts into any load.
Charles, playback distortion in a component has nothing to do with the original unrecorded source. The job of the play back system is to reproduce as faithfully as possible what was actually recorded, distortion and all. But you knew that:) |
My point is that dynamics is an inherent part of music as is timing and the unique and individual tonal signature of a instrument. So how does a system reproduce(retain) music's dynamics yet avoid this distortion Ralph attributes? The ear/brain easily perceive gradients from soft to loud(dynamics) , so hearing a component portray this is due to distortion cues? Doesn't seem logical.
Regards, |
The system is stupid. It doesn't know how to do anything but play back the recording. Ralph was referring to an apparent sonic enhancement caused by the gear. |
Definitely agree with Atmasphere detail/brightness comments. Good or improved detail, upgrading a system component for example, to me is when you are able to hear things that were more hinted at but not defined before and relaxed presentation would also apply unless the recording calls for some thing different. Brightness definitely adds to fatigue. I guess what I am calling dynamics would be the ability for the system to reproduce accurately subtle as well as very energetic or loud musical passages. Accurately being the key phrase. This ability should make the music more interesting and less fatiguing IMO. I realize increased SPLs caused can cause amp clipping, speaker inablilty to reproduce, etc. and there must be a "noise" threshold for fatigue. Dynamic range might also be part of this discussion and seems strange to me. I think that a good analogy would be overly compressed mp3 files compared to HD FLAC files (well recorded and mixed ones). I say strange because 15ips reel to reel recordings do not have the dynamic range of say DSD, but there is something to them beyond their increased level of detail that makes them special. Maybe dynamics? |
Charles1dad does have a point here. While I fully understand Atmasphere's point he makes about substituting distortion for dynamics (I agree that what many people call brightness is actually distortion), Charles is right that this is oversimplification. Any musician does not naturally associate those two terms at all. Different types of systems reproduce amplitude differently, some much better than others, and I don't mean just on the loud end, but also the very soft end, which is especially important when listening to acoustically produced music, whether orchestral or jazz. This is an entirely separate thing from distortion. This is one big reason, for instance, why many professional musicians still prefer lower powered amps coupled with very high efficiency speakers - this combo, generally speaking of course, reproduces the entire dynamic spectrum more easily and more naturally sounding. That's getting pretty old school nowadays, with all the higher powered amps and lower efficiency speaker designs out there, but that's how most of us musicians who play acoustic instruments feel. |
Learsfool,
Yes, you certainly understand the point I'm expressing. I totally agree that too often brightness is mistaken for detail. Many components that go the ultra detail and ultra resolution route sound false and artificial. They tend to sacrifice the actual full body and tone that's present when instruments are heard in a live setting.When you strip or thin out the tonality the resulting sound is less natural.
Dynamics are just as crucial at low/softer levels of music as they are at higher levels to communicate the music's emotion and full expression(similar to a voice inflection).
Learsfool, I have also personally reached the conclusion that lower power amplifiers with higher efficiency speakers produce a more natural and believable presentation.I can relate to you and your fellow musicians on that choice.
Regards, |
I get fatigued with my music when I try to trim out my collection. I am not listening to it to enjoy it but to eliminate items. It must be done but I do not enjoy it hence fatigue. It lasts a while after so I find I do not listen intently for at least a few weeks after. |
Charles1dad, to your point the problem we are having with semantics is that distortion often masquerades as dynamics. This is so common with audiophiles that I no longer use the term- I use impact instead, when referring to actual changes in dynamic contrast.
An excellent example in recorded from is side one band 2 of the Soria series (RCA) Verdi Requiem. Here you can experience the dynamic range from triple pianissimo (ppp) to triple forte (fff), IOW from very quiet to very loud, such that to play it properly will bring most systems to their knees in just a few seconds.
Now, with respect to the comment of lower powered amps on high efficiency speakers by Learsfool:
SETs have a particular distortion character that is exactly what I am talking about (although other systems can do similar things). In an SET, to really hear what the amp does you need to have a high efficiency speaker. This is because the distortion of the amp vanishes at lower power levels. When there is distortion it obscures detail. This is why SETs always get good marks for low level detail.
At power levels up to about 25%, the main distortion is the 2nd harmonic, followed in much lower amounts by the 3rd and 4th harmonics. These harmonics contribute to the lush character that SETs are known for. I have often thought that SETs have become more popular with digital products, as they seem to add harmonic structure that digital often seems to lack.
At power levels above 25-30%, the higher ordered harmonics come into play. SETs will typically have about 10% THD at full power. The higher orders contain in addition to more even-ordered harmonics, also the odd orders, the 5th, 7th and 9th (used by the brain to sort out how loud the sound is). Their presence is masked to our conscious hearing by the presence of even ordered harmonics, for example the 4th, which is louder than the 5th, masks the presence of the 5th.
However music is processed by the limbic system in the brain, and the presence of the odd ordered harmonics is not missed even though consciously we are not aware of distortion. Music has a lot of transients (dynamics) which demand greater power out of the amp. If you are playing the amp on a moderate to high efficiency speaker, depending on the power capabilities of the amp and the efficiency of the speaker, the power levels above that 25-30% level will only be showing up on the transients.
What this means is that the artificial loudness cues (odd ordered harmonics) will only show up on the transients. **This is why** SETs are often cited for having dynamics that seem far above what one should expect for such a low powered amp. We have all seen those comments in plenty of reviews.
The bottom line is what we are seeing in this example is distortion masquerading as dynamics. |
SET amplifiers as a niche have finite limitations as do any other amplifier type, be it solid state, class D, OTL, push pull tube etc. Within a given amplifier category there's a hierarchy of quality and execution success. I find the limitations of SET or other lower power amps an acceptable tradeoff to get the superior sense of realism and naturalness they provide relative to other choices available (obviously YMMV)). There's compromise intrinsic to any and all amplifier topologies.Semantics, that's all it is. Call it impact or dynamics, the bottom line is this is a mandatory component of music.Without it, music is lifeless and unrealistic.
Regards, |
Thanks for the explanation, Atmasphere. I think much of this is a question of semantics, as you say - from your perspective, I understand even more now why you substitute the one term for the other in the context of most audiophile talk. I almost felt guilty even bringing it up, since normally you are the person on this board who is the very best at describing technical/electrical type things in layman's terms. I have learned very much from you about WHY I hear the things I do in various types of equipment and therefore have learned more about why my ear prefers the things it does. There are several other audiophile terms that musicians find the use of to be strange, but I'll drop the subject now - we've had threads about that before. |
Does it follow from the previous responses that a large amount of amplifier "headroom" should reduce listener fatigue, assuming the amp is capable of low distortion sound reproduction? I keep running into the relationship between fatigue and I'll call it peaked interest. I think there might be a relationship but more complicated than a perfectly converse one. More simply does boredom equal fatigue? |
Yes, sometimes. Fatigue has more than one definition. Distortion is clearly the prominent one, with you also. Where's the dilemma? You're aware of both kinds. Either one calls for an upgrade, no? |
No dilemma Csontos, interested in other responses, thanks for yours. Agree with your upgrade comment, including source material. I'm a believer in plan your work and work your plan. I find that if you don't know what you want, you have very little chance of getting "it". Even opinions that I might not agree with often teach me something.Interesting thread. |
Distortion + associated fatigue tends to be higher at higher volumes in general, right?
Good listening pattern is music draws you in and desire to keep wanting to up the volume to draw you in even more. Down side is that listening at levels >80-85 db for extended periods is commonly cited as having destructive effects on our ears, no matter how good it may sound.
Bad listening pattern is music is not engaging and turning things up makes things worse. |
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Several months ago now I posted a thread about volume and related hearing damage. Anyone interested should look it up. |
The thread was called Sound Exposure and Potential Hearing Loss. For some reason I am unable to provide a link, sorry. |
I saw it. I never did like facing the truth. |
If one is exposed to sounds greater than 90 dB for an average of eight hours per day without hearing protection, hearing loss will most likely result. As the volume increases, the safe time of exposure decreases. Quote from Stoneybrook School of Medicine website. That's pretty loud and alot of listening. The site also said occupational noise has been replaced by headphone use as the number one cause of environmental hearing loss which is impacting mostly the younger generation, so purchase a good set of speakers, leave the headphones on the shelf, and enjoy the music. |
Learsfool, I remember seeing that one too. I recently downloaded a db app for my iphone and find myself listening in the 75-85 db range when I'm really rockin out but normally listen in the 65-75 range. Something I found scary, and stupid, is the accepted db work levels set by osha - 90 db for eight hours a day? 100 db for 2 hours a day? Are you kidding me?
Anyways, back on topic, alot has changed recently in my system, as usual, but I haven't experienced the physical fatigue that I had felt in the past which made me start this thread in the first place.
I think the factors that helped were switching to speakers that are way more laid back in there presentation and reducing distortion that I didn't even know was there through the use of acoustic panels.
I'm really loving my system now and it is not fatiguing in any way anymore :-) |
