WHY are high-efficiency speakers are better at conveying emotion of music vs. audiophile vocabulary?

morricab

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Yes, they distort when cranked
Well, what's underpinning all I said is some understanding of how auditory perception works & how THD & various stock measurements used in audio are not in any way correlating to what we perceive in the sound. I'm sure you are aware that THD bears little significance to how something sounds?

I could go on a bit (but I don;t have the time) about my pet theory at the moment of noise floor modulation being one very strong candidate for a category of distortions in active electronic devices which is audible but currently a measurement has not been devices to reveal it


Again, I don't have time to elaborate (3am here) but I just wanted to make the basic point that when active device are operating at a small percentage of their full capability, there tends to be a magic to the sound - I have my ideas of why, you may disagree with my ideas but I'm going to sleep now & will dream sweetly, I hope


Just to clarify something here in your post that is perhaps not so obvious. You are talking about noise floor modulation but you did not talk about HOW this modulation occurs and why it would be bad for sound.

If I am understanding you correctly (please correct me if I am wrong), you are talking about the phenomenon that was described by Crowhurst where he posits that because of negative feedback a signal will create a myriad of distortion products that will be indistingushable from noise EXCEPT for the fact that it is correlated with the signal and therefore not true noise.

The problem with this correlation with the signal is how our ear/brain processes such a "noise" is not the same as true random noise...like tape hiss. With true random noise it has been shown that you can hear below this noise floor to signals that are correlated with the music...kind of a neural "lock-in amplifier" that allows us to hear those signals because they are not noise. Of course there are limits to this. With a music correlated and modulated "noise" floor you have two issues, 1) the "noise" floor is changing constantly, rising and falling with the music amplitude and complexity and 2) Now that it is not random and uncorrelated with the signal you can no longer hear below this "noise" floor.

This impacts how we perceive low level signals and hearing soft sounds in the presence of much louder sounds...or as my late friend Allen Wright used to call it "Downward Dynamic Range". Soft sounds will now get masked by a correlated mush caused by a myriad of distortion products. This will also impact decay of notes and ambient sound cues.
 
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morricab

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I suspect that the only person this actually makes sense to is you.

He meant to say, " Because the distortions from electronics are less natural than the distortions from SPEAKERS even though, on a pure THD basis, the numbers are far lower for electronics"

Then it makes a lot of sense.
 
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morricab

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I think this may be your worst post ever. There is nothing useful in it. Distortions that can’t be measured, but exhibit huge swings in ground reference? No. That doesn’t makese sense. Also it isn’t completely clear what you mean. There are problems with electronics, but it isn’t that simple, nor necessarily the electronics fault.

High efficiency speakers actually use less voltage relative to wattage required. They are the opposite of what you are saying, even though they use less current. They are using less because the voltage is lower. But why it isn’t respective to current is because the resistance is either more or the same for high efficiency speakers, so they draw the same amount per volt. At impedance peaks maybe they are different, depends on driver and how much of one a peak it has. The formula for current (I) is I = V/R . If the driver is more sensitive it is louder at 1V. The voltage is the limit of usable watts, at least in a pure volume sense (higher watts, but not higher volume can come from higher current use, because W=V*I and voltage is capped by power supply of amp).

I believe you could elaborate and tell us something, not seen in that post.

Keep in mind that high sensitivity speakers tend to have higher impedance (8 or even 16 ohms as opposed to the 4 ohm or less in a lot of average sensitivity speakers), which would indicate then a demand for voltage and less for current. Yes, it would require less of each for a given SPL rating but the ratio and therefore demand placed on the amplifier would be different. A lot of SS amps will not be super happy into 16 ohms (their power will be half that at 8 ohms approximately) but a lot of tube amps will deliver the same power (or even slightly more), which indicates a larger voltage swing to get the same power.

Also, please look at the series of articles in Stereophile by Peter van Willenswaard where he demonstrates the huge voltage swings a 300B SET can generate compared to a nominally much higher rated SS amplifier with tamborine strikes. Swinging voltage is indeed what they are good at relative to delivering current and why the 4ohm or less crowd with 86db sensitivity is not ideal for swinging voltage but would demand relatively a lot of current. Now there are some SETs out there that don't flinch at that but they are not 300B amps.
 

jkeny

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I suspect that the only person this actually makes sense to is you.
Sorry for using the wrong word - late night posting (I must avoid) - corrected now
 
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jkeny

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Just to clarify something here in your post that is perhaps not so obvious. You are talking about noise floor modulation but you did not talk about HOW this modulation occurs and why it would be bad for sound.
OK, let's call it NFM for short. If you look at a plot of IMD you will see the spurious IM tones created because of the non-linearity of the device. Multiply the number of tones to 500 or whatever you consider best represents a music signal & the number of IMD tones become very numerous & overlapping to the extent that they form a broadband distortion which is modulating with the signal. It's modulating in complex ways with changes along the axes of pattern, spectral makeup & amplitude. But that's just one simple explanation & there are many other ways that the noise floor can be modulated - I use liFePO4 battery power because of its low noise & high stability & anywhere I have tried it (In the reply chain), it has improved the sound Vs stock PSes. This is power direct from the battery output - even using a low noise voltage regulator such as TPS7A4700 or LT3042 degrades the sound. My conclusion: active devices are introducing some level of instability in the ground noise.

It's difficult to isolate just NFM & say how it sounds alone but in my experience & my reading of others experiments where I believe ground noise stability is being improved, the predominant audible difference is that there is a perceived increase in dynamics, in solidity of the soundstage, in realism of the illusion created by the playback. Look at RogerD's thread on heavy gauge ground wires between chassis of his playback devices - to my way of thinking what is happening here is that the ground impedance differences between devices are being eliminated/minimised & noise on the signal ground (reference ground) is now stable (He's effectively providing a lower impedance path for ground currents which may have been on his interconnect shields or ground wires) His reports of the sound is exactly the same as what I & others describe & I believe the underlying mechanism is the same - a more stable signal ground/reference.

Why this should be perceived in this way requires a deep dive into the workings of auditory perception but if we consider just NFM then auditory perception continually categorises the incoming soundstream into foreground & background layers - the background is relatively ignored with just a watching brief from auditory perception. So, for instance, we generally can ignore (hear through) the hiss of analogue playback, of room ambiance, etc. We continue to ignore this background sound unless something changes in it (the watching brief picks this up) & our focus is automatically shifted to the change in the background sound (this is a survival mechanism) & is called mismatch negativity in perceptual research.

It's not difficult to see what's happening in NFM somehow affecting our perception but it isn't as simple as above, in that it seems to affect the way we perceive the foreground sounds 7 we don't perceive our attention being drawn to the background sound layer. But I don't subscribe to the idea that all we perceive must be consciously registered - there is a lot happening to our perception subconsciously which colours our final perception.

If I am understanding you correctly (please correct me if I am wrong), you are talking about the phenomenon that was described by Crowhurst where he posits that because of negative feedback a signal will create a myriad of distortion products that will be indistingushable from noise EXCEPT for the fact that it is correlated with the signal and therefore not true noise.

The problem with this correlation with the signal is how our ear/brain processes such a "noise" is not the same as true random noise...like tape hiss. With true random noise it has been shown that you can hear below this noise floor to signals that are correlated with the music...kind of a neural "lock-in amplifier" that allows us to hear those signals because they are not noise. Of course there are limits to this. With a music correlated and modulated "noise" floor you have two issues, 1) the "noise" floor is changing constantly, rising and falling with the music amplitude and complexity and 2) Now that it is not random and uncorrelated with the signal you can no longer hear below this "noise" floor.

This impacts how we perceive low level signals and hearing soft sounds in the presence of much louder sounds...or as my late friend Allen Wright used to call it "Downward Dynamic Range". Soft sounds will now get masked by a correlated mush caused by a myriad of distortion products. This will also impact decay of notes and ambient sound cues.
Yes, you got it but I don't think it is just due to negative feedback - NFM can be created from many different sources - I mentioned PSes. I also believe that noise on the data wires of USB also intrudes & causes NFM. I've experimented with the output stage of certain DAC chips which have their current bias exposed through a pin & using a CCS instead of the recommended resistor noticeably improves the sound

When you think about it, it's not just soft sounds that are affected, t's also affecting the start of all sounds (they all start from soft) - so the precise timing of the start of sounds is being slightly changed by NFM. The solidity of the soundstage is one of the characteristics noted when NFM is reduced/eliminated.

I believe an understanding of NFM is the next breakthrough to be made in improving audio playback but it will require a measurement approach which can isolate it or maybe a way of simulating it & studying the various characteristics & their effect on perception.

This is what was behind my post about electronics distortions being more noticeable to our auditory perception than speaker distortion even though the gross THD figures would suggest otherwise - we are perceiving the distortions in different ways.

Look at horn speakers - usually very efficient but regarded as highly distorting, yet when not cranked too loud they can sound exquisite. I'm sure you can pitch in about Aries Cerat, horns, morricab?

Thanks morricab
 
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jkeny

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He meant to say, " Because the distortions from electronics are less natural than the distortions from SPEAKERS even though, on a pure THD basis, the numbers are far lower for electronics"

Then it makes a lot of sense.
Thanks for the understanding & correction - I slept through this.

When I say "more natural" we have to understand what is judging the sound - our auditory perception mechanism. This mechanism is optimised towards the way sounds behave in the world. Physics defines how objects reverberate & the resultant pressure waves transmitted through the air. We are born with a nascent ability which develops into our fully fledged auditory perception by learning from the sounds of the world. So we inherently know what's natural & what isn't - play a sound backwards & you will recognise the attack portion is at the end - it sounds unnatural - play the Beatles backwards & you will hear "Paul is dead" - it's just not natural ;)
 
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Al M.

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Does digital jitter also cause noise floor modulation? If so, this would explain in part why it is so pernicious compared to analog wow and flutter, which can be magnitudes higher.
 

jkeny

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Does digital jitter also cause noise floor modulation? If so, this would explain in part why it is so pernicious compared to analog wow and flutter, which can be magnitudes higher.
Good question & I don't know the answer but if we look at S-D DAC chips then the noise shaping in all these chips is an obvious mechanism where noise floor modulation can originate. Mallinson, once the chief designer from ESS had a good video on this.

One of the many characteristics of digital jitter that distinguishes it from the wow & flutter coming from tape or vinyl replay is that W+F arises from mechanical origins so it has a slower ramp up time (& fall off time) as the physics of rotating objects would predict - there's no instantaneous change in timing as there can be in jitter - jitter doesn't necessarily have this ramp-up/fall-off characteristic. It's difficult to work through the audible effects of jitter.
 
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morricab

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OK, let's call it NFM for short. If you look at a plot of IMD you will see the spurious IM tones created because of the non-linearity of the device. Multiply the number of tones to 500 or whatever you consider best represents a music signal & the number of IMD tones become very numerous & overlapping to the extent that they form a broadband distortion which is modulating with the signal. It's modulating in complex ways with changes along the axes of pattern, spectral makeup & amplitude. But that's just one simple explanation & there are many other ways that the noise floor can be modulated - I use liFePO4 battery power because of its low noise & high stability & anywhere I have tried it (In the reply chain), it has improved the sound Vs stock PSes. This is power direct from the battery output - even using a low noise voltage regulator such as TPS7A4700 or LT3042 degrades the sound. My conclusion: active devices are introducing some level of instability in the ground noise.

It's difficult to isolate just NFM & say how it sounds alone but in my experience & my reading of others experiments where I believe ground noise stability is being improved, the predominant audible difference is that there is a perceived increase in dynamics, in solidity of the soundstage, in realism of the illusion created by the playback. Look at RogerD's thread on heavy gauge ground wires between chassis of his playback devices - to my way of thinking what is happening here is that the ground impedance differences between devices are being eliminated/minimised & noise on the signal ground (reference ground) is now stable (He's effectively providing a lower impedance path for ground currents which may have been on his interconnect shields or ground wires) His reports of the sound is exactly the same as what I & others describe & I believe the underlying mechanism is the same - a more stable signal ground/reference.

Why this should be perceived in this way requires a deep dive into the workings of auditory perception but if we consider just NFM then auditory perception continually categorises the incoming soundstream into foreground & background layers - the background is relatively ignored with just a watching brief from auditory perception. So, for instance, we generally can ignore (hear through) the hiss of analogue playback, of room ambiance, etc. We continue to ignore this background sound unless something changes in it (the watching brief picks this up) & our focus is automatically shifted to the change in the background sound (this is a survival mechanism) & is called mismatch negativity in perceptual research.

It's not difficult to see what's happening in NFM somehow affecting our perception but it isn't as simple as above, in that it seems to affect the way we perceive the foreground sounds 7 we don't perceive our attention being drawn to the background sound layer. But I don't subscribe to the idea that all we perceive must be consciously registered - there is a lot happening to our perception subconsciously which colours our final perception.


Yes, you got it but I don't think it is just due to negative feedback - NFM can be created from many different sources - I mentioned PSes. I also believe that noise on the data wires of USB also intrudes & causes NFM. I've experimented with the output stage of certain DAC chips which have their current bias exposed through a pin & using a CCS instead of the recommended resistor noticeably improves the sound

When you think about it, it's not just soft sounds that are affected, t's also affecting the start of all sounds (they all start from soft) - so the precise timing of the start of sounds is being slightly changed by NFM. The solidity of the soundstage is one of the characteristics noted when NFM is reduced/eliminated.

I believe an understanding of NFM is the next breakthrough to be made in improving audio playback but it will require a measurement approach which can isolate it or maybe a way of simulating it & studying the various characteristics & their effect on perception.

This is what was behind my post about electronics distortions being more noticeable to our auditory perception than speaker distortion even though the gross THD figures would suggest otherwise - we are perceiving the distortions in different ways.

Look at horn speakers - usually very efficient but regarded as highly distorting, yet when not cranked too loud they can sound exquisite. I'm sure you can pitch in about Aries Cerat, horns, morricab?

Thanks morricab

My pleasure...one of my favorite audio topics :).

Well, one thing you mentioned about the power and grounding is that you can easily get distortion products that are due to intermodulation between the power supply harmonic and a signal harmonic...thus further complicating the picture. You can see this in some amplifiers FFT spectra at 1Khz where you will have the main harmonics and "side" harmonics that are modulation products with 60 (or 50) hz, 120 (or 100)Hz etc. THEN you have the intermodulation of the intermodulation and so on and so on... removing the spurious power supply ripple harmonics can reduce the degree of messiness one gets from all this intermodulation (not all amps show significant power supply ripple or intermodulation with the power supply harmonics). Of course it is not just amps but DACs, preamps, phonostages etc. that all inject their messiness into the signal that only serves to reduce the realism contained in the signal by cueing our brains that it just isn't real...sigh!
 

morricab

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Does digital jitter also cause noise floor modulation? If so, this would explain in part why it is so pernicious compared to analog wow and flutter, which can be magnitudes higher.

There are these plots of Jitter in Stereophile where sometimes the noise floor is clearly higher with some DACs than with other DACs. This is usually associated with higher jitter so the question then is how much of the degradation of sound is the jitter or the noise floor increase...if any?
 

microstrip

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There are these plots of Jitter in Stereophile where sometimes the noise floor is clearly higher with some DACs than with other DACs. This is usually associated with higher jitter so the question then is how much of the degradation of sound is the jitter or the noise floor increase...if any?

As far as I can see there is no direct correlation between jitter measurements and subjective sound quality (that is established by user preference) . Preference of users is due mostly to system matching or the type of sound they like.

The few existing measurements or opinions are in too small quantity or carried in very specific conditions. IMHO they are interesting reading, but too limited to be of real value to answer our questions. It is why the debates on jitter in audio forums will never end ... ;)
 

jkeny

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As far as I can see there is no direct correlation between jitter measurements and subjective sound quality (that is established by user preference) . Preference of users is due mostly to system matching or the type of sound they like.

The few existing measurements or opinions are in too small quantity or carried in very specific conditions. IMHO they are interesting reading, but too limited to be of real value to answer our questions. It is why the debates on jitter in audio forums will never end ... ;)
Yea, it's difficult to tease out the audible effects of jitter at the low levels that it exists in most modern digital audio equipment. One of the problems it's that you can't really trust the specs, even the clock manufacturers don't show the jitter spectrum unless you are buying custom. I always wanted to investigate close-in phase noise & its audibility but it wasn't until Jocko Homo started to measure & select from the batch of NDK oscillators that I could trust I was getting a osc with this characteristic.
Used on my DAC it provided a small improvement, I think but wasn't fully sure - an improvement which seemed to give better soundstage & solidity but not nearly the same improvement jump as my other tweaks. Remember this DAC used battery power & USB isolation/relocking - the clock also powered from battery - so a lot of the sources of distortion are already dealt with. I still have these osc which I will try again at some stage.

But I believe most of the improvement people hear with add on clocks is related to ps supplying the clock - this is the low hanging fruit
 

Al M.

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There are these plots of Jitter in Stereophile where sometimes the noise floor is clearly higher with some DACs than with other DACs. This is usually associated with higher jitter so the question then is how much of the degradation of sound is the jitter or the noise floor increase...if any?

The question is also, how does that noise floor change with the musical signal? The usual stead-state measurements with test tones will not give us an answer. A static higher noise floor may be less detrimental than a fluctuating lower one.
 
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caesar

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In a recent Stereophile review of the Klipschorn speaker (https://www.stereophile.com/content/klipsch-klipschorn-ak6-loudspeaker), Art Dudley nicely summarizes what this thread is about:

"...
In the years since the Klipschorn's debut, loudspeaker technology has progressed in many ways. Speakers that sound timbrally neutral and uncolored are much more common today, as are speakers with consistent and effective dispersion across their operating range. Thanks to the pioneering work of people like Jon Dahlquist, Jim Thiel, Richard Vandersteen, and John Fuselier, physical time alignment of drivers in a dynamic loudspeaker system is virtually a given these days, and the problem of baffle edge diffraction has been identified and smacked upside the head. The result is a great selection of loudspeakers that offer apparently flat frequency response, superb stereo imaging, and great airiness and transparency.

And what did we give up to gain such easy access to all those things? Natural-sounding dynamics. Impact. Pluck. Snap. Body—especially body. And soul."
 

Jägerst.

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Live music is really dynamic. And its easier for high efficiency speakers to provide that via simple physics (if peaks need to be 105dbs, much easier to do that with 100db speakers than 85)

As one dealer friend put it, inefficient speakers are sometimes like hearing music through a straw. Also, many lower efficiency models have larger, more complicated higher order crossovers. Many horns on the other hand have a simple cap in the path or roll off gently.

I find there's merit to above statement, especially the "through a straw" description of listening to low efficiency, passively driven speakers. Obviously comparing a high eff. and low eff. speaker segment in general terms involves more than simply dealing with a discrepancy in efficiency alone (no "all things being equal" here), and more like coming to terms with different design principles, driver types, size requirements and overall implementation. What follows with HE speakers is usually horn-loading (or the use of waveguides), be it hybrids or all-horns, pro style woofer/mids and compression drivers, and large size - much dictated by physics - all of which sums up to a sonic imprinting that's oftentimes more visceral, vivid, present/direct and effortless. To me at least these traits can be quite supportive in creating an emotional reaction that's less in-the-head and more in-the-body, if you would, and I would have to believe this is at least partially due to an element of loss of control that happens in the face of dynamic prowess, uninhibited presence and not least effortlessness. Moreover I've heard a range of passive speakers converted to active config., i.e.: where 'all things being equal' more readily applies, and throughout has found their passive iteration (especially with complex filters) to be somewhat thicker/dull sounding, less transiently snappy, and less transparent and resolved. Couple that (i.e.: active) with the typical traits of HE speakers, and there are interesting qualities to be potentially extracted here.

I've very much come to cherish what some HE speakers can bring to the table sonically, not least actively driven, even when it involves compromises - and which there mostly are one way or the other, HE or LE, but I rarely if ever think of it as a compromised presentation in my specific, active HE set-up. What is detrimental to my ears is the feeling of what's heard is "bottlenecked" or like someone standing on the garden hose; this becomes much more apparent and easier to identify when getting used to listening to active HE speakers. Of course, that's just one aspect of sound reproduction, but an important one to me.
 

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