Sound differences between cap brands? Test results?

[Alex/Tubewonder]

To improve your score you should introduce "feel" to the test. I suggest playing air guitar while listening to the clips.

[Steve Conner]

I had a '59 air Les Paul, but it got contaminated with 2007 air.

[guitician]

Mil Glass caps look interesting.... http://www.mouser.com/catalog/suppli...Dielectric.pdf

I wonder if listening to the clips using the skull bone instead of the eardrum would be better?How an objective audiometric test can become even more reliable

[Jazz P Bass]

Whoa.
The plot thickens.
Quote from the above Audiometric link.
"the human ear is always tuned to a major scale. If the ear hears the two upper tones of a major triad, the ear itself produces the third, lowest, tone of the chord. This tone is called "distortion product otoacoustic emission (OAE)" and is generated due to anatomic and physical laws."

[Bruce / Mission Amps]

I find the caps wound on the Cottonelle cardboard roll sound softer than those wound on the Scott Tissue rolls. Try as I might, though, I cannot find anything that sounds better than the Alcoa foil.

Actually 1/16" thick glass and Alcoa foil is the bomb!! Yeah a little big, but the tonal response is stunning.

[guitician]

That'll get ya glassy tone.... I prefer earwax rolled in vintage foil/paper burger wrapper which gives a tasty ear full.

[Enzo]

You beast me to the clear glassy tone.


The problem with these glass caps is that they are such a pane to make.

[stormbringer]

anyone care to comment on the overtones on the lead runs in the metroamp clips? Are they primarily second harmonics?

[Chuck H]

Whoa.
The plot thickens.
Quote from the above Audiometric link.
"the human ear is always tuned to a major scale. If the ear hears the two upper tones of a major triad, the ear itself produces the third, lowest, tone of the chord. This tone is called "distortion product otoacoustic emission (OAE)" and is generated due to anatomic and physical laws."

I think that statement should be taken with a grain (or a bag) of salt. Perhaps much, or most of the world, is pre conditioned to the twelve note based diatonic scales. But the Japanese used a 24 note scale for centuries! What we hear as harmonious or dissonant may be more about culture than wavelenths. Math can certainly find all manor of relationships for wavelenths. That is to say that the twelve notes we use may not be the only "natural" choices. There just the ones we chose.

[g1]

Chuck: Not sure if you read the article or just the quote. They are not talking about us "filling in" the missing note mentally, but an actual sympathetic vibration produced by the ear that can be measured with microphones.
The beginning of that quote was "Regardless of where people come from, whether they are Europeans or Asians, the human ear is always tuned to a major scale".
Related: Otoacoustic emission - Wikipedia, the free encyclopedia
But, if you're just questioning whether this is only occurring with major scales, the article wasn't too clear on that.

[R.G.]

Just when we thought it was safe to say what people hear, we encounter the tritone paradox. See:

Paradoxes of Musical Pitch

Diana Deutsch - Tritone paradox

It appears that the perception of rising/falling sequences of tones may be *culturally* different between groups.

[km6xz]

In the study of perception, it has been found that a harmonic sequence, if missing the fundamental, the brain synthesizes the perception of the fundamental. This does vary with genetics and cultural.
But what is fundamental to all humans is if the phase relationship between the higher order harmonics is distorted enough, that "hearing" the harmonic sequence as a whole ends and multiple tones are heard. The brain does most of the hearing, the inner ear, very little, in that what the ear is subjected to is nothing like how we "hear" sounds.
Sound is a very low quality information conveyance. In that I mean, based on information theory, it is low bandwidth, non-vectored and low repetition, with high percentages of noise. The noise mostly is in the form of multiple versions of the original wave front arriving at different times with different spectrum content. The brain has the very difficult job of filtering out from our consciousness, the additional noise, ineffective information so we are not confused by a mass of conflicting cues.
The brain does not toss all that unintelligible information out however. It synthesizes additional meaning of location and direction, the elements of perceiving our position in an acoustic environment by grouping the sounds that appear to be related to the original source waveform, to generate a sense of direction, distance and the impression of the materials and size of the space we are in. We usually call it reverberation fields or echo but the proper term would be noise. Being able to sense direction and the nature of an acoustic space has positive survival benefits.
If the brain tries to correlate multiple examples of the same information but the time between examples becomes more difficult to determine if the sound are in fact related, we become aware of them as if they are new additional information. We experience that when echo or reverberation fields are too long in delay or of a amplitude or spectrum that is too far removed from the original such as when adding artificial reverb. We hear it if it is bad reverb but would not perceive it if it was good reverb. So we often add bad reverb in recording to trick the brain into letting it pass onto our consciousness. A sound becomes "thicker" sounding but at the same time information is increased but intelligence has decreased.

So what does this have to do with caps? Well, not a lot but any caps that have a non-linear dissipation, or dialectic absorption will change our perception. But that is of such a small degree of change compared to any significant changes to the sound that would occur for example by moving 3 feet closer to the left wall or sitting down compared to standing....you know..big changes like that. Any time the products of the original wave becomes less relate-able to the first incident wave, the more we hear it. So we handle the gigantic change in tone that moving a few inches results in quite in stride, the brain can handle that and we notice very little change while a calibrated microphone would measure 10 db changes at some frequencies. We are not sensitive to frequency response, we synthesize missing information if the harmonics are in expected, natural phase and amplitude relationship to the source sound. We have evolved that way.

We are also not very sensitive to harmonic distortion, the brain compensates. But some distortion is harder to ignore, any distortion that introduces sounds that are not naturally harmonically related to the original will be heard as new distinct information so the brain makes us aware of them. That is why we are very much more sensitive to inter-modulation distortion because the products are not harmonically related. This is where caps come into play, as well as any other non-linear transfer function. Mixing of two signals in a non-linear circuit produces sums and differences of the two original signals which are not harmonically related to either. Caps can be non-linear in a number of way, the worst offenders are those that change in physical dimension when a changing voltage is across them. Ceramic disc caps have a piezo electric effect. They get minutely larger and smaller in some dimensions with variations in the potential across them. We can easily measure that in IM distortion tests but IM testing usually uses only 2 pure tones. Music have a very complex set of harmonics and fundamentals so the IM distortion becomes significant with every harmonic mixing with every other one to produce distortion products that are not related harmonically to the original waveforms. Is this a problem? Well, these products are minute but they are there and can produce weariness in the brain by working it overtime in trying to figure out what is related and what appears to be be new information. We call that ear fatigue but it has little do do with the ear. The more complex the sounds the more IM distortion is produced. We can measure that also with a programmable arbitrary waveform generator, sort of a repeatable complex tone generator, that if put into a device under test that has non-linear elements( such as any amplifier element, and to a much lesser degree, caps and resistors), and normalize the output to the same level as the input and invert one, the resulting output will be only products that were produced in the device under test. The more complex the waveform the more of these products are generated.
All this adds up to the simple fact is that we should hear more products with complex waveforms that normal distortions tests reveal. But bear in mind that we do not like clean undistorted systems, they sound sterile, cold and less interesting because they are more hi-fidelity. We like organized noise mixed in with sounds that are natural, natural in the sense that the harmonic content is what could be expected by the brain with naturally occurring sounds. Sounds that can't happen in nature are potentially interesting to us if we become used to them. What we like in sound has a lot to do with our first impressions growing up, just like many of our preferences are based on what we learned first.
With so many forms of distortion, many of them intentional, we are swapped with waveforms that are hard to isolate the original content so it just seems like too much focus on elements that have a real but minute impact on our enjoyment of a sonic experience when there are major differences that are addressable but are not as much fun to argue about, such as playing skill, and song writing. Most effort in getting a particular tone that can't really be explained by the person seeking, has to do with recreating a characteristic of something they first experienced years ago, and not creating a new enjoyable experience for others. New enjoyable experiences come from songs that mean something to someone, not tone characteristics. If it was a new and enjoyable experience, no matter what the tone characteristics, the listener will learn that the tone of this new experience becomes identified with pleasure. The tone itself matters little.
So tone for a guitar player is usually a journey to recreate pleasure from the past. That is what amateur or hobbyist guitarist are much more concerned with tone than those who's journey is to create new experiences that will become the goal for others( and sell a lot of records in the meantime). I have worked extensively with some of the great stylists who are household words and few are as concerned with tone or the gear as amateurs. That is expected however. We do not seek sounds for objective purposes, we try to recreate pleasurable learned experiences. What sounds great to one person who grew up with a different sonic environment will be crap to someone else who developed a different habit of sound as it relates to pleasure. It is very cultural and regional even and has little to do with any universal quality of music.
All this could be summed up as "we like what we like, because we liked it early in our lives". Our brains are so much involved in the what we are made aware of that has much less to do with what wavefronts impressed on our eardrums, that learning new music with different characteristics in tonality is the best way to "hear" pleasure from a wider variety of tone characteristics. The broader the early exposure is to different styles of music, the less concern there is with deriving pleasure from just one sound.

[Steve Conner]

It's a little glib to say that our ears are "tuned to the major scale". We made the musical scales to fit the physics of our ears, just like we make gloves with 5 fingers and T-shirts with one head hole. The ear came first and the whole of music is tuned to it.

[frus]

so does it mean that if I hear, say, E and G (which is a minor interval), my ear will generate the C note, and I'm more likely to hear C major chord than E minor?

[Enzo]

At the risk of diverging, I have been looking for an auditory effect this touches on.


There is a sound that is generated, and it sounds to the ear like a falling note. But a perpetual falling note. The sound is unchanging overall, yet your ear perceives it - or your head, whatever - as a falling tone. Like the sound version of an optical illusion. I was looking yesterday at a picture that appeared to be a spiral disappearing down into the center of the image, but in reality it was a series of concentric rings. And I know you all have seen the pictures of parallel lines that do not appear to be so. But I want the sound version.


I don't know what to call it. I look for ever-falling tone or similar and I get the above discussion.


I have listened to it, but don;t recall where. It predates the internet by a LONG time.