New Age "wine enhancement"

So you are only a macro-visual existentialist? :-)

Reply to
Richard Crowley
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That would be my limit. Anyone who thinks he can visualize the small stuff is fooling himself.

:-)

d
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Pearce Consulting
http://www.pearce.uk.com
Reply to
Don Pearce

Huh? QM is a mathematical description; photons are an example of a subatomic particle whose existence is clearly supported by such empirical phenomena as the photoelectric effect and diffraction. Or are you making an oblique reference to any of the various superstring theories, for which there is as yet not a shred of empirical support?

Mark Lipton

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alt.food.wine FAQ:  http://winefaq.hostexcellence.com
Reply to
Mark Lipton

You are witnessing macro effects - that is all you can witness. You can not make the leap from that to claiming there is a particle. The very word is a macro-dimensioned conceit, and has no meaning in the sub-atomic world. It is no more than a rather poor analogy in words we can understand.

d
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Pearce Consulting
http://www.pearce.uk.com
Reply to
Don Pearce

OK, I'm with you now, Don. It's true that the best description of any QM object is its wavefunction, which is nothing but a mathematical construct and exists over all space. The problem I have is when you say that because all I can witness are macroscopic phenomena (true, but tautological) I cannot claim that there is a particle: all that I'm saying is that we can claim that there is a photon; what word we use to describe it is mere semantics and -- as you say -- there is no word that will adequately describe a photon. Please note, though, that at various points in my career I have been performing QM computations, so I learned long ago to dispense with any attempt to visualize the species I was studying as ultimately misleading and a waste of effort.

Mark Lipton

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alt.food.wine FAQ:  http://winefaq.hostexcellence.com
Reply to
Mark Lipton

OK we agree. The problem is that it is far to easy to confuse the label with the phenomenon. And as you conclude - as far as we are concerned, the maths is really all there is.

d
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Pearce Consulting
http://www.pearce.uk.com
Reply to
Don Pearce

Mark,

If I had even an inkling about what QM and NMR are, I'd be glad to attempt an answer! :->)

As for waves resonating, a room can resonate and waves are the result. Likewise for an electrical circuit. In this case, the poster is clearly clueless. These new-agers kill me when they use terms like resonance and "energy" in a way that shows they have no idea what they're talking about.

--Ethan

Reply to
Ethan Winer

I really wouldn't be too picky if I were you, Ethan. You use the term resonance when you are actually talking about modes. Easily done, isn't it? ;-)

d
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Pearce Consulting
http://www.pearce.uk.com
Reply to
Don Pearce

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I'd agree with you, but I'm too busy aligning my chakras with specially tuned quartz crystals and placing the finishing touches on my Orgone box to spare the brain cells needed to do so.

Mark Lipton

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alt.food.wine FAQ:  http://winefaq.hostexcellence.com
Reply to
Mark Lipton

In Victorian times, the ancestors of those newage (rhymes with "sewage") types were chattering about "vibrations." I wonder how long it will take the mystics to jump on string theory?

I liked your article on comb-filter effects caused by room resonances. So far, none of the "high-end audio" vendors has seriously offered a listening chair with straps to hold the audiophool's head in the exact sweet spot, although I have seen the concept in a cartoon.

The audiophools would probably be horrified to hear of the sloppy conditions under which their favorite recordings were actually produced. Why, they didn't bother to adjust the composition, or even the _pressure_ of the air in the studio! They probably even used a *mixture* of gold- and silver-plated connectors!

Reply to
Stephen J. Rush

Well he did mention Quantum Mechanics by name already, and NMR I assume is Nuclear Magnetic Resonance. It's not too hard to Google these things if you really wanted to know. Obviously not I guess.

MrT.

Reply to
Mr.T

Mark,

Okay, thanks.

What's that have to do with wine? :->)

--Ethan

Reply to
Ethan Winer

Don,

Don't get me started! :->)

Seriously, a mode is a propensity to vibrate. There's no wave or resonance until the mode is excited. Sort of like an EQ set to a narrow boost, but with the power switch turned off. I'd say with no signal rather than turned off, except the residual input noise is a signal so there's still some resonance. Versus a room mode that is silent until something in the room makes a sound at or near the mode's frequency.

--Ethan

Reply to
Ethan Winer

But they lack the vital central component of resonance - energy storage in two complementary forms, with periodic transfer between those two forms. Springs and masses do this between kinetic and potential energy. Electronic circuits do it between magnetic and electric fields. Rooms do it (in Helmholz resonator mode) the same way as springs and masses.

But modes don't do this. All that happens is that waves travelling in two directions will add in some places and cancel in others. So the biggest "gain" you can see is 3dB at any point, while dips can approach infinity. This is radically different behaviour from resonance. For example, there is no meaningful Q factor associated with a mode.

If you want to simulate modes with eq, don't set for narrow boost - that is entirely the wrong thing. Set for narrow cut, with several dips at harmonically related frequencies.

I could go on, but I won't. I'm sure you can see what I'm getting at.

d
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Pearce Consulting
http://www.pearce.uk.com
Reply to
Don Pearce

Don,

Not sure where you draw the line between "rooms" and "modes." A room does resonate. In that case it seems to me the air is both the mass and the spring.

You can DEFINITELY have peaks larger than 3 dB. First, a single reflection off a boundary (comb filter) gives a 6 dB peak, not 3 dB. But in a real room multiple reflections from multiple boundaries can combine to give a total peak larger than 6 dB. Since the response in a smallish room varies dramatically over distances as small as a few inches, even at very low frequencies, it's tough to say for sure where a peak ends and a null begins.

Actually, I don't see what you're getting at. Room modes, when excited, are like an EQ boost with a fairly high Q. This is easily seen in waterfall plots such as this one:

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--Ethan

Reply to
Ethan Winer

I'm talking about a Helmholz resonance, where the mass of air in - say

- a doorway moves in and out of the room, using the air inside the room as a spring. When the air is all the way in or out, the energy is held in the compression. When the air is moving, the energy is held in the movement. That IS a resonance - it has the two energy-swapping phases.

You are right, my maths was all over the place. But the peaks are never sharp. Nulls, on the other hand are incredibly sensitive to position. This because they are caused by phase cancellations. The peaks are simply phase additions. There is no energy storage going on

- hence no resonance.

I see why you would conclude that, but high Q is not what is going on there. They look peaky simply because they are close together. The important part of this, though is really the places where cancellations occur, not the reinforcements.

Look, you have a really good video on comb filtering and how it happens, and why it happens. This is simply a limit case of that phenomenon. You only confuse things when you try to describe it as a resonance.

d
--
Pearce Consulting
http://www.pearce.uk.com
Reply to
Don Pearce

Don,

Yes, agreed.

Look at the GIF file I linked to again and tell me those peaks are not sharp! Then look at the ringing trails and tell me there's no resonance. Yes, there is resonance, and it's due to the wall-wall (or floor-ceiling) spacing reinforcing a wave repeatedly. It's easy to calculate the frequency of the resonance from the spacing between boundaries.

I think both are important. A resonant peak that sustains bass frequencies makes a muddy mess of bass notes, as some notes linger and mask subsequent notes. Resonant peaks also impart their frequency onto nearby bass notes that excite them, often making bass notes sound out of tune even when they're not. That is, if a room has a strong resonance at 112 Hz, every A bass note will sound sharp in that room.

I do agree that nulls are a big problem too, and probably worse than nulls. The most common room acoustics problem I hear is from people who make a mix that sounds great, then they play it in their car or somewhere else and the bass is greatly exaggerated. This is because there's always one or more deep nulls at the mix position, somewhere between 80 and 150 Hz, so when mixing the person adds too much bass EQ to compensate.

--Ethan

Reply to
Ethan Winer

No, that truly isn't resonance - it is reverberation, which is an entirely different thing. The reverberation is reinforced at certain frequencies because things are arriving in phase. I promise you this is an entirely different phenomenon to resonance. The tails are not Q related - you are witnessing mode collapse. And unlike Q, you can't rely on them to collapse at a given rate - measure ten times, and you will get ten different answers.

But what do you mean by a room having a resonant peak at 112Hz? Move a couple of feet and you won't hear the note at all.

Nulls are a disaster in a mixing room. You find yourself winding up the eq to hear a note at proper volume, then when you play it somewhere else you end up with the cones hanging out of the bass speakers. At the very least you need to be pushing your chair back and forth to hear what is really there.

d
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Pearce Consulting
http://www.pearce.uk.com
Reply to
Don Pearce

Don,

I promise you are simply wrong on this point. :->)

Small rooms don't even have true reverberation. Real reverb builds over time, but small rooms have a collection of individual reflections with each decaying quickly. Small rooms also have modal ringing, which is the resonance I keep referring to. Google "room resonance" if you don't believe me. This is Physics 101 so I'm really surprised to see you dispute that rooms resonate!

They ARE related to Q. As bass traps are added to a room, three things happen to the modes as observed in a waterfall chart:

1) The ringing times are shortened. 2) The mode Qs are lowered. 3) The mode frequencies shift down in frequency slightly.

The link between 1 and 2 above indicates resonance. Here's a pair of graphs for the same room I linked above, and these show the room with and without bass traps:

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You can clearly see all three of the above parameters change.

Exactly.

--Ethan

Reply to
Ethan Winer

In those graphs I see exactly what I expected to see. The modes collapse more quickly because there isn't so much energy returned into them by the walls. But because there is no energy transduction - it remains solely in the wave - there is no resonance.

The big effect is on the nulls - the peaks flatten out in consequence of the nulls filling in.

The frequency drops slightly because the room is effectively lengthened by the presence of an absorber, in which the speed of sound is reduced.

Here's a thing I'd like you to discuss. Comb filtering. If you plot the frequency response of a speaker close to a wall, positioned as in your comb filtering demo, it exhibits peaks and dips in the frequency response because at some frequencies the waves add, and at others they cancel. Do you regard the high spot between those dips as a resonance, with a Q, and all the usual good resonant stuff?

Your answer to that will tell me if there is any chance that we can agree on the rest.

d
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Pearce Consulting
http://www.pearce.uk.com
Reply to
Don Pearce

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