are you sick of that digital sound?

[AZeitung]

Originally Posted by John Eppstein

Man with that "for all time" stuff you should write science fiction (which I happen to love, btw - it's all I read besides tech manuals/magazines).

I don't have time to make a full response to this with everything I'd like to say, since I have to leave for that wedding in about 30 minutes, except to say that this is the technique that's used to solve differential equations, and that no matter how many times you call it science fiction, it is used in real world applications all the time to produce correct results.

Once again, transforming back and forth between the frequency and time basis does not introduce any error or approximation. The frequency basis does not include time coordinates. It is a time independant basis, and you have not produced a single argument to demonstrate that the kind of coordinate transformation I have introduced is impossible.

It's a difficult, confusing concept, I understand, but I have repeatedly demonstrated why it makes sense. We transform from a time dependant basis to a time independant basis, solve the new differential equation in the time independant basis, then rewrite the functions we're working with in the time independant basis so we can use our solution. It is ALWAYS possible and it is ALWAYS mathematically valid.

Does your friend really not understand that any function can be written as a combination of e^ikx's from t=-infinity to t=+infinity? And does he really not understand that if we figure out how to solve a differential equation on e^ikx's that we can solve it for any arbitrary function by rewriting it in terms of e^ikx's and summing our solution over all e^ikx's.

If not, I can't believe he's ever even had a single semester of differential equations, because that is one of the main techniques used to solve nearly ALL real world problems.

It's too complicated for you, I get it. But if your friend really has "published" in mathematics, he should be familiar with that technique and know that it is used all the time to solve differential equations under arbitrary driving functions.

"horse pucky" is not a valid argument. This time, I really am done responding to this thread for good, since you cannot provide a single REAL argument against anything I've said. I know I'm right, narcoman agrees with me, and my friend finishing up her PhD in math agrees that I'm write (and that your position is trivially wrong).

Bye.

[AZeitung]

One last thing--that picture doesn't really demonstrate anything. All the functions you used very obviously run from -infinity to +infinity in that case. Not very worthwhile if your goal was to demonstrate that there are functions that can't be expressed as a sum of e^ikx's that run from +infinity to -infinity. And nothing is phase shifted by 360 degrees. I completely agree that example D and E are what happens under a less than 360 degree phase shift.

PS, the reason it's phase shifted by 45 degrees is because you measured your degrees incorrectly. You measured using the phase of the fundimental, when you need to be using the phase of the harmonic.

For example:
if I have sin(t) and sin(1.5t), sin(t) is displaced by 360 degrees when I change it to sin((t+2pi))
if I change sin(1.5t) to sin(1.5*(t+2pi)) that is NOT a 360 degree phase shift.
sin(2t)=>sin(1.5t+2pi) = sin(1.5(t+4/3pi)) is a 360 degree phase shift.

That's where you screwed up.

Anyway, that's the last word I'm saying on this.

[John Eppstein]

Originally Posted by AZeitung

One last thing--that picture doesn't really demonstrate anything. All the functions you used very obviously run from -infinity to +infinity in that case. Not very worthwhile if your goal was to demonstrate that there are functions that can't be expressed as a sum of e^ikx's that run from +infinity to -infinity. And nothing is phase shifted by 360 degrees. I completely agree that example D and E are what happens under a less than 360 degree phase shift.

PS, the reason it's phase shifted by 45 degrees is because you measured your degrees incorrectly. You measured using the phase of the fundimental, when you need to be using the phase of the first harmonic.

For example:
if I have sin(t) and sin(2t), sin(t) is displaced by 360 degrees when I change it to sin((t+2pi))
if I change sin(2t) to sin(2*(t+2pi)) that is NOT a 360 degree phase shift.
sin(2t)=>sin(2t+2pi) = sin(2(t+pi)) is a 360 degree phase shift.

That's where you screwed up.

Anyway, that's the last word I'm saying on this.

Reread what I said. The harmonic is shifted by 360 degrees relative to itself and 45 degrees relative to the fundamental (examples (D) and (E)). And it certainly does NOT extend to infinity. If it did the waveform would be as in example (C) and the phase shift would actually be meaningless.

If you can't read a simple scope trace I'm afraid you're hopeless.......

[narcoman]

Originally Posted by John Eppstein

Reread what I said. The harmonic is shifted by 360 degrees relative to itself and 45 degrees relative to the fundamental (examples (D) and (E)). And it certainly does NOT extend to infinity. If it did the waveform would be as in example (C) and the phase shift would actually be meaningless.

The math is wrong from the perspective of what parts do what. Go back and check.

Anyway - my last word on this - as with AZ I've left this argument. This is less about an exchange of ideas and discussing things as you determined to be "right". Which you're not.

Sorry man - can't work with ya........

[John Eppstein]

Originally Posted by narcoman

The math is wrong from the perspective of what parts do what. Go back and check.

Anyway - my last word on this - as with AZ I've left this argument. This is less about an exchange of ideas and discussing things as you determined to be "right". Which you're not.

Sorry man - can't work with ya........

Whatever - I don't really understand why we got off into this particular mathematical argument anyway. My original point is that when you have a situation like you do with examples D and E - ignoring the math, which isn't actually mine anyway - the phase shift in the harmonic will actually make an audible difference in the waveform. Somebody - I forget who - was claiming that such a phase shift is not audible. You can't tell me that two waveforms as different as D and E are going to sound the same.

THAT'S my point, and I actually don't give a rat's ass about the math. I'm interested in what I can see on a scope and what it sounds like. Period. The harmonic is phase shifted and the difference in waveform is audible. End of story.

[tommy lee]

Yes I am!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[John Eppstein]

Disclaimer: I drew the intial trace illustrations by hand, based on waveforms I have observed on an oscilloscope. I gave the drawings to TJ to render in mathcad. The formulae accompanying the rendered drawings were what TJ came up with to get mathcad to render my drawings. I make no claims for the formulae beyond that, and frankly they are tangential to my point at best. If you have arguments with the math I'll relay them to TJ, but really none of that has anything to do with my point or my argument. Neither does any theoretical hoopla about the harmonics extending to infinity, because there is no infinity involved in my finite, real world examples.

Right now I'm going to try to get some sleep - I have a rehearsal tonight, a recording session tomorrow afternoon, and a live sound gig tomorrow night and I've been up all night dealing with this......

[monomer]

Originally Posted by Audiop

Here's an article that should put some of the debate to sleep:

Human Hearing - Phase Distortion Audibility Part 2 — Reviews and News from Audioholics

It's about the audibility of phase distortion and there's a nice pic that illustrates how phase distortion delays parts of the spectrum in a wide bandwith signal even when no frequencies are removed.. ie. the transfer function is linear in the frequency domain but not in the time domain.


/Peter

Interesting.
The way this article describes phase distortion is that it's a delay thing, not a phase thing.
It's semantics.

But i asked you guys before if you mean delay when you say phase distortion.
And you made fun at me iirc.
....

from the article:
"It turns out that, within very generous tolerances, humans are insensitive to phase shifts. Under carefully contrived circumstances, special signals auditioned in anechoic conditions, or through headphones, people have heard slight differences. However, even these limited results have failed to provide clear evidence of a 'preference' for a lack of phase shift. When auditioned in real rooms, these differences disappear.. ."

So, phase shifting is not realy hearable.
And now that i'm positive that phase distortion is frequency depedant delay then i completely agree that it is a hearable and bad thing.

Funny too that my own research into phase change said the same thing as these researchers found out.
And it was exactly the point i was trying to make when proposing the tests with the phaser.

[Chrislpp]

Yea 'Tubes will give you the warm creamy tonez!!11''

It's all in your head I say!

[monomer]

Originally Posted by John Eppstein

OK, here's the waveforms. The last two examples show a 360 degree phase shift of the parasitic harmonic riding on top of the fundamental. The two waveforms are not equivalent and will not sound the same despite having identical harmonic content except for the phase shift.. Note that the phase shift is relative to the harmonic, not the fundamental. The harmonic in the last two examples is the same frequency as in example B, but is not a continuous (or "steady state") waveform - it only occurs at specific points on the cycle of the parent wave. Harmonics of this type are quite common in the waveforms of distorting guitar amps, to cite one real-world example. As the harmonic is displaced by 360 degrees - of the harmonic, not the parent fundamental, it significantly alters the resulting complex wave in a way that is quite definitely audible. In this case a 360 degree phase shift of the harmonic (relative to itself), displaces it by 45 degrees relative to the parent fundamental.

My thanks to TJ Wetzel for assistance in rendering the waveforms from my rough drawing and working out the descriptive math.

The whole point is that you not only shift the phase of the 'riding' wave, you also change the 'phase' of the windowing function (the conditional amplitude multiplier).
This together is exactly the same thing as delaying the whole occurence by the length of a period.

[monomer]

Originally Posted by John Eppstein

Disclaimer: I drew the intial trace illustrations by hand, based on waveforms I have observed on an oscilloscope. I gave the drawings to TJ to render in mathcad. The formulae accompanying the rendered drawings were what TJ came up with to get mathcad to render my drawings. I make no claims for the formulae beyond that, and frankly they are tangential to my point at best. If you have arguments with the math I'll relay them to TJ, but really none of that has anything to do with my point or my argument. Neither does any theoretical hoopla about the harmonics extending to infinity, because there is no infinity involved in my finite, real world examples.

Right now I'm going to try to get some sleep - I have a rehearsal tonight, a recording session tomorrow afternoon, and a live sound gig tomorrow night and I've been up all night dealing with this......

I think it illustrates the point just fine.
We have been debating semantics.

But a phase change is not the correct description of what is going on here.
Phase is being used for two things, to change the phase of the harmonic AND to conveniently describe the position of the windowing function.

This can only work because the windowing function is periodic.
But in natural sounds the windowing functions are almost never periodic so only examples like this can be correctly described by phase, and then there are some other restrictions too.

[John Eppstein]

Originally Posted by monomer

The whole point is that you not only shift the phase of the 'riding' wave, you also change the 'phase' of the windowing function (the conditional amplitude multiplier).
This together is exactly the same thing as delaying the whole occurence by the length of a period.

yes, it is - if you're talking about the occurrance of the harmonic, not the fundamental.

[John Eppstein]

TJ has been playing around with phase-shifted harmonics in MathCad and has come up with some very interesting waveforms - some of which use continuous, not "gated" harmonics. Should have something to post later tonight or tomorrow.......

[monomer]

Originally Posted by John Eppstein

yes, it is - if you're talking about the occurrance of the harmonic, not the fundamental.

The fundamental and all harmonics can be considered separately.
(note i said considered, of course they belong together)

Of course you can relate the fundamental or any harmonic to another harmonic, but that is just adding new stuff to the basis.

A sound can be composed of multiple fundamentals and a multitude of overlapping harmonic series.
So in analisys there is no difference between fundamental and harmonics.

You can use it to get a bearing (by placing restrictions like using a single continuous signal at a steady frequency) but it does not change the way they are projected mathematicly.

[monomer]

Originally Posted by John Eppstein

TJ has been playing around with phase-shifted harmonics in MathCad and has come up with some very interesting waveforms - some of which use continuous, not "gated" harmonics. Should have something to post later tonight or tomorrow.......

Those are interesting

Try if you can make a saw wave with the harmonics shifted in various ways.

[Em Kay]

I have a hybrid setup but I LOVE the digital sound (in the right context)! Each tool has its uses

[John Eppstein]

Originally Posted by monomer

Those are interesting

Try if you can make a saw wave with the harmonics shifted in various ways.

He has a couple of waveform plots where shifting the phase of the harmonic transforms the plot from a pseudo-triangle wave to a pseudo-square wave. These don't even require gated harmonics - it works steady-state. I doesn't bear on the "over 360 degree" aspect, but it certainly does on the audibility of -phase shift. The interesting thing about it is that since Fourier analysis doesn't differentiate by phase shift both these wave forms are identical under Fourier - which pretty much demonstrates that Fourier analysis doesn't have a heck of a lot to do with what the signal actually sounds like..... Interesting..... He hasn't given me the files yet, been busy with other stuff, hopefully will get them up today or tonight.

[TonyBelmont]

Originally Posted by John Eppstein

He has a couple of waveform plots where shifting the phase of the harmonic transforms the plot from a pseudo-triangle wave to a pseudo-square wave. These don't even require gated harmonics - it works steady-state. I doesn't bear on the "over 360 degree" aspect, but it certainly does on the audibility of -phase shift. The interesting thing about it is that since Fourier analysis doesn't differentiate by phase shift both these wave forms are identical under Fourier - which pretty much demonstrates that Fourier analysis doesn't have a heck of a lot to do with what the signal actually sounds like..... Interesting..... He hasn't given me the files yet, been busy with other stuff, hopefully will get them up today or tonight.

John,

You are the posting King... You've been a member for one month and already have over 1100 posts. Posts Per Day: 34.73 WOW... I think that's a new record!

[John Eppstein]

Well, Tony, I've had a lot of time on my hands recently while trying to get some help on getting the darn Studer working, and when I get into something I tend to really get into it..... which is why I avoided GS for years until recently. Now it's become to me what the New York Times was to my dad - a major diversion, my "morning paper", etc, etc......

Plus I do truly love talking about gear and acoustics and I have an awful lot of experience to share - I started mixing sound when a good band PA was a 100 watt Bogen Challenger, 3 HiZ Unidyne IIIs, and 4 JBL D120Fs in home made cabinets......

This particular thread has been a very interesting one, in spite of the fact that a large percentage of the posts have essentially been arguing semantics..... I've been expressing some ideas that have been worked out over a long period of time, but my actual terminology is not always as precise as it might be since I am not a mathematician - which does not invalidate the concepts, it just gets in the way of communication. I've recently tapped a mathematical friend to help, which does slow down the posting rate in the thread as it takes him some time to work out the things that I explain to him.

[vincentvangogo]

Originally Posted by Chrislpp

Yea 'Tubes will give you the warm creamy tonez!!11''

It's all in your head I say!

I think you'll find it's not.

[Jamzone]

What sound?

[filipv]

Originally Posted by John Eppstein

read the posts. I gave a simple experiment that you can try for yourself.

Yes, but that experiment of yours doesn't prove that there are audible harmonics above 20kHz. It just proves that 11kHz sine and square wave sound different. In your experiment, the difference in harmonic content is not above 20kHz, it's below, and for the reasons which have nothing to do with digital being intristically flawed.

My friend, I think you don't understand digital audio as much as you think you do, and I don't mean to be mean. It's more of an invitation to do thorough research - it's fascinating stuff! You will be amazed how things really work.

[Nelson89]

wow...way to resurrect an old thread...

Possibly the biggest tangent EVER...considering the answer to the original question was to probably just track with better pre's, or run the final mix through a coloured pre...

[filipv]

Originally Posted by Nelson89

wow...way to resurrect an old thread...

Yeah, I didn't notice the date

I appologize to everyone!

[Nelson89]

Originally Posted by filipv

Yeah, I didn't notice the date

I appologize to everyone!

It's alright, i see you're about as bored as i am...not as many people posting with Christmas and all...

[theblue1]

Originally Posted by musicmatt

I'm a composer, currently making beats and catchy little synch stuff for promotional music.. I'm finally getting the sound I want, after all these years. Its punchy, dynamic and smooth at the same time.

BUT, it lacks warmth and spaciousness. I'm mixing ITB with LOGIC, usually slapping tons of Waves SSL channels, and then the BUS comp, and then sending to another bus paralleling a crushing BUS comp.

Sounds good, but it just doesn't have that warmth.. it sounds harsh.

Here is the conundrum, I want a piece of analog gear in my chain that I can run everything through. I own an RNC which doesn't impart any sonic characteristic, and an API A2D. I've narrowed it down to two compressor:

Distressor or API 2500. Going to do everything from Vocals, to Bass, to Beats and Software Orchestra.. I'm leaning towards the 2500, but if anyone else can point me in the right direction?

So did my apartment this morning, but I turned on every piece of vacuum tube gear in the place and it's finally starting to warm up. It's still kind crowded though...

[Nelson89]

Originally Posted by theblue1

So did my apartment this morning, but I turned on every piece of vacuum tube gear in the place and it's finally starting to warm up. It's still kind crowded though...

haha...

[kats]

Originally Posted by filipv

It's more of an invitation to do thorough research - it's fascinating stuff! You will be amazed how things really work.

An ironic suggestion considering your location typo.

[filipv]

Originally Posted by kats

An ironic suggestion considering your location typo.

What do you mean?

[AllAboutTone]

No, Im not paying the high price for analog.