"What HiFi" - can it be trusted?
 

On Mon, 19 Jan 2004 17:42:51 +0000 (UTC),
(Stewart Pinkerton) wrote:

Or are you suggesting that the pressure peaks DONT move in and outr of
phase in the 400/450 case?

This only occurs if you have two separate *sound* sources, it does
*not* occur in a linear system with a single speaker.

Have you tried? I just did.

Open Wavelab, SoundForge or whatever you have handy.

Create a few seconds of sine wave, frequency 440Hz on the L channel.

Create a few seconds of sine wave, frequency 441Hz on the R channel.

Pan both hard R or L. Or, if you haven't got a mixer, somehow
otherwise arrange for both signals to come through the same
amp/speaker channel.

Play. Note the 1Hz beat frequency.

Now, explain just what you're talking about in the post above :-)

"What HiFi" - can it be trusted?
 

On Mon, 19 Jan 2004 19:43:29 +0000, Kurt Hamster
wrote:

I just did what you suggested and I all could hear was the same tone
coming from either speaker (I panned hard using Audition's pan
facility).

What was I supposed to hear? In plain laymen's terms please :)

You did pan BOTH channels the same way? Not the usual R hard right,
L hard left? Or maybe you're listening on a crap computer sound
system (like the one I'm typing on ;-)

OK, I'll make it easier for you. I've posted some demos.

http://mysite.freeserve.com/LP1/index.html

....contains two wav files.

A stereo wav containing one channel: sinewave 440Hz, the other:
sinewave 441Hz.

A mono wav containing a ,mix of the two, 6dB down, to avoid overload.

Now, on the laptop I'm using, both are mainly a demonstration of how
crap a laptop speaker is :-) At normal volume, the speaker turns it
into a square wave! But turn it low, or play on a decent system,
you'll hear the beats.

If you play the stereo file IN STEREO, the brain seems to want to turn
the beats into spatial information. "Tune in" one way, you'll hear
beats; another way, you'll hear a sound moving between the speakers.
Rather like those trick pictures that can be perceived two ways. But
mono the mix, there's no question. Even when overloading a laptop
speaker, those beats are clearly audible.

To make it easier, I've added a mono mix of the two channels. Look at
the waveform in your wave editor, listen to it. The beats are
impossible to miss!

"What HiFi" - can it be trusted?
 

Ah well. Presented with hard evidence, everyone's gone quiet!
That's Usenet for you :-)

"What HiFi" - can it be trusted?
 

On Tue, 20 Jan 2004 01:49:37 +0000, Laurence Payne
wrote:

Ah well. Presented with hard evidence, everyone's gone quiet!
That's Usenet for you :-)

What? Hard evidence of *what*? Please *quote* what you're being so
smug about....................
--

Stewart Pinkerton | Music is Art - Audio is Engineering

"What HiFi" - can it be trusted?
 

On Mon, 19 Jan 2004 18:14:30 +0000, Julian Fowler
wrote:

On Mon, 19 Jan 2004 08:05:13 +0000 (UTC),
(Stewart Pinkerton) wrote:

On Sun, 18 Jan 2004 18:05:14 +0000, Julian Fowler
wrote:

On Sat, 17 Jan 2004 11:51:36 +0000 (UTC),
(Stewart Pinkerton) wrote:


You can get at least 200 CDs onto a 120GB hard disk if you insist on
computer storage, and I don't know *anyone* who listens to more than
200 different discs in an average year.

RAOTFL ...

A quick estimate suggests that I probably listen to something like
2000 different discs in an average year.

I hope you get paid for that................

Nope (and why should I?). Can't imagine what it would be like to only
listen to 200 different discs in the course of a year ...

I can't imagine how sad you have to be, to listen to half a dozen
*different* albums *every* day......................
--

Stewart Pinkerton | Music is Art - Audio is Engineering

"What HiFi" - can it be trusted?
 

On Mon, 19 Jan 2004 18:29:47 +0000, Laurence Payne
wrote:

On Mon, 19 Jan 2004 09:42:43 +0000, Chris Isbell
wrote:

No, I could go on at great length about tuning and pitch. ;-)

The question I was trying to get at was that it the chain from the
instrument to my ear/brain is substantially linear, then why do I hear
beat frequencies? (If it is not linear, then why is linearity such a
concern for Hi-Fi systems?)

How did we get sidetracked into this "linear" argument?

You hear beats because they are a simple physical result of mixing two
sounds of close pitch. That's it.

But these are a result of *separate* sound sources, nothing to do with
what happens in the electronics of a hi-fi system.

If you set up a series of pitches approximating to the overtones of a
low note, your brain will sometimes "hear" the low note. This isn't
mumbo-jumbo, it's an established technique in church organ
construction, and probably elsewhere. But it's nothing to do with
beats.

Er, that has *everything* to do with beats! How that trick is done, is
*not* by false overtones, it's by constructive interference. If done
accidentally, they're called 'wolf' notes, but they really do exist.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

"What HiFi" - can it be trusted?
 

On Tue, 20 Jan 2004 08:01:45 +0000 (UTC),
(Stewart Pinkerton) wrote:

On Mon, 19 Jan 2004 18:14:30 +0000, Julian Fowler
wrote:

On Mon, 19 Jan 2004 08:05:13 +0000 (UTC),
(Stewart Pinkerton) wrote:

On Sun, 18 Jan 2004 18:05:14 +0000, Julian Fowler
wrote:

On Sat, 17 Jan 2004 11:51:36 +0000 (UTC),
(Stewart Pinkerton) wrote:


You can get at least 200 CDs onto a 120GB hard disk if you insist on
computer storage, and I don't know *anyone* who listens to more than
200 different discs in an average year.

RAOTFL ...

A quick estimate suggests that I probably listen to something like
2000 different discs in an average year.

I hope you get paid for that................

Nope (and why should I?). Can't imagine what it would be like to only
listen to 200 different discs in the course of a year ...

I can't imagine how sad you have to be, to listen to half a dozen
*different* albums *every* day......................

Who said anything about "albums"?

--
Julian Fowler
julian (at) bellevue-barn (dot) org (dot) uk

"What HiFi" - can it be trusted?
 

Stewart Pinkerton wrote:

Nope (and why should I?). Can't imagine what it would be like to
only listen to 200 different discs in the course of a year ...

I can't imagine how sad you have to be, to listen to half a dozen
*different* albums *every* day......................

Sounds like the perfect example of the hi-fi geek who is more concerned
about the equipment than actually listening to music. Some of us just love
listening to (and, more importantly, playing) music - 24/7 if possible.
Ideally on decent kit but if that's not available then on whatever's to
hand.

Given a choice I'd *rather* play my 59 Les Paul but, fcuk it, if it's got
approximately 6 strings and is in something vaguely approaching tune then
I'll play anything rather than play nothing.

Working for a living and NOT being able to listen to at least half a dozen
*different* albums *every* day seems sadder to me ;-)

"What HiFi" - can it be trusted?
 

On Tue, 20 Jan 2004 08:01:45 +0000 (UTC)
(Stewart Pinkerton) wrote:

I can't imagine how sad you have to be, to listen to half a dozen
*different* albums *every* day......................

Variety is the spice of life...

--
Spyros lair: http://www.mnementh.co.uk/ |||| Maintainer: arm26 linux

Do not meddle in the affairs of Dragons, for you are tasty and good with ketchup.

"What HiFi" - can it be trusted?
 

On Tue, 20 Jan 2004 08:01:45 +0000 (UTC)
(Stewart Pinkerton) wrote:

You hear beats because they are a simple physical result of mixing two
sounds of close pitch. That's it.

But these are a result of *separate* sound sources, nothing to do with
what happens in the electronics of a hi-fi system.

I dont think anyone was suggesting the hifi system should *introduce* the tone...

--
Spyros lair: http://www.mnementh.co.uk/ |||| Maintainer: arm26 linux

Do not meddle in the affairs of Dragons, for you are tasty and good with ketchup.