Variac said:
I thought it was about NOT just another gainclone.
Er excuse me, I need to get some marshmellows so as not to waste the flames this discussion is sure to lead to ....
Uh... marshmallows? Marshmallows are for sitting around campfires singing sappy Jesus love-fest songs like Kumbaya.
Go get a case of hotdogs (REAL hotdogs, not any of those girly-man low-fat turkey dogs), a tribe size bottle of French's mustard and at least five kegs of beer.
se
Sorry to jump in and disturb your cozy little discussion, but I
would like to ask a stupid question. I thought I knew what the
debate was about until somebody mentioned "absolute polarity".
I thus take it that absolute phase and absolute polarity are
two different things, and I no longer know what either is. I
thought absolute phase just meant that we don't invert the signal
somewhere along the line, but I now suspect that this is what
absolute polarity might mean. But then, what does absolute
phase mean???
would like to ask a stupid question. I thought I knew what the
debate was about until somebody mentioned "absolute polarity".
I thus take it that absolute phase and absolute polarity are
two different things, and I no longer know what either is. I
thought absolute phase just meant that we don't invert the signal
somewhere along the line, but I now suspect that this is what
absolute polarity might mean. But then, what does absolute
phase mean???
Re: WHAT THE ****** IS THIS?
Frank, please!! Don't bring up wire directionality too. This is
already confusing enough.
fdegrove said:Hi,
Sorry...where did this thread originate?
I see terms such as absolute phase, absolute polarity and wire directionality.
Can someone tell what where to look so I can follow this....I am just as confused as Christer here.
Cheers,
Frank, please!! Don't bring up wire directionality too. This is
already confusing enough.
SY said:
I take it that my guess on absolute polarity was correct then?
According to the definition you give, I would say that
calling it "rather uninteresting" is quite an understatement.
It is enirely meaningless unless we state exactly what part
of the sound chain we measure it over. Is it from CD to speaker,
from CD to listeners ear, from the violin originally recorded to
the listeners ear and in that case...? Even then, it seem pretty
useless for most purposes.
Sure, that will sound different, but it has nothing to do with polarity. Here's a simple experiment: set up a mike and a scope (preferably, a storage scope). Have a person face the mike and make a "puh!" sound. Note the polarity of the first wavefront. Now have him face away and make the same sound. Note the polarity. The *waveform* will look different because the frequency response is different, but the first wavefront to reach the mike will still have the same polarity.
You can do an analogous experiment with a pulse-FFT tester (I did it with my IMP) and a loudspeaker.
AP.
Hi,
Thank you,Pink Mouse.
Here, when we talk about polarity it either refers to speaker wires or xover designs that have their wires +/- reversed to correct...you guessed it, phase behaviour.
You could also refer to polariry of the mains being reversed with respect to the elcectronics powering it, causing excessive current leakage etc.
Absolute phase is reversed every time the signal is going through an amplifying stage.
Most people don't have a clue whether their is system reverses absolute phase or not.
With tubes it is easy enough to count the number of amplifying stages once you understand the circuitry involved.
It would be safe to say that an even # of amplifying stage respect absolute phase, an odd # reverses it with respect to the source.
The effect of it can be easily demonstrated and visualised with the simple reversal of the polarity of the speaker cable.
Or even easier is you have a woofer outside a cabinet you can take a 1.5V battery and watch the effect when you briefly connect it to it's binding posts: hold the negative of the battery to the - pole of the woofer and touch the + pole of the woofer briefly.
You'll hear a distintive sound and see the cone move forward.
Repeat but with the leads of the battery reversed.
The cone will move towards the magnet and the sound will have a completely different tone.
From the different sounds coming from the unloaded woofer it should be quite obvious that listening to music in reversed polarity mode will give you a totally false image of what was intended by the soundengineers.
While I won't blame anyone for not hearing the difference, to me it makes or breaks my enjoyment of a piece of music.
Cheers,
Hi,
Thank you,Pink Mouse.
Here, when we talk about polarity it either refers to speaker wires or xover designs that have their wires +/- reversed to correct...you guessed it, phase behaviour.
You could also refer to polariry of the mains being reversed with respect to the elcectronics powering it, causing excessive current leakage etc.
Absolute phase is reversed every time the signal is going through an amplifying stage.
Most people don't have a clue whether their is system reverses absolute phase or not.
With tubes it is easy enough to count the number of amplifying stages once you understand the circuitry involved.
It would be safe to say that an even # of amplifying stage respect absolute phase, an odd # reverses it with respect to the source.
The effect of it can be easily demonstrated and visualised with the simple reversal of the polarity of the speaker cable.
Or even easier is you have a woofer outside a cabinet you can take a 1.5V battery and watch the effect when you briefly connect it to it's binding posts: hold the negative of the battery to the - pole of the woofer and touch the + pole of the woofer briefly.
You'll hear a distintive sound and see the cone move forward.
Repeat but with the leads of the battery reversed.
The cone will move towards the magnet and the sound will have a completely different tone.
From the different sounds coming from the unloaded woofer it should be quite obvious that listening to music in reversed polarity mode will give you a totally false image of what was intended by the soundengineers.
While I won't blame anyone for not hearing the difference, to me it makes or breaks my enjoyment of a piece of music.
Cheers,
Well, Christer, it depends on how "absolute" you want to be. To be truly absolute, you need to start with the soundwave leaving the original instrument or voice. "Absolute polarity" is a much more accurate description of what people are talking about here.
Sorry to rant about this, but imprecision in terminology can make discussions quite confusing and unproductive. I get just as annoyed about the misuse of "bias" to mean "idle current."
Sorry to rant about this, but imprecision in terminology can make discussions quite confusing and unproductive. I get just as annoyed about the misuse of "bias" to mean "idle current."
AP-PART II
Hi,
It is not as meaningless as you seem to make out.
A speaker that does not exhibit correct phase behaviour will never image correctly for instance.
One of the reasons not to overdo overal feedback loops is that it messes up phase behaviour big time and why modern designers with a pair of ears steer clear away from it.
Cheers,
Hi,
It is not as meaningless as you seem to make out.
A speaker that does not exhibit correct phase behaviour will never image correctly for instance.
One of the reasons not to overdo overal feedback loops is that it messes up phase behaviour big time and why modern designers with a pair of ears steer clear away from it.
Cheers,
SY said:
I don't mind you ranting about it. I also prefer precision in
terminology when there is a risk of misunderstanging. Let
me add another example to the list. It is quite common that
people write cascade when they mean cascode. Two quite
different things. That being said, I am sure I fail to be precise
enough at times, and I hope people will point it out if there
is a risk of misunderstandings.
Re: AP-PART II
Maybe I misunderstood SYs definition, but aren't you speaking
of phase linearity rather? If all frequencies have the same
time delay it shouldn't matter.
fdegrove said:Hi,
It is not as meaningless as you seem to make out.
A speaker that does not exhibit correct phase behaviour will never image correctly for instance.
One of the reasons not to overdo overal feedback loops is that it messes up phase behaviour big time and why modern designers with a pair of ears steer clear away from it.
Cheers,
Maybe I misunderstood SYs definition, but aren't you speaking
of phase linearity rather? If all frequencies have the same
time delay it shouldn't matter.
AP-III
Hi,
Those examples are rather uncommon in audio design , aren't they?
Admittedly, I should have been more specific.
Phase linearity is an important aspect of audio design IMO, one reason I prefer wide bandwith designs is that a falling response in the 100 to 200 kHz range is less likely to affect phase linearity in the audio band.
This is one of the problems CDPs are facing with their brickwall filtering.
I thought I'd point it out while were at it.
Cheers,
Hi,
Those examples are rather uncommon in audio design , aren't they?
Admittedly, I should have been more specific.
Phase linearity is an important aspect of audio design IMO, one reason I prefer wide bandwith designs is that a falling response in the 100 to 200 kHz range is less likely to affect phase linearity in the audio band.
This is one of the problems CDPs are facing with their brickwall filtering.
I thought I'd point it out while were at it.
Cheers,
AP-III CONTINUED.
Hi,
In semi-conductor amplifying blocks possibly,yes.
Sy and I referred explicitly to tubed stages though.
The net result is obtaining linear phase behaviour from a multi-way design by reversing polarity of a unit.
This is often necessary with second order filter slopes for instance where one unit in say, a 3-way system, is driven out phase with respect to the others.
This can be the midrange or tweeter for example.
Cheers,
Hi,
In semi-conductor amplifying blocks possibly,yes.
Sy and I referred explicitly to tubed stages though.
The net result is obtaining linear phase behaviour from a multi-way design by reversing polarity of a unit.
This is often necessary with second order filter slopes for instance where one unit in say, a 3-way system, is driven out phase with respect to the others.
This can be the midrange or tweeter for example.
Cheers,
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