The tubulator should be interesting because on their web site, they make some objectively verifiable claims about measurable distortion in chips- given without any data, of course. Seems like they shouldn't object to those claims being verified, eh?
BTW, go back and look at Steve's first set of pictures. Imagine that the waveform he shows is the waveform we're interested in- not too much of a reach, since musical instruments play notes of finite duration. If you take two identical speakers, play this note through them while the polarity of one speaker is reversed, the note cancels, it sums to zero. That corresponds to summing (acoustically) the first two pictures.
Now, put the polarity back the way it was. Play the note through one speaker while playing the note phase shifted (or time delayed) through the other. Doesn't sum to zero, does it? *Phase shift of 180 degrees and polarity inversion are only the same for periodic signals of infinite duration* That doesn't describe music very well. (edit: Jphn G said this already, but perhaps not explicitly enough)
I like my Ciney served at cellar temperature, please.
BTW, go back and look at Steve's first set of pictures. Imagine that the waveform he shows is the waveform we're interested in- not too much of a reach, since musical instruments play notes of finite duration. If you take two identical speakers, play this note through them while the polarity of one speaker is reversed, the note cancels, it sums to zero. That corresponds to summing (acoustically) the first two pictures.
Now, put the polarity back the way it was. Play the note through one speaker while playing the note phase shifted (or time delayed) through the other. Doesn't sum to zero, does it? *Phase shift of 180 degrees and polarity inversion are only the same for periodic signals of infinite duration* That doesn't describe music very well. (edit: Jphn G said this already, but perhaps not explicitly enough)
I like my Ciney served at cellar temperature, please.
Back In Phase
Ok, I'm back from the GF, and awake now.
Good things have been said, and it boils down to long term incorrect usage of language.
Think about - polarity inversion is perfect language, but phase inversion is not - phase can be altered etc WRT to a defined particular reference, but it cannot be inverted - in my understanding of English at least.
The phase relationship between two signals can be inverted - eg, signal A can be delayed WRT signal B, and vica versa, but this is still not polarity inversion.
So Frank, I look forward to sampling a few in your good company in the future.
I think I started this discussion (it evolved) to bring to notice (for those unfamiliar) with the ABSOLUTE importance of correct AP of in room sound.
I hope that DIYers are now more clearly aware of this mission critical parameter in audio reproduction - Steve, have you put reversing switches in your transformer boxes yet - if not I'll be around to guzzle your beer too !.
Eric / - No Fosters For Me Mate, That **** Is Girlie Beer.
Must go now - off to my first Rave - in technical support capacity of course.
Ok, I'm back from the GF, and awake now.
Good things have been said, and it boils down to long term incorrect usage of language.
Think about - polarity inversion is perfect language, but phase inversion is not - phase can be altered etc WRT to a defined particular reference, but it cannot be inverted - in my understanding of English at least.
The phase relationship between two signals can be inverted - eg, signal A can be delayed WRT signal B, and vica versa, but this is still not polarity inversion.
So Frank, I look forward to sampling a few in your good company in the future.
I think I started this discussion (it evolved) to bring to notice (for those unfamiliar) with the ABSOLUTE importance of correct AP of in room sound.
I hope that DIYers are now more clearly aware of this mission critical parameter in audio reproduction - Steve, have you put reversing switches in your transformer boxes yet - if not I'll be around to guzzle your beer too !.
Eric / - No Fosters For Me Mate, That **** Is Girlie Beer.
Must go now - off to my first Rave - in technical support capacity of course.
Re: Back In Phase
Naaaaah. That's not really where they should be anyway. Plus the boxes are meant to be tucked away where getting at any such switches would be a hassle.
Need to work on the folks makin' preamps. :smash"
Yes, I know no self-respecting Ozzie actually drinks Fosters. Just yankin' your chain.
Mmmm. That'll be interesting picturing you sucking on one of those candy pacifiers...
se
mrfeedback said:
Naaaaah. That's not really where they should be anyway. Plus the boxes are meant to be tucked away where getting at any such switches would be a hassle.
Need to work on the folks makin' preamps. :smash"
Yes, I know no self-respecting Ozzie actually drinks Fosters. Just yankin' your chain.
Mmmm. That'll be interesting picturing you sucking on one of those candy pacifiers...
se
'E'ffecting Audio...
Well then, ya need to make it into a box and make polarity control a feature of it.
Yeah, I would not let YOU drink it.
If you get the chance, hunt down some Coopers Sparkling Ale and get stuck into a belly/head full - beware, on tap it goes down real easy, but the next day it can visciously remind you that you had much too good a night !.
I'm there to take a look at babes that I am much too old to be friends with ....
No more seriously, I am helping a mate setup his big rig, and perform some interesting audio experiments on unwitting subjects - should be interesting.
Eric / - Back to Earth tomorrow.
Steve Eddy said:
Well then, ya need to make it into a box and make polarity control a feature of it.
You mean that I am missing something ? - which thread ?.
Yes, I know no self-respecting Ozzie actually drinks Fosters. Just yankin' your chain.
Yeah, I would not let YOU drink it.
If you get the chance, hunt down some Coopers Sparkling Ale and get stuck into a belly/head full - beware, on tap it goes down real easy, but the next day it can visciously remind you that you had much too good a night !.
Mmmm. That'll be interesting picturing you sucking on one of those candy pacifiers...
I'm there to take a look at babes that I am much too old to be friends with ....
No more seriously, I am helping a mate setup his big rig, and perform some interesting audio experiments on unwitting subjects - should be interesting.
Eric / - Back to Earth tomorrow.
AP.
Hi,
So what is AP?
Absolute Polarity or Absolute Phase?
Symon sayz: if we take both signals in the pictures from SE and sum these we and up with an acoustical short.
Frank sayz this is absolutely correct because the two are absolutely out of phase with respect to one another.
Polarity doesn't have any meaning in this context and picture C proves that since I could have it shifted in time to any degree with respect to both A and B.
If we take the time shifted signal on its' own and send it to the speaker on its' own it wouldn't have any significance whatsoever,it will only have meaning when referenced to either signal A or B since it has been delayed with respect to that reference.
It has been shifted in the time domain.
If you send signal B to a speaker with correctly wired polarity it will make the speaker pull inwards ( -180 degrees out of phase),if we reverse the polarity of the speaker at its' terminals (swapping the + and - leads around) it will make the speaker push forward and will be exactly the same as signal A.
It would be all too easy to refer to phase inversion as being a polarity inversion.
In that case you could argue that a simple inversion of the positive lead and negative lead of a preamp coaxwire would give a 180 degree inversion.
We all know that that does not work in a single ended topology, don't we.
So you'll all have to work a little harder for your beers for none has me convinced I'm wrong in what I say.
Too early to have a beer yet,
Hi,
So what is AP?
Absolute Polarity or Absolute Phase?
Symon sayz: if we take both signals in the pictures from SE and sum these we and up with an acoustical short.
Frank sayz this is absolutely correct because the two are absolutely out of phase with respect to one another.
Polarity doesn't have any meaning in this context and picture C proves that since I could have it shifted in time to any degree with respect to both A and B.
If we take the time shifted signal on its' own and send it to the speaker on its' own it wouldn't have any significance whatsoever,it will only have meaning when referenced to either signal A or B since it has been delayed with respect to that reference.
It has been shifted in the time domain.
If you send signal B to a speaker with correctly wired polarity it will make the speaker pull inwards ( -180 degrees out of phase),if we reverse the polarity of the speaker at its' terminals (swapping the + and - leads around) it will make the speaker push forward and will be exactly the same as signal A.
It would be all too easy to refer to phase inversion as being a polarity inversion.
In that case you could argue that a simple inversion of the positive lead and negative lead of a preamp coaxwire would give a 180 degree inversion.
We all know that that does not work in a single ended topology, don't we.
So you'll all have to work a little harder for your beers for none has me convinced I'm wrong in what I say.
Too early to have a beer yet,
Not sure what you are trying to say Frank, but I think we won't
get any further without bringing in some math to get more
precise. Can we agree on the following
Given a periodic signal f(wt) where w = 2*pi*f
-f(wt) is inverted (has inverse polararity) wrt. f(wt)
f(wt+a) is phase shifted a rad. wrt. f(wt)
I don't know what "inverted phase" would mean, unless you
mean f(wt+pi) which is a phase shift by 180 deg., not an inversion.
get any further without bringing in some math to get more
precise. Can we agree on the following
Given a periodic signal f(wt) where w = 2*pi*f
-f(wt) is inverted (has inverse polararity) wrt. f(wt)
f(wt+a) is phase shifted a rad. wrt. f(wt)
I don't know what "inverted phase" would mean, unless you
mean f(wt+pi) which is a phase shift by 180 deg., not an inversion.
Re: AP.
So, if I connect to batteries like this:
<center>
<img src="http://www.q-audio.com/images/battery1.jpg">
</center>
The batteries are "in phase" and if I connect them like this:
<center>
<img src="http://www.q-audio.com/images/battery1.jpg">
</center>
The batteries are "out of phase"?
C'mon, Frank. You're really grasping at straws here.
But but shifting it in time, you shift the phase. No shift in time, no shift in phase.
And again, a shift in time is a shift in phase.
If you send it signal A, B or C, it alternately moves in AND out AND the polarity changes every half cycle. Which way the cone moves on the application of a voltage of a given polarity has absolutely nothing to do with phase, Frank.
I simply can't understand why you think that a POLARITY inversion at the amplifier terminal or the speaker terminal or whatever results in a PHASE inversion at the loudspeaker.
Just what is it, Frank, that converts what is otherwise a polarity inversion to phase inversion? You say that at the amplifier terminals it's a polarity inversion. Yet at the speaker cone it magically turns into phase inversion.
It's easiest to refer to things as what they are.
Well, YOU would say it was a 180 degree inversion. I would say it was a polarity inversion.
Er, we do?
That's funny. I'm sitting here listening as we speak to Tom Petty's Girl On LSD with a set of jumpers swapping the leads of the RCAs (i.e. hot on one cable going to ground on the other and vice versa) running from my sound card (Sound Blaster AWE-64) to my little JVC "executive" system (FS-2000) on my desk. Works both ways.
So I guess we don't all know that.
Well, Tom Petty says you're wrong with regard to at least one thing you've said.
se
fdegrove said:
So, if I connect to batteries like this:
<center>
<img src="http://www.q-audio.com/images/battery1.jpg">
</center>
The batteries are "in phase" and if I connect them like this:
<center>
<img src="http://www.q-audio.com/images/battery1.jpg">
</center>
The batteries are "out of phase"?
C'mon, Frank. You're really grasping at straws here.
But but shifting it in time, you shift the phase. No shift in time, no shift in phase.
And again, a shift in time is a shift in phase.
If you send it signal A, B or C, it alternately moves in AND out AND the polarity changes every half cycle. Which way the cone moves on the application of a voltage of a given polarity has absolutely nothing to do with phase, Frank.
I simply can't understand why you think that a POLARITY inversion at the amplifier terminal or the speaker terminal or whatever results in a PHASE inversion at the loudspeaker.
Just what is it, Frank, that converts what is otherwise a polarity inversion to phase inversion? You say that at the amplifier terminals it's a polarity inversion. Yet at the speaker cone it magically turns into phase inversion.
It's easiest to refer to things as what they are.
Well, YOU would say it was a 180 degree inversion. I would say it was a polarity inversion.
Er, we do?
That's funny. I'm sitting here listening as we speak to Tom Petty's Girl On LSD with a set of jumpers swapping the leads of the RCAs (i.e. hot on one cable going to ground on the other and vice versa) running from my sound card (Sound Blaster AWE-64) to my little JVC "executive" system (FS-2000) on my desk. Works both ways.
So I guess we don't all know that.
Well, Tom Petty says you're wrong with regard to at least one thing you've said.
se
AP.
Hi,
Did I somewhere say that it would stop the gear from working?
No, I did not.
What you use that switch for I don't know, unless it is preceded by a transformer simply reversing the polarity of the RCA connector will not inverse phase to 180 degrees with respect to the input.
From what you say one could then do the same at the input of a phase inverting amplifier and voila problem solved.
Cheers,
Hi,
Did I somewhere say that it would stop the gear from working?
No, I did not.
What you use that switch for I don't know, unless it is preceded by a transformer simply reversing the polarity of the RCA connector will not inverse phase to 180 degrees with respect to the input.
From what you say one could then do the same at the input of a phase inverting amplifier and voila problem solved.
Cheers,
Re: AP.
And did I say you said that it would stop the gear from working? No, I did not.
What switch? I don't recall saying anything about a switch.
And no, it doesn't invert phase 180 degrees. It inverts polarity.
You mean a polarity inverting amplifier. And yes, you could do just that.
The reason you might not want to do it that way however is because now the ground references of the two devices are separated by the output impedance of the source device, which would be akin to putting a resistor of the same value in series with the ground connection in a "normal" configuration.
The greater the resistance/imedance between the two ground references, the worse your noise problems are with regard to interchassis currents (i.e. ground loops, etc.).
But the ultimate result is the same. Polarity inversion of the signal.
So while your polarity problem is (voila) solved, you create another problem. Voila. Increased noise.
se
fdegrove said:
And did I say you said that it would stop the gear from working? No, I did not.
What switch? I don't recall saying anything about a switch.
And no, it doesn't invert phase 180 degrees. It inverts polarity.
You mean a polarity inverting amplifier. And yes, you could do just that.
The reason you might not want to do it that way however is because now the ground references of the two devices are separated by the output impedance of the source device, which would be akin to putting a resistor of the same value in series with the ground connection in a "normal" configuration.
The greater the resistance/imedance between the two ground references, the worse your noise problems are with regard to interchassis currents (i.e. ground loops, etc.).
But the ultimate result is the same. Polarity inversion of the signal.
So while your polarity problem is (voila) solved, you create another problem. Voila. Increased noise.
se
A slow Saturday
Sitting grazin through Radio Engineer's Handbook by
F. E. Terman that just came in the mail ($20 on E-bay) and he says:
" In the push-pull amplifier two tubes are arranged as shown in figure 16c, with the grids excited by equal voltages 180deg out of phase......."
First Edition, 9th Printing (1943), Pg. 382
Bailiff, whack his PP.
When youze guys sit down with a beer at days end do you watch the sun set or the earth turn?
Cheers
Craig Ryder
Sitting grazin through Radio Engineer's Handbook by
F. E. Terman that just came in the mail ($20 on E-bay) and he says:
" In the push-pull amplifier two tubes are arranged as shown in figure 16c, with the grids excited by equal voltages 180deg out of phase......."
First Edition, 9th Printing (1943), Pg. 382
Bailiff, whack his PP.
When youze guys sit down with a beer at days end do you watch the sun set or the earth turn?
Cheers
Craig Ryder
Re: AP.
Ok.
But let's get back to the gist of your argument.
You said that swapping the positive and negative lead in a single-ended topology wouldn't result in a 180 degree inversion (i.e. polarity inversion).
However it does indeed result in a polarity inversion.
So where does that leave your argument?
se
fdegrove said:
Ok.
But let's get back to the gist of your argument.
You said that swapping the positive and negative lead in a single-ended topology wouldn't result in a 180 degree inversion (i.e. polarity inversion).
However it does indeed result in a polarity inversion.
So where does that leave your argument?
se
Re: A slow Saturday
Just because an inaccurate term is commonly used doesn't make the term any more accurate.
Check out the US and international standards organizations' standards for wiring of XLR connectors (AES14-1992, ANSI S4.48-1992, IEC 268-12) and you'll find they use the accurate and approprate term, polarity, not phase.
<a href="http://www.aes.org/standards/b_pub/aes14-1992.pdf">AES Standard For Professional Audio Equipment -- Application Of Connectors, Part 1, XLR-Type Polarity And Gender</a>
For an XLR connector, pin 2 is positive, not 0 degrees and pin 3 is negative, not 180 degrees.
End of subject.
se
Ryder said:Sitting grazin through Radio Engineer's Handbook by
F. E. Terman that just came in the mail ($20 on E-bay) and he says:
" In the push-pull amplifier two tubes are arranged as shown in figure 16c, with the grids excited by equal voltages 180deg out of phase......."
First Edition, 9th Printing (1943), Pg. 382
Bailiff, whack his PP.
Just because an inaccurate term is commonly used doesn't make the term any more accurate.
Check out the US and international standards organizations' standards for wiring of XLR connectors (AES14-1992, ANSI S4.48-1992, IEC 268-12) and you'll find they use the accurate and approprate term, polarity, not phase.
<a href="http://www.aes.org/standards/b_pub/aes14-1992.pdf">AES Standard For Professional Audio Equipment -- Application Of Connectors, Part 1, XLR-Type Polarity And Gender</a>
For an XLR connector, pin 2 is positive, not 0 degrees and pin 3 is negative, not 180 degrees.
End of subject.
se
Didn't mean to push the polarity button
Hi Steve
Hey don't blow a fuse over me. I'm just kiddin.
Actually, for the most part I agree with you. Not that it matters if I agree as I'm a beginner. My point is that it is a common convention to talk in that manner and Terman is an educated man. He and his colleague Spangenberg set a bit of a standard in "tube talk."
For sure you can get into trouble if you are sloppy about it. I believe you had a post taking about asymmetric wave forms a while back. I think you were right on point. I think M. JOnes puts it just that way in his book.
I enjoy reading your posts.
Cheers
Craig Rdyer
Hi Steve
Hey don't blow a fuse over me. I'm just kiddin.
Actually, for the most part I agree with you. Not that it matters if I agree as I'm a beginner. My point is that it is a common convention to talk in that manner and Terman is an educated man. He and his colleague Spangenberg set a bit of a standard in "tube talk."
For sure you can get into trouble if you are sloppy about it. I believe you had a post taking about asymmetric wave forms a while back. I think you were right on point. I think M. JOnes puts it just that way in his book.
I enjoy reading your posts.
Cheers
Craig Rdyer
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