[Cipher]

What are the differences between phase and time alignment? This confuses
me.

SOrry for my assanine questions.

[Don Pearce[_3_]]

On Tue, 14 Apr 2009 09:47:19 -0500, Cipher
wrote:

What are the differences between phase and time alignment? This confuses
me.

SOrry for my assanine questions.

Phase repeats every 360 degrees (complete wave), whilst time alignment
happens at one unique point. Is that what you meant?

d

[Cipher]

(Don Pearce) wrote in news:4a1aa304.695651375@localhost:

On Tue, 14 Apr 2009 09:47:19 -0500, Cipher
wrote:

What are the differences between phase and time alignment? This confuses
me.

SOrry for my assanine questions.

Phase repeats every 360 degrees (complete wave), whilst time alignment
happens at one unique point. Is that what you meant?

d


If I were to picture 2 signals as a sine waves and nudge one in a DAW so
that both have their respective peak and valleys at the exact moment in a
time scale= in phase, right?

[Ian Bell[_2_]]

Cipher wrote:
(Don Pearce) wrote in news:4a1aa304.695651375@localhost:

On Tue, 14 Apr 2009 09:47:19 -0500, Cipher
wrote:

What are the differences between phase and time alignment? This confuses
me.

SOrry for my assanine questions.
Phase repeats every 360 degrees (complete wave), whilst time alignment
happens at one unique point. Is that what you meant?

d


If I were to picture 2 signals as a sine waves and nudge one in a DAW so
that both have their respective peak and valleys at the exact moment in a
time scale= in phase, right?

True, but only if the signals are of the same frequency. If they differ,
even slightly, then after a number of cycles they will no longer be in
phase.

Time aligned is often used in reference to signals arriving at different
microphones from the same source at different times because of being at
different distances from the source. So if you close mic an instrument
then also use a more distant room mic, the signal from the room mic will
arrive later then that from the close mic because the room mic is
further away. To time align these signals you might move one of them in
time in a DAW so it lines up with the other.

Hope that helps

Cheers

Ian

[Patrick Turner]

Cipher wrote:

What are the differences between phase and time alignment? This confuses
me.

SOrry for my assanine questions.

Time alignement is where all multi way speakers have all voice coils the
same distance from one's ears.
So the sound of all drivers arives at the same time to the ear.
The phase of the signal could be the same as the input signal to the amp
if the amp has low phase shift and all drivers are phase coherent and if
there isn't any phase shift due to crossovers. But of course there *is*
lots of phase shift caused by crossovers and speakers and in many cases
the midrange of a 3 way speaker system has the midrange connected 180
degrees out of phase. It means a compression wave arrives at your ear
instead of a suction wave. The ear cannot distinguish the difference. If
the voice coils are aligned, the sound all arrives at the same time
regardless of how the speakers are connected, ie, normal phase, red wire
to red terminal, black wire to black terminal or reverse phase, or with
red wire to black, and black wire to red. The reason for the reverse
phase connectiuon of midranges is to get a smoother transition or a
flatter response without big dip in response at the crossover F because
of the nulling effect of 90degree phase lead in one spaker and 90 degree
phase lag in the other speaker at the Xover F. Second order filters can
produce 90degrees phase shift at the -3dB point in the response.

Patrick Turner.

[Don Pearce[_3_]]

On Wed, 15 Apr 2009 07:24:35 GMT, Patrick Turner
wrote:



Cipher wrote:

What are the differences between phase and time alignment? This confuses
me.

SOrry for my assanine questions.

Time alignement is where all multi way speakers have all voice coils the
same distance from one's ears.
So the sound of all drivers arives at the same time to the ear.
The phase of the signal could be the same as the input signal to the amp
if the amp has low phase shift and all drivers are phase coherent and if
there isn't any phase shift due to crossovers. But of course there *is*
lots of phase shift caused by crossovers and speakers and in many cases
the midrange of a 3 way speaker system has the midrange connected 180
degrees out of phase. It means a compression wave arrives at your ear
instead of a suction wave. The ear cannot distinguish the difference. If
the voice coils are aligned, the sound all arrives at the same time
regardless of how the speakers are connected, ie, normal phase, red wire
to red terminal, black wire to black terminal or reverse phase, or with
red wire to black, and black wire to red. The reason for the reverse
phase connectiuon of midranges is to get a smoother transition or a
flatter response without big dip in response at the crossover F because
of the nulling effect of 90degree phase lead in one spaker and 90 degree
phase lag in the other speaker at the Xover F. Second order filters can
produce 90degrees phase shift at the -3dB point in the response.

Patrick Turner.

What made you think this was a question about speaker drivers?

d

[Patrick Turner]

Don Pearce wrote:

On Wed, 15 Apr 2009 07:24:35 GMT, Patrick Turner
wrote:



Cipher wrote:

What are the differences between phase and time alignment? This confuses
me.

SOrry for my assanine questions.

Time alignement is where all multi way speakers have all voice coils the
same distance from one's ears.
So the sound of all drivers arives at the same time to the ear.
The phase of the signal could be the same as the input signal to the amp
if the amp has low phase shift and all drivers are phase coherent and if
there isn't any phase shift due to crossovers. But of course there *is*
lots of phase shift caused by crossovers and speakers and in many cases
the midrange of a 3 way speaker system has the midrange connected 180
degrees out of phase. It means a compression wave arrives at your ear
instead of a suction wave. The ear cannot distinguish the difference. If
the voice coils are aligned, the sound all arrives at the same time
regardless of how the speakers are connected, ie, normal phase, red wire
to red terminal, black wire to black terminal or reverse phase, or with
red wire to black, and black wire to red. The reason for the reverse
phase connectiuon of midranges is to get a smoother transition or a
flatter response without big dip in response at the crossover F because
of the nulling effect of 90degree phase lead in one spaker and 90 degree
phase lag in the other speaker at the Xover F. Second order filters can
produce 90degrees phase shift at the -3dB point in the response.

Patrick Turner.

What made you think this was a question about speaker drivers?

Because when time alignment and phase are ever mentioned, its usually in
relation to speaker voice coil positions and how speakers are phased.
Anyone who understands the basics about phase angles in electronic
signals and phase phenomonae in loudspeakers and acoustics wouldn't have
asked the question that was asked.

But I may be entirely wrong though.

Ideas about phase trip many people up. Its hard to grasp ideas about
phase. For example, with phase lead, the wave crests at the output of
some filter might seem to occur before the crests in the input wave. How
can that be? Did the electricity arrive before it left?

Phase lag is easily understood, electricty takes time to go through a
circuit, and delays occur to wave crests. That's common sense. In fact
it ain't so simple......

In the real world when we listen to a violinist waving his violin around
as he plays the relative phase of different F change dramatically second
by second. If recorded, some people might sense the musician is moving
around when the recording is replayed through speakers, but many would
not. And whether there are 20 violinists or 30 and how each one is
moving cannot be accurately guessed by most.
So a whole number of frequencies are summing and nulling all randomly
and frequently and we enjoy the result despite what relative phase is
doing.

And in many concert halls they might use audio gear to amplify a lone
soloist in front of 1,200 people. Time alignment is terrible between the
musician with a lone acoustic guitar and the "reinforcement speaker".
Phase is all over the joint.
People prefer to hear it that way than strain to hear it without sound
reinforcement.

The studio recording and good replay gear will allow you to hear that
guitarist better than going to the concert. Less phase bothers for
starters, and no reverberation.


Patrick Turner.



d

[Don Pearce[_3_]]

On Wed, 15 Apr 2009 09:46:02 GMT, Patrick Turner
wrote:



Don Pearce wrote:

On Wed, 15 Apr 2009 07:24:35 GMT, Patrick Turner
wrote:



Cipher wrote:

What are the differences between phase and time alignment? This confuses
me.

SOrry for my assanine questions.

Time alignement is where all multi way speakers have all voice coils the
same distance from one's ears.
So the sound of all drivers arives at the same time to the ear.
The phase of the signal could be the same as the input signal to the amp
if the amp has low phase shift and all drivers are phase coherent and if
there isn't any phase shift due to crossovers. But of course there *is*
lots of phase shift caused by crossovers and speakers and in many cases
the midrange of a 3 way speaker system has the midrange connected 180
degrees out of phase. It means a compression wave arrives at your ear
instead of a suction wave. The ear cannot distinguish the difference. If
the voice coils are aligned, the sound all arrives at the same time
regardless of how the speakers are connected, ie, normal phase, red wire
to red terminal, black wire to black terminal or reverse phase, or with
red wire to black, and black wire to red. The reason for the reverse
phase connectiuon of midranges is to get a smoother transition or a
flatter response without big dip in response at the crossover F because
of the nulling effect of 90degree phase lead in one spaker and 90 degree
phase lag in the other speaker at the Xover F. Second order filters can
produce 90degrees phase shift at the -3dB point in the response.

Patrick Turner.

What made you think this was a question about speaker drivers?

Because when time alignment and phase are ever mentioned, its usually in
relation to speaker voice coil positions and how speakers are phased.
Anyone who understands the basics about phase angles in electronic
signals and phase phenomonae in loudspeakers and acoustics wouldn't have
asked the question that was asked.

But I may be entirely wrong though.

Ideas about phase trip many people up. Its hard to grasp ideas about
phase. For example, with phase lead, the wave crests at the output of
some filter might seem to occur before the crests in the input wave. How
can that be? Did the electricity arrive before it left?

Phase lag is easily understood, electricty takes time to go through a
circuit, and delays occur to wave crests. That's common sense. In fact
it ain't so simple......

In the real world when we listen to a violinist waving his violin around
as he plays the relative phase of different F change dramatically second
by second. If recorded, some people might sense the musician is moving
around when the recording is replayed through speakers, but many would
not. And whether there are 20 violinists or 30 and how each one is
moving cannot be accurately guessed by most.
So a whole number of frequencies are summing and nulling all randomly
and frequently and we enjoy the result despite what relative phase is
doing.

And in many concert halls they might use audio gear to amplify a lone
soloist in front of 1,200 people. Time alignment is terrible between the
musician with a lone acoustic guitar and the "reinforcement speaker".
Phase is all over the joint.
People prefer to hear it that way than strain to hear it without sound
reinforcement.

The studio recording and good replay gear will allow you to hear that
guitarist better than going to the concert. Less phase bothers for
starters, and no reverberation.


Patrick Turner.

Ok, interesting angle. When I think of time alignment, I am instantly
drawn to multiple microphone placement and their various distances
from sources, because that is something that is under my control. With
speaker drives, you pretty much get what you are given.

But when asked the bare question about the difference between phase
and time alignment, I forget all that and think of them in the
abstract. Phase is probably one of the most abused terms in
electronics. It gets confused with polarity, and means nothing when
applied to a complex wave containing many frequencies - the only
single number you can put to that is group delay. And of course that
is where it starts to rub shoulders with time alignment. One could
write a book about this.

d

[jim greg]

"Don Pearce" wrote in message
news:4a1dad4b.763801328@localhost...
On Wed, 15 Apr 2009 09:46:02 GMT, Patrick Turner
wrote:



Don Pearce wrote:

On Wed, 15 Apr 2009 07:24:35 GMT, Patrick Turner
wrote:



Cipher wrote:

What are the differences between phase and time alignment? This
confuses
me.

SOrry for my assanine questions.

Time alignement is where all multi way speakers have all voice coils
the
same distance from one's ears.
So the sound of all drivers arives at the same time to the ear.
The phase of the signal could be the same as the input signal to the
amp
if the amp has low phase shift and all drivers are phase coherent and
if
there isn't any phase shift due to crossovers. But of course there *is*
lots of phase shift caused by crossovers and speakers and in many cases
the midrange of a 3 way speaker system has the midrange connected 180
degrees out of phase. It means a compression wave arrives at your ear
instead of a suction wave. The ear cannot distinguish the difference.
If
the voice coils are aligned, the sound all arrives at the same time
regardless of how the speakers are connected, ie, normal phase, red
wire
to red terminal, black wire to black terminal or reverse phase, or with
red wire to black, and black wire to red. The reason for the reverse
phase connectiuon of midranges is to get a smoother transition or a
flatter response without big dip in response at the crossover F because
of the nulling effect of 90degree phase lead in one spaker and 90
degree
phase lag in the other speaker at the Xover F. Second order filters can
produce 90degrees phase shift at the -3dB point in the response.

Patrick Turner.

What made you think this was a question about speaker drivers?

Because when time alignment and phase are ever mentioned, its usually in
relation to speaker voice coil positions and how speakers are phased.
Anyone who understands the basics about phase angles in electronic
signals and phase phenomonae in loudspeakers and acoustics wouldn't have
asked the question that was asked.

But I may be entirely wrong though.

Ideas about phase trip many people up. Its hard to grasp ideas about
phase. For example, with phase lead, the wave crests at the output of
some filter might seem to occur before the crests in the input wave. How
can that be? Did the electricity arrive before it left?

Phase lag is easily understood, electricty takes time to go through a
circuit, and delays occur to wave crests. That's common sense. In fact
it ain't so simple......

In the real world when we listen to a violinist waving his violin around
as he plays the relative phase of different F change dramatically second
by second. If recorded, some people might sense the musician is moving
around when the recording is replayed through speakers, but many would
not. And whether there are 20 violinists or 30 and how each one is
moving cannot be accurately guessed by most.
So a whole number of frequencies are summing and nulling all randomly
and frequently and we enjoy the result despite what relative phase is
doing.

And in many concert halls they might use audio gear to amplify a lone
soloist in front of 1,200 people. Time alignment is terrible between the
musician with a lone acoustic guitar and the "reinforcement speaker".
Phase is all over the joint.
People prefer to hear it that way than strain to hear it without sound
reinforcement.

The studio recording and good replay gear will allow you to hear that
guitarist better than going to the concert. Less phase bothers for
starters, and no reverberation.


Patrick Turner.

Ok, interesting angle. When I think of time alignment, I am instantly
drawn to multiple microphone placement and their various distances
from sources, because that is something that is under my control. With
speaker drives, you pretty much get what you are given.

But when asked the bare question about the difference between phase
and time alignment, I forget all that and think of them in the
abstract. Phase is probably one of the most abused terms in
electronics. It gets confused with polarity, and means nothing when
applied to a complex wave containing many frequencies - the only
single number you can put to that is group delay. And of course that
is where it starts to rub shoulders with time alignment. One could
write a book about this.

d


I think 'time-aligned' and 'phase-aligned' are cliche's that are added at
sales meetings to promote 'buy-me' intricate l/s systems.
These are bought usually on a whim and stuck inside some living room or
dedicated parlour, mostly sporting odd acoustics.
The repro selections powered into those systems [or any other] will never
ever sound right -
because of the differences in monitoring arrays used on those complex
productions, often giving band colour where there should be none.
The idiosyncratic misinterpretation would get offset by endless Eq tweakings
down the line, be it analogue or digital, but each producing inevitable
micro phase and timing errors!

This purist, idealistic theory likely applies to one positioned, slanted
enclosure accurately feeding one
ear of a participant on one seat, with tones at some given audio
frequencies.
Jim

[Patrick Turner]

Don Pearce wrote:

On Wed, 15 Apr 2009 09:46:02 GMT, Patrick Turner
wrote:


snip


The studio recording and good replay gear will allow you to hear that
guitarist better than going to the concert. Less phase bothers for
starters, and no reverberation.


Patrick Turner.

Ok, interesting angle. When I think of time alignment, I am instantly
drawn to multiple microphone placement and their various distances
from sources, because that is something that is under my control. With
speaker drives, you pretty much get what you are given.

But when asked the bare question about the difference between phase
and time alignment, I forget all that and think of them in the
abstract. Phase is probably one of the most abused terms in
electronics. It gets confused with polarity, and means nothing when
applied to a complex wave containing many frequencies - the only
single number you can put to that is group delay. And of course that
is where it starts to rub shoulders with time alignment. One could
write a book about this.

There has been much written on the benefits of time aligning bass, mid
and treble speakers.

And a lot written about the benefits of minimizing phase differences
between drivers at crossover frequencies.

I have not the time to include another book in this email.

Patrick Turner.





d