Sign in with
Sign up | Sign in
Your question

Useful application of Phase Display

Last response: in Home Audio
Share
Anonymous
August 10, 2004 3:09:20 AM

Archived from groups: rec.audio.pro (More info?)

Wavelab software (and probably others also ?) provide an X/Y Phase Scope
display in the recording window as an option. While it's great fun to watch
this mutating cotton ball in action during recording, what useful info. does
it convey ? I know it can quickly identify an out-of-phase wired mic, but
can it give useful clues about mic placement, spacing between capsules,
phase cancellations off boundary surfaces, etc ? I frequently use spaced
omni mics, and random phase interactions are faithfully rendered and
entrancing to watch but.....what is the most useful information one can
expect to derive from the Phase Display ?
Thanks for any input,
Ray


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.734 / Virus Database: 488 - Release Date: 4/08/2004
Anonymous
August 10, 2004 3:09:21 AM

Archived from groups: rec.audio.pro (More info?)

>Wavelab software (and probably others also ?) provide an X/Y Phase Scope
>display in the recording window as an option. While it's great fun to watch
>this mutating cotton ball in action during recording, what useful info.
>does
>it convey ? I know it can quickly identify an out-of-phase wired mic, but
>can it give useful clues about mic placement, spacing between capsules,
>phase cancellations off boundary surfaces, etc ? I frequently use spaced
>omni mics, and random phase interactions are faithfully rendered and
>entrancing to watch but.....what is the most useful information one can
>expect to derive from the Phase Display

It can tell you a lt but you have to look at it a lot and learn that way. No
quick way. after about 6 months or so it'll start to make sense.
Phil Brown
Anonymous
August 10, 2004 3:09:21 AM

Archived from groups: rec.audio.pro (More info?)

>"Ray Thomas" rthomas@chariot.net.au

>Wavelab software (and probably others also ?) provide an X/Y Phase Scope
>display in the recording window as an option. While it's great fun to watch
>this mutating cotton ball in action during recording, what useful info. does
>it convey ? I know it can quickly identify an out-of-phase wired mic, but
>can it give useful clues about mic placement, spacing between capsules,
>phase cancellations off boundary surfaces, etc ? I frequently use spaced
>omni mics, and random phase interactions are faithfully rendered and
>entrancing to watch but.....what is the most useful information one can
>expect to derive from the Phase Display ?

Depends on the Phase display, but on my Tektronixs 760a you can see if a
stereo signal is wide or narrow, you can balance left and right channels
exactly by using "sum /difference" settings and which shos the difference
between left and right, on an older console's stereo module you will be amazed
to see how badly matched the eq is on the left and right by the amount of
difference signal, you can see if a stereo signal is mostly in or mostly out of
phase, you can see if it's real stereo or artificial stereo, you can see what
the level of the signal with left and right summed is.

The Phase Display plug in should have a manual, Print it out and check
the reference examples. Or find a manual for some such device and download
that, like AEA's "Winkie Blinkie"...

http://www.wesdooley.com/pdf/ld2020_manual.pdf

Or the Tektronix 760a (requires some contact info).

http://www.tek.com/site/mn/mnfinder_detail/1,1096,,00.h...



Will Miho
NY Music & TV Audio Guy
Off the Morning Show! & sleepin' In... / Fox News
"The large print giveth and the small print taketh away..." Tom Waits
Related resources
Anonymous
August 10, 2004 3:09:21 AM

Archived from groups: rec.audio.pro (More info?)

In article <41177e97_2@news.chariot.net.au> rthomas@chariot.net.au writes:

> Wavelab software (and probably others also ?) provide an X/Y Phase Scope
> display in the recording window as an option. While it's great fun to watch
> this mutating cotton ball in action during recording, what useful info. does
> it convey ? I know it can quickly identify an out-of-phase wired mic, but
> can it give useful clues about mic placement, spacing between capsules,
> phase cancellations off boundary surfaces, etc ?

Those are all things that affect phase between two mic signals. But if
you're just monitoring the stereo mix of a multitrack session, it's
not likely to scream TILT at you if you have a mic in the wrong place.
If you can plug it in so that it's monitoring a specific pair of mics,
it can tell you a lot about what they're doing. But then, so can
listening to the mics.


--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Anonymous
August 10, 2004 3:09:21 AM

Archived from groups: rec.audio.pro (More info?)

"Ray Thomas" <rthomas@chariot.net.au> wrote in message
news:41177e97_2@news.chariot.net.au
> Wavelab software (and probably others also ?) provide an X/Y Phase
> Scope display in the recording window as an option. While it's great
> fun to watch this mutating cotton ball in action during recording,
> what useful info. does it convey ? I know it can quickly identify an
> out-of-phase wired mic, but can it give useful clues about mic
> placement, spacing between capsules, phase cancellations off boundary
> surfaces, etc ? I frequently use spaced omni mics, and random phase
> interactions are faithfully rendered and entrancing to watch
> but.....what is the most useful information one can expect to derive
> from the Phase Display ? Thanks for any input,

X/Y phase displays can be valuable when adjusting tone arms. Many kinds of
mistracking show up as flat-lining of the squiggle.

X/Y displays of other audio functions, such as the input/output
characteristic of a power amp, can also show various kinds of misbehavior.
Anonymous
August 10, 2004 3:09:22 AM

Archived from groups: rec.audio.pro (More info?)

>mrivers@d-and-d.com (Mike Rivers)

>If you can plug it in so that it's monitoring a specific pair of mics,
>it can tell you a lot about what they're doing. But then, so can
>listening to the mics.
>

Or on your monitor chain, so you can do in-place soloing and check specific
mic combinations and levels.

Will Miho
NY Music & TV Audio Guy
Off the Morning Show! & sleepin' In... / Fox News
"The large print giveth and the small print taketh away..." Tom Waits
Anonymous
August 10, 2004 4:42:29 AM

Archived from groups: rec.audio.pro (More info?)

ok......so, it's a Zen kind of a thing then...?
Ray
-------------------------------------------------------------------------
"Phil Brown" <philcycles@aol.communged> wrote in message
news:20040809103450.19087.00003057@mb-m06.aol.com...
>
> It can tell you a lt but you have to look at it a lot and learn that way.
No
> quick way. after about 6 months or so it'll start to make sense.
> Phil Brown


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.734 / Virus Database: 488 - Release Date: 5/08/2004
Anonymous
August 10, 2004 4:42:30 AM

Archived from groups: rec.audio.pro (More info?)

>ok......so, it's a Zen kind of a thing then...?
>Ray

To a certain extent. I was a mastering engineer and we have then up all the
time and after a while you can discover that a cetain pattern produces a
certain result. There's an lot of information there but discerning it takes
experience. Just keep looking and experimenting. If you can move mics around
and see what it does to the display it will speed up the process. Sadly the
advent of the CD has made many engineers unmindful of the phase relationships
in their recordings.
Phil Brown
Anonymous
August 10, 2004 4:51:45 AM

Archived from groups: rec.audio.pro (More info?)

"WillStG" <willstg@aol.comnospam> wrote in message news:20040809161748.21423.00001187@mb-m18.aol.com...
> >mrivers@d-and-d.com (Mike Rivers)
>
> >If you can plug it in so that it's monitoring a specific pair of mics,
> >it can tell you a lot about what they're doing. But then, so can
> >listening to the mics.
> >
>
> Or on your monitor chain, so you can do in-place soloing and check specific
> mic combinations and levels.

Offhand, I'd say that even on the 2-bus, if it constantly looks like
a real 'cotton-ball' there are still some sensitivity parameters to
tweak.

DM
Anonymous
August 10, 2004 8:13:21 AM

Archived from groups: rec.audio.pro (More info?)

<< ok......so, it's a Zen kind of a thing then...? >>

Well, no, it's a real visual analogy of your stereo width, signal strength, &
in-ness through random-ness to out-ness of your stereo phase. It's pretty
intuitive, even more so if the display is rotated 45 degrees anti-clockwise
from a true XY scope orientation.


Scott Fraser
Anonymous
August 10, 2004 8:15:07 AM

Archived from groups: rec.audio.pro (More info?)

>Offhand, I'd say that even on the 2-bus, if it constantly looks like
>a real 'cotton-ball' there are still some sensitivity parameters to
>tweak.

Or phase problems to resolve.
Phil Brown
Anonymous
August 10, 2004 8:16:58 AM

Archived from groups: rec.audio.pro (More info?)

<< Sadly the
advent of the CD has made many engineers unmindful of the phase relationships
in their recordings. >>

This, I think, is one of the major failings in current audio education. If all
would-be engineers had to have their work cut to LP before being allowed to
make CDs I think we'd stop having to hear so much out-of-phase bad stereo.


Scott Fraser
Anonymous
August 10, 2004 10:44:51 AM

Archived from groups: rec.audio.pro (More info?)

<< scotfraser@aol.com (ScotFraser) >>
<< This, I think, is one of the major failings in current audio education. If
all
would-be engineers had to have their work cut to LP before being allowed to
make CDs I think we'd stop having to hear so much out-of-phase bad stereo. >>

Learning to mix in mono might help too... <g>


Will Miho
NY Music & TV Audio Guy
Off the Morning Show! & sleepin' In... / Fox News
"The large print giveth and the small print taketh away..." Tom Waits
Anonymous
August 10, 2004 11:09:10 AM

Archived from groups: rec.audio.pro (More info?)

<< Learning to mix in mono might help too... <g> >>


Yeah, but I'm told that nobody listens to mono anymore.
<g>

Scott Fraser
Anonymous
August 10, 2004 11:44:03 AM

Archived from groups: rec.audio.pro (More info?)

In article <20040809161748.21423.00001187@mb-m18.aol.com> willstg@aol.comnospam writes:

> >If you can plug it in so that it's monitoring a specific pair of mics,
> >it can tell you a lot about what they're doing.

> Or on your monitor chain, so you can do in-place soloing and check specific
> mic combinations and levels.

That would work as long as your solo was solo-in-place and the mics
were panned full left and right. It won't tell you much with mics
panned in the same place or even very far off hard L/R.



--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Anonymous
August 10, 2004 1:50:03 PM

Archived from groups: rec.audio.pro (More info?)

ScotFraser <scotfraser@aol.com> wrote:
><< Sadly the
>advent of the CD has made many engineers unmindful of the phase relationships
>in their recordings. >>
>
>This, I think, is one of the major failings in current audio education. If all
>would-be engineers had to have their work cut to LP before being allowed to
>make CDs I think we'd stop having to hear so much out-of-phase bad stereo.

I think if everyone had a chance to actually hear a speaker system that
had proper imaging and got a sense of what things actually sound like,
we'd see a lot less of it, too.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
August 10, 2004 2:52:54 PM

Archived from groups: rec.audio.pro (More info?)

"ScotFraser" <scotfraser@aol.com> wrote in message
news:20040810030910.02800.00001493@mb-m04.aol.com...

> Yeah, but I'm told that nobody listens to mono anymore.
> <g>


One of the grand old men of local audio told me recently that he thinks
stereo is bushwah (perhaps not those exact words, but let's say
unnecessary).

He figures that once the volume gets to the point that most pop music is
listened to, all the imaging cues are so reflected and refracted and stuff,
that there's no way to tell which sound came from where originally.

Dave O'H
oheareATmagmaDOTca
Anonymous
August 10, 2004 5:25:03 PM

Archived from groups: rec.audio.pro (More info?)

Arny Krueger <arnyk@hotpop.com> wrote:

> X/Y phase displays can be valuable when adjusting tone arms. Many kinds of
> mistracking show up as flat-lining of the squiggle.

> X/Y displays of other audio functions, such as the input/output
> characteristic of a power amp, can also show various kinds of misbehavior.

Would it be a useful tool for callibrating a stereo compressor like a set
of linked 2254s?

Rob R.
Anonymous
August 10, 2004 5:25:04 PM

Archived from groups: rec.audio.pro (More info?)

"Rob Reedijk" <reedijk@hera.med.utoronto.ca> wrote in message
news:cfaibf$rvf$1@news1.chem.utoronto.ca
> Arny Krueger <arnyk@hotpop.com> wrote:
>
>> X/Y phase displays can be valuable when adjusting tone arms. Many
>> kinds of mistracking show up as flat-lining of the squiggle.
>
>> X/Y displays of other audio functions, such as the input/output
>> characteristic of a power amp, can also show various kinds of
>> misbehavior.
>
> Would it be a useful tool for callibrating a stereo compressor like a
> set of linked 2254s?

Sounds like a pregnant application. Never tried it, though.
Anonymous
August 10, 2004 7:36:34 PM

Archived from groups: rec.audio.pro (More info?)

<< He figures that once the volume gets to the point that most pop music is
listened to, all the imaging cues are so reflected and refracted and stuff,
that there's no way to tell which sound came from where originally.>>

Yes, although this is not exclusive to loud pop music. Substantial mono summing
takes place in any stereo listening environment, other than headphones or
anechoic rooms. The <g> in my statement was for the several detractors who have
argued against this point with me in the past, claiming mono compatibility is
irrelevant with CDs.


Scott Fraser
Anonymous
August 10, 2004 8:03:40 PM

Archived from groups: rec.audio.pro (More info?)

<< I think if everyone had a chance to actually hear a speaker system that
had proper imaging and got a sense of what things actually sound like,
we'd see a lot less of it, too. >>

That would involve getting a lot of people out of their
nearfields-as-headphones monitoring environments in order to hear what real
depth can sound like.


Scott Fraser
Anonymous
August 11, 2004 3:18:41 AM

Archived from groups: rec.audio.pro (More info?)

"ScotFraser" <scotfraser@aol.com> wrote in message news:20040810113634.04711.00000744@mb-m21.aol.com...
> << He figures that once the volume gets to the point that most pop music is
> listened to, all the imaging cues are so reflected and refracted and stuff,
> that there's no way to tell which sound came from where originally.>>
>
> Yes, although this is not exclusive to loud pop music. Substantial mono summing
> takes place in any stereo listening environment, other than headphones or
> anechoic rooms. The <g> in my statement was for the several detractors who have
> argued against this point with me in the past, claiming mono compatibility is
> irrelevant with CDs.

It wasn't me. Mono compatibility is still imperical in my estimation; it's just
that CDs don't have to adhere to the same 'cutting' parameters as did records.
Most of the people I know still have small mono table radios and mono portable
TVs, etc..

--
David Morgan (MAMS)
http://www.m-a-m-s DOT com
Morgan Audio Media Service
Dallas, Texas (214) 662-9901
_______________________________________
http://www.artisan-recordingstudio.com
Anonymous
August 11, 2004 5:53:55 AM

Archived from groups: rec.audio.pro (More info?)

>Yes, although this is not exclusive to loud pop music. Substantial mono
>summing
>takes place in any stereo listening environment, other than headphones or
>anechoic rooms.

Isn't that the room's doing though, rather than the recording? Any room that
smears a stereo image to the point of "substantial mono summing" would most
likely skew a mono signal pretty substantially too. I'm not arguing for
ignoring microphone phase relationships, but if listening environments are
going to mess up the image that badly, why sweat a little phase phunk in the
recording?




Joe Egan
EMP
Colchester, VT
www.eganmedia.com
Anonymous
August 11, 2004 6:29:53 AM

Archived from groups: rec.audio.pro (More info?)

<< It wasn't me. Mono compatibility is still imperical in my estimation; it's
just
that CDs don't have to adhere to the same 'cutting' parameters as did records.
Most of the people I know still have small mono table radios and mono portable
TVs, etc.. >>

Beyond those mono devices, many people listen to stereos in non-anechoic
spaces.


Scott Fraser
Anonymous
August 11, 2004 7:51:18 AM

Archived from groups: rec.audio.pro (More info?)

"EganMedia" <eganmedia@aol.com> wrote in message...

> why sweat a little "phase phunk"


May I use that term ?

;-)
Anonymous
August 11, 2004 8:37:44 AM

Archived from groups: rec.audio.pro (More info?)

<< Isn't that the room's doing though, rather than the recording? >>

That's the point. As soon as it emerges from speakers, the stereo is getting
mixed in the room.

<< Any room that
smears a stereo image to the point of "substantial mono summing" would most
likely skew a mono signal pretty substantially too.>>

Any room that isn't anechoic is going to cause a good deal of mixing of the
stereo.

<< I'm not arguing for
ignoring microphone phase relationships, but if listening environments are
going to mess up the image that badly,>>

Mono summing isn't so much messing up the image as it is decreasing the
separation.

<< why sweat a little phase phunk in the
recording? >>

Just keep pressing the mono check button often.


Scott Fraser
Anonymous
August 11, 2004 9:39:37 AM

Archived from groups: rec.audio.pro (More info?)

In article <cfaibf$rvf$1@news1.chem.utoronto.ca>,
Rob Reedijk <reedijk@hera.med.utoronto.ca> wrote:

> Arny Krueger <arnyk@hotpop.com> wrote:
>
> > X/Y phase displays can be valuable when adjusting tone arms. Many kinds of
> > mistracking show up as flat-lining of the squiggle.
>
> > X/Y displays of other audio functions, such as the input/output
> > characteristic of a power amp, can also show various kinds of misbehavior.
>
> Would it be a useful tool for callibrating a stereo compressor like a set
> of linked 2254s?

Sure... feed a mono signal to both channels and put the outputs into the
XY display. If the two channels were matched well, the output would
also still be mono (a thin line). If you have any tracking problems,
you'll get something closer to the normal fuzzball that you get when
looking at stereo. Of course, there won't be time differences between
channels, but there will be amplitude differences that will cause the
display to deviate from a straight line.


Regards,

Monte McGuire
monte.mcguire@verizon.net
Anonymous
August 12, 2004 5:24:04 AM

Archived from groups: rec.audio.pro (More info?)

On or about 11 Aug 2004 02:29:53 GMT, ScotFraser allegedly wrote:

> << It wasn't me. Mono compatibility is still imperical in my estimation; it's
> just
> that CDs don't have to adhere to the same 'cutting' parameters as did records.
> Most of the people I know still have small mono table radios and mono portable
> TVs, etc.. >>
>
> Beyond those mono devices, many people listen to stereos in non-anechoic
> spaces.

Or with the speakers 6 inches apart.


Noel Bachelor noelbachelorAT(From:_domain)
Language Recordings Inc (Darwin Australia)
Anonymous
August 13, 2004 11:14:37 PM

Archived from groups: rec.audio.pro (More info?)

>Monte McGuire monte.mcguire@verizon.net

>Sure... feed a mono signal to both channels and put the outputs into the
>XY display. If the two channels were matched well, the output would
>also still be mono (a thin line).

I like to do this with left minus right metering, on my tektronix the meter
showing the summed "minused" signal is a lot more precise in judging level
differences between channels than going by how thin the line on the crt display
is.

Will Miho
NY Music & TV Audio Guy
Off the Morning Show! & sleepin' In... / Fox News
"The large print giveth and the small print taketh away..." Tom Waits
Anonymous
August 15, 2004 1:00:38 AM

Archived from groups: rec.audio.pro (More info?)

> I like to do this with left minus right metering, on my tektronix the meter
>showing the summed "minused" signal is a lot more precise in judging level
>differences between channels than going by how thin the line on the crt
>display

This is the infamous phase meter so beloved of Rupert Neve. All Neve consoles
used to have one.
Phil Brown
!