[Luxey]

On 18 äÕÑ, 14:29, "Arny Krueger" wrote:
"Scott Dorsey" wrote in message







In article ,
hank alrich wrote:
Bill Graham wrote:

Scott Dorsey wrote:
Bill Graham wrote:

Yes. - I wonder if my horn can do something like
this....There are many different sounds that some
people can get out of it. I will have to think about
it for a while.....

Yup. *Trumpet is one of the most asymmetric waveforms
there is, with positive-going peaks that are enormous
compared with the negative-going ones.

Correspondingly you can use aggressive limiting on
trumpet without changing the tone all that much.

I have a suspicion that while the positive part of the
wave might not look like the negative part, the area
between the two curves and the base line should be the
same.

For an "engineer" you are remarkably prone to guessing,
and guessing wrong. Again, put the music into a DAW and
take a look.

If the wave were directly measuring air pressure, it
would have to be that way because the total pressure has
to be the same before and after the note.
The thing is... what a cardioid microphone measures isn't
direct air pressure or anything much like it.

Thing is that a velocity microphone like a cardioid is by definition a high
pass filter with zero gain at DC.

But, forget about the mic, the mic preamp is AC coupled. *So, the following
must always be true no matter what the microphone:

Without DC coupling and with reasonable linearity, the integral of the
voltage in the recording above zero *must* *be equal to the integral of the
voltage below zero.

Or as Bill correctly said:

"...while the positive part of the *wave might not look like the negative
part, the area *between the two curves and the base line should be the
same."

A tragic example of an attempt by a mob to mis-define technical truth by
political means. Bill is unpopular with some people, so an apparent error is
created out of a true thing that he said.

Sad. :-(- ÁÐÚàØø ÝÐÒÕÔÕÝØ ÕÚá -

- ¿àØÚÐÖØ ÕÚá Ø×ÜÕòã ÝÐÒÞÔÝØÚÐ -

DNFTT

[Luxey]

On 19 äÕÑ, 06:55, "Bill Graham" wrote:
Arny Krueger wrote:
"Scott Dorsey" wrote in message

In article ,
hank alrich wrote:
Bill Graham wrote:

Scott Dorsey wrote:
Bill Graham wrote:

Yes. - I wonder if my horn can do something like
this....There are many different sounds that some
people can get out of it. I will have to think about
it for a while.....

Yup. *Trumpet is one of the most asymmetric waveforms
there is, with positive-going peaks that are enormous
compared with the negative-going ones.

Correspondingly you can use aggressive limiting on
trumpet without changing the tone all that much.

I have a suspicion that while the positive part of the
wave might not look like the negative part, the area
between the two curves and the base line should be the
same.

For an "engineer" you are remarkably prone to guessing,
and guessing wrong. Again, put the music into a DAW and
take a look.

If the wave were directly measuring air pressure, it
would have to be that way because the total pressure has
to be the same before and after the note.

The thing is... what a cardioid microphone measures isn't
direct air pressure or anything much like it.

Thing is that a velocity microphone like a cardioid is by definition
a high pass filter with zero gain at DC.

But, forget about the mic, the mic preamp is AC coupled. *So, the
following must always be true no matter what the microphone:

Without DC coupling and with reasonable linearity, the integral of the
voltage in the recording above zero *must* *be equal to the integral
of the voltage below zero.

Or as Bill correctly said:

"...while the positive part of the *wave might not look like the
negative part, the area *between the two curves and the base line
should be the same."

A tragic example of an attempt by a mob to mis-define technical truth
by political means. Bill is unpopular with some people, so an
apparent error is created out of a true thing that he said.

Sad. :-(

Well, another way to look at it, is where would you draw the baseline given
any random audio waveform? You could put it halfway between the peaks, or at
the average voltage point, or where the areas below it and above it are
equal. I believe a scope puts it, defacto, at the average voltage point,
since you set it yourself based on no voltage input at all, and the scope
deflects it up or down based on voltage input.- ÁÐÚàØø ÝÐÒÕÔÕÝØ ÕÚá -

- ¿àØÚÐÖØ ÕÚá Ø×ÜÕòã ÝÐÒÞÔÝØÚÐ -

I used to use some VST (or DX) plugin, supposed to emulate tube
distortion,
it'd make waveform (on screen, in DAW) totaly asymetical, as if whole
thing slided down across zero line.

[Ty Ford]

On Thu, 17 Feb 2011 14:04:44 -0500, Peter Larsen wrote
(in article ):

nterestingly positive sounds slightly sharp while negative sounds slightly
flat.

Really!?

Peter,

Not that I doubt you, but do you have a more detailed source for this?

I'm a negative peaker. Does that mean I should try to go over the note
intended to hit pitch?

Regards,

Ty Ford

--Audio Equipment Reviews Audio Production Services
Acting and Voiceover Demos http://www.tyford.com
Guitar player?:http://www.youtube.com/watch?v=yWaPRHMGhGA

[Peter Larsen[_3_]]

Ty Ford wrote:

On Thu, 17 Feb 2011 14:04:44 -0500, Peter Larsen wrote
(in article ):

nterestingly positive sounds slightly sharp while negative sounds
slightly flat.

Really!?

That's my guideline to rapid perception of the polarity of vox humana,
another is the continuity of the stereo image across the center, also the
perceived length of the delay between sound and reverb seems to me to be too
short in case the polarity is wrong.

Peter,

Not that I doubt you, but do you have a more detailed source for this?

This goes way back to when late Steen Duelund taught me to listen for
loudspeaker oddities way back 1975-ish when he was modifying 8" loudspeakers
to tame their requency response and delayed resonances for use in his rear
loaded horn designs. I have seen some reference of it in the newsgroups,
possibly in the context of a debate I had with Arny about this way back,
probably between 1999 and 2001 over in rec.audio.tech.

It was Arny who explained how equal harmonic acts as a detection bias by
adding asymmetry to the waveform. That correlates very well with the
importance attributed to the effects of polarity when using rear loaded
horns with their asymmetric loading of the loudspeaker membrane.
Consequently as Arny stated back then it is not in itself a positive quality
for a transducer system, aka loudspeaker or headphone, in case polarity is
easily audible.

I'm a negative peaker. Does that mean I should try to go over the note
intended to hit pitch?

Nobody is purely "positive" or "negative". I think you should just "be the
pitch" and not worry, it is very subtle and more about the colour of the
chord than about the intonation, trusst your brain. It is the death metal
music guys that have to worry because pitch perception is influenced by
level in sones.

Some albums are fun to use for listening practice because of polarity
oddities, they are just never right. Elton John's Brown Dirt Cowboy is one
of them. Listen also for center image stability and whether sources are
"inside the stereo image" or "on the outside of it".

In case someone wants to attribute the latter to channel inversion, yes they
are right, it sounds somewhat similar, but to a lesser extent. This is about
subtleties and not about shiploads and it may not matter to some, not all
hearing faculties work in the same manner.

Ty Ford

Kind regards

Peter Larsen