Alter the pitch without altering the speed.

[Radium]

Hi:

Adobe Audition seems to be able to change the pitch of an audio file
without changing the speed at which it plays.

http://www.adobe.com/products/audition/overview2.html#kmhead3

"Time and pitch processing: Change tempo without shifting pitch — or
shift pitch without changing tempo — and never introduce audio
artifacts."

I wonder if this technique could enable astronomers to hear the sun
"sing" with having to increase the speed of the data they record. The
sun's acoustic signals are way too low-pitched for humans to hear. So
either the recording of the sun's acoustic signals has to be sped up
until the pitch is high enough for humans to hear or the pitch itself
needs to be changed using some intense processing [such as that of
Adobe Auditon]. It seems that the former method is used instead of the
latter. Why? If the audio software has sufficient abilities to increase
the pitch of infrasonic signals to that in the human audio-range --
without increase the playback speed -- then why isn't such a method
used?

To find out more about solar sound:

http://solar-center.stanford.edu/singing/singing.html


Thanks,

Radium

 

[John O'Flaherty]

Hi:

Adobe Audition seems to be able to change the pitch of an audio file
without changing the speed at which it plays.

http://www.adobe.com/products/audition/overview2.html#kmhead3

"Time and pitch processing: Change tempo without shifting pitch - or
shift pitch without changing tempo - and never introduce audio
artifacts."

I wonder if this technique could enable astronomers to hear the sun
"sing" with having to increase the speed of the data they record. The
sun's acoustic signals are way too low-pitched for humans to hear. So
either the recording of the sun's acoustic signals has to be sped up
until the pitch is high enough for humans to hear or the pitch itself
needs to be changed using some intense processing [such as that of
Adobe Auditon]. It seems that the former method is used instead of the
latter. Why? If the audio software has sufficient abilities to increase
the pitch of infrasonic signals to that in the human audio-range --
without increase the playback speed -- then why isn't such a method
used?

Maybe because the tempo of solar music is so slow that both it and the
pitch need to be speeded up for humans to dance to it.

 

[[email protected]]

Hi:

Adobe Audition seems to be able to change the pitch of an audio file
without changing the speed at which it plays.

http://www.adobe.com/products/audition/overview2.html#kmhead3

"Time and pitch processing: Change tempo without shifting pitch - or
shift pitch without changing tempo - and never introduce audio
artifacts."

I wonder if this technique could enable astronomers to hear the sun
"sing" with having to increase the speed of the data they record. The
sun's acoustic signals are way too low-pitched for humans to hear. So
either the recording of the sun's acoustic signals has to be sped up
until the pitch is high enough for humans to hear or the pitch itself
needs to be changed using some intense processing [such as that of
Adobe Auditon]. It seems that the former method is used instead of the
latter. Why? If the audio software has sufficient abilities to increase
the pitch of infrasonic signals to that in the human audio-range --
without increase the playback speed -- then why isn't such a method
used?

To find out more about solar sound:

http://solar-center.stanford.edu/singing/singing.html


Thanks,

Radium

Changing pitch without changing tempo causes some audio 'twitches' even
in Audition - not terrible but you'd notice. Changing pitch and tempo
together (same effect as playing a tape at a different speed ) is just
a re-sample and has undetectable audio errors. I've used it for this
many times with great success. I only have V1.5 so they might have
improved it in 2.0 but I doubt it.

GG

 

[Radium]

Hi:

Adobe Audition seems to be able to change the pitch of an audio file
without changing the speed at which it plays.

http://www.adobe.com/products/audition/overview2.html#kmhead3

"Time and pitch processing: Change tempo without shifting pitch - or
shift pitch without changing tempo - and never introduce audio
artifacts."

I wonder if this technique could enable astronomers to hear the sun
"sing" with having to increase the speed of the data they record. The
sun's acoustic signals are way too low-pitched for humans to hear. So
either the recording of the sun's acoustic signals has to be sped up
until the pitch is high enough for humans to hear or the pitch itself
needs to be changed using some intense processing [such as that of
Adobe Auditon]. It seems that the former method is used instead of the
latter. Why? If the audio software has sufficient abilities to increase
the pitch of infrasonic signals to that in the human audio-range --
without increase the playback speed -- then why isn't such a method
used?

To find out more about solar sound:

http://solar-center.stanford.edu/singing/singing.html


Thanks,

Radium

Changing pitch without changing tempo causes some audio 'twitches' even
in Audition - not terrible but you'd notice. Changing pitch and tempo
together (same effect as playing a tape at a different speed ) is just
a re-sample and has undetectable audio errors. I've used it for this
many times with great success. I only have V1.5 so they might have
improved it in 2.0 but I doubt it.

GG

Well maybe the astronomers could use a V10000000 ;-)

 

[Radium]

Changing pitch without changing tempo causes some audio 'twitches' even
in Audition - not terrible but you'd notice.

What are "twitches"?

 

[Radium]

Well maybe the astronomers could use a V10000000 ;-)

V = version

 

[RC]

Hi:

Adobe Audition seems to be able to change the pitch of an audio file
without changing the speed at which it plays.

I wonder if this technique could enable astronomers to hear the sun
"sing" with having to increase the speed of the data they record.

I am convinced that this could be accomplished (raising the pitch of
the Sun's low frequency "sound" emissions to within human audible range
without altering the tempo) through digital audio processing, but the
resulting "song" most likely would not be pleasing to the ear.

If you think about the dynamics involved in the process it makes sense;
the sub-sonic low frequency "sound" wave oscillates very slowly
compared to an audible wave. It therefore wouldn't be able to exhibit
any changes in its' pitch (frequency) more rapidly than the time it
takes the original wave to complete one cycle, because this would
change the base frequency itself. (I think the physics of audio
dynamics actually limits the fastest possible change in pitch to a
multiple of the frequency, something similar to the "Nyquist sampling
factor" used in digital audio reproduction.) So while the "sound" would
be able to be heard it would be a relatively long, steady, nearly
unchanging tone. Probably sound like a telephone dial tone, or the beep
made by continuously holding down one of the keys on the handset,
depending upon what frequency the pitch is raised to.

On the other hand, the changes of tone that we identify as music, well
most of us at least, occur much more rapidly.

Interesting that using analog audio recording it is not possible to
alter the tempo without affecting the pitch and vice versa. The wonders
possible in the digital age are only beginning to be uncovered.

 

[Radium]

Hi:

Adobe Audition seems to be able to change the pitch of an audio file
without changing the speed at which it plays.

http://www.adobe.com/products/audition/overview2.html#kmhead3

"Time and pitch processing: Change tempo without shifting pitch - or
shift pitch without changing tempo - and never introduce audio
artifacts."

I wonder if this technique could enable astronomers to hear the sun
"sing" with having to increase the speed of the data they record. The
sun's acoustic signals are way too low-pitched for humans to hear. So
either the recording of the sun's acoustic signals has to be sped up
until the pitch is high enough for humans to hear or the pitch itself
needs to be changed using some intense processing [such as that of
Adobe Auditon]. It seems that the former method is used instead of the
latter. Why? If the audio software has sufficient abilities to increase
the pitch of infrasonic signals to that in the human audio-range --
without increase the playback speed -- then why isn't such a method
used?

To find out more about solar sound:

http://solar-center.stanford.edu/singing/singing.html


Thanks,

Radium

Changing pitch without changing tempo causes some audio 'twitches' even
in Audition - not terrible but you'd notice. Changing pitch and tempo
together (same effect as playing a tape at a different speed ) is just
a re-sample and has undetectable audio errors. I've used it for this
many times with great success. I only have V1.5 so they might have
improved it in 2.0 but I doubt it.

GG

Is there a video equivalent of altering the frequency of a signal with
changing its speed?

 

[Jamie]

I am convinced that this could be accomplished (raising the pitch of
the Sun's low frequency "sound" emissions to within human audible range
without altering the tempo) through digital audio processing, but the
resulting "song" most likely would not be pleasing to the ear.

If you think about the dynamics involved in the process it makes sense;
the sub-sonic low frequency "sound" wave oscillates very slowly
compared to an audible wave. It therefore wouldn't be able to exhibit
any changes in its' pitch (frequency) more rapidly than the time it
takes the original wave to complete one cycle, because this would
change the base frequency itself. (I think the physics of audio
dynamics actually limits the fastest possible change in pitch to a
multiple of the frequency, something similar to the "Nyquist sampling
factor" used in digital audio reproduction.) So while the "sound" would
be able to be heard it would be a relatively long, steady, nearly
unchanging tone. Probably sound like a telephone dial tone, or the beep
made by continuously holding down one of the keys on the handset,
depending upon what frequency the pitch is raised to.

On the other hand, the changes of tone that we identify as music, well
most of us at least, occur much more rapidly.

Interesting that using analog audio recording it is not possible to
alter the tempo without affecting the pitch and vice versa. The wonders
possible in the digital age are only beginning to be uncovered.

yes, it can be done.
use a LM1496 (double balance modulator) on a high freq carrier and
then another BFO to drop it down to your selectable range of listening.
tempo will remain at the same rate, freq of pitch will vary according
on the BFO injection settings.

 

[Bob Masta]

yes, it can be done.
use a LM1496 (double balance modulator) on a high freq carrier and
then another BFO to drop it down to your selectable range of listening.
tempo will remain at the same rate, freq of pitch will vary according
on the BFO injection settings.

Note that this doesn't give the results most people want. All
frequencies are *shifted* by a constant amount, which destroys
harmonic structure. For example, if the original was a square
wave with components at 1000, 3000, 5000, etc and you
shift it down by 100 Hz, you get 900, 2900, 4900.. no longer
the same harmonics and definitely not the same timbre.

Best regards,


Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Home of DaqGen, the FREEWARE signal generator

 

[Bob Masta]

Is there a video equivalent of altering the frequency of a signal with
changing its speed?

Spatial frequencies in an image are expressed as cycles per mm,
so all you need to do is enlarge or reduce the displayed size to
change the frequencies. Not terribly exciting!

Best regards,



Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Home of DaqGen, the FREEWARE signal generator

 

[Radium]

Spatial frequencies in an image are expressed as cycles per mm,
so all you need to do is enlarge or reduce the displayed size to
change the frequencies. Not terribly exciting!

What if I want to decrease the "pitch" of the video so I can record
into a device with a much slower sample rate? I do not want to
eliminate the high frequency contents of the video, instead I want to
decrease the frequency of the high-frequency contents [to prevent
aliasing in the device with a slower sample rate] without increasing
the length of the movie I am transferring to the slower-sample rate
device. How would I do this?

Here is a auditory analogy:

I have a 44.1 Khz wave file with an audio signal whose highest
frequency is 13 khz. I want to transfer this audio to a wave file of
11.025 khz. To prevent aliasing in thr 11.025 khz file, I need to
somehow decrease the 13 khz sound down to 5,000 hz or lower. Lets say I
want to decrease the 13 khz down to 5 khz without increase the length
of the 44.1 khz wave. I would use Adobe Audition's pitch shifter [which
does not change the tempo] and decrease the pitch accordingly, so that
the 11.025 khz wave file is safe from aliasing.

What would be the video equivalent of this?

 

[John O'Flaherty]

Spatial frequencies in an image are expressed as cycles per mm,
so all you need to do is enlarge or reduce the displayed size to
change the frequencies. Not terribly exciting!

What if I want to decrease the "pitch" of the video so I can record
into a device with a much slower sample rate? I do not want to
eliminate the high frequency contents of the video, instead I want to
decrease the frequency of the high-frequency contents [to prevent
aliasing in the device with a slower sample rate] without increasing
the length of the movie I am transferring to the slower-sample rate
device. How would I do this?

Here is a auditory analogy:

I have a 44.1 Khz wave file with an audio signal whose highest
frequency is 13 khz. I want to transfer this audio to a wave file of
11.025 khz. To prevent aliasing in thr 11.025 khz file, I need to
somehow decrease the 13 khz sound down to 5,000 hz or lower. Lets say I
want to decrease the 13 khz down to 5 khz without increase the length
of the 44.1 khz wave. I would use Adobe Audition's pitch shifter [which
does not change the tempo] and decrease the pitch accordingly, so that
the 11.025 khz wave file is safe from aliasing.

What would be the video equivalent of this?

The video has no temporal frequency; it's all there at once. The
frequency you use to scan it into a time domain signal is up to you.
You can scan it at 1 pixel per second, and send the information across
a channel that can carry it, and reassemble the picture with no losses.
It might take a while to send one picture, like the slow video sent
from distant spacecraft, but it gets there.

 

[Jamie]

Bob Masta wrote:

Spatial frequencies in an image are expressed as cycles per mm,
so all you need to do is enlarge or reduce the displayed size to
change the frequencies. Not terribly exciting!

What if I want to decrease the "pitch" of the video so I can record
into a device with a much slower sample rate? I do not want to
eliminate the high frequency contents of the video, instead I want to
decrease the frequency of the high-frequency contents [to prevent
aliasing in the device with a slower sample rate] without increasing
the length of the movie I am transferring to the slower-sample rate
device. How would I do this?

Here is a auditory analogy:

I have a 44.1 Khz wave file with an audio signal whose highest
frequency is 13 khz. I want to transfer this audio to a wave file of
11.025 khz. To prevent aliasing in thr 11.025 khz file, I need to
somehow decrease the 13 khz sound down to 5,000 hz or lower. Lets say I
want to decrease the 13 khz down to 5 khz without increase the length
of the 44.1 khz wave. I would use Adobe Audition's pitch shifter [which
does not change the tempo] and decrease the pitch accordingly, so that
the 11.025 khz wave file is safe from aliasing.

What would be the video equivalent of this?

then i would say, you have a problem..

 

[Ron Capik]

Spatial frequencies in an image are expressed as cycles per mm,
so all you need to do is enlarge or reduce the displayed size to
change the frequencies. Not terribly exciting!

What if I want to decrease the "pitch" of the video so I can record
into a device with a much slower sample rate? I do not want to
eliminate the high frequency contents of the video, instead I want to
decrease the frequency of the high-frequency contents [to prevent
aliasing in the device with a slower sample rate] without increasing
the length of the movie I am transferring to the slower-sample rate
device. How would I do this?

Here is a auditory analogy:

I have a 44.1 Khz wave file with an audio signal whose highest
frequency is 13 khz. I want to transfer this audio to a wave file of
11.025 khz. To prevent aliasing in thr 11.025 khz file, I need to
somehow decrease the 13 khz sound down to 5,000 hz or lower. Lets say I
want to decrease the 13 khz down to 5 khz without increase the length
of the 44.1 khz wave. I would use Adobe Audition's pitch shifter [which
does not change the tempo] and decrease the pitch accordingly, so that
the 11.025 khz wave file is safe from aliasing.

What would be the video equivalent of this?

The video has no temporal frequency; it's all there at once. The
frequency you use to scan it into a time domain signal is up to you.
You can scan it at 1 pixel per second, and send the information across
a channel that can carry it, and reassemble the picture with no losses.
It might take a while to send one picture, like the slow video sent
from distant spacecraft, but it gets there.

Put another way: what is the frequency of a photograph?

Later...
R.C.
--