Pan moves the input sound from left to right, and combines this with attenuation, or gain, if desired. This process has no effect on mono files.
The position of the sound in the plane from left to right, from -100 to +100%, 0 corresponds to the center position.
Attenuation of the sound from -36 dB to 0 dB.
The Auto Pan effect moves a stereo signal back and forth between the left and right channel. At lower speeds, the effect is one of a gradual pan between speakers. At higher speeds, the effect is similar to a rotating speaker sound. At extremely high speeds, the effect introduces interesting stereo amplitude modulation effects. This effect doesn't work with mono files.
This pan position control determines the amount of time the panned signal will spend in the left or right channels. Technically speaking, this parameter varies the "duty cycle" of the low frequency oscillator that drives the Auto Pan effect. At a setting of 0%, the Auto Pan swings the sound equally between left and right channels in a sinusoidal pattern, much like a pendulum swings back and forth evenly about it's center.
However, Position settings below 0% will cause the sound to spend correspondingly more time in the left channel, thus appearing to alter it's "position" relative to the center of the stereo field. Position settings above 0 will cause the sound to spend correspondingly more time in the right channel. At extreme Position settings (near +/-100%), the sound appears only as a momentary "blip" in one channel or the other. This can sound especially interesting at high Depth and Frequency settings.
Frequency of the panning motion, from 0.01 to 2000 Hz. This controls the speed at which the sound is panned back and forth between channels.
Depth of the effect, by default from 0 to 100%. The Depth setting controls how pronounced the effect is. At 0%, there is no effect. At 100%, when the sound is being panned to the left channel, the right channel will be completely silent. At intermediate settings, the sound will not be completely muted in the "quiet" channel even at the instant is at it maximum level in the opposite channel.
Quasi Stereo acts on the common (mono) portion of a stereo signal. It divides the "shared" signal into a stereo path and applies complementary comb filters to each channel. These filters disperse their outputs to the left and right channels in such a way as to alter the impression of the stereo image. This process has no effect on mono files.
Complementary comb filters in Quasi Stereo
The apparent size of the quasi stereo image, where 0 means mono (the input is routed to both outputs with no change), 100 means 100% pseudo stereo.
The comb filtering used to create the pseudo-stereo image uses a short delay. The Delay Time slider lets you adjust the amount of the delay, from 0 to 100 milliseconds. A setting of 0 will cancel the effect,while higher settings make for progressively wider results.
Cutoff frequency for a 12 dB per octave high pass filter. The range is from 13 to 10,000 Hz. At a value of 13 the effect is switched off. As you raise the filter it attenuates low frequencies in the range up to 10,000 Hz before they are injected into the Quasi Stereo algorithm. These frequencies will still be present in the final signal. By using the filter, you can reduce low-frequency artifacts at the expense of a slightly narrower stereo image.
When you apply QuasiStereo to a two-channel stereo input
signal, the effect acts on only the mono (common) part of the signal. The
discrete stereo channel information is added to the processed pseudo stereo
signals to form the output.
This algorithm was really designed for doing mono-to-stereo
conversion (as seen in the Power Mac Hyperprism 2) but we're not allowed
to take in mono signal and give back stereo signal in the DirectX plug-in
format. As a result, this particular process is somewhat less exciting than
its sister version on the Mac platform. However, it still has some usefulness
in stereo processing so we've chosen to included it in the DX package.
Stereo Dynamics spatializes the input sound, positioning it in a virtual space situated in front of the listener. It moves the input sound from front to back and from left to right, depending on the effect's gain values. Use this effect with stereo files to adjust the relative right/left channel volumes with a single mouse move.
This process has no effect on mono files.
Right minus left gain, which controls the proportion of one channel relative to the other. For example, moving the tracer to the right will increase the proportion of the right channel in the output. Ranges from 0-100%.
Right plus left gain, that is, the overall amplitude of both channels. Ranges from 0-100%.
The figure below shows the layout of the play zone for the Stereo Dynamics effect.
Default layout of the play zone for Stereo Dynamics
Notice in the figure below, that as you move the tracer from top left to bottom right, you pan the sound.
Tracer path for a panning motion
As you move from top right to bottom left, the signal is attenuated. So if you combine the two motions, as the following figure shows, the sound appears to spin in a circle in front of the listener situated precisely between two loudspeakers. This is also an excellent effect on headphones.
Tracer path for a spinning motion
Unfortunately, all these motion applications can only
be heard in preview. Here we're up against the limitations of the DirectX
format. Namely, Hyperprism is not allowed to pass parameter automation values
to the host application, so you can't create or save motion effects which
involve real-time parameter changes in this version of Hyperprism. As a
result, this effect is much less glamourous in its DirectX implementation
than its "sister" effect in the Power Macintosh Hyperprism 2 program.
More Stereo alters the stereo effect by widening or narrowing the spatial image without changing the overall volume. It optionally applies a variable-cutoff high pass filter to signal, reducing potential phase-cancellation artifacts in the low-frequency content of the original sound file.
Width of the stereo image, where 0.00 means mono, 1.00 means normal stereo (no change to the input). 2.00 doubles the proportion of the discrete channel information in the output by attenuating the common or mono part of the signal, and 3.00 triples it. A horizontal value greater than 1.00 has the effect of widening the stereo image, pushing the sound to the extreme lateral poles.
Cutoff frequency for a 12 dB per octave high pass filter. At the value of 0 the effect is switched off. As you raise value, a high pass filter attenuates low frequencies in the range up to 6000 Hz before they are injected into the widening algorithm. These frequencies will still be present in the final signal. By using the filter, you can control low-frequency artifacts at the expense of a slightly narrower stereo image.
Open any stereo file from your library of sounds, in
your host application. Play it and then select the More Stereo effect.
Adjust the SLevel parameter from left (0) to right (3.00).
At the left-most position, the output is monaural, with the contributions
from both channels mixed and sent to both outputs. At the 1.00 setting the
stereo sound file is played back unchanged. In the extreme right position
(3.00) the stereo image widens to the left and right, with less sound in
the middle.
More Stereo has no effect on mono input signals. It treats only the discrete stereo part of the signal (that part of the signal that is not common to both channels).
M-S refers to either Mid-Side or Mono-Stereo. This classic stereo recording technique has the advantage that one can change the apparent width of the stereo image after the recording session, using a device called an M-S decoder. In the past, an M-S decoder took the form of an external analog circuit. The M-S Matrix effect replaces this circuit, making experimentation with the M-S technique as easy as tracing a line in the Blue Window. The description below tells you how to use Hyperprism's M-S decoding facilities.
M-S microphone configuration
In order to perform M-S decoding you first need to make M-S encoded recordings. This requires two microphones. One of these microphones faces front, toward the audio source. Its polar pattern is usually cardioid. (A variation on the M-S technique uses an omnidirectional microphone in the center.) The other microphone is bidirectional (also called figure-eight). The cardioid microphone captures the middle or mono part of the stereo image. The bidirectional microphone picks up the sides or discrete stereo part of the image. You record the output of these microphones on a two-channel recorder, with one channel called M and the other S, as opposed to the usual left (L) and right (R).
Assuming you have made an M-S recording, connect the M output of your recorder to the left channel of your computer's sound input, and the S output to the right channel.
Displacement of the stereo image in degrees [-90, +90], where the center position 0 degrees means no change. This can be useful in processing sound tracks recorded on location where the dialog is off-center, and one wants to restore it to the center position.
This parameter maintains constant power at any position,
so that at extreme left or right positions the level is boosted.
Gives you control over the level of the stereo part of the signal. In M-S processing, the higher the stereo level, the wider the apparent stereo image. The range is -96 to +6 dB.
Middle Left and Side Left. By default M-S Matrix assumes that the signal going into the "Left" input jack is the Mid part of the M-S signal. By selecting Side=Left , the program assumes that the left input is the Side part of the M-S signal. Click on this button to switch input settings.
This button can correct for an out-of-phase microphone configuration. It determines the phase of the M source. M+S in Left is the normal case; the M input sums positively. Click on this button to switch output channels.
Load the example sound file Clifden.wav. This is an
M-S encoded file.
Select the M-S Matrix effect
Set Center Position to 0 degrees and the Side Volume
to 0 dB. Do this and listen to the sound for a while.
Now decrease the Side Volume. As you drag toward the
bottom of the range you'll hear the sound gradually becoming mono.
As you boost Side Volume above 0 dB you'll hear the
sound image becoming wider and wider.
With the Side Volume up high, move the Center Position
control. The apparent "center" of the stereo image shifts to the
right and left, just as if you were readjusting the position of the M microphone
during a recording session.
The polar diagrams below show the range of spatial patterns obtainable from a single M-S recording using the M-S Matrix effect. The captions list the X and Y positions of the tracers followed by a figure in decibels that indicates the level of the S part of the signal relative to the M part.
Directivity patterns for a bi-directional (--) and cardioid (++) microphone in M-S recording configuration. This reflects the physical configuration of the microphones in the original recording session.
M-S Matrix: pattern at -3 dB
M-S Matrix: pattern at -6 dB
M-S Matrix: pattern at - 12 dB
M-S Matrix: pattern at -20 dB
M-S Matrix has no effect on mono input signals but
interesting effects can be obtained with rich frequency spectrum stereo
signals.
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