PLACE -- stationary source room-simulation
in RTcmix/insts/std/MOVE

quick syntax:
PLACE(outskip, inskip, dur, AMP, dist-xpos, angle-ypos, (-)dist_between_mikes, reverb_amp[, input_channel)

space(dist_to_front, dist_to_right, -dist_to_back, -dist_to_left, height, abs_fact, rvbtime)

mikes(mike_angle, pattern_factor)


matrix(amp, matrixval1, matrixval2, ... matrixval144)

PLACE employs several subcommands to set the room-simulation characteristics.

NOTE: This is an older RTcmix instrument, the newer MPLACE instrument is probably better to use.


   p0 = output start time (seconds)
   p1 = input start time (seconds)
   p2 = duration (or endtime if negative) (seconds)
   p3 = amplitude multiplier (relative multiplier of input signal)
   p4 = distance (feet) to sound source, or x-coordinate (feet) of sound source
   p5 = angle to sound source (degrees; 0 degrees is straight in front),
      or y-coordinate (feet) of sound source
   p6 = distance between 'mics' (stereo receivers) in the room (feet)
      NOTE: if p6 is negative, p4/p5 will be interpreted as x- and y- coordinates,
      otherwise p4/p5 will set polar coordinates for the sound source location
   p7 = amplitude of reverberation (relative multiplier of input signal)
   p8 = input channel [optional, default is 0]

   p3 (amplitude) can receive dynamic updates from a table or real-time control source.

   p0 = distance to front wall of room (feet)
   p1 = distance to right-hand wall of room (feet)
   p2 = distance to back wall of room (feet) [< 0.0]
   p3 = distance to left-hand wall of room (feet) [< 0.0]
   p4 = distance to ceiling of room (feet)
   p5 = wall absorption factor (0-10; 0 == more 'dead', 10 == more 'live')
   p6 = reverberation time (seconds)

   NOTE: this subcommand is required for PLACE to function

   p0 = microphone angle (degrees, 0 degrees is straight in front)
   p1 = microphone pattern (0-1; 0 == omnidirectional, 1 == highly directional)

   NOTE: this subcommand is optional for PLACE to function (the default is "mikes_off")

   no pfields, this defeats the microphone angle and pattern settings for binaural simulation

   NOTE: this subcommand is optional for PLACE to function

   p0 = total matrix gain (relative multiplier of input signal)
   p1-p145 = 12 x 12 matrix amp/feedback coefficients [optional; defaults to internal matrix]

   NOTE: this subcommand is optional for PLACE to function

PLACE is Doug Scott's room simulation RTcmix instrument. It places a sound in a room of your design and simulates the acoustic resonances of the room. Early reflections are computed using a ray-tracing approach based in the distances between the source, the listening 'microphones' and the walls. The generalized room reverberation is simulated using a 12 x 12 matrix of delay elements with feedback and filtering designed to imitate the global reverberation response of the specified room.

NOTE: This is an older RTcmix instrument, the newer MPLACE instrument is probably better to use.

Usage Notes

The room design for PLACE depends on parameters specified in the setup subcommand. The parameters work by assuming that the listener (YOU) is placed at point [0,0] in a coordinate space. The locations of the four walls are specified in this x,y coordinate system ("front", "right", "-back", "-left"):

Therefore the distance to the back and left walls must be specified as negative. All, including height, are in feet. "absorb" is a number between 0 (minimum) and 10 (maximum) that determines how reflective the walls are. "rvbtime" is the approximate length of reverb in seconds (the actual length depends on the size of the room).

PLACE sets the location of the source sound by specifying the distance to the sound ("dist-xpos") and the angle ("angle_ypos") of the sound:

                                  0.0    source
                                   |    /
                                   |   /
                                   |  /
                                   | /
using feet and degrees, respectively (see below for an alternative method of specifying the source location). Be sure to stay inside bounds of the room (it may take a bit of trigonometry [or guessing] to do that) The "AMP" pfield is a multipler of the input audio prior to any processing by PLACE. The "dist_mikes" parameter sets how far apart the two 'listening' points are from the [0,0] center of the coordinate room (you can choose to think of this is how big the listener's head is...).

When specifying the parameters for PLACE, be aware that the interpretation of the p4 and p5 pfields ("dist-xpos", "angle-ypos") depends on whether or not p6 ("dist_mikes") is positive or negative. The distance to the mikes (p6) will be interpreted as a positive number in any case, but if it is entered as negative it will cause p4 and p5 to be interpreted as cartesian coordinates on a coordinate plane where the center of the listener is located at [0, 0]. The default interpretation is to use polar coordinates for the sound source information (distance to sound, angle to sound).

p7 ("reverb_amp") can be used to adjust the amount of reverberant sound coming from the matrix reverberator relative to the direct sound and the early wall reflections.

The optional subcommands that may be used to set the parameters for PLACE include mikes and mikes_off. mikes is a setup call for times when you wish to simulate microphone recording (most of the time, actually). The arguments are "mike_angle", which is the angle each microphone makes with a line drawn between them (i.e., 45 puts them at a 90 degree angle FROM EACH OTHER). "pattern" is a value between 0 and one; 0 produces an omnidirectional mike, 1 produces a hypercardioid pattern, 0.5 produces the familiar cardioid pattern. The default pattern will be omnidirectional.

mikes_off is used following a previous call to mikes in order to cancel mike mode in the event that you wish to use binaural mode, or default to omnidirectional.

matrix is used to replace the default set of amplitude/feedback coefficients for the RVB matrix -- all 144 of them. This is tricky to use.

PLACE requires stereo output.

Sample Scores

basic use:

   rtsetparams(44100,  2)
   space(400, 400, -400, -400, 400, 8., 10.)
   PLACE(0, 0, 14.3, 20, 10, 20, -1, 1.)

See Also