Snd

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Written and developed at CCRMA by Bill Shottstaedt, SND is a sound editor modeled loosely after Emacs, an old, sorely-missed PDP-10 sound editor named Dpysnd. It can accommodate any number of sounds each with any number of channels, and can be customized and extended using guile and Ruby. It can be customized and extended using either s7 (included in the Snd sources), Ruby, or Forth. Snd can be started on any PlanetCCRMA Linux workstation by selecting the application on the PlanetCCRMA menu and the editors tab. Otherwise SND is started by typing the 'snd' command on a terminal window or shell.


Contents

Starting SND

On a terminal shell (Linux or OSX), SND can be started by typing:


    snd &      

If you have a sound you want to listen, you can type for instance,


    snd /zap/dog.snd &     

and your soundfile will be loaded and opened directly on SND. This is a good way to get familiar with the SND interface.

Once SND is running, go to the file menu, and open another soundfile or close the one already opened. To hear the sound, click the 'play' button. To see an FFT, click the 'f' button on the left. The left mouse button is used for most pointing operations; the middle button pastes in the current selection; the right button brings up the SND pop up menu. Make sure you go through the help pull down menu to find more about all the features SND. In addition to this nutshell, there is an enormous amount of information in the SND manual or search its documentation on its index

Note: You might need to run Jack with Qjackctl in order to get some sound out of the Linux workstations.


Instant Gratification

Alternatively if you don't have a soundfile, you can create one by means of using SND's own audio synthesis engine. At CCRMA or in standard Linux installation you can look for a file named "bird.scm" which should be located at SND's source directory."bird.scm" at PlanetCCRMA Linux worstations is located at:

      /usr/ccrma/lisp/src/snd

A good idea is to copy this file to working or temporary directories so that you leave the original intact. You can copy "bird.scm" to the "zap" directory at CCRMA workstations by using the following commands on the terminal shell (some knowledge of terminal shells is good to accomplish these guidelines).

       cd /zap
       cp /usr/ccrma/lisp/src/snd/bird.scm /zap/.


Now you can open SND directly on the shell as stated before by issuing the 'snd' command:

       snd & 

SND's window interface should open and show only pull-down menus. Go to the 'View' menu and select 'Show Listener' option. SND listener opens only showing a prompt ">". On this prompt you type "Scheme" code which is processed and compliled by SND's s7. In order to have SND synthesize a sound with "bird.scm", you need to load the file into the interpreter and the run a function(sub-program) which generates the soundfile. You do this by typing on the listener the function to load the file and then running the returned name of the function as follows:

        > (load "/zap/bird.scm")

Note that a prompt ">" means that the listener is ready to accept another function call.

After a carriage return (entering) '(load "/zap/bird.scm")', the listener returns:

        make-birds
        >


Now you know there is a function in SND called 'make-birds'. To get the bird's songs you need to issue a function call (run the sub-program) to 'make-birds' on SND's listener:

        > (make-birds)

The soundfile window should open showing a waveform just created. To listen to this waveform you can click on the play button or alternatively use the function call '(play)' on the listener.

        > (play)


A screen shot of SND with the procedures outline might look like:

Get Familiar with SND's waveform interface: move horizontal scrollbars to change the depth of the waveform, and vertical scrollbars to change the amplitude viewing scale. The [w] button shows the waveform while the [f] button shows the spectra. Notice that both waveform and spectra change while your move the focus on your soundfile.


Editing soundfiles with SND

SND editing is not "point-and-drag" like in most waveform editors. Instead, "razor-cut" editing and trimming can be accomplish by using markers to select regions and key binding commands that work on regions or on the soundfile as a whole.

To edit soundfiles using SND, good advice is to use 'emacs-like' keyboard combinations (see below), and then try them on a SND listener window. To make things easier start with a short (3 secs) mono (one-channel) soundfile.


c-x means control-x or the keyboard combination <ctrl>-<x>
M-x means meta-x and at CCRMA is the keyboard combination <esc>-<x>


If you have a soundfile in the active window try the following combinations and watch the cursor in the displayed soundfile active window. If you don't have a soundfile you can use the open command in the file pull-down menu of SND.

c-a: move cursor to window start
c-e: move cursor to window end
c-v: move cursor to mid-window
c-l: position window so cursor is in the middle
c-f: move cursor ahead one sample
c-b: move cursor back one sample
c-q: play current channel starting at cursor
c-t: stop playing
c-[Space]: start selection definition
c-m: place (or remove) mark at cursor location
c-j: goto mark
c-w: delete (cut) current region
M-w: (copy) current region
c-y: paste in last deleted region
c-_: undo
c-x c-s: save your current edition.

Playing a Soundfile

  • To play a sound file from a place other than the beginning:
  1. Activate sync or sync/unite modes in the lower right check-boxes
  2. Create a synchronize marker by:
        c-s-M (control-shift capital M)
-You should you get markers for all the channels.
  • To play from that location just click on the triangle in any of the markers.
  1. Playback should start.
  2. You can also move this markers and even 'rock the reels' by dragging the mouse.
  • More complex operations:
  1. To move forward or backwards in the Soundfile use the following key combinations:
      c-a                     ;;; move cursosr to the beginning
      c-u 0.4 c-f             ;;; move cursor forward 0.4 seconds
      c-e                     ;;; move cursor to the end
      c-u 1.12 c-b            ;;; nove cursor backwards 1.12 seconds
      c-[Space]               ;;; start selection definition
      c-e                     ;;; a selection of 1.12 seconds
Note: These combinations and more can be viewed on the online Help menu at the overview command at the right side of the SND active window.


More info at Users at PlanetCCRMA:SND

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