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Assignment 3

For students ew to PD, please extend what we did together in class, creating a classical "tap delay" in PD.  All of the objects required for this patch can be found in the attached document, "delay_requirements.pd".  You may also wish to refer to the PD "Help" browser found in the help menu, especially "3.audio.exmaples/GO2.delay.loop.pd".  Please download the PD-extended application for your operating system from this site:

PD-extended installers

You may wish to have multiple "delread~" objects reading from the same "delwrite~" buffer.

2)  Construct a graphical interface for your audio engine.  Use the assumption that someone else is going to operate the patch in performance.

Question: Are there any artifacts or interuptions in the signal when the delay is adjusted?  If so, why?  See the "vd~" object for more information and a potential solution.

Secure shell access, remote login

Command Line SSH

Secure Shell Access

Command line access via a Unix terminal/shell is the most reliable, powerful method of accessing the Digital Music Studios.  With it users can login and use the functionality and processing power of the CDMS computers remotely.

To login, open a terminal shell (on Mac, Applications --> Terminal; on Windows use Cygwin; on Linux or other Unix just open a standard xterm).  Then at the command prompt type:

ssh REMOTE_MACHINE_NAME

...where REMOTE_MACHINE_NAME is the name of the machine you wish to access, for example digital.music.cornell.edu.  If you use a different username on your local system than the one on the system you are logging into, you will also need to specify your remote username :

ssh USERNAME@REMOTE_MACHINE_NAME

CEMC systems are named by room as follows:

b27.music.cornell.edu
b25b.music.cornell.edu
b25c.music.cornell.edu
b25d.music.cornell.edu
digital.music.cornell.edu (server system)

On CEMC systems, convenient command shortcuts are also available using a standard syntax:

sshb27 (same as ssh b27.music.cornell.edu)
sshb (same as ssh devel.music.cornell.edu)
sshb (same as ssh b25d.music.cornell.edu)
sshc (same as ssh b25c.music.cornell.edu)
sshd (same as ssh b25d.music.cornell.edu)
sshdig (same as ssh digital.music.cornell.edu)

When logging in from the outside you will be prompted for your password.  Enter it and you will be logged in immediately.  Logins from within the studios are governed by secure authorized keys meaning your account will automatically be verified when a remote shell is requested and you will not have to type your password.  This will become important later on as we seek to run remote processes inline with local programs.

You may also wish to create password keys between systems, enabling passwordless movement among studio systems.  To set this up, type “cornellkeygen” and follow the directions entering no passphrase.

Secure Shell Copying

To copy files to and from local or remote computers, use the scp (secure copy) command.  The syntax is identical to ordinary copying with cp.

scp FILE_TO_COPY [MORE_FILES_TO_COPY] DESTINATION

Unlike cp, the file to copy and/or their destination may be a remote computer.  The user must specify the remote machine name and directory as a prefix.  So for example, to copy a local file named myfile to my remote home directory ("/home/kevinernste") on digital.music.cornell.edu, I would type:

scp myfile digital.music.cornell.edu:/home/kevinernste/

Note the colon ":" between the machine name and the directory in the destination argument.  This syntax should be followed carefully.

As with cp (and other Unix commands), all unix "wildcards" will work, so:

scp *  digital.music.cornell.edu:/home/kevinernste/

...will copy all files in the current directory to the destination directory on b27.  To copy directories and subdirectories, just add "-r" (for “recursive), so:

scp -r *  digital.music.cornell.edu:/home/kevinernste/

GUI SSH tools

If you wish, there are also several graphical SSH/SCP/SFTP clients available. Most limited to simple file copying, but some include terminal shell functions as well.  To peruse the list of clients available for your operating system of choice, please visit openssh.com and follow the links in the left-hand panel.

Assignment 2, Due Tuesday September 22nd

1.  WIth the recording techniques discussed so far, record and edit together your own soundfile library, a collection of individual sounds suitable.  You may use whatever sound making resources/instruments you have or can muster.  Edit and save these samples as short "notes" or individual sounds.  One can alway build phrases, loops, melodies, or other time-varying material from these smaller soundfiles.  Please  look toward creating 15-20 individual soundfiles.

2.  Using the samples you created in #1 in addition to samples from the  CEMC soundfile library (/snd/sflib) or other legal sources (freesound, for example), create a short "mix" or "study".  This little "piece" should be no longer than 1 minute (2 max!) should suffice.  Be creative.  You may wish to use the pieces played and discussed in class as models.

Related resources:

Freesound

NOTE: If you have difficulty exporting from Cubase, "Unexpected Error" or otherwise, please double check the Cubase export procedure found in the FAQ:

http://digital.music.cornell.edu/cubaseexport

Assignment 1, Due Thursday September 10th

1. Make a recording of the human voice using Audacity.  You may be as creative as you like with what is said, sung, rapped, or read but the resulting sound file should illustrate your understanding of the principles of signal quality as discussed in class.  Work toward a full, warm, sound exemplified by the classic "radio voice".  The resulting file should be approximately 15-20 seconds long.

Please turn in your finished assignment in on the network drive (linked on the Desktop in all studios).  Please name the file in a way that makes it's ownership obvious to the TA.  I recommend the following file naming scheme assuming I am turning in a soundfile titled "Yokel Vocal":

1421-assign1-kme32-yokel_vocal.wav

coursenumber-assignmentnumber-netid-title_of_track.wav

You may wish to consult the following tutorials during your exploration of Audacity and in its use for this assignment:

Audacity Manual Tutorials

Assignments

Below is a listing of assignments for Music 620.

Basic Unix Commands

Unix commands (HOME DIR)

Note: All unix commands take the basic form:
    command file (where “file” is the file to execute “command” upon)

Or more generically:
    command argument1 argument2 [argument3]

ls    lists current directory contents

ls -l     long listing (owner, permissions, size, etc) – add “-h” for human readable sizes

ls -a     list all, including those files that start with a dot (.).

pwd     print working directory

mkdir [directory name]  create a subdirectory

cd     change working directory
    - cd [directory name]
    - cd .. moves up 1 directory level
    - cd - toggles back to previous directory

cp     copy a file
    - cp [filename1] [filename2] (-R does recursive copy of all subdirectiries)

mv     move (or rename) a file
    - mv [filename1] [filename2]

less     view a file one page at a time, advance pages with SPACE
    less [filename] or less [filename]

rm     remove (delete) a file (Note: there is no “undo”)
    - rm [filename] (-r does recursive removal...useful, but be CAREFUL)

rmdir [directory name] note: the directory has to be empty

cat     view the contents of a file (or better, “output” its contents), concatinate

>       redirect output to a new file
        cat [file1] [file2] > [newfile]

>>    adds or “appends” to an existing file
        cat [file1] [file2] [file3] >> temp_file

|     Pipe, allows you to pass the results (stdout) of a command to another command
    - ls | more

history     shown a list of previously executed commands (-h for no command numbers)

!!     run previous command in history (also “up-arrow”) number in history

!#     run command from “history” where “#” is the command number

*    wild card used to stand for “all”
    - ls *.txt list all files with the extension .txt

Soundfile directory commands (SFDIR)

lsf     lists current soundfile directory contents

lsf -l     long listing (owner, permissions, size, etc)s

pwdsf     print working directory

mkdirsf [directory name] create a subdirectory

cdsf     change working directory
    - cdsf [directory name]
    - cdsf .. moves up 1 directory level (or “../../” for up two, etc)
    - cdsf - toggles to previous directory (like “Back” in a browser)

cpsf     copy a file
    cpsf [filename1] [filename2] (-R does recursive copy of all subdirectiries)

mvsf     move (and/or rename) a file
    - mvsf [filename1] [filename2]

rmsf     remove (erase) a file
    - rmsf [filename] (-r does recursive removal...useful, but be CAREFUL)

rmdirsf [directory name] note: the directory has to be empty

play (p) play a soundfile or soundfiles in your current working directory
    - p soundfile1.wav [soundfile-n.wav]

sfinfo view information about a soundfile in your current directory
    - sfinfo soundfile1.wav [soundfile-n.wav]

playsflib(psfl) play a soundfile from the soundfile directories
    - psfl  fl.c4.wav

findsflib     search the soundfile directory by character string
    - findsflib character_string

findsflib -p     search the soundfile directory by character string and play them as they are found
    - findsflib -p character_string

CEMC specific commands (more to come)

lsex    list available tutorial examples

getex    obtain a copy of a tutorial example
    - getex tutorial1 > mytutorial1

lstp    list available templates (blank examples)

gettp    obtain a copy of a template (blank examples)

cemchelp    view available help files and read file designated by argument

cs    shortcut to “csound”
    - cs orc sout (compile files “orc” and “sout” with Csound

ssgdig  shortcut for ssh access to "digital.music.cornell.edu"
ssgdev  shortcut for ssh access to "devel.music.cornell.edu"

Recording with a microphone

Recording with a microphone

Gain Staging

Gain Staging is a fancy term for something simple but very important.  A "gain stage" is any point in the signal path where a gain boost or attenuation is available.  In other words, it's any place in the chain where you have amplitude control, such as the output knob on an electric guitar, or the input level on an amplifier, etc.

Let's use the hypothetical guitar/amplifier signal-path scenario to illustrate the importance of gain staging.  Say our guitar player turns the volume/output knob on his instrument almost all the way down, while turning the amplifier input all the way up.  In this case, the amplifier is being taxed to compensate for the guitar's weak signal.  The result will be a very thin sound for the guitar as well as an unpleasant amplification of circuit noise inherent in the amplifier.  We are not maximizing our signal at all...and may in fact be harming our amplifier.

Now let's reverse the scenario, the guitar level is "cranked" while the amplifier input is almost to nothing.  Here again the problems are both timbral/aural and physical.  The amplifier is not taking advantage of the incoming signal, acting as a barrier to the guitar rather than a support.  Regardless, the overfed guitar signal might be overloading the amplifier input, causing physical damage.

The above is a simple case.  Yours will be more complex including 3 and 4 gain stages.  You will need to understand your signal path fully in order to get the best results.

Again to repeat a rule of thumb: the shorter the path, fewer signal traps along the way.  You will have gain stages where the signal must be raised or lowered while the ideal of many gain stages is to be transparent, to simply pass along the signal without impacting it, without boosting or attenuating.

Libraries fear digital lockdown

Original URL: http://news.bbc.co.uk/2/hi/technology/4675280.stm

By Ian Youngs
BBC News

Libraries have warned that the rise of digital publishing may make it harder or even impossible to access items in their collections in the future.

Many publishers put restrictions on how digital books and journals can be used.

Such digital rights management (DRM) controls may block some legitimate uses, the British Library has said.

And there are fears that restricted works may not be safe for future generations if people can no longer unlock them when technology evolves.

The British Library spends £2m of its £16m annual acquisitions budget on digital material, mainly reference books and journals.

This is going to be one of the significant challenges for us over the next few years Dr Clive Field, British Library
But by 2020, 90% of newly published work will be available digitally - twice the amount that is printed - according to British Library predictions published last year.

Libraries are allowed to give access to, copy and distribute items through "fair dealing" and "library privilege" clauses in copyright law.

But as publishers attempt to stop the public illegally sharing books and articles, the DRM they employ may not cater for libraries' legal uses.

"We have genuinely tried to maintain that balance between the public interest and respecting rights holders," Dr Clive Field, the British Library's director of scholarships and collections told the BBC News website.

"We are genuinely concerned that technology inadvertently may be disturbing that balance, and that would be unhelpful ultimately to the national interest."

We have grave concerns about the potential use of DRMs by rightholders to override existing copyright exceptions.
Libraries and Archives Copyright Alliance
The All Party Parliamentary Internet Group is conducting an inquiry into DRM.

In written evidence, the Libraries and Archives Copyright Alliance (Laca) said there were "widespread concerns in the library, archive and information community" about the potentially harmful effects of DRMs.

"We have grave concerns about the potential use of DRMs by rightholders to override existing copyright exceptions," its statement said.

In the long term, the restrictions would not expire when a work went out of copyright, it said, and it may be impossible to trace the rights holders by that time.

"It is probable that no key would still exist to unlock the DRMs," Laca said. "For libraries this is serious.

'Threaten'

"As custodians of human memory, a number would keep digital works in perpetuity and may need to be able to transfer them to other formats in order to preserve them and make the content fully accessible and usable once out of copyright."

In its written submission to the group, the British Library said DRM must not "exert excessive control on access to information".

"This will fundamentally threaten the longstanding and accepted concepts of fair dealing and library privilege and undermine, or even prevent, legitimate public good access."

Fair dealing and library privilege must be "re-interpreted and sustained for the digital age", it added.

Dr Field said: "This is going to be one of the significant challenges for us over the next few years."

Story from BBC NEWS:
http://news.bbc.co.uk/go/pr/fr/-/2/hi/technology/4675280.stm

Published: 2006/02/03 09:57:30 GMT

© BBC MMVII

Links and information of further interest

Original text of the DMCA, 1998 -- PDF
DMCA on Electronic Freedom Foundation
Lawrence Lessig Blog
The Creative Common

...more to come.

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