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Sound filter question_ for my solo show — Parallax Forums

Sound filter question_ for my solo show

ArchiverArchiver Posts: 46,084
edited 2003-09-28 13:16 in General Discussion
Hi,
My name is Federico Muelas, I’m an artist working with technology and I’m
having a solo show in Barcelona at the end of the year titled “the sound of
the chocolate smell” where I’m showing my recent installation pieces, you
can check the info of the sound and more extended info about the piece at
www.federicomuelas.com

I Have a problem with one of the pieces named “Dripping Sounds” and I wonder
if anyone have an idea to overcome this problem.

Description of the piece “dripping sounds”

The "dripping machine" and the "sound Screen" are the two apparatus the
installation is comprised of. The first one, constituted by A 0,22 gallons
water container, a lighting and two lenses device, a ink dripping system and
a microcontrolled flushing system, is in charge of the following three
tasks; the optical projection of the enlarged image of the drop branching,
the drops dispensation and the water renovation cycle of the liquid
container where the ink is dripped. The second one translates the moving
image projected over its surface into sound through the 20 photosensitive
independent modules installed in its back face.

The modules, wired individually to 20 speakers encircling the screen, are
distributed in an equidistant grid of five columns by four rows, each row
comprises four elements connected in parallel; three individual modules and
an electronic circuit that provides an exclusive sound. Having the same
natural source, the five different sounds are modified in order to transform
their pitch value, increasing vertically in a range from low frequency in
the lower part of the screen to high in the upper one.

The photocapacitor installed in each module determines the variable
volume of the sound it broadcasts through the speaker.
The quantity of light this device receives is inversely correspondent to the
volume of the wave it emits and viceversa.

Therefore the projected image of the drop, while it is growing and
ascending from bottom to top (due to the image vertical flipping due to the
combination of two concave lenses), activates the sensors installed over the
screen and produces a sound that goes from low to high frequency values.

Description of the circuit I have problems with in the piece:

-A 20 seconds sound recording circuit sends a sound signal to a 1-watt
amplifier.
-The signal input of the 1-watt amplifier is connected to a photocell
connected to ground that increases or decreases the incoming sound signal
depending on the light it receiving.
-The 1-watt amplifier is connected to a speaker that emits the sound

Description of the problem:
-Supposedly the volume of the sound emitted by the speaker should be
inversely proportional to intensity of light reaching the photocell.
-Therefore when the photocell is receiving light the speaker shouldn’t emit
any sound, but this doesn’t happen, there is always a sound in the
background and since there are in the piece 20 of these circuits the sound
is really annoying.

The solution I’m looking for:
_What I need is to “cut” any sound emitted by the speaker under a
determinate volume threshold, let’s say under 18 dB.

I would really appreciate any suggestion, you can e-mail me at
d2ec@h...

Thanks a lot.

Federico Muelas

_________________________________________________________________
Add photos to your e-mail with MSN 8. Get 2 months FREE*.
http://join.msn.com/?page=features/featuredemail

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2003-09-27 22:04
    In the world of audio, this piece of equipment is called a noise gate.
    We use gates in our studios to reduce air conditioning and computer
    noise through the microphones when our disc jockeys aren't talking.
    This circuit shouldn't be hard to design using some op-amps in a class-c
    mode or perhaps some schottky diodes. If you're looking for a
    prepackaged solution RDL has many different "stick-on" solutions that
    might suit your needs http://www.rdlnet.com/stgla1.htm

    I hope this helps,
    Dave

    David Casey
    dtcasey@c...
    Original Message
    From: D2 equipo creativo [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=0FtxfpEVEzQCOFXZnJJbrTkWpF7-C2sXmEq52_kcyVCmt3_-AwEtAFxvUrxEPJwP_YfFDxhandCy]d2ec@h...[/url
    Sent: Saturday, September 27, 2003 10:37 AM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] Sound filter question_ for my solo show

    Hi,
    My name is Federico Muelas, I'm an artist working with technology and
    I'm
    having a solo show in Barcelona at the end of the year titled "the sound
    of
    the chocolate smell" where I'm showing my recent installation pieces,
    you
    can check the info of the sound and more extended info about the piece
    at
    www.federicomuelas.com

    I Have a problem with one of the pieces named "Dripping Sounds" and I
    wonder
    if anyone have an idea to overcome this problem.

    Description of the piece "dripping sounds"

    The "dripping machine" and the "sound Screen" are the two apparatus the
    installation is comprised of. The first one, constituted by A 0,22
    gallons
    water container, a lighting and two lenses device, a ink dripping system
    and
    a microcontrolled flushing system, is in charge of the following three
    tasks; the optical projection of the enlarged image of the drop
    branching,
    the drops dispensation and the water renovation cycle of the liquid
    container where the ink is dripped. The second one translates the
    moving
    image projected over its surface into sound through the 20
    photosensitive
    independent modules installed in its back face.

    The modules, wired individually to 20 speakers encircling the screen,
    are
    distributed in an equidistant grid of five columns by four rows, each
    row
    comprises four elements connected in parallel; three individual modules
    and
    an electronic circuit that provides an exclusive sound. Having the same
    natural source, the five different sounds are modified in order to
    transform
    their pitch value, increasing vertically in a range from low frequency
    in
    the lower part of the screen to high in the upper one.

    The photocapacitor installed in each module determines the variable
    volume of the sound it broadcasts through the speaker.
    The quantity of light this device receives is inversely correspondent to
    the
    volume of the wave it emits and viceversa.

    Therefore the projected image of the drop, while it is growing and
    ascending from bottom to top (due to the image vertical flipping due to
    the
    combination of two concave lenses), activates the sensors installed over
    the
    screen and produces a sound that goes from low to high frequency values.

    Description of the circuit I have problems with in the piece:

    -A 20 seconds sound recording circuit sends a sound signal to a 1-watt
    amplifier.
    -The signal input of the 1-watt amplifier is connected to a photocell
    connected to ground that increases or decreases the incoming sound
    signal
    depending on the light it receiving.
    -The 1-watt amplifier is connected to a speaker that emits the sound

    Description of the problem:
    -Supposedly the volume of the sound emitted by the speaker should be
    inversely proportional to intensity of light reaching the photocell.
    -Therefore when the photocell is receiving light the speaker shouldn't
    emit
    any sound, but this doesn't happen, there is always a sound in the
    background and since there are in the piece 20 of these circuits the
    sound
    is really annoying.

    The solution I'm looking for:
    _What I need is to "cut" any sound emitted by the speaker under a
    determinate volume threshold, let's say under 18 dB.

    I would really appreciate any suggestion, you can e-mail me at
    d2ec@h...

    Thanks a lot.

    Federico Muelas

    _________________________________________________________________
    Add photos to your e-mail with MSN 8. Get 2 months FREE*.
    http://join.msn.com/?page=features/featuredemail



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  • ArchiverArchiver Posts: 46,084
    edited 2003-09-28 13:16
    Yes, you need a gate or expander of some sort. Of course, you could use a
    bunch of reed relays under some sort of remote control, but I assume you
    just want the noise to go away until the drip event occurs. In that case a
    bank of gates set to trigger on just above the nominal noise threshold is a
    good way to go. Typically, these work by using a VCA (Voltage Controlled
    Amplifier) under some sort of hysteresis enabled trigger (so it doesn't
    jitter on and off for mid-level signals). Of course, you can do this with a
    bunch of analog circuits, but if you had the budget and/or gear, many audio
    mixing programs exist that will easily do this on a Mac or PC such as
    Steinberg Nuendo/Cubase, Digital Performer, MaxTracks, etc. If you already
    have 16 inputs and 16 outputs from your PC or Mac, it would be simple. Of
    course, if you have to purchase this gear, it would be an expensive
    solution. Can you borrow this to try.

    I don't think there's enough horsepower in a BS2 to operate on the audio
    directly, but it could probably sense the level of the 16 inputs and decide
    when to open the proper relays or VCAs. Has anyone in the group done
    anything like this?

    Mike Sokol
    www.modernrecording.com
    mikes@m...


    " One should not increase, beyond what is necessary,
    the number of entities required to explain anything"...
    -William of Occam-

    Original Message
    From: "Dave Casey" <dtcasey@c...>
    To: <basicstamps@yahoogroups.com>; <d2ec@h...>
    Sent: Saturday, September 27, 2003 5:04 PM
    Subject: RE: [noparse][[/noparse]basicstamps] Sound filter question_ for my solo show


    > In the world of audio, this piece of equipment is called a noise gate.
    > We use gates in our studios to reduce air conditioning and computer
    > noise through the microphones when our disc jockeys aren't talking.
    > This circuit shouldn't be hard to design using some op-amps in a class-c
    > mode or perhaps some schottky diodes. If you're looking for a
    > prepackaged solution RDL has many different "stick-on" solutions that
    > might suit your needs http://www.rdlnet.com/stgla1.htm
    >
    > I hope this helps,
    > Dave
    >
    > David Casey
    > dtcasey@c...
    >
    Original Message
    > From: D2 equipo creativo [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=rrZWii7wdiANUPv8YcaWqpMuTdcb-5u6yZN9xbfsjqRktP8X9RYzBrPDw3DV-O9DShbPWO8zXlr9HBs]d2ec@h...[/url
    > Sent: Saturday, September 27, 2003 10:37 AM
    > To: basicstamps@yahoogroups.com
    > Subject: [noparse][[/noparse]basicstamps] Sound filter question_ for my solo show
    >
    > Hi,
    > My name is Federico Muelas, I'm an artist working with technology and
    > I'm
    > having a solo show in Barcelona at the end of the year titled "the sound
    > of
    > the chocolate smell" where I'm showing my recent installation pieces,
    > you
    > can check the info of the sound and more extended info about the piece
    > at
    > www.federicomuelas.com
    >
    > I Have a problem with one of the pieces named "Dripping Sounds" and I
    > wonder
    > if anyone have an idea to overcome this problem.
    >
    > Description of the piece "dripping sounds"
    >
    > The "dripping machine" and the "sound Screen" are the two apparatus the
    > installation is comprised of. The first one, constituted by A 0,22
    > gallons
    > water container, a lighting and two lenses device, a ink dripping system
    > and
    > a microcontrolled flushing system, is in charge of the following three
    > tasks; the optical projection of the enlarged image of the drop
    > branching,
    > the drops dispensation and the water renovation cycle of the liquid
    > container where the ink is dripped. The second one translates the
    > moving
    > image projected over its surface into sound through the 20
    > photosensitive
    > independent modules installed in its back face.
    >
    > The modules, wired individually to 20 speakers encircling the screen,
    > are
    > distributed in an equidistant grid of five columns by four rows, each
    > row
    > comprises four elements connected in parallel; three individual modules
    > and
    > an electronic circuit that provides an exclusive sound. Having the same
    > natural source, the five different sounds are modified in order to
    > transform
    > their pitch value, increasing vertically in a range from low frequency
    > in
    > the lower part of the screen to high in the upper one.
    >
    > The photocapacitor installed in each module determines the variable
    > volume of the sound it broadcasts through the speaker.
    > The quantity of light this device receives is inversely correspondent to
    > the
    > volume of the wave it emits and viceversa.
    >
    > Therefore the projected image of the drop, while it is growing and
    > ascending from bottom to top (due to the image vertical flipping due to
    > the
    > combination of two concave lenses), activates the sensors installed over
    > the
    > screen and produces a sound that goes from low to high frequency values.
    >
    > Description of the circuit I have problems with in the piece:
    >
    > -A 20 seconds sound recording circuit sends a sound signal to a 1-watt
    > amplifier.
    > -The signal input of the 1-watt amplifier is connected to a photocell
    > connected to ground that increases or decreases the incoming sound
    > signal
    > depending on the light it receiving.
    > -The 1-watt amplifier is connected to a speaker that emits the sound
    >
    > Description of the problem:
    > -Supposedly the volume of the sound emitted by the speaker should be
    > inversely proportional to intensity of light reaching the photocell.
    > -Therefore when the photocell is receiving light the speaker shouldn't
    > emit
    > any sound, but this doesn't happen, there is always a sound in the
    > background and since there are in the piece 20 of these circuits the
    > sound
    > is really annoying.
    >
    > The solution I'm looking for:
    > _What I need is to "cut" any sound emitted by the speaker under a
    > determinate volume threshold, let's say under 18 dB.
    >
    > I would really appreciate any suggestion, you can e-mail me at
    > d2ec@h...
    >
    > Thanks a lot.
    >
    > Federico Muelas
    >
    > _________________________________________________________________
    > Add photos to your e-mail with MSN 8. Get 2 months FREE*.
    > http://join.msn.com/?page=features/featuredemail
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject
    > and Body of the message will be ignored.
    >
    >
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    > http://docs.yahoo.com/info/terms/
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and
    Body of the message will be ignored.
    >
    >
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    >
    >
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