Forums

  • avatar
    0 sounds
    1 post

    Hi,can anybody help me?

    I've made two different circuits to receive RF using LM386 but they don't work. I've changed the values of C2 and L1 to change the frequency. I've also changed the gain but nothing happens.

    The problem is that I hear a sound of noise or buzz from the speaker. When I touch Pin 3 (The input) or the Antenna, The sound become higher but anyway no radio station is received.

    I've made a radio transmitter using a transistor before so, I turned it on. The receiver circuit received the song which is the input of the transmitter. It receives no matter the values of the C2 and L1 of the Tank circuit so, I removed the tank circuit and connected the antenna directly to pin 3 and It also works receiving the song.

    Why it doesn't receive any radio station although it receive the signals that are transmitted by the transmitter circuit that I've made ?

    What can I do to receive radio stations ? ( I live in area where I can receive good radio stations AM and FM from my cell phone and Radio device )
    here is the details of the IC :http://www.kynix.com/Detail/274538/LM386.html

    [img]https://i.stack.imgur.com/sI7Mb.png[/img]

  • avatar
    0 sounds
    1 post

    Hi,

    Not sure if this counts as a dare, but we recently completed a 2 minute short film. Well, actually it's more like a technical test than a short film.

    It's basically this short reel that looks something like 2001 crossed with a video game.
    There's no music in this one, so it's all Audio and Foley that will carry the sound on this short.

    Right now we're doing this purely for studying purposes so if anyone wants to use this for practice/learning. That's exactly what I'm looking for. smile

    At less than 2 minutes running time, I think this is quite manageable. smile
    If anyone of you is interested, please email me at cgipadawan@gmail.com

    Some of you might have seen another short film we worked on a few years ago:

    http://reversionmovie.blogspot.com

    Thanks to all and cheers!

  • avatar
    1 sound
    1 post

    Hey Gus smile Try this and see if it works for you: https://www.freesound.org/people/Scott%20Simpson/sounds/382214/

    Just uploaded and pending moderation. I can recut for timing or delivery as needed. Hope this helps!

    Scott

  • avatar
    0 sounds
    1 post

    Hi! I'm working in a surrealist short film where in one scene a guy enters in the body of a dead by the abdomen, and he is swallowed by the body (i know that is very extrange...)
    I'm stuck thinking about the sound when the body swallow the guy. Somebody can help me please?
    Thanks a lot.

  • avatar
    0 sounds
    13 posts

    Hello freesound community,
    I was wondering if I could get a sample of someone saying Get Down for my producer tag on my beats. I'm thinking more of an African American male voice here as well but I'm willing to listen or use different voices here as well and will take what I can get. I even want to hear a female voice or two to get an ideal of what it would sound like. Also because I will be using it as part of my producer tag I would love it if it could be uploaded under the creative common 0 license or no copyright.

    Thank you very much!

  • avatar
    56 sounds
    115 posts

    no problem, you can always try your best to seperate the sentences/words manually yourself, you didnt go into much detail about how i should read it or anything so i just guessed a lot.

  • avatar
    0 sounds
    3 posts

    Thank you very much for taking the time to help me out. Awesome quality, nicely done. I like your voice and the accent is great. The only thing that doesn't seem to fit exactly to my project is that I find it a little bit flat and rushed at some points, like it was one big sentence. But hey... I really really appreciate your help.

    Thank you.

  • avatar
    13 sounds
    384 posts

    I think dheming has come up with the only practical (Read affordable - off the shelf components) solution.

    I agree there are caveats, which unfortunately make task more a lot more complicated.

    Firstly it requires a bigger amplifier than ceramic transducers and will not work driven directly from a GPIO output.

    Tweeters dome or ribbon AMT, are only maybe 10-20% efficient which means that the bulk of electrical energy put into them is turned into heat. The usual cause of failure of a tweeter is thermal. The coil or ribbon element heats up like an electric fire and eventually burns out like a fuse(See edit note*). (To visualise the problem, imagine holding a lit 15 Watt Pygmy light bulb in your hand. Ouch - HOT! That's only 15W of heat, but it's enough to make a tungsten element glow white hot! Think what 15w would do to an aluminium element of similar mass.)

    An AMT tweeter (or any other) might be specified for a 20W or 100W amplifier, but it's not designed to handle continuous high level signals. In practice with a musical signal in a properly designed system, a 100W amplifier might typically only deliver 2 to 10 watts to the tweeter averaged over a second or two, with very short peaks up to 50 or 60 watts.

    To reduce the chances of burning out the tweeter there are three things to watch.

    1. Do not drive with ultrasonic continuously but in short bursts. For example, a 200ms burst every 2 seconds reduces the heating by 90% but should still squeak the sh** out of squirrels.

    2. Guard against DC and all low frequency’s below, say, 10kHz with a high-pass filter. All this energy would be turned directly into heat.

    3. Never drive the Tweeter directly with square waves, either from the output of the pi or due to clipping in the amp. This could be achieved with a low-pass filter set @ ~50-60kHz. A square wave will produce about 1.4 times more heat than a sine wave of equal peak magnitude.

    I've not been able to find any Power Handling V frequency specs. for AMT tweeters, but I suspect they need to be strongly de-rated at the higher frequencies. The typical figures I've used are pure guess work, even though I'm confident the principles are sound, so no guarantees. You might have to blow up a tweeter or two to find the actual limits...

    (About me - Before I retired and sold my shares I used to design the electronics & amps for Quested Studio Monitors but my experience is mainly with conventional dome tweeters more than AMTs)

    Anyway, good luck with the project,

    Wibby

    EDIT note*.
    A conventional tweeter with a voice coil will actually fail way before the voice coil blows like a fuse because the "glue" fixing the coil to it's former melts and burns. The voice coil distorts and rubs itself to death against the magnet. A ribbon or AMT tweeter wont fail in this way, but is still able to die because of thermal stress.

  • avatar
    56 sounds
    115 posts

    here you go https://www.freesound.org/people/Kodack/sounds/381993/ it is still being moderated at the moment, so you may have to wait a little, also you did not mention what accent you want so i decided to just use my natural voice and accent, i hope you can find this usefull.

  • avatar
    0 sounds
    1 post

    You can do it by using your voice recorder in a proper way.

  • avatar
    92 sounds
    34 posts

    Most ultrasonic transducers that have high acoustic output are limited to one frequency only, the designed resonant frequency. The cheap "buzzers" are simply a little slab of piezo crystal glued to a plastic or paper cone. If you try to drive them at a different frequency the output and power handling drastically falls.

    How much acoustic power you need? Short distance or far throw? The AMT tweeter used in ADAM studio monitors is quoted as operating up to 50kHz. The Pi connected to an audio "chip" amplifier connected to a wide bandwidth tweeter would be a reasonable approach for a variable frequency ultrasonic setup. There are caveats of course, but it all depends on what you're trying to do.

  • avatar
    0 sounds
    4 posts

    The length requirement is the hard part but I may have found a few.

    http://freesound.org/people/codeplague/sounds/202172/ (being French should make it more indistinct)
    http://freesound.org/people/Nickleus/sounds/220671/
    http://freesound.org/people/conleec/sounds/149443/
    http://freesound.org/people/Uplistener/sounds/324265/ (quite loud)

  • avatar
    2 sounds
    1 post

    This may work!
    https://www.freesound.org/s/352315/

  • avatar
    0 sounds
    1 post

    I'm looking for a speaker or module, that I can control with the Pi, in order to generate sound frequencies between 10kHz and 60kHz.

    I've been reading a lot about piezo buzzers that you can control connected to a GPIO lead (3.3v) and a ground lead. However these only seem to go up to around 20-25 kHz from what I can find. They also seem to be relatively quiet and I'm looking for something with more volume.

    When I start searching for "ultrasonic transmitter" instead, I only get results that are modules for ultrasonic distance detectors. Or other "continuous sounding" buzzers that only operate at nominal frequencies of 40KHz.

    Basically, what speaker and power supply does the ultrasonic transmitter of this product use? I would like only the ultrasonic transmitter piece of this product and want to control the frequency using the Pi.
    https://smile.amazon.com/Ultrasonic-Repellent-Repeller-Squirrel-Chipmunk/dp/B01M6EBICB

    Thank you!

  • avatar
    1179 sounds
    285 posts

    Great, well done! It is quite the real thing smile

    Geweldig hoor, ik hoor nauwelijks het verschil met het 'echte' geluid, dank!

    LG

  • avatar
    56 sounds
    115 posts

    yes good post for beginners, this is the bare minimum you could do to make a decent vocal recording. also if you dont have a pop filter you could talk away from the microphone just so your breath does not come in direct contact with the microphone. you would probably need to touch it up a bit though.

    then comes EQ'ing etc

  • avatar
    120 sounds
    79 posts

    Oh i saw that only 29 minutes after your post the file has been moderated.

  • avatar
    120 sounds
    79 posts

    All uploaded sounds have to be moderated first. After that they will be available. Only the uploader himself can open the page until this happens.

    Try again the next day wink

  • avatar
    0 sounds
    1 post

    Hello, I need a Voicetag:

    "Coet-Productions"
    The "COET" like "Moet" listen as I with the speech is here possible: https://youtu.be/uO9013JgJxk?t=1m22s

    I would be glad if I could count on the Voicetag as soon as possible.

    Many Thanks

    XCoet
    Coet Productions

  • avatar
    0 sounds
    3 posts

    Page not found?