need little help with audio device

Discussion in 'The Projects Forum' started by corner_boy, Nov 29, 2008.

  1. corner_boy

    Thread Starter Active Member

    Jun 24, 2008
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    hey everyone

    I had a question about trying to create a volume control. To fully explain i am gonna have a box that i want the audio from a computer to go into, then connected to a small amplifier then like a potentiometer.

    The next step is to connect the wires to some kind of output, almost like what mp3's or any other audio devices uses. I don't know what they are called or where to get one.

    If anyone has any questions or suggestions on what i should do here, i would greatly appreciate it. (so far you guess have really been helping me alot).

    PS is there a way to splice 2 audio inputs so one speaker will play both audios?
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
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    Amplifiers have fixed gains, and it is conventional to vary the level of audio into the amplifier, rather than try to attenuate it on the way to the speaker. A 50K pot should work fine.

    Amplifiers play back using electromechanical transducers called speakers, or, if very small, headphones or ear buds. The power requirements are very different - watts into speakers, milliwatts into ear buds.

    An op amp set up as inverting can mix two or more inputs. You would want to do the mixing before the level control.
     
  3. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Usually, you have a "line level" audio source, and then a potentiometer to control the volume, and then the amplifier.

    You might go to National Semiconductor's site, and look at the datasheet for an LM386 for an example of a low-voltage, low-power amplifier. There are several example circuits on page 5.

    You mean like a speaker or headphones?

    Well, you could feed one input to one end of a pot, and the other input to the other end of the pot, and take the signal out from the wiper. That way you could adjust the balance between the channels.

    You'd use that balancing pot before the volume control pot.
     
  4. corner_boy

    Thread Starter Active Member

    Jun 24, 2008
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    the audio output for a lets say an MP3 player, where all you need to do is plug in the headphones (ones available at best buy or whatever)
     
  5. SgtWookie

    Expert

    Jul 17, 2007
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    Yes, an LM386 can power headphones directly.
     
  6. corner_boy

    Thread Starter Active Member

    Jun 24, 2008
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    what do i attached to a a box so a headphone can just be plugged in?
     
  7. rbxslvr

    Member

    Nov 30, 2008
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  8. corner_boy

    Thread Starter Active Member

    Jun 24, 2008
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  9. rbxslvr

    Member

    Nov 30, 2008
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    Well, they all do. What determines that is the project itself. The audio jack is simply a connector... it doesn't do anything by itself. So, yes there is. It would be the same thing (for a 1/8" mic...). For a professional-style mic, you would probably need a 1/4" connector (the same thing that is used with guitars/amps). You can't have a mic going straight to a speaker without some kind of amplification. You can find many kits for microphone pre-amps. I would recommend buying one of those and just playing around a little bit.

    If you are looking to create a "project", more than the end result, I would recommend just getting a kit like this one: http://store.qkits.com/moreinfo.cfm/FK647 ... and then maybe just spend some time on google learning about various microphone projects and the difference between pre-amplifiers and amplifiers, and where each would fit into your project. (You did say you were using an amp, right?)
     
    Last edited: Dec 1, 2008
  10. corner_boy

    Thread Starter Active Member

    Jun 24, 2008
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    What i meant was to use this for connecting for a mic and headphone, like the connections used for a wireless phone.
     
  11. rbxslvr

    Member

    Nov 30, 2008
    14
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    So, do you want a male end that will plug into a cell phone/wireless phone. Or do you just want that effect with standard size headphone plugs?

    (I'm not someone you should ask about the circuitry of it... but I definately know my connectors and adapters :D)
     
    Last edited: Dec 1, 2008
  12. corner_boy

    Thread Starter Active Member

    Jun 24, 2008
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    Edited*****

    after doing some research i learned what i was kinda looking for. The headphone jacks will have a certain number of "stripes" to identify them as 2(1-stripe),3 (2-stripes), and 4 conductor(3-stripes) jacks. I will be using a 3 conductor jack for the computer audio and for the phone, i will need to nab a 4 conductor jack. That will allow it to have a mic on the same "line."

    I think that the 4 conductor female jacks for the houses and cellphones, (and the xbox 360) male ends are smaller than what are available online.
    Are there adapter available for this problem or am i shopping for the wrong female and female connector jack?


    (lol, its all good rbxslvr, you've been great help so far.)

    link to different jacks - http://www.showmecables.com/showProducts.asp?category_id=16942
     
    Last edited: Dec 2, 2008
  13. corner_boy

    Thread Starter Active Member

    Jun 24, 2008
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    anyone?^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
     
  14. rbxslvr

    Member

    Nov 30, 2008
    14
    0
    First off, the stipes don't identify them. Well, they do in a sense. They seperate the conductors. So, if you count the conductor sections, there will be one more than the number of stripes.

    Now, I have a y-adapter that seperates a single headset-size female connector into a 1/8" mic and 1/8" a speaker. Remember, the wire you are using to connect the 4 conductor plugs have to be 4-conductor wires.

    If that sounds like what you need, I'd just go into a store that carries audio adapters and ask about it. On mine, the speaker and mic plugs are different colors (one is red, one is black). I bought if from radioshack.
     
  15. corner_boy

    Thread Starter Active Member

    Jun 24, 2008
    36
    0
    I understand what you are saying but what i am looking for is where would they sell the smaller 4 conductor male end that connects to female end seen in cellphones, 360 controllers, and a lot of house hold cordless phones.

    The ones sold at radio shack are like what my new sony headphones i own (4 conductor male end and a mic), the male end will fit any of the cd or mp3 players but but not a phone. Where do i get the male and female ends to fit a female end already in a phone?
     
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