1. Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
    Dismiss Notice

Noise Filter on Speaker

Discussion in 'General Electronics Chat' started by c5trc101, Sep 4, 2017.

  1. c5trc101

    c5trc101 New Member

    Joined:
    Mar 23, 2017
    Messages:
    7
    Likes:
    0
    Location:
    Pto. Ordaz, Cdad. Guayana, Edo. Bolivar
    Hi, Im in need of a noise filter for a speaker, like the founded in icom or kenwood speaker for example, i have looked that bhi has a good speaker system whit this system, but for us in Venezuela, is not affordable to obtain greens, and the most of us, try to make ours cables, interfaces and filters.

    Can someone help me to make one to use whit a homemade box and 8Ω speaker ? Tnx in advance and excuse my english ;-)
     
  2. MikeMl

    MikeMl Well-Known Member Most Helpful Member

    Joined:
    Mar 17, 2009
    Messages:
    11,058
    Likes:
    541
    Location:
    AZ 86334
    What are you trying to filter out of the sound that the speaker produces without a filter installed? Is this for ham radio?
     
  3. c5trc101

    c5trc101 New Member

    Joined:
    Mar 23, 2017
    Messages:
    7
    Likes:
    0
    Location:
    Pto. Ordaz, Cdad. Guayana, Edo. Bolivar
    Hi Mike, yes it is for filter out the sound reproduced by the radio, im ham operator yv6ca
     
  4. dave

    Dave New Member

    Joined:
    Jan 12, 1997
    Messages:
    -
    Likes:
    0


     
  5. MikeMl

    MikeMl Well-Known Member Most Helpful Member

    Joined:
    Mar 17, 2009
    Messages:
    11,058
    Likes:
    541
    Location:
    AZ 86334

    Here are a lot of commercial products that are specifically designed to improve voice intelligibility in noisy radio environments. How elaborate do you want to go?
     
  6. c5trc101

    c5trc101 New Member

    Joined:
    Mar 23, 2017
    Messages:
    7
    Likes:
    0
    Location:
    Pto. Ordaz, Cdad. Guayana, Edo. Bolivar
    Hi mike,yes, i have looked this commercials speakers, but like i said, for the common people here, are very difficult to obtain currency, and the exchange are very high, for that reason, im looking for resource to make a homemade noise filter for a speaker like these that you show me in the link. how much elaborated? well im not an engineer, but im try to put my best effort
     
  7. MikeMl

    MikeMl Well-Known Member Most Helpful Member

    Joined:
    Mar 17, 2009
    Messages:
    11,058
    Likes:
    541
    Location:
    AZ 86334
    Can you obtain a set of powered computer speakers normally used with a desktop PC.? Hereabouts, these are very cheap at local thrift shops and yard sales; I have seen them sell from as little as $3.

    If you can obtain a set of those, they are ideal for hacking. They usually have a stereo amplifier powered with an external wall-wart plug-in power supply, usually 9 to 12Vdc. These are usually good fidelity for music, and as such can be considered as too wide in frequency response for voice-only or CW communication. However, it is simple to add some simple op-amp high-pass and low-pass filter stages at the input of the speaker amp(s) to tailor the frequency response better suited to voice.

    You could even install some sound processing software on a PC, temporarily run the audio from your receiver through the sound-card, experiment with filtering it while listening to typical QSOs, and then when you find a set of filters you like, convert them to a set of analog filters to be used with the computer speakers I mentioned above.

    Before we had PCs, I have done something like this using a Hi-Fi stereo amplifer equipped with a multi-band Graphic Equalizer. I could set the equalizer bands to get the filtering of the audio that improved intelligibility.
     
    Last edited: Sep 5, 2017
  8. c5trc101

    c5trc101 New Member

    Joined:
    Mar 23, 2017
    Messages:
    7
    Likes:
    0
    Location:
    Pto. Ordaz, Cdad. Guayana, Edo. Bolivar
    Hi, yes i have a pair of these pc speaker, (1 genius and 1 silver-point 2.1), have used one time trying to equalize the sound of the radio (kenwood ts400sat) via pc using its eq, and one time using tone control of the speaker, but its not the same result when its used the filters on kenwood or icom speaker, for this reason i m looking for a circuit to make, in fact i have done a board whit a tda2030a, thinking on use whit these type of filter, the only that wait me its the form of calculate de band pass, honestly i havent understand some of publication founded in the web
     
  9. MikeMl

    MikeMl Well-Known Member Most Helpful Member

    Joined:
    Mar 17, 2009
    Messages:
    11,058
    Likes:
    541
    Location:
    AZ 86334
    Do you have specs and/or a schematic of what Kenwood or Icom puts in their external speakers? We might be able to reverse-engineer it. We need to know what you want to build before we start building...

    If the equalizer built-in to the sound-card on your PC is not enough, there is some free-download audio processor software that might let you try more aggressive filters than the simplistic ones in the sound-card equalizer. Maybe someone reading this can suggest one?

    I have some analog op-amp filter design software that can come up with low-pass, high-pass, band-pass, and band-reject filters of up to several orders, but I can't guess what would turn your high-fi speaker into one optimized for voice communications.
     
  10. c5trc101

    c5trc101 New Member

    Joined:
    Mar 23, 2017
    Messages:
    7
    Likes:
    0
    Location:
    Pto. Ordaz, Cdad. Guayana, Edo. Bolivar
    Hi Mike, sorry for delay, no i havent specs whats speakers have inside, i have only listened once and the filters works, but nothing like bhi of course.

    I think there will be a lot of software that do these work via pc, but i want to try built it

    The problem not is my skills in built the circuit, its to understand how to calculate the filters, like you have said me, high, low, bandpass; i have reading some articles, but not are very clear the formulas.

    im know that i havent the same skills or studies like an engineer or a person that studied electronics, but i wish to try to do my own filters
     
  11. MikeMl

    MikeMl Well-Known Member Most Helpful Member

    Joined:
    Mar 17, 2009
    Messages:
    11,058
    Likes:
    541
    Location:
    AZ 86334
    The reason I suggested using the software was to try different filters until you discover what type of filtering improves the intelligibility of the voice from the ham rig, and then build opamp filters only after you know what you want to build...

    I have analog filter designs, but I dont have specs...
     
    Last edited: Sep 9, 2017
  12. c5trc101

    c5trc101 New Member

    Joined:
    Mar 23, 2017
    Messages:
    7
    Likes:
    0
    Location:
    Pto. Ordaz, Cdad. Guayana, Edo. Bolivar
    Ok Mike, I understand, have you the name of soft that i can try? Tnx!
     
  13. MikeMl

    MikeMl Well-Known Member Most Helpful Member

    Joined:
    Mar 17, 2009
    Messages:
    11,058
    Likes:
    541
    Location:
    AZ 86334
    one
    two
    three
    four

    Some of the previous may be too old. Try this Google search: "audio spectrogram and filtering software"
     
    Last edited: Sep 9, 2017
  14. c5trc101

    c5trc101 New Member

    Joined:
    Mar 23, 2017
    Messages:
    7
    Likes:
    0
    Location:
    Pto. Ordaz, Cdad. Guayana, Edo. Bolivar
    Thank you so much Mike!
     

Share This Page